vircommand.c 70.7 KB
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/*
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 * vircommand.c: Child command execution
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 *
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 * Copyright (C) 2010-2013 Red Hat, Inc.
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 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library.  If not, see
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 * <http://www.gnu.org/licenses/>.
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 *
 */

#include <config.h>

#include <poll.h>
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#include <signal.h>
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#include <stdarg.h>
#include <stdlib.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <fcntl.h>

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#if WITH_CAPNG
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# include <cap-ng.h>
#endif
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#if defined(WITH_SECDRIVER_SELINUX)
# include <selinux/selinux.h>
#endif
#if defined(WITH_SECDRIVER_APPARMOR)
# include <sys/apparmor.h>
#endif

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#include "vircommand.h"
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#include "viralloc.h"
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#include "virerror.h"
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#include "virutil.h"
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#include "virlog.h"
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#include "virfile.h"
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#include "virpidfile.h"
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#include "virprocess.h"
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#include "virbuffer.h"
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#include "virthread.h"
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#define VIR_FROM_THIS VIR_FROM_NONE

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/* Flags for virExec */
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enum {
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    VIR_EXEC_NONE       = 0,
    VIR_EXEC_NONBLOCK   = (1 << 0),
    VIR_EXEC_DAEMON     = (1 << 1),
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    VIR_EXEC_CLEAR_CAPS = (1 << 2),
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    VIR_EXEC_RUN_SYNC   = (1 << 3),
    VIR_EXEC_ASYNC_IO   = (1 << 4),
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};

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struct _virCommand {
    int has_error; /* ENOMEM on allocation failure, -1 for anything else.  */

    char **args;
    size_t nargs;
    size_t maxargs;

    char **env;
    size_t nenv;
    size_t maxenv;

    char *pwd;

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    int *preserve; /* FDs to pass to child. */
    int preserve_size;
    int *transfer; /* FDs to close in parent. */
    int transfer_size;
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    unsigned int flags;

    char *inbuf;
    char **outbuf;
    char **errbuf;

    int infd;
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    int inpipe;
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    int outfd;
    int errfd;
    int *outfdptr;
    int *errfdptr;

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    virThreadPtr asyncioThread;
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    bool handshake;
    int handshakeWait[2];
    int handshakeNotify[2];

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    virExecHook hook;
    void *opaque;

    pid_t pid;
    char *pidfile;
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    bool reap;
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    uid_t uid;
    gid_t gid;
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    unsigned long long capabilities;
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#if defined(WITH_SECDRIVER_SELINUX)
    char *seLinuxLabel;
#endif
#if defined(WITH_SECDRIVER_APPARMOR)
    char *appArmorProfile;
#endif
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};

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static int virCommandHandshakeChild(virCommandPtr cmd);
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/*
 * virCommandFDIsSet:
 * @fd: FD to test
 * @set: the set
 * @set_size: actual size of @set
 *
 * Check if FD is already in @set or not.
 *
 * Returns true if @set contains @fd,
 * false otherwise.
 */
static bool
virCommandFDIsSet(int fd,
                  const int *set,
                  int set_size)
{
    int i = 0;

    while (i < set_size)
        if (set[i++] == fd)
            return true;

    return false;
}

/*
 * virCommandFDSet:
 * @fd: FD to be put into @set
 * @set: the set
 * @set_size: actual size of @set
 *
 * This is practically generalized implementation
 * of FD_SET() as we do not want to be limited
 * by FD_SETSIZE.
 *
 * Returns: 0 on success,
 *          -1 on usage error,
 *          ENOMEM on OOM
 */
static int
virCommandFDSet(int fd,
                int **set,
                int *set_size)
{
    if (fd < 0 || !set || !set_size)
        return -1;

    if (virCommandFDIsSet(fd, *set, *set_size))
        return 0;

    if (VIR_REALLOC_N(*set, *set_size + 1) < 0) {
        return ENOMEM;
    }

    (*set)[*set_size] = fd;
    (*set_size)++;

    return 0;
}
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#ifndef WIN32

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static int virClearCapabilities(void) ATTRIBUTE_UNUSED;
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# if WITH_CAPNG
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static int virClearCapabilities(void)
{
    int ret;

    capng_clear(CAPNG_SELECT_BOTH);

    if ((ret = capng_apply(CAPNG_SELECT_BOTH)) < 0) {
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        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("cannot clear process capabilities %d"), ret);
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        return -1;
    }

    return 0;
}
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/**
 * virSetCapabilities:
 *  @capabilities - capability flag to set.
 *                  In case of 0, this function is identical to
 *                  virClearCapabilities()
 *
 */
static int virSetCapabilities(unsigned long long capabilities)
{
    int ret, i;

    capng_clear(CAPNG_SELECT_BOTH);

    for (i = 0; i <= CAP_LAST_CAP; i++) {
        if (capabilities & (1ULL << i))
            capng_update(CAPNG_ADD, CAPNG_BOUNDING_SET, i);
    }

    if ((ret = capng_apply(CAPNG_SELECT_BOTH)) < 0) {
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        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("cannot apply process capabilities %d"), ret);
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        return -1;
    }

    return 0;
}
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# else
static int virClearCapabilities(void)
{
//    VIR_WARN("libcap-ng support not compiled in, unable to clear "
//             "capabilities");
    return 0;
}
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static int
virSetCapabilities(unsigned long long capabilities ATTRIBUTE_UNUSED)
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{
    return 0;
}
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# endif

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/**
 * virFork:
 * @pid - a pointer to a pid_t that will receive the return value from
 *        fork()
 *
 * fork a new process while avoiding various race/deadlock conditions
 *
 * on return from virFork(), if *pid < 0, the fork failed and there is
 * no new process. Otherwise, just like fork(), if *pid == 0, it is the
 * child process returning, and if *pid > 0, it is the parent.
 *
 * Even if *pid >= 0, if the return value from virFork() is < 0, it
 * indicates a failure that occurred in the parent or child process
 * after the fork. In this case, the child process should call
 * _exit(EXIT_FAILURE) after doing any additional error reporting.
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 */
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int
virFork(pid_t *pid)
{
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    sigset_t oldmask, newmask;
    struct sigaction sig_action;
    int saved_errno, ret = -1;

    *pid = -1;

    /*
     * Need to block signals now, so that child process can safely
     * kill off caller's signal handlers without a race.
     */
    sigfillset(&newmask);
    if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
        saved_errno = errno;
        virReportSystemError(errno,
                             "%s", _("cannot block signals"));
        goto cleanup;
    }

    /* Ensure we hold the logging lock, to protect child processes
     * from deadlocking on another thread's inherited mutex state */
    virLogLock();

    *pid = fork();
    saved_errno = errno; /* save for caller */

    /* Unlock for both parent and child process */
    virLogUnlock();

    if (*pid < 0) {
        /* attempt to restore signal mask, but ignore failure, to
           avoid obscuring the fork failure */
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        ignore_value(pthread_sigmask(SIG_SETMASK, &oldmask, NULL));
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        virReportSystemError(saved_errno,
                             "%s", _("cannot fork child process"));
        goto cleanup;
    }

    if (*pid) {

        /* parent process */

        /* Restore our original signal mask now that the child is
           safely running */
        if (pthread_sigmask(SIG_SETMASK, &oldmask, NULL) != 0) {
            saved_errno = errno; /* save for caller */
            virReportSystemError(errno, "%s", _("cannot unblock signals"));
            goto cleanup;
        }
        ret = 0;

    } else {

        /* child process */

        int logprio;
        int i;

        /* Remove any error callback so errors in child now
           get sent to stderr where they stand a fighting chance
           of being seen / logged */
        virSetErrorFunc(NULL, NULL);
        virSetErrorLogPriorityFunc(NULL);

        /* Make sure any hook logging is sent to stderr, since child
         * process may close the logfile FDs */
        logprio = virLogGetDefaultPriority();
        virLogReset();
        virLogSetDefaultPriority(logprio);

        /* Clear out all signal handlers from parent so nothing
           unexpected can happen in our child once we unblock
           signals */
        sig_action.sa_handler = SIG_DFL;
        sig_action.sa_flags = 0;
        sigemptyset(&sig_action.sa_mask);

        for (i = 1; i < NSIG; i++) {
            /* Only possible errors are EFAULT or EINVAL
               The former wont happen, the latter we
               expect, so no need to check return value */

            sigaction(i, &sig_action, NULL);
        }

        /* Unmask all signals in child, since we've no idea
           what the caller's done with their signal mask
           and don't want to propagate that to children */
        sigemptyset(&newmask);
        if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
            saved_errno = errno; /* save for caller */
            virReportSystemError(errno, "%s", _("cannot unblock signals"));
            goto cleanup;
        }
        ret = 0;
    }

cleanup:
    if (ret < 0)
        errno = saved_errno;
    return ret;
}

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/*
 * Ensure that *null is an fd visiting /dev/null.  Return 0 on
 * success, -1 on failure.  Allows for lazy opening of shared
 * /dev/null fd only as required.
 */
static int
getDevNull(int *null)
{
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    if (*null == -1 && (*null = open("/dev/null", O_RDWR|O_CLOEXEC)) < 0) {
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        virReportSystemError(errno,
                             _("cannot open %s"),
                             "/dev/null");
        return -1;
    }
    return 0;
}

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/* Ensure that STD is an inheritable copy of FD.  Return 0 on success,
 * -1 on failure.  */
static int
prepareStdFd(int fd, int std)
{
    if (fd == std)
        return virSetInherit(fd, true);
    if (dup2(fd, std) != std)
        return -1;
    return 0;
}

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/*
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 * virExec:
 * @cmd virCommandPtr containing all information about the program to
 *      exec.
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 */
static int
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virExec(virCommandPtr cmd)
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{
    pid_t pid;
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    int null = -1, i, openmax;
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    int pipeout[2] = {-1,-1};
    int pipeerr[2] = {-1,-1};
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    int childin = cmd->infd;
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    int childout = -1;
    int childerr = -1;
    int tmpfd;
    const char *binary = NULL;
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    int forkRet, ret;
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    struct sigaction waxon, waxoff;
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    if (cmd->args[0][0] != '/') {
        if (!(binary = virFindFileInPath(cmd->args[0]))) {
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            virReportSystemError(ENOENT,
                                 _("Cannot find '%s' in path"),
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                                 cmd->args[0]);
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            return -1;
        }
    } else {
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        binary = cmd->args[0];
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    }

425
    if (childin < 0) {
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        if (getDevNull(&null) < 0)
            goto cleanup;
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        childin = null;
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    }

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    if (cmd->outfdptr != NULL) {
        if (*cmd->outfdptr == -1) {
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            if (pipe2(pipeout, O_CLOEXEC) < 0) {
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                virReportSystemError(errno,
                                     "%s", _("cannot create pipe"));
                goto cleanup;
            }

