strace.c

#include <stdio.h>
#include <errno.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/select.h>
#include <sys/types.h>
#include <unistd.h>
#include "qemu.h"

int do_strace=0;

struct syscallname {
    int nr;
    char *name;
    char *format;
    void (*call)(struct syscallname *,
                 target_long, target_long, target_long,
                 target_long, target_long, target_long);
    void (*result)(struct syscallname *, target_long);
};

/*
 * Utility functions
 */
static void
print_ipc_cmd(int cmd)
{
#define output_cmd(val) \
if( cmd == val ) { \
    gemu_log(#val); \
    return; \
}

    cmd &= 0xff;

    /* General IPC commands */
    output_cmd( IPC_RMID );
    output_cmd( IPC_SET );
    output_cmd( IPC_STAT );
    output_cmd( IPC_INFO );
    /* msgctl() commands */
    #ifdef __USER_MISC
    output_cmd( MSG_STAT );
    output_cmd( MSG_INFO );
    #endif
    /* shmctl() commands */
    output_cmd( SHM_LOCK );
    output_cmd( SHM_UNLOCK );
    output_cmd( SHM_STAT );
    output_cmd( SHM_INFO );
    /* semctl() commands */
    output_cmd( GETPID );
    output_cmd( GETVAL );
    output_cmd( GETALL );
    output_cmd( GETNCNT );
    output_cmd( GETZCNT );
    output_cmd( SETVAL );
    output_cmd( SETALL );
    output_cmd( SEM_STAT );
    output_cmd( SEM_INFO );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );
    output_cmd( IPC_RMID );

    /* Some value we don't recognize */
    gemu_log("%d",cmd);
}

static void
print_fdset(int n, target_ulong target_fds_addr)
{
    int i;

    gemu_log("[");
    if( target_fds_addr ) {
        target_long *target_fds;

        if (!access_ok(VERIFY_READ, target_fds_addr, sizeof(*target_fds)*(n / TARGET_LONG_BITS + 1)))
            return;

        target_fds = lock_user(target_fds_addr, sizeof(*target_fds)*(n / TARGET_LONG_BITS + 1), 1);
        for (i=n; i>=0; i--) {
            if ((tswapl(target_fds[i / TARGET_LONG_BITS]) >> (i & (TARGET_LONG_BITS - 1))) & 1)
                gemu_log("%d,", i );
            }
        unlock_user(target_fds, target_fds_addr, 0);
    }
    gemu_log("]");
}

static void
print_timeval(target_ulong tv_addr)
{
    if( tv_addr ) {
        struct target_timeval *tv;

	if (!access_ok(VERIFY_READ, tv_addr, sizeof(*tv)))
            return;

	tv = lock_user(tv_addr, sizeof(*tv), 1);
        gemu_log("{" TARGET_ABI_FMT_ld "," TARGET_ABI_FMT_ld "}",
        	 tv->tv_sec, tv->tv_usec);
        unlock_user(tv, tv_addr, 0);
    } else
        gemu_log("NULL");
}

/*
 * Sysycall specific output functions
 */

/* select */
static long newselect_arg1 = 0;
static long newselect_arg2 = 0;
static long newselect_arg3 = 0;
static long newselect_arg4 = 0;
static long newselect_arg5 = 0;

static void
print_newselect(struct syscallname *name,
                target_long arg1, target_long arg2, target_long arg3,
                target_long arg4, target_long arg5, target_long arg6)
{
    gemu_log("%s(" TARGET_FMT_ld ",", name->name, arg1);
    print_fdset(arg1, arg2);
    gemu_log(",");
    print_fdset(arg1, arg3);
    gemu_log(",");
    print_fdset(arg1, arg4);
    gemu_log(",");
    print_timeval(arg5);
    gemu_log(")");