439
            if ((cmd->flags & VIR_EXEC_NONBLOCK) &&
440
                virSetNonBlock(pipeout[0]) == -1) {
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                virReportSystemError(errno, "%s",
                                     _("Failed to set non-blocking file descriptor flag"));
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                goto cleanup;
            }

            childout = pipeout[1];
        } else {
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            childout = *cmd->outfdptr;
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        }
    } else {
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        if (getDevNull(&null) < 0)
            goto cleanup;
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        childout = null;
    }

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    if (cmd->errfdptr != NULL) {
        if (cmd->errfdptr == cmd->outfdptr) {
458
            childerr = childout;
459
        } else if (*cmd->errfdptr == -1) {
460
            if (pipe2(pipeerr, O_CLOEXEC) < 0) {
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                virReportSystemError(errno,
                                     "%s", _("Failed to create pipe"));
                goto cleanup;
            }

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            if ((cmd->flags & VIR_EXEC_NONBLOCK) &&
467
                virSetNonBlock(pipeerr[0]) == -1) {
468 469
                virReportSystemError(errno, "%s",
                                     _("Failed to set non-blocking file descriptor flag"));
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                goto cleanup;
            }

            childerr = pipeerr[1];
        } else {
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            childerr = *cmd->errfdptr;
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        }
    } else {
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        if (getDevNull(&null) < 0)
            goto cleanup;
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        childerr = null;
    }

    forkRet = virFork(&pid);

    if (pid < 0) {
        goto cleanup;
    }

    if (pid) { /* parent */
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        if (forkRet < 0) {
            goto cleanup;
        }

494
        VIR_FORCE_CLOSE(null);
495
        if (cmd->outfdptr && *cmd->outfdptr == -1) {
496
            VIR_FORCE_CLOSE(pipeout[1]);
497
            *cmd->outfdptr = pipeout[0];
498
        }
499
        if (cmd->errfdptr && *cmd->errfdptr == -1) {
500
            VIR_FORCE_CLOSE(pipeerr[1]);
501
            *cmd->errfdptr = pipeerr[0];
502 503
        }

504
        cmd->pid = pid;
505

506
        if (binary != cmd->args[0])
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            VIR_FREE(binary);

        return 0;
    }

    /* child */

    if (forkRet < 0) {
        /* The fork was successful, but after that there was an error
         * in the child (which was already logged).
        */
        goto fork_error;
    }

    openmax = sysconf(_SC_OPEN_MAX);
522
    for (i = 3; i < openmax; i++) {
523
        if (i == childin || i == childout || i == childerr)
524
            continue;
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        if (!cmd->preserve ||
            !virCommandFDIsSet(i, cmd->preserve, cmd->preserve_size)) {
527
            tmpfd = i;
528
            VIR_MASS_CLOSE(tmpfd);
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        } else if (virSetInherit(i, true) < 0) {
            virReportSystemError(errno, _("failed to preserve fd %d"), i);
            goto fork_error;
532
        }
533
    }
534

535
    if (prepareStdFd(childin, STDIN_FILENO) < 0) {
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        virReportSystemError(errno,
                             "%s", _("failed to setup stdin file handle"));
        goto fork_error;
    }
540
    if (childout > 0 && prepareStdFd(childout, STDOUT_FILENO) < 0) {
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        virReportSystemError(errno,
                             "%s", _("failed to setup stdout file handle"));
        goto fork_error;
    }
545
    if (childerr > 0 && prepareStdFd(childerr, STDERR_FILENO) < 0) {
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        virReportSystemError(errno,
                             "%s", _("failed to setup stderr file handle"));
        goto fork_error;
    }

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    if (childin != STDIN_FILENO && childin != null &&
        childin != childerr && childin != childout)
        VIR_FORCE_CLOSE(childin);
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    if (childout > STDERR_FILENO && childout != null && childout != childerr)
        VIR_FORCE_CLOSE(childout);
    if (childerr > STDERR_FILENO && childerr != null)
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        VIR_FORCE_CLOSE(childerr);
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    VIR_FORCE_CLOSE(null);
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    /* Initialize full logging for a while */
    virLogSetFromEnv();

    /* Daemonize as late as possible, so the parent process can detect
     * the above errors with wait* */
565
    if (cmd->flags & VIR_EXEC_DAEMON) {
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        if (setsid() < 0) {
            virReportSystemError(errno,
                                 "%s", _("cannot become session leader"));
            goto fork_error;
        }

        if (chdir("/") < 0) {
            virReportSystemError(errno,
                                 "%s", _("cannot change to root directory"));
            goto fork_error;
        }

        pid = fork();
        if (pid < 0) {
            virReportSystemError(errno,
                                 "%s", _("cannot fork child process"));
            goto fork_error;
        }

        if (pid > 0) {
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            if (cmd->pidfile && (virPidFileWritePath(cmd->pidfile, pid) < 0)) {
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                kill(pid, SIGTERM);
                usleep(500*1000);
                kill(pid, SIGTERM);
                virReportSystemError(errno,
                                     _("could not write pidfile %s for %d"),
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                                     cmd->pidfile, pid);
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                goto fork_error;
            }
            _exit(0);
        }
    }

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    /* virFork reset all signal handlers to the defaults.
     * This is good for the child process, but our hook
     * risks running something that generates SIGPIPE,
     * so we need to temporarily block that again
     */
    memset(&waxoff, 0, sizeof(waxoff));
    waxoff.sa_handler = SIG_IGN;
    sigemptyset(&waxoff.sa_mask);
    memset(&waxon, 0, sizeof(waxon));
    if (sigaction(SIGPIPE, &waxoff, &waxon) < 0) {
        virReportSystemError(errno, "%s",
                             _("Could not disable SIGPIPE"));
        goto fork_error;
    }
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    if (cmd->hook) {
        VIR_DEBUG("Run hook %p %p", cmd->hook, cmd->opaque);
        ret = cmd->hook(cmd->opaque);
        VIR_DEBUG("Done hook %d", ret);
        if (ret < 0)
           goto fork_error;
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    }
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# if defined(WITH_SECDRIVER_SELINUX)
    if (cmd->seLinuxLabel) {
        VIR_DEBUG("Setting child security label to %s", cmd->seLinuxLabel);
        if (setexeccon_raw(cmd->seLinuxLabel) == -1) {
            virReportSystemError(errno,
                                 _("unable to set SELinux security context "
                                   "'%s' for '%s'"),
                                 cmd->seLinuxLabel, cmd->args[0]);
            if (security_getenforce() == 1)
                goto fork_error;
        }
    }
# endif
# if defined(WITH_SECDRIVER_APPARMOR)
    if (cmd->appArmorProfile) {
        VIR_DEBUG("Setting child AppArmor profile to %s", cmd->appArmorProfile);
        if (aa_change_profile(cmd->appArmorProfile) < 0) {
            virReportSystemError(errno,
                                 _("unable to set AppArmor profile '%s' "
                                   "for '%s'"),
                                 cmd->appArmorProfile, cmd->args[0]);
            goto fork_error;
        }
    }
# endif

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    if (cmd->uid != (uid_t)-1 || cmd->gid != (gid_t)-1) {
        VIR_DEBUG("Setting child uid:gid to %d:%d",
                  (int)cmd->uid, (int)cmd->gid);
        if (virSetUIDGID(cmd->uid, cmd->gid) < 0)
            goto fork_error;
    }

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    /* The steps above may need todo something privileged, so
     * we delay clearing capabilities until the last minute */
    if (cmd->capabilities || (cmd->flags & VIR_EXEC_CLEAR_CAPS))
        if (virSetCapabilities(cmd->capabilities) < 0)
            goto fork_error;

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    if (cmd->pwd) {
        VIR_DEBUG("Running child in %s", cmd->pwd);
        if (chdir(cmd->pwd) < 0) {
            virReportSystemError(errno,
                                 _("Unable to change to %s"), cmd->pwd);
            goto fork_error;
        }
    }

    if (virCommandHandshakeChild(cmd) < 0)
       goto fork_error;

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    if (sigaction(SIGPIPE, &waxon, NULL) < 0) {
        virReportSystemError(errno, "%s",
                             _("Could not re-enable SIGPIPE"));
        goto fork_error;
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    }

    /* Close logging again to ensure no FDs leak to child */
    virLogReset();

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    if (cmd->env)
        execve(binary, cmd->args, cmd->env);
684
    else
685
        execv(binary, cmd->args);
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    virReportSystemError(errno,
                         _("cannot execute binary %s"),
689
                         cmd->args[0]);
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 fork_error:
    virDispatchError(NULL);
    _exit(EXIT_FAILURE);

 cleanup:
    /* This is cleanup of parent process only - child
       should never jump here on error */

699
    if (binary != cmd->args[0])
700 701
        VIR_FREE(binary);

702 703
    /* NB we don't virReportError() on any failures here
       because the code which jumped here already raised
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       an error condition which we must not overwrite */
    VIR_FORCE_CLOSE(pipeerr[0]);
    VIR_FORCE_CLOSE(pipeerr[1]);
    VIR_FORCE_CLOSE(pipeout[0]);
    VIR_FORCE_CLOSE(pipeout[1]);
    VIR_FORCE_CLOSE(null);
    return -1;
}

/**
E
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 * virRun:
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 * @argv NULL terminated argv to run
 * @status optional variable to return exit status in
 *
 * Run a command without using the shell.
 *
 * If status is NULL, then return 0 if the command run and
 * exited with 0 status; Otherwise return -1
 *
 * If status is not-NULL, then return 0 if the command ran.
 * The status variable is filled with the command exit status
 * and should be checked by caller for success. Return -1
 * only if the command could not be run.
 */
int
virRun(const char *const*argv, int *status)
{
    int ret;
    virCommandPtr cmd = virCommandNewArgs(argv);

    ret = virCommandRun(cmd, status);
    virCommandFree(cmd);
    return ret;
}

#else /* WIN32 */

int
virRun(const char *const *argv ATTRIBUTE_UNUSED,
       int *status)
{
    if (status)
        *status = ENOTSUP;
    else
748 749
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       "%s", _("virRun is not implemented for WIN32"));
750 751 752 753
    return -1;
}

static int
754
virExec(virCommandPtr cmd ATTRIBUTE_UNUSED)
755 756 757 758
{
    /* XXX: Some day we can implement pieces of virCommand/virExec on
     * top of _spawn() or CreateProcess(), but we can't implement
     * everything, since mingw completely lacks fork(), so we cannot
759
     * run our own code in the child process.  */
760 761
    virReportError(VIR_ERR_INTERNAL_ERROR,
                   "%s", _("virExec is not implemented for WIN32"));
762 763 764 765 766 767 768 769 770 771 772 773 774 775 776
    return -1;
}

int
virFork(pid_t *pid)
{
    *pid = -1;
    errno = ENOTSUP;

    return -1;
}

#endif /* WIN32 */


E
Eric Blake 已提交
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/**
 * virCommandNew:
 * @binary: program to run
 *
 * Create a new command for named binary.  If @binary is relative,
 * it will be found via a PATH search of the parent's PATH (and not
 * any altered PATH set by virCommandAddEnv* commands).
784 785 786 787 788 789 790 791 792
 */
virCommandPtr
virCommandNew(const char *binary)
{
    const char *const args[] = { binary, NULL };

    return virCommandNewArgs(args);
}

E
Eric Blake 已提交
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/**
 * virCommandNewArgs:
 * @args: array of arguments
 *
797
 * Create a new command with a NULL terminated
E
Eric Blake 已提交
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 * set of args, taking binary from args[0].  More arguments can
 * be added later.  @args[0] is handled like @binary of virCommandNew.
800 801 802 803 804 805 806 807 808
 */
virCommandPtr
virCommandNewArgs(const char *const*args)
{
    virCommandPtr cmd;

    if (VIR_ALLOC(cmd) < 0)
        return NULL;

809 810 811 812 813
    cmd->handshakeWait[0] = -1;
    cmd->handshakeWait[1] = -1;
    cmd->handshakeNotify[0] = -1;
    cmd->handshakeNotify[1] = -1;

814
    cmd->infd = cmd->inpipe = cmd->outfd = cmd->errfd = -1;
815
    cmd->pid = -1;
816 817
    cmd->uid = -1;
    cmd->gid = -1;
818 819 820 821 822 823

    virCommandAddArgSet(cmd, args);

    return cmd;
}

E
Eric Blake 已提交
824 825 826 827 828
/**
 * virCommandNewArgList:
 * @binary: program to run
 * @...: additional arguments
 *
829
 * Create a new command with a NULL terminated
E
Eric Blake 已提交
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 * list of args, starting with the binary to run.  More arguments can
 * be added later.  @binary is handled as in virCommandNew.
832 833 834 835 836 837 838 839 840
 */
virCommandPtr
virCommandNewArgList(const char *binary, ...)
{
    virCommandPtr cmd = virCommandNew(binary);
    va_list list;
    const char *arg;

    if (!cmd || cmd->has_error)
E
Eric Blake 已提交
841
        return cmd;
842 843 844 845 846 847 848 849

    va_start(list, binary);
    while ((arg = va_arg(list, const char *)) != NULL)
        virCommandAddArg(cmd, arg);
    va_end(list);
    return cmd;
}

850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871
/**
 * virCommandNewVAList:
 * @binary: program to run
 * @va_list: additional arguments
 *
 * Create a new command with a NULL terminated
 * variable argument list.  @binary is handled as in virCommandNew.
 */
virCommandPtr
virCommandNewVAList(const char *binary, va_list list)
{
    virCommandPtr cmd = virCommandNew(binary);
    const char *arg;

    if (!cmd || cmd->has_error)
        return cmd;

    while ((arg = va_arg(list, const char *)) != NULL)
        virCommandAddArg(cmd, arg);
    return cmd;
}

872 873 874 875 876 877

/*
 * Preserve the specified file descriptor in the child, instead of
 * closing it.  FD must not be one of the three standard streams.  If
 * transfer is true, then fd will be closed in the parent after a call
 * to Run/RunAsync/Free, otherwise caller is still responsible for fd.
E
Eric Blake 已提交
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 * Returns true if a transferring caller should close FD now, and
 * false if the transfer is successfully recorded.
880
 */
E
Eric Blake 已提交
881
static bool
882 883
virCommandKeepFD(virCommandPtr cmd, int fd, bool transfer)
{
884 885
    int ret = 0;

886
    if (!cmd)
E
Eric Blake 已提交
887
        return fd > STDERR_FILENO;
888

889 890 891 892
    if (fd <= STDERR_FILENO ||
        (ret = virCommandFDSet(fd, &cmd->preserve, &cmd->preserve_size)) ||
        (transfer && (ret = virCommandFDSet(fd, &cmd->transfer,
                                            &cmd->transfer_size)))) {
893
        if (!cmd->has_error)
894
            cmd->has_error = ret ? ret : -1 ;
895
        VIR_DEBUG("cannot preserve %d", fd);
E
Eric Blake 已提交
896
        return fd > STDERR_FILENO;
897 898
    }

E
Eric Blake 已提交
899
    return false;
900 901
}

E
Eric Blake 已提交
902 903 904 905 906
/**
 * virCommandPreserveFD:
 * @cmd: the command to modify
 * @fd: fd to mark for inheritance into child
 *
907
 * Preserve the specified file descriptor
E
Eric Blake 已提交
908
 * in the child, instead of closing it on exec.
909 910 911 912 913
 * The parent is still responsible for managing fd.
 */
void
virCommandPreserveFD(virCommandPtr cmd, int fd)
{
E
Eric Blake 已提交
914
    virCommandKeepFD(cmd, fd, false);
915 916
}

E
Eric Blake 已提交
917 918 919 920 921
/**
 * virCommandTransferFD:
 * @cmd: the command to modify
 * @fd: fd to reassign to the child
 *
922
 * Transfer the specified file descriptor
E
Eric Blake 已提交
923
 * to the child, instead of closing it on exec.
E
Eric Blake 已提交
924 925
 * The parent should no longer use fd, and the parent's copy will
 * be automatically closed no later than during Run/RunAsync/Free.
926 927 928 929
 */
void
virCommandTransferFD(virCommandPtr cmd, int fd)
{
E
Eric Blake 已提交
930 931
    if (virCommandKeepFD(cmd, fd, true))
        VIR_FORCE_CLOSE(fd);
932 933 934
}


E
Eric Blake 已提交
935 936 937 938 939 940 941
/**
 * virCommandSetPidFile:
 * @cmd: the command to modify
 * @pidfile: filename to use
 *
 * Save the child PID in a pidfile.  The pidfile will be populated
 * before the exec of the child.
942 943 944 945 946 947 948 949 950 951 952 953 954 955
 */
void
virCommandSetPidFile(virCommandPtr cmd, const char *pidfile)
{
    if (!cmd || cmd->has_error)
        return;

    VIR_FREE(cmd->pidfile);
    if (!(cmd->pidfile = strdup(pidfile))) {
        cmd->has_error = ENOMEM;
    }
}


956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973
void
virCommandSetGID(virCommandPtr cmd, gid_t gid)
{
    if (!cmd || cmd->has_error)
        return;

    cmd->gid = gid;
}

void
virCommandSetUID(virCommandPtr cmd, uid_t uid)
{
    if (!cmd || cmd->has_error)
        return;

    cmd->uid = uid;
}

E
Eric Blake 已提交
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/**
 * virCommandClearCaps:
 * @cmd: the command to modify
 *
 * Remove all capabilities from the child, after any hooks have been run.
979 980 981 982 983 984 985 986 987 988
 */
void
virCommandClearCaps(virCommandPtr cmd)
{
    if (!cmd || cmd->has_error)
        return;

    cmd->flags |= VIR_EXEC_CLEAR_CAPS;
}

E
Eric Blake 已提交
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/**
 * virCommandAllowCap:
 * @cmd: the command to modify
 * @capability: what to allow
 *
994
 * Allow specific capabilities
995 996 997
 */
void
virCommandAllowCap(virCommandPtr cmd,
998
                   int capability)
999 1000 1001 1002
{
    if (!cmd || cmd->has_error)
        return;

1003
    cmd->capabilities |= (1ULL << capability);
1004 1005 1006
}


1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056
/**
 * virCommandSetSELinuxLabel:
 * @cmd: the command to modify
 * @label: the SELinux label to use for the child process
 *
 * Saves a copy of @label to use when setting the SELinux context
 * label (with setexeccon_raw()) after the child process has been
 * started. If SELinux isn't compiled into libvirt, or if label is
 * NULL, nothing will be done.
 */
void
virCommandSetSELinuxLabel(virCommandPtr cmd,
                          const char *label ATTRIBUTE_UNUSED)
{
    if (!cmd || cmd->has_error)
        return;

#if defined(WITH_SECDRIVER_SELINUX)
    VIR_FREE(cmd->seLinuxLabel);
    if (label && !(cmd->seLinuxLabel = strdup(label)))
        cmd->has_error = ENOMEM;
#endif
    return;
}


/**
 * virCommandSetAppArmorProfile:
 * @cmd: the command to modify
 * @profile: the AppArmor profile to use
 *
 * Saves a copy of @profile to use when aa_change_profile() after the
 * child process has been started. If AppArmor support isn't
 * configured into libvirt, or if profile is NULL, nothing will be done.
 */
void
virCommandSetAppArmorProfile(virCommandPtr cmd,
                             const char *profile ATTRIBUTE_UNUSED)
{
    if (!cmd || cmd->has_error)
        return;

#if defined(WITH_SECDRIVER_APPARMOR)
    VIR_FREE(cmd->appArmorProfile);
    if (profile && !(cmd->appArmorProfile = strdup(profile)))
        cmd->has_error = ENOMEM;
#endif
    return;
}

1057

E
Eric Blake 已提交
1058 1059 1060 1061 1062 1063 1064
/**
 * virCommandDaemonize:
 * @cmd: the command to modify
 *
 * Daemonize the child process.  The child will have a current working
 * directory of /, and must be started with virCommandRun, which will
 * complete as soon as the daemon grandchild has started.
1065 1066 1067 1068 1069 1070 1071 1072 1073 1074
 */
void
virCommandDaemonize(virCommandPtr cmd)
{
    if (!cmd || cmd->has_error)
        return;

    cmd->flags |= VIR_EXEC_DAEMON;
}

E
Eric Blake 已提交
1075 1076 1077 1078
/**
 * virCommandNonblockingFDs:
 * @cmd: the command to modify
 *
1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090
 * Set FDs created by virCommandSetOutputFD and virCommandSetErrorFD
 * as non-blocking in the parent.
 */
void
virCommandNonblockingFDs(virCommandPtr cmd)
{
    if (!cmd || cmd->has_error)
        return;

    cmd->flags |= VIR_EXEC_NONBLOCK;
}

1091
/* Add an environment variable to the cmd->env list.  'env' is a
1092 1093
 * string like "name=value".  If the named environment variable is
 * already set, then it is replaced in the list.
1094 1095 1096 1097
 */
static inline void
virCommandAddEnv(virCommandPtr cmd, char *env)
{
1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111
    size_t namelen;
    size_t i;

    /* Search for the name in the existing environment. */
    namelen = strcspn(env, "=");
    for (i = 0; i < cmd->nenv; ++i) {
        /* + 1 because we want to match the '=' character too. */
        if (STREQLEN(cmd->env[i], env, namelen + 1)) {
            VIR_FREE(cmd->env[i]);
            cmd->env[i] = env;
            return;
        }
    }