    /* save for use in the return output function below */
    newselect_arg1=arg1;
    newselect_arg2=arg2;
    newselect_arg3=arg3;
    newselect_arg4=arg4;
    newselect_arg5=arg5;
}

static void
print_semctl(struct syscallname *name,
             target_long arg1, target_long arg2, target_long arg3,
             target_long arg4, target_long arg5, target_long arg6)
{
    gemu_log("%s(" TARGET_FMT_ld "," TARGET_FMT_ld ",", name->name, arg1, arg2);
    print_ipc_cmd(arg3);
    gemu_log(",0x" TARGET_FMT_lx ")", arg4);
}

static void
print_execve(struct syscallname *name,
             target_long arg1, target_long arg2, target_long arg3,
             target_long arg4, target_long arg5, target_long arg6)
{
    target_ulong arg_ptr_addr;
    char *s;

    if (!access_ok(VERIFY_READ, arg1, 1))
        return;

    s = lock_user_string(arg1);
    gemu_log("%s(\"%s\",{", name->name, s);
    unlock_user(s, arg1, 0);

    for (arg_ptr_addr = arg2; ; arg_ptr_addr += sizeof(target_ulong)) {
        target_ulong *arg_ptr, arg_addr, s_addr;

        if (!access_ok(VERIFY_READ, arg_ptr_addr, sizeof(target_ulong)))
            return;

	arg_ptr = lock_user(arg_ptr_addr, sizeof(target_ulong), 1);
	arg_addr = tswapl(*arg_ptr);
	unlock_user(arg_ptr, arg_ptr_addr, 0);
        if (!arg_addr)
            break;
        s = lock_user_string(arg_addr);
        gemu_log("\"%s\",", s);
        unlock_user(s, s_addr, 0);
    }

    gemu_log("NULL})");
}

static void
print_ipc(struct syscallname *name,
          target_long arg1, target_long arg2, target_long arg3,
          target_long arg4, target_long arg5, target_long arg6)
{
    switch(arg1) {
    case IPCOP_semctl:
        name->name = "semctl";
        print_semctl(name,arg2,arg3,arg4,arg5,arg6,0);
        break;
    default:
        gemu_log("%s(" TARGET_FMT_ld "," TARGET_FMT_ld "," TARGET_FMT_ld "," TARGET_FMT_ld ")",
                 name->name, arg1, arg2, arg3, arg4);
    }
}

/*
 * Variants for the return value output function
 */

static void
print_syscall_ret_addr(struct syscallname *name, target_long ret)
{
if( ret == -1 ) {
        gemu_log(" = -1 errno=%d (%s)\n", errno, target_strerror(errno));
    } else {
        gemu_log(" = " TARGET_FMT_lx "\n", ret);
    }
}

#if 0 /* currently unused */
static void
print_syscall_ret_raw(struct syscallname *name, target_long ret)
{
        gemu_log(" = " TARGET_FMT_lx "\n", ret);
}
#endif

#ifdef TARGET_NR__newselect
static void
print_syscall_ret_newselect(struct syscallname *name, target_long ret)
{
    gemu_log(" = " TARGET_FMT_lx " (", ret);
    print_fdset(newselect_arg1,newselect_arg2);
    gemu_log(",");
    print_fdset(newselect_arg1,newselect_arg3);
    gemu_log(",");
    print_fdset(newselect_arg1,newselect_arg4);
    gemu_log(",");
    print_timeval(newselect_arg5);
    gemu_log(")\n");
}
#endif

/*
 * An array of all of the syscalls we know about
 */

static struct syscallname scnames[] = {
#include "strace.list"
};

static int nsyscalls = sizeof(scnames)/sizeof(struct syscallname);

/*
 * The public interface to this module.
 */
void
print_syscall(int num,
              target_long arg1, target_long arg2, target_long arg3,
              target_long arg4, target_long arg5, target_long arg6)
{
    int i;
    char *format="%s(%ld,%ld,%ld,%ld,%ld,%ld)";

    gemu_log("%d ", getpid() );

    for(i=0;i<nsyscalls;i++)
        if( scnames[i].nr == num ) {
            if( scnames[i].call != NULL ) {
                scnames[i].call(&scnames[i],arg1,arg2,arg3,arg4,arg5,arg6);
            } else {
                if( scnames[i].format != NULL )
                    format = scnames[i].format;
                gemu_log(format,scnames[i].name, arg1,arg2,arg3,arg4,arg5,arg6);
            }
            break;
        }
}


void
print_syscall_ret(int num, target_long ret)
{
    int i;

    for(i=0;i<nsyscalls;i++)
        if( scnames[i].nr == num ) {
            if( scnames[i].result != NULL ) {
                scnames[i].result(&scnames[i],ret);
            } else {
                if( ret < 0 ) {
                    gemu_log(" = -1 errno=%d (%s)\n", -ret, target_strerror(-ret));
                } else {
                    gemu_log(" = %d\n", ret);
                }
            }
            break;
        }
}