1112 1113 1114 1115 1116 1117 1118 1119 1120 1121
    /* Arg plus trailing NULL. */
    if (VIR_RESIZE_N(cmd->env, cmd->maxenv, cmd->nenv, 1 + 1) < 0) {
        VIR_FREE(env);
        cmd->has_error = ENOMEM;
        return;
    }

    cmd->env[cmd->nenv++] = env;
}

E
Eric Blake 已提交
1122 1123 1124 1125 1126 1127 1128
/**
 * virCommandAddEnvFormat:
 * @cmd: the command to modify
 * @format: format of arguments, end result must be in name=value format
 * @...: arguments to be formatted
 *
 * Add an environment variable to the child created by a printf-style format.
1129 1130
 */
void
1131
virCommandAddEnvFormat(virCommandPtr cmd, const char *format, ...)
1132 1133
{
    char *env;
1134
    va_list list;
1135 1136 1137 1138

    if (!cmd || cmd->has_error)
        return;

1139 1140
    va_start(list, format);
    if (virVasprintf(&env, format, list) < 0) {
1141
        cmd->has_error = ENOMEM;
1142
        va_end(list);
1143 1144
        return;
    }
1145
    va_end(list);
1146

1147
    virCommandAddEnv(cmd, env);
1148 1149
}

E
Eric Blake 已提交
1150 1151 1152 1153 1154 1155
/**
 * virCommandAddEnvPair:
 * @cmd: the command to modify
 * @name: variable name, must not contain =
 * @value: value to assign to name
 *
1156 1157 1158 1159 1160 1161 1162 1163 1164
 * Add an environment variable to the child
 * using separate name & value strings
 */
void
virCommandAddEnvPair(virCommandPtr cmd, const char *name, const char *value)
{
    virCommandAddEnvFormat(cmd, "%s=%s", name, value);
}

1165

E
Eric Blake 已提交
1166 1167 1168 1169 1170
/**
 * virCommandAddEnvString:
 * @cmd: the command to modify
 * @str: name=value format
 *
1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186
 * Add an environment variable to the child
 * using a preformatted env string FOO=BAR
 */
void
virCommandAddEnvString(virCommandPtr cmd, const char *str)
{
    char *env;

    if (!cmd || cmd->has_error)
        return;

    if (!(env = strdup(str))) {
        cmd->has_error = ENOMEM;
        return;
    }

1187
    virCommandAddEnv(cmd, env);
1188 1189 1190
}


E
Eric Blake 已提交
1191 1192 1193 1194 1195
/**
 * virCommandAddEnvBuffer:
 * @cmd: the command to modify
 * @buf: buffer that contains name=value string, which will be reset on return
 *
1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207
 * Convert a buffer containing preformatted name=value into an
 * environment variable of the child.
 * Correctly transfers memory errors or contents from buf to cmd.
 */
void
virCommandAddEnvBuffer(virCommandPtr cmd, virBufferPtr buf)
{
    if (!cmd || cmd->has_error) {
        virBufferFreeAndReset(buf);
        return;
    }

1208
    if (virBufferError(buf)) {
1209 1210 1211 1212
        cmd->has_error = ENOMEM;
        virBufferFreeAndReset(buf);
        return;
    }
1213 1214 1215 1216
    if (!virBufferUse(buf)) {
        cmd->has_error = EINVAL;
        return;
    }
1217

1218
    virCommandAddEnv(cmd, virBufferContentAndReset(buf));
1219 1220 1221
}


E
Eric Blake 已提交
1222 1223 1224 1225 1226
/**
 * virCommandAddEnvPass:
 * @cmd: the command to modify
 * @name: the name to look up in current environment
 *
1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242
 * Pass an environment variable to the child
 * using current process' value
 */
void
virCommandAddEnvPass(virCommandPtr cmd, const char *name)
{
    char *value;
    if (!cmd || cmd->has_error)
        return;

    value = getenv(name);
    if (value)
        virCommandAddEnvPair(cmd, name, value);
}


E
Eric Blake 已提交
1243 1244 1245 1246
/**
 * virCommandAddEnvPassCommon:
 * @cmd: the command to modify
 *
1247
 * Set LC_ALL to C, and propagate other essential environment
E
Eric Blake 已提交
1248
 * variables (such as PATH) from the parent process.
1249 1250 1251 1252
 */
void
virCommandAddEnvPassCommon(virCommandPtr cmd)
{
1253 1254 1255
    if (!cmd || cmd->has_error)
        return;

1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270
    /* Attempt to Pre-allocate; allocation failure will be detected
     * later during virCommandAdd*.  */
    ignore_value(VIR_RESIZE_N(cmd->env, cmd->maxenv, cmd->nenv, 9));

    virCommandAddEnvPair(cmd, "LC_ALL", "C");

    virCommandAddEnvPass(cmd, "LD_PRELOAD");
    virCommandAddEnvPass(cmd, "LD_LIBRARY_PATH");
    virCommandAddEnvPass(cmd, "PATH");
    virCommandAddEnvPass(cmd, "HOME");
    virCommandAddEnvPass(cmd, "USER");
    virCommandAddEnvPass(cmd, "LOGNAME");
    virCommandAddEnvPass(cmd, "TMPDIR");
}

E
Eric Blake 已提交
1271 1272 1273 1274 1275
/**
 * virCommandAddArg:
 * @cmd: the command to modify
 * @val: the argument to add
 *
1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301
 * Add a command line argument to the child
 */
void
virCommandAddArg(virCommandPtr cmd, const char *val)
{
    char *arg;

    if (!cmd || cmd->has_error)
        return;

    if (!(arg = strdup(val))) {
        cmd->has_error = ENOMEM;
        return;
    }

    /* Arg plus trailing NULL. */
    if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, 1 + 1) < 0) {
        VIR_FREE(arg);
        cmd->has_error = ENOMEM;
        return;
    }

    cmd->args[cmd->nargs++] = arg;
}


E
Eric Blake 已提交
1302 1303 1304 1305 1306
/**
 * virCommandAddArgBuffer:
 * @cmd: the command to modify
 * @buf: buffer that contains argument string, which will be reset on return
 *
1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325
 * Convert a buffer into a command line argument to the child.
 * Correctly transfers memory errors or contents from buf to cmd.
 */
void
virCommandAddArgBuffer(virCommandPtr cmd, virBufferPtr buf)
{
    if (!cmd || cmd->has_error) {
        virBufferFreeAndReset(buf);
        return;
    }

    /* Arg plus trailing NULL. */
    if (virBufferError(buf) ||
        VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, 1 + 1) < 0) {
        cmd->has_error = ENOMEM;
        virBufferFreeAndReset(buf);
        return;
    }

1326 1327 1328 1329 1330 1331 1332 1333
    cmd->args[cmd->nargs] = virBufferContentAndReset(buf);
    if (!cmd->args[cmd->nargs])
        cmd->args[cmd->nargs] = strdup("");
    if (!cmd->args[cmd->nargs]) {
        cmd->has_error = ENOMEM;
        return;
    }
    cmd->nargs++;
1334 1335 1336
}


E
Eric Blake 已提交
1337 1338 1339 1340 1341 1342 1343
/**
 * virCommandAddArgFormat:
 * @cmd: the command to modify
 * @format: format of arguments, end result must be in name=value format
 * @...: arguments to be formatted
 *
 * Add a command line argument created by a printf-style format.
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
 */
void
virCommandAddArgFormat(virCommandPtr cmd, const char *format, ...)
{
    char *arg;
    va_list list;

    if (!cmd || cmd->has_error)
        return;

    va_start(list, format);
    if (virVasprintf(&arg, format, list) < 0) {
        cmd->has_error = ENOMEM;
        va_end(list);
        return;
    }
    va_end(list);

    /* Arg plus trailing NULL. */
    if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, 1 + 1) < 0) {
        VIR_FREE(arg);
        cmd->has_error = ENOMEM;
        return;
    }

    cmd->args[cmd->nargs++] = arg;
}

E
Eric Blake 已提交
1372 1373 1374 1375 1376 1377
/**
 * virCommandAddArgPair:
 * @cmd: the command to modify
 * @name: left half of argument
 * @value: right half of argument
 *
1378 1379 1380 1381 1382 1383 1384 1385
 * Add "NAME=VAL" as a single command line argument to the child
 */
void
virCommandAddArgPair(virCommandPtr cmd, const char *name, const char *val)
{
    virCommandAddArgFormat(cmd, "%s=%s", name, val);
}

E
Eric Blake 已提交
1386 1387 1388 1389 1390
/**
 * virCommandAddArgSet:
 * @cmd: the command to modify
 * @vals: array of arguments to add
 *
1391 1392 1393 1394 1395 1396 1397 1398 1399 1400
 * Add a NULL terminated list of args
 */
void
virCommandAddArgSet(virCommandPtr cmd, const char *const*vals)
{
    int narg = 0;

    if (!cmd || cmd->has_error)
        return;

1401 1402 1403 1404 1405
    if (vals[0] == NULL) {
        cmd->has_error = EINVAL;
        return;
    }

1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
    while (vals[narg] != NULL)
        narg++;

    /* narg plus trailing NULL. */
    if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, narg + 1) < 0) {
        cmd->has_error = ENOMEM;
        return;
    }

    narg = 0;
    while (vals[narg] != NULL) {
        char *arg = strdup(vals[narg++]);
        if (!arg) {
            cmd->has_error = ENOMEM;
            return;
        }
        cmd->args[cmd->nargs++] = arg;
    }
}

E
Eric Blake 已提交
1426 1427 1428 1429 1430 1431
/**
 * virCommandAddArgList:
 * @cmd: the command to modify
 * @...: list of arguments to add
 *
 * Add a NULL terminated list of args.
1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468
 */
void
virCommandAddArgList(virCommandPtr cmd, ...)
{
    va_list list;
    int narg = 0;

    if (!cmd || cmd->has_error)
        return;

    va_start(list, cmd);
    while (va_arg(list, const char *) != NULL)
        narg++;
    va_end(list);

    /* narg plus trailing NULL. */
    if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, narg + 1) < 0) {
        cmd->has_error = ENOMEM;
        return;
    }

    va_start(list, cmd);
    while (1) {
        char *arg = va_arg(list, char *);
        if (!arg)
            break;
        arg = strdup(arg);
        if (!arg) {
            cmd->has_error = ENOMEM;
            va_end(list);
            return;
        }
        cmd->args[cmd->nargs++] = arg;
    }
    va_end(list);
}

E
Eric Blake 已提交
1469 1470 1471 1472 1473
/**
 * virCommandSetWorkingDirectory:
 * @cmd: the command to modify
 * @pwd: directory to use
 *
1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485
 * Set the working directory of a non-daemon child process, rather
 * than the parent's working directory.  Daemons automatically get /
 * without using this call.
 */
void
virCommandSetWorkingDirectory(virCommandPtr cmd, const char *pwd)
{
    if (!cmd || cmd->has_error)
        return;

    if (cmd->pwd) {
        cmd->has_error = -1;
1486
        VIR_DEBUG("cannot set directory twice");
1487 1488 1489 1490 1491 1492 1493 1494
    } else {
        cmd->pwd = strdup(pwd);
        if (!cmd->pwd)
            cmd->has_error = ENOMEM;
    }
}


E
Eric Blake 已提交
1495 1496 1497 1498 1499
/**
 * virCommandSetInputBuffer:
 * @cmd: the command to modify
 * @inbuf: string to feed to stdin
 *
1500 1501 1502
 * Feed the child's stdin from a string buffer.  This requires the
 * use of virCommandRun() or combination of virCommandDoAsyncIO and
 * virCommandRunAsync. The buffer is forgotten after each @cmd run.
1503 1504 1505 1506 1507 1508 1509 1510 1511
 */
void
virCommandSetInputBuffer(virCommandPtr cmd, const char *inbuf)
{
    if (!cmd || cmd->has_error)
        return;

    if (cmd->infd != -1 || cmd->inbuf) {
        cmd->has_error = -1;
1512
        VIR_DEBUG("cannot specify input twice");
1513 1514 1515 1516 1517 1518 1519 1520 1521
        return;
    }

    cmd->inbuf = strdup(inbuf);
    if (!cmd->inbuf)
        cmd->has_error = ENOMEM;
}


E
Eric Blake 已提交
1522 1523 1524 1525 1526
/**
 * virCommandSetOutputBuffer:
 * @cmd: the command to modify
 * @outbuf: address of variable to store malloced result buffer
 *
1527 1528 1529
 * Capture the child's stdout to a string buffer.  *outbuf is
 * guaranteed to be allocated after successful virCommandRun or
 * virCommandWait, and is best-effort allocated after failed
1530 1531 1532 1533
 * virCommandRun or virCommandRunAsync; caller is responsible for
 * freeing *outbuf. This requires the use of virCommandRun() or
 * combination of virCommandDoAsyncIO and virCommandRunAsync. The
 * buffer is forgotten after each @cmd run.
1534 1535 1536 1537
 */
void
virCommandSetOutputBuffer(virCommandPtr cmd, char **outbuf)
{
1538
    *outbuf = NULL;
1539 1540 1541 1542 1543
    if (!cmd || cmd->has_error)
        return;

    if (cmd->outfdptr) {
        cmd->has_error = -1;
1544
        VIR_DEBUG("cannot specify output twice");
1545 1546 1547 1548 1549 1550 1551 1552
        return;
    }

    cmd->outbuf = outbuf;
    cmd->outfdptr = &cmd->outfd;
}


E
Eric Blake 已提交
1553 1554 1555 1556 1557
/**
 * virCommandSetErrorBuffer:
 * @cmd: the command to modify
 * @errbuf: address of variable to store malloced result buffer
 *
1558 1559 1560
 * Capture the child's stderr to a string buffer.  *errbuf is
 * guaranteed to be allocated after successful virCommandRun or
 * virCommandWait, and is best-effort allocated after failed
1561 1562 1563 1564 1565 1566 1567
 * virCommandRun or virCommandRunAsync; caller is responsible for
 * freeing *errbuf. It is possible to pass the same pointer as
 * for virCommandSetOutputBuffer(), in which case the child
 * process will interleave all output into a single string.  This
 * requires the use of virCommandRun() or combination of
 * virCommandDoAsyncIO and virCommandRunAsync.The buffer is
 * forgotten after each @cmd run.
1568 1569 1570 1571
 */
void
virCommandSetErrorBuffer(virCommandPtr cmd, char **errbuf)
{
1572
    *errbuf = NULL;
1573 1574 1575 1576 1577
    if (!cmd || cmd->has_error)
        return;

    if (cmd->errfdptr) {
        cmd->has_error = -1;
1578
        VIR_DEBUG("cannot specify stderr twice");
1579 1580 1581 1582 1583 1584 1585 1586
        return;
    }

    cmd->errbuf = errbuf;
    cmd->errfdptr = &cmd->errfd;
}


E
Eric Blake 已提交
1587 1588 1589 1590 1591
/**
 * virCommandSetInputFD:
 * @cmd: the command to modify
 * @infd: the descriptor to use
 *
1592 1593 1594 1595 1596 1597 1598 1599 1600 1601
 * Attach a file descriptor to the child's stdin
 */
void
virCommandSetInputFD(virCommandPtr cmd, int infd)
{
    if (!cmd || cmd->has_error)
        return;

    if (cmd->infd != -1 || cmd->inbuf) {
        cmd->has_error = -1;
1602
        VIR_DEBUG("cannot specify input twice");
1603 1604 1605 1606
        return;
    }
    if (infd < 0) {
        cmd->has_error = -1;
1607
        VIR_DEBUG("cannot specify invalid input fd");
1608 1609 1610 1611 1612 1613 1614
        return;
    }

    cmd->infd = infd;
}


E
Eric Blake 已提交
1615 1616 1617 1618 1619 1620 1621 1622
/**
 * virCommandSetOutputFD:
 * @cmd: the command to modify
 * @outfd: location of output fd
 *
 * Attach a file descriptor to the child's stdout.  If *@outfd is -1 on
 * entry, then a pipe will be created and returned in this variable when
 * the child is run.  Otherwise, *@outfd is used as the output.
1623 1624 1625 1626 1627 1628 1629 1630 1631
 */
void
virCommandSetOutputFD(virCommandPtr cmd, int *outfd)
{
    if (!cmd || cmd->has_error)
        return;

    if (cmd->outfdptr) {
        cmd->has_error = -1;
1632
        VIR_DEBUG("cannot specify output twice");
1633 1634 1635 1636 1637 1638 1639
        return;
    }

    cmd->outfdptr = outfd;
}


E
Eric Blake 已提交
1640 1641 1642 1643 1644 1645 1646 1647 1648
/**
 * virCommandSetErrorFD:
 * @cmd: the command to modify
 * @errfd: location of error fd
 *
 * Attach a file descriptor to the child's stderr.  If *@errfd is -1 on
 * entry, then a pipe will be created and returned in this variable when
 * the child is run.  Otherwise, *@errfd is used for error collection,
 * and may be the same as outfd given to virCommandSetOutputFD().
1649 1650 1651 1652 1653 1654 1655 1656 1657
 */
void
virCommandSetErrorFD(virCommandPtr cmd, int *errfd)
{
    if (!cmd || cmd->has_error)
        return;

    if (cmd->errfdptr) {
        cmd->has_error = -1;
1658
        VIR_DEBUG("cannot specify stderr twice");
1659 1660 1661 1662 1663 1664 1665
        return;
    }

    cmd->errfdptr = errfd;
}


E
Eric Blake 已提交
1666 1667 1668 1669 1670 1671
/**
 * virCommandSetPreExecHook:
 * @cmd: the command to modify
 * @hook: the hook to run
 * @opaque: argument to pass to the hook
 *
1672 1673 1674
 * Run HOOK(OPAQUE) in the child as the last thing before changing
 * directories, dropping capabilities, and executing the new process.
 * Force the child to fail if HOOK does not return zero.
E
Eric Blake 已提交
1675 1676 1677
 *
 * Since @hook runs in the child, it should be careful to avoid
 * any functions that are not async-signal-safe.
1678 1679 1680 1681 1682 1683 1684 1685 1686
 */
void
virCommandSetPreExecHook(virCommandPtr cmd, virExecHook hook, void *opaque)
{
    if (!cmd || cmd->has_error)
        return;

    if (cmd->hook) {
        cmd->has_error = -1;
1687
        VIR_DEBUG("cannot specify hook twice");
1688 1689 1690 1691 1692 1693 1694
        return;
    }
    cmd->hook = hook;
    cmd->opaque = opaque;
}


E
Eric Blake 已提交
1695 1696 1697 1698 1699
/**
 * virCommandWriteArgLog:
 * @cmd: the command to log
 * @logfd: where to log the results
 *
1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731
 * Call after adding all arguments and environment settings, but before
 * Run/RunAsync, to immediately output the environment and arguments of
 * cmd to logfd.  If virCommandRun cannot succeed (because of an
 * out-of-memory condition while building cmd), nothing will be logged.
 */
void
virCommandWriteArgLog(virCommandPtr cmd, int logfd)
{
    int ioError = 0;
    size_t i;

    /* Any errors will be reported later by virCommandRun, which means
     * no command will be run, so there is nothing to log. */
    if (!cmd || cmd->has_error)
        return;

    for (i = 0 ; i < cmd->nenv ; i++) {
        if (safewrite(logfd, cmd->env[i], strlen(cmd->env[i])) < 0)
            ioError = errno;
        if (safewrite(logfd, " ", 1) < 0)
            ioError = errno;
    }
    for (i = 0 ; i < cmd->nargs ; i++) {
        if (safewrite(logfd, cmd->args[i], strlen(cmd->args[i])) < 0)
            ioError = errno;
        if (safewrite(logfd, i == cmd->nargs - 1 ? "\n" : " ", 1) < 0)
            ioError = errno;
    }

    if (ioError) {
        char ebuf[1024];
        VIR_WARN("Unable to write command %s args to logfile: %s",
1732
                 cmd->args[0], virStrerror(ioError, ebuf, sizeof(ebuf)));
1733 1734 1735 1736
    }
}


E
Eric Blake 已提交
1737 1738 1739 1740
/**
 * virCommandToString:
 * @cmd: the command to convert
 *
1741 1742 1743 1744
 * Call after adding all arguments and environment settings, but
 * before Run/RunAsync, to return a string representation of the
 * environment and arguments of cmd, suitably quoted for pasting into
 * a shell.  If virCommandRun cannot succeed (because of an
1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755
 * out-of-memory condition while building cmd), NULL will be returned.
 * Caller is responsible for freeing the resulting string.
 */
char *
virCommandToString(virCommandPtr cmd)
{
    size_t i;
    virBuffer buf = VIR_BUFFER_INITIALIZER;

    /* Cannot assume virCommandRun will be called; so report the error
     * now.  If virCommandRun is called, it will report the same error. */
1756 1757
    if (!cmd ||cmd->has_error == ENOMEM) {
        virReportOOMError();
1758 1759
        return NULL;
    }
1760
    if (cmd->has_error) {
1761 1762
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("invalid use of command API"));
1763 1764 1765 1766
        return NULL;
    }

    for (i = 0; i < cmd->nenv; i++) {
1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779
        /* In shell, a='b c' has a different meaning than 'a=b c', so
         * we must determine where the '=' lives.  */
        char *eq = strchr(cmd->env[i], '=');

        if (!eq) {
            virBufferFreeAndReset(&buf);
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("invalid use of command API"));
            return NULL;
        }
        eq++;
        virBufferAdd(&buf, cmd->env[i], eq - cmd->env[i]);
        virBufferEscapeShell(&buf, eq);
1780 1781
        virBufferAddChar(&buf, ' ');
    }
1782
    virBufferEscapeShell(&buf, cmd->args[0]);
1783 1784
    for (i = 1; i < cmd->nargs; i++) {
        virBufferAddChar(&buf, ' ');
1785
        virBufferEscapeShell(&buf, cmd->args[i]);
1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801
    }

    if (virBufferError(&buf)) {
        virBufferFreeAndReset(&buf);
        virReportOOMError();
        return NULL;
    }

    return virBufferContentAndReset(&buf);
}


/*
 * Manage input and output to the child process.
 */
static int
1802
virCommandProcessIO(virCommandPtr cmd)
1803
{
1804
    int outfd = -1, errfd = -1;
1805 1806
    size_t inlen = 0, outlen = 0, errlen = 0;
    size_t inoff = 0;
1807
    int ret = 0;
1808 1809 1810

    /* With an input buffer, feed data to child
     * via pipe */
1811
    if (cmd->inbuf)
1812 1813
        inlen = strlen(cmd->inbuf);

1814 1815 1816 1817 1818
    /* With out/err buffer, the outfd/errfd have been filled with an
     * FD for us.  Guarantee an allocated string with partial results
     * even if we encounter a later failure, as well as freeing any
     * results accumulated over a prior run of the same command.  */
    if (cmd->outbuf) {
1819
        outfd = cmd->outfd;
1820 1821 1822 1823 1824 1825
        if (VIR_REALLOC_N(*cmd->outbuf, 1) < 0) {
            virReportOOMError();
            ret = -1;
        }
    }
    if (cmd->errbuf) {
1826
        errfd = cmd->errfd;
1827 1828 1829 1830 1831 1832 1833 1834
        if (VIR_REALLOC_N(*cmd->errbuf, 1) < 0) {
            virReportOOMError();
            ret = -1;
        }
    }
    if (ret == -1)
        goto cleanup;
    ret = -1;
1835 1836 1837 1838 1839 1840

    for (;;) {
        int i;
        struct pollfd fds[3];
        int nfds = 0;

1841 1842
        if (cmd->inpipe != -1) {
            fds[nfds].fd = cmd->inpipe;
1843
            fds[nfds].events = POLLOUT;
1844
            fds[nfds].revents = 0;
1845 1846 1847 1848 1849
            nfds++;
        }
        if (outfd != -1) {
            fds[nfds].fd = outfd;
            fds[nfds].events = POLLIN;
1850
            fds[nfds].revents = 0;
1851 1852 1853 1854 1855
            nfds++;
        }
        if (errfd != -1) {
            fds[nfds].fd = errfd;
            fds[nfds].events = POLLIN;
1856
            fds[nfds].revents = 0;
1857 1858 1859 1860 1861 1862 1863
            nfds++;
        }

        if (nfds == 0)
            break;

        if (poll(fds, nfds, -1) < 0) {
1864
            if (errno == EAGAIN || errno == EINTR)
1865 1866 1867
                continue;
            virReportSystemError(errno, "%s",
                                 _("unable to poll on child"));
1868
            goto cleanup;
1869 1870 1871
        }

        for (i = 0; i < nfds ; i++) {
1872
            if (fds[i].revents & (POLLIN | POLLHUP | POLLERR) &&
1873
                (fds[i].fd == errfd || fds[i].fd == outfd)) {
1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884
                char data[1024];
                char **buf;
                size_t *len;
                int done;
                if (fds[i].fd == outfd) {
                    buf = cmd->outbuf;
                    len = &outlen;
                } else {
                    buf = cmd->errbuf;
                    len = &errlen;
                }
1885 1886
                /* Silence a false positive from clang. */
                sa_assert(buf);
1887 1888 1889 1890 1891 1892

                done = read(fds[i].fd, data, sizeof(data));
                if (done < 0) {
                    if (errno != EINTR &&
                        errno != EAGAIN) {
                        virReportSystemError(errno, "%s",
1893 1894 1895
                                             (fds[i].fd == outfd) ?
                                             _("unable to read child stdout") :
                                             _("unable to read child stderr"));
1896
                        goto cleanup;
1897 1898 1899 1900 1901 1902 1903 1904 1905
                    }
                } else if (done == 0) {
                    if (fds[i].fd == outfd)
                        outfd = -1;
                    else
                        errfd = -1;
                } else {
                    if (VIR_REALLOC_N(*buf, *len + done + 1) < 0) {
                        virReportOOMError();
1906
                        goto cleanup;
1907 1908 1909 1910
                    }
                    memcpy(*buf + *len, data, done);
                    *len += done;
                }
1911 1912
            }

1913
            if (fds[i].revents & (POLLOUT | POLLERR) &&
1914
                fds[i].fd == cmd->inpipe) {
1915 1916
                int done;

1917 1918 1919
                /* Coverity 5.3.0 can't see that we only get here if
                 * infd is in the set because it was non-negative.  */
                sa_assert(infd != -1);
1920
                done = write(cmd->inpipe, cmd->inbuf + inoff,
1921 1922
                             inlen - inoff);
                if (done < 0) {
1923 1924
                    if (errno == EPIPE) {
                        VIR_DEBUG("child closed stdin early, ignoring EPIPE "
1925 1926
                                  "on fd %d", cmd->inpipe);
                        VIR_FORCE_CLOSE(cmd->inpipe);
1927
                    } else if (errno != EINTR && errno != EAGAIN) {
1928 1929
                        virReportSystemError(errno, "%s",
                                             _("unable to write to child input"));
1930
                        goto cleanup;
1931 1932 1933
                    }
                } else {
                    inoff += done;
1934 1935
                    if (inoff == inlen)
                        VIR_FORCE_CLOSE(cmd->inpipe);
1936 1937 1938 1939 1940
                }
            }
        }
    }

1941 1942
    ret = 0;
cleanup:
1943
    if (cmd->outbuf && *cmd->outbuf)
1944
        (*cmd->outbuf)[outlen] = '\0';
1945
    if (cmd->errbuf && *cmd->errbuf)
1946 1947
        (*cmd->errbuf)[errlen] = '\0';
    return ret;
1948 1949
}

E
Eric Blake 已提交
1950 1951 1952 1953
/**
 * virCommandExec:
 * @cmd: command to run
 *
1954
 * Exec the command, replacing the current process. Meant to be called
E
Eric Blake 已提交
1955 1956
 * in the hook after already forking / cloning, so does not attempt to
 * daemonize or preserve any FDs.
1957 1958 1959 1960
 *
 * Returns -1 on any error executing the command.
 * Will not return on success.
 */
1961
#ifndef WIN32
1962 1963 1964 1965 1966 1967 1968
int virCommandExec(virCommandPtr cmd)
{
    if (!cmd ||cmd->has_error == ENOMEM) {
        virReportOOMError();
        return -1;
    }
    if (cmd->has_error) {
1969 1970
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("invalid use of command API"));
1971 1972 1973 1974 1975
        return -1;
    }

    return execve(cmd->args[0], cmd->args, cmd->env);
}
1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
#else
int virCommandExec(virCommandPtr cmd ATTRIBUTE_UNUSED)
{
    /* Mingw execve() has a broken signature. Disable this
     * function until gnulib fixes the signature, since we
     * don't really need this on Win32 anyway.
     */
    virReportSystemError(ENOSYS, "%s",
                         _("Executing new processes is not supported on Win32 platform"));
    return -1;
}
#endif
1988

E
Eric Blake 已提交
1989 1990 1991 1992 1993
/**
 * virCommandRun:
 * @cmd: command to run
 * @exitstatus: optional status collection
 *
1994 1995 1996
 * Run the command and wait for completion.
 * Returns -1 on any error executing the
 * command. Returns 0 if the command executed,
E
Eric Blake 已提交
1997 1998
 * with the exit status set.  If @exitstatus is NULL, then the
 * child must exit with status 0 for this to succeed.
1999 2000 2001 2002 2003 2004 2005
 */
int
virCommandRun(virCommandPtr cmd, int *exitstatus)
{
    int ret = 0;
    char *outbuf = NULL;
    char *errbuf = NULL;
2006 2007 2008
    struct stat st;
    bool string_io;
    bool async_io = false;
2009
    char *str;
2010
    int tmpfd;
2011

2012 2013
    if (!cmd ||cmd->has_error == ENOMEM) {
        virReportOOMError();
2014 2015
        return -1;
    }
2016
    if (cmd->has_error) {
2017 2018
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("invalid use of command API"));
2019 2020 2021
        return -1;
    }

2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038
    /* Avoid deadlock, by requiring that any open fd not under our
     * control must be visiting a regular file, or that we are
     * daemonized and no string io is required.  */
    string_io = cmd->inbuf || cmd->outbuf || cmd->errbuf;
    if (cmd->infd != -1 &&
        (fstat(cmd->infd, &st) < 0 || !S_ISREG(st.st_mode)))
        async_io = true;
    if (cmd->outfdptr && cmd->outfdptr != &cmd->outfd &&
        (*cmd->outfdptr == -1 ||
         fstat(*cmd->outfdptr, &st) < 0 || !S_ISREG(st.st_mode)))
        async_io = true;
    if (cmd->errfdptr && cmd->errfdptr != &cmd->errfd &&
        (*cmd->errfdptr == -1 ||
         fstat(*cmd->errfdptr, &st) < 0 || !S_ISREG(st.st_mode)))
        async_io = true;
    if (async_io) {
        if (!(cmd->flags & VIR_EXEC_DAEMON) || string_io) {
2039 2040
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("cannot mix caller fds with blocking execution"));
2041 2042 2043 2044
            return -1;
        }
    } else {
        if ((cmd->flags & VIR_EXEC_DAEMON) && string_io) {
2045 2046
            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                           _("cannot mix string I/O with daemon"));
2047 2048 2049 2050
            return -1;
        }
    }

2051 2052 2053 2054 2055 2056 2057
    /* If caller requested the same string for stdout and stderr, then
     * merge those into one string.  */
    if (cmd->outbuf && cmd->outbuf == cmd->errbuf) {
        cmd->errfdptr = &cmd->outfd;
        cmd->errbuf = NULL;
    }

2058
    /* If caller hasn't requested capture of stdout/err, then capture
2059 2060 2061
     * it ourselves so we can log it.  But the intermediate child for
     * a daemon has no expected output, and we don't want our
     * capturing pipes passed on to the daemon grandchild.
2062
     */
2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073
    if (!(cmd->flags & VIR_EXEC_DAEMON)) {
        if (!cmd->outfdptr) {
            cmd->outfdptr = &cmd->outfd;
            cmd->outbuf = &outbuf;
            string_io = true;
        }
        if (!cmd->errfdptr) {
            cmd->errfdptr = &cmd->errfd;
            cmd->errbuf = &errbuf;
            string_io = true;
        }
2074 2075
    }

2076
    cmd->flags |= VIR_EXEC_RUN_SYNC;
2077 2078 2079 2080 2081
    if (virCommandRunAsync(cmd, NULL) < 0) {
        cmd->has_error = -1;
        return -1;
    }

2082 2083 2084 2085
    if (string_io) {
        VIR_FORCE_CLOSE(cmd->infd);
        ret = virCommandProcessIO(cmd);
    }
2086 2087 2088 2089

    if (virCommandWait(cmd, exitstatus) < 0)
        ret = -1;

2090
    str = (exitstatus ? virProcessTranslateStatus(*exitstatus)
2091 2092 2093
           : (char *) "status 0");
    VIR_DEBUG("Result %s, stdout: '%s' stderr: '%s'",
              NULLSTR(str),
2094 2095
              cmd->outbuf ? NULLSTR(*cmd->outbuf) : "(null)",
              cmd->errbuf ? NULLSTR(*cmd->errbuf) : "(null)");
2096 2097
    if (exitstatus)
        VIR_FREE(str);
2098 2099 2100

    /* Reset any capturing, in case caller runs
     * this identical command again */
2101
    VIR_FORCE_CLOSE(cmd->inpipe);
2102
    if (cmd->outbuf == &outbuf) {
2103
        tmpfd = cmd->outfd;
2104 2105 2106 2107
        if (VIR_CLOSE(cmd->outfd) < 0)
            VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
        cmd->outfdptr = NULL;
        cmd->outbuf = NULL;
E
Eric Blake 已提交
2108
        VIR_FREE(outbuf);
2109 2110
    }
    if (cmd->errbuf == &errbuf) {
2111
        tmpfd = cmd->errfd;
2112 2113 2114 2115
        if (VIR_CLOSE(cmd->errfd) < 0)
            VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
        cmd->errfdptr = NULL;
        cmd->errbuf = NULL;
E
Eric Blake 已提交
2116
        VIR_FREE(errbuf);
2117 2118 2119 2120 2121 2122
    }

    return ret;
}


2123
static void
2124
virCommandDoAsyncIOHelper(void *opaque)
2125
{
2126 2127 2128 2129
    virCommandPtr cmd = opaque;
    if (virCommandProcessIO(cmd) < 0) {
        /* If something went wrong, save errno or -1*/
        cmd->has_error = errno ? errno : -1;
2130 2131 2132 2133
    }
}


E
Eric Blake 已提交
2134 2135 2136 2137 2138
/**
 * virCommandRunAsync:
 * @cmd: command to start
 * @pid: optional variable to track child pid
 *
2139 2140 2141
 * Run the command asynchronously
 * Returns -1 on any error executing the
 * command. Returns 0 if the command executed.
2142 2143 2144 2145 2146 2147 2148 2149 2150 2151
 *
 * There are two approaches to child process cleanup.
 * 1. Use auto-cleanup, by passing NULL for pid.  The child will be
 * auto-reaped by virCommandFree, unless you reap it earlier via
 * virCommandWait or virCommandAbort.  Good for where cmd is in
 * scope for the duration of the child process.
 * 2. Use manual cleanup, by passing the address of a pid_t variable
 * for pid.  While cmd is still in scope, you may reap the child via
 * virCommandWait or virCommandAbort.  But after virCommandFree, if
 * you have not yet reaped the child, then it continues to run until
2152
 * you call virProcessWait or virProcessAbort.
2153 2154 2155 2156
 */
int
virCommandRunAsync(virCommandPtr cmd, pid_t *pid)
{
2157
    int ret = -1;
2158 2159
    char *str;
    int i;
2160
    bool synchronous = false;
2161
    int infd[2] = {-1, -1};
2162

2163 2164
    if (!cmd || cmd->has_error == ENOMEM) {
        virReportOOMError();
2165 2166
        return -1;
    }
2167
    if (cmd->has_error) {
2168 2169
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("invalid use of command API"));
2170 2171 2172
        return -1;
    }

2173 2174 2175
    synchronous = cmd->flags & VIR_EXEC_RUN_SYNC;
    cmd->flags &= ~VIR_EXEC_RUN_SYNC;

2176 2177 2178 2179 2180 2181 2182 2183 2184
    /* Buffer management can only be requested via virCommandRun or
     * virCommandDoAsyncIO. */
    if (cmd->inbuf && cmd->infd == -1 &&
        (synchronous || cmd->flags & VIR_EXEC_ASYNC_IO)) {
        if (pipe2(infd, O_CLOEXEC) < 0) {
            virReportSystemError(errno, "%s",
                                 _("unable to open pipe"));
            cmd->has_error = -1;
            return -1;
2185
        }
2186 2187
        cmd->infd = infd[0];
        cmd->inpipe = infd[1];
2188
    } else if ((cmd->inbuf && cmd->infd == -1) ||
2189 2190
               (cmd->outbuf && cmd->outfdptr != &cmd->outfd) ||
               (cmd->errbuf && cmd->errfdptr != &cmd->errfd)) {
2191 2192
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("cannot mix string I/O with asynchronous command"));
2193 2194 2195
        return -1;
    }

2196
    if (cmd->pid != -1) {
2197 2198 2199
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("command is already running as pid %lld"),
                       (long long) cmd->pid);
2200
        goto cleanup;
2201 2202
    }

2203
    if (!synchronous && (cmd->flags & VIR_EXEC_DAEMON)) {
2204 2205
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("daemonized command cannot use virCommandRunAsync"));
2206
        goto cleanup;
2207
    }
2208
    if (cmd->pwd && (cmd->flags & VIR_EXEC_DAEMON)) {
2209 2210 2211
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("daemonized command cannot set working directory %s"),
                       cmd->pwd);
2212
        goto cleanup;
2213
    }
2214
    if (cmd->pidfile && !(cmd->flags & VIR_EXEC_DAEMON)) {
2215 2216
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("creation of pid file requires daemonized command"));
2217
        goto cleanup;
2218
    }
2219 2220 2221 2222 2223

    str = virCommandToString(cmd);
    VIR_DEBUG("About to run %s", str ? str : cmd->args[0]);
    VIR_FREE(str);

2224
    ret = virExec(cmd);
2225 2226 2227
    VIR_DEBUG("Command result %d, with PID %d",
              ret, (int)cmd->pid);

2228 2229
    for (i = 0; i < cmd->transfer_size; i++) {
        VIR_FORCE_CLOSE(cmd->transfer[i]);
2230
    }
2231 2232
    cmd->transfer_size = 0;
    VIR_FREE(cmd->transfer);
2233 2234 2235

    if (ret == 0 && pid)
        *pid = cmd->pid;
2236 2237
    else
        cmd->reap = true;
2238

2239
    if (ret == 0 && cmd->flags & VIR_EXEC_ASYNC_IO) {
2240
        if (cmd->inbuf)
2241
            VIR_FORCE_CLOSE(cmd->infd);
2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252
        /* clear any error so we can catch if the helper thread reports one */
        cmd->has_error = 0;
        if (VIR_ALLOC(cmd->asyncioThread) < 0 ||
            virThreadCreate(cmd->asyncioThread, true,
                            virCommandDoAsyncIOHelper, cmd) < 0) {
            virReportSystemError(errno, "%s",
                                 _("Unable to create thread "
                                   "to process command's IO"));
            VIR_FREE(cmd->asyncioThread);
            virCommandAbort(cmd);
            ret = -1;
2253 2254 2255
        }
    }

2256 2257 2258 2259 2260
cleanup:
    if (ret < 0) {
        VIR_FORCE_CLOSE(cmd->infd);
        VIR_FORCE_CLOSE(cmd->inpipe);
    }
2261 2262 2263 2264
    return ret;
}


E
Eric Blake 已提交
2265 2266 2267 2268 2269 2270 2271
/**
 * virCommandWait:
 * @cmd: command to wait on
 * @exitstatus: optional status collection
 *
 * Wait for the command previously started with virCommandRunAsync()
 * to complete. Return -1 on any error waiting for
2272
 * completion. Returns 0 if the command
E
Eric Blake 已提交
2273 2274
 * finished with the exit status set.  If @exitstatus is NULL, then the
 * child must exit with status 0 for this to succeed.
2275 2276 2277 2278 2279
 */
int
virCommandWait(virCommandPtr cmd, int *exitstatus)
{
    int ret;
2280
    int status = 0;
2281

2282 2283
    if (!cmd ||cmd->has_error == ENOMEM) {
        virReportOOMError();
2284 2285
        return -1;
    }
2286
    if (cmd->has_error) {
2287 2288
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("invalid use of command API"));
2289 2290 2291 2292
        return -1;
    }

    if (cmd->pid == -1) {
2293 2294
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("command is not yet running"));
2295 2296 2297
        return -1;
    }

2298
    /* If virProcessWait reaps pid but then returns failure because
2299 2300 2301
     * exitstatus was NULL, then a second virCommandWait would risk
     * calling waitpid on an unrelated process.  Besides, that error
     * message is not as detailed as what we can provide.  So, we
2302
     * guarantee that virProcessWait only fails due to failure to wait,
2303
     * and repeat the exitstatus check code ourselves.  */
2304
    ret = virProcessWait(cmd->pid, exitstatus ? exitstatus : &status);
2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317
    if (cmd->flags & VIR_EXEC_ASYNC_IO) {
        cmd->flags &= ~VIR_EXEC_ASYNC_IO;
        virThreadJoin(cmd->asyncioThread);
        VIR_FREE(cmd->asyncioThread);
        VIR_FORCE_CLOSE(cmd->inpipe);
        if (cmd->has_error) {
            const char *msg = _("Error while processing command's IO");
            if (cmd->has_error < 0)
                virReportError(VIR_ERR_INTERNAL_ERROR, "%s", msg);
            else
                virReportSystemError(cmd->has_error, "%s", msg);
            ret = -1;
        }
2318
    }
2319 2320 2321 2322
    if (ret == 0) {
        cmd->pid = -1;
        cmd->reap = false;
        if (status) {
2323
            char *str = virCommandToString(cmd);
2324
            char *st = virProcessTranslateStatus(status);
2325 2326
            bool haveErrMsg = cmd->errbuf && *cmd->errbuf && (*cmd->errbuf)[0];

2327
            virReportError(VIR_ERR_INTERNAL_ERROR,
2328 2329 2330 2331
                           _("Child process (%s) unexpected %s%s%s"),
                           str ? str : cmd->args[0], NULLSTR(st),
                           haveErrMsg ? ": " : "",
                           haveErrMsg ? *cmd->errbuf : "");
2332
            VIR_FREE(str);
2333
            VIR_FREE(st);
2334 2335 2336 2337
            return -1;
        }
    }

2338
    return ret;
2339 2340 2341
}


E
Eric Blake 已提交
2342
#ifndef WIN32
E
Eric Blake 已提交
2343 2344 2345 2346
/**
 * virCommandAbort:
 * @cmd: command to abort
 *
2347 2348 2349 2350 2351 2352 2353 2354 2355 2356
 * Abort an async command if it is running, without issuing
 * any errors or affecting errno.  Designed for error paths
 * where some but not all paths to the cleanup code might
 * have started the child process.
 */
void
virCommandAbort(virCommandPtr cmd)
{
    if (!cmd || cmd->pid == -1)
        return;
2357
    virProcessAbort(cmd->pid);
2358 2359 2360
    cmd->pid = -1;
    cmd->reap = false;
}
E
Eric Blake 已提交
2361 2362 2363 2364 2365
#else /* WIN32 */
void
virCommandAbort(virCommandPtr cmd ATTRIBUTE_UNUSED)
{
    /* Mingw lacks WNOHANG and kill().  But since we haven't ported
2366
     * virExec to mingw yet, there's no process to be killed,
E
Eric Blake 已提交
2367 2368 2369
     * making this implementation trivially correct for now :)  */
}
#endif
2370

2371

E
Eric Blake 已提交
2372 2373 2374 2375 2376 2377 2378 2379 2380
/**
 * virCommandRequireHandshake:
 * @cmd: command to modify
 *
 * Request that the child perform a handshake with
 * the parent when the hook function has completed
 * execution. The child will not exec() until the
 * parent has notified
 */
2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391
void virCommandRequireHandshake(virCommandPtr cmd)
{
    if (!cmd || cmd->has_error)
        return;

    if (cmd->handshake) {
        cmd->has_error = -1;
        VIR_DEBUG("Cannot require handshake twice");
        return;
    }

2392
    if (pipe2(cmd->handshakeWait, O_CLOEXEC) < 0) {
2393 2394 2395
        cmd->has_error = errno;
        return;
    }
2396
    if (pipe2(cmd->handshakeNotify, O_CLOEXEC) < 0) {
2397 2398 2399 2400 2401 2402
        VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
        VIR_FORCE_CLOSE(cmd->handshakeWait[1]);
        cmd->has_error = errno;
        return;
    }

2403 2404 2405 2406
    VIR_DEBUG("Transfer handshake wait=%d notify=%d, "
              "keep handshake wait=%d notify=%d",
              cmd->handshakeWait[1], cmd->handshakeNotify[0],
              cmd->handshakeWait[0], cmd->handshakeNotify[1]);
2407 2408 2409 2410 2411
    virCommandTransferFD(cmd, cmd->handshakeWait[1]);
    virCommandTransferFD(cmd, cmd->handshakeNotify[0]);
    cmd->handshake = true;
}

2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459
/* virCommandHandshakeChild:
 *
 *   child side of handshake - called by child process in virExec() to
 *   indicate to parent that the child process has successfully
 *   completed its pre-exec initialization.
 */
static int
virCommandHandshakeChild(virCommandPtr cmd)
{
    char c = '1';
    int rv;

    if (!cmd->handshake)
       return true;

    VIR_DEBUG("Notifying parent for handshake start on %d",
              cmd->handshakeWait[1]);
    if (safewrite(cmd->handshakeWait[1], &c, sizeof(c)) != sizeof(c)) {
        virReportSystemError(errno, "%s",
                             _("Unable to notify parent process"));
        return -1;
    }

    VIR_DEBUG("Waiting on parent for handshake complete on %d",
              cmd->handshakeNotify[0]);
    if ((rv = saferead(cmd->handshakeNotify[0], &c,
                       sizeof(c))) != sizeof(c)) {
        if (rv < 0)
            virReportSystemError(errno, "%s",
                                 _("Unable to wait on parent process"));
        else
            virReportSystemError(EIO, "%s",
                                 _("libvirtd quit during handshake"));
        return -1;
    }
    if (c != '1') {
        virReportSystemError(EINVAL,
                             _("Unexpected confirm code '%c' from parent"),
                             c);
        return -1;
    }
    VIR_FORCE_CLOSE(cmd->handshakeWait[1]);
    VIR_FORCE_CLOSE(cmd->handshakeNotify[0]);

    VIR_DEBUG("Handshake with parent is done");
    return 0;
}

E
Eric Blake 已提交
2460 2461 2462 2463 2464 2465 2466
/**
 * virCommandHandshakeWait:
 * @cmd: command to wait on
 *
 * Wait for the child to complete execution of its
 * hook function.  To be called in the parent.
 */
2467 2468 2469 2470 2471 2472 2473 2474 2475
int virCommandHandshakeWait(virCommandPtr cmd)
{
    char c;
    int rv;
    if (!cmd ||cmd->has_error == ENOMEM) {
        virReportOOMError();
        return -1;
    }
    if (cmd->has_error || !cmd->handshake) {
2476 2477
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("invalid use of command API"));
2478 2479 2480 2481
        return -1;
    }

    if (cmd->handshakeWait[0] == -1) {
2482 2483
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("Handshake is already complete"));
2484 2485 2486 2487 2488 2489
        return -1;
    }

    VIR_DEBUG("Wait for handshake on %d", cmd->handshakeWait[0]);
    if ((rv = saferead(cmd->handshakeWait[0], &c, sizeof(c))) != sizeof(c)) {
        if (rv < 0)
2490 2491
            virReportSystemError(errno, "%s",
                                 _("Unable to wait for child process"));
2492
        else
2493 2494
            virReportSystemError(EIO, "%s",
                                 _("Child quit during startup handshake"));
2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505
        VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
        return -1;
    }
    if (c != '1') {
        char *msg;
        ssize_t len;
        if (VIR_ALLOC_N(msg, 1024) < 0) {
            virReportOOMError();
            VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
            return -1;
        }
2506 2507 2508 2509 2510
        /* Close the handshakeNotify fd before trying to read anything
         * further on the handshakeWait pipe; so that a child waiting
         * on our acknowledgment will die rather than deadlock.  */
        VIR_FORCE_CLOSE(cmd->handshakeNotify[1]);

2511 2512 2513
        if ((len = saferead(cmd->handshakeWait[0], msg, 1024)) < 0) {
            VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
            VIR_FREE(msg);
2514 2515
            virReportSystemError(errno, "%s",
                                 _("No error message from child failure"));
2516 2517 2518 2519
            return -1;
        }
        VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
        msg[len-1] = '\0';
2520
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s", msg);
2521 2522 2523 2524 2525 2526 2527
        VIR_FREE(msg);
        return -1;
    }
    VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
    return 0;
}

E
Eric Blake 已提交
2528 2529 2530 2531 2532 2533 2534
/**
 * virCommandHandshakeNotify:
 * @cmd: command to resume
 *
 * Notify the child that it is OK to exec() the
 * real binary now.  To be called in the parent.
 */
2535 2536 2537 2538 2539 2540 2541 2542
int virCommandHandshakeNotify(virCommandPtr cmd)
{
    char c = '1';
    if (!cmd ||cmd->has_error == ENOMEM) {
        virReportOOMError();
        return -1;
    }
    if (cmd->has_error || !cmd->handshake) {
2543 2544
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("invalid use of command API"));
2545 2546 2547 2548
        return -1;
    }

    if (cmd->handshakeNotify[1] == -1) {
2549 2550
        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                       _("Handshake is already complete"));
2551 2552 2553
        return -1;
    }

2554
    VIR_DEBUG("Notify handshake on %d", cmd->handshakeNotify[1]);
2555 2556 2557 2558 2559 2560 2561 2562 2563 2564
    if (safewrite(cmd->handshakeNotify[1], &c, sizeof(c)) != sizeof(c)) {
        virReportSystemError(errno, "%s", _("Unable to notify child process"));
        VIR_FORCE_CLOSE(cmd->handshakeNotify[1]);
        return -1;
    }
    VIR_FORCE_CLOSE(cmd->handshakeNotify[1]);
    return 0;
}


E
Eric Blake 已提交
2565 2566 2567 2568
/**
 * virCommandFree:
 * @cmd: optional command to free
 *
2569 2570
 * Release all resources.  The only exception is that if you called
 * virCommandRunAsync with a non-null pid, then the asynchronous child
2571
 * is not reaped, and you must call virProcessWait() or virProcessAbort() yourself.
2572 2573 2574 2575 2576 2577 2578 2579
 */
void
virCommandFree(virCommandPtr cmd)
{
    int i;
    if (!cmd)
        return;

2580 2581
    for (i = 0; i < cmd->transfer_size; i++) {
        VIR_FORCE_CLOSE(cmd->transfer[i]);
2582 2583
    }

2584 2585 2586 2587
    if (cmd->asyncioThread) {
        virThreadJoin(cmd->asyncioThread);
        VIR_FREE(cmd->asyncioThread);
    }
E
Eric Blake 已提交
2588
    VIR_FREE(cmd->inbuf);
2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601
    VIR_FORCE_CLOSE(cmd->outfd);
    VIR_FORCE_CLOSE(cmd->errfd);

    for (i = 0 ; i < cmd->nargs ; i++)
        VIR_FREE(cmd->args[i]);
    VIR_FREE(cmd->args);

    for (i = 0 ; i < cmd->nenv ; i++)
        VIR_FREE(cmd->env[i]);
    VIR_FREE(cmd->env);

    VIR_FREE(cmd->pwd);

2602 2603 2604 2605 2606 2607 2608 2609
    if (cmd->handshake) {
        /* The other 2 fds in these arrays are closed
         * due to use with virCommandTransferFD
         */
        VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
        VIR_FORCE_CLOSE(cmd->handshakeNotify[1]);
    }

2610 2611
    VIR_FREE(cmd->pidfile);

2612 2613 2614
    if (cmd->reap)
        virCommandAbort(cmd);

2615 2616
    VIR_FREE(cmd->transfer);
    VIR_FREE(cmd->preserve);
2617 2618 2619 2620 2621 2622
#if defined(WITH_SECDRIVER_SELINUX)
    VIR_FREE(cmd->seLinuxLabel);
#endif
#if defined(WITH_SECDRIVER_APPARMOR)
    VIR_FREE(cmd->appArmorProfile);
#endif
2623

2624 2625
    VIR_FREE(cmd);
}
2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672

/**
 * virCommandDoAsyncIO:
 * @cmd: command to do async IO on
 *
 * This requests asynchronous string IO on @cmd. It is useful in
 * combination with virCommandRunAsync():
 *
 *      virCommandPtr cmd = virCommandNew*(...);
 *      char *buf = NULL;
 *
 *      ...
 *
 *      virCommandSetOutputBuffer(cmd, &buf);
 *      virCommandDoAsyncIO(cmd);
 *
 *      if (virCommandRunAsync(cmd, NULL) < 0)
 *          goto cleanup;
 *
 *      ...
 *
 *      if (virCommandWait(cmd, NULL) < 0)
 *          goto cleanup;
 *
 *      // @buf now contains @cmd's stdout
 *      VIR_DEBUG("STDOUT: %s", NULLSTR(buf));
 *
 *      ...
 *
 *  cleanup:
 *      VIR_FREE(buf);
 *      virCommandFree(cmd);
 *
 * The libvirt's event loop is used for handling stdios of @cmd.
 * Since current implementation uses strlen to determine length
 * of data to be written to @cmd's stdin, don't pass any binary
 * data. If you want to re-run command, you need to call this and
 * buffer setting functions (virCommandSet.*Buffer) prior each run.
 */
void
virCommandDoAsyncIO(virCommandPtr cmd)
{
   if (!cmd || cmd->has_error)
       return;

   cmd->flags |= VIR_EXEC_ASYNC_IO | VIR_EXEC_NONBLOCK;
}