virtio-9p: Create a commandline option -fsdev

This patch creates a new command line option named -fsdev to hold any file
system specific information.

The option will currently hold the following attributes:
-fsdev fstype id=id,path=path_to_share
where
fstype: Type of the file system.
id:     Identifier used to refer to this fsdev
path:   The path on the host that is identified by this fsdev.

[aneesh.kumar@linux.vnet.ibm.com: Abstraction using FsContext]
Signed-off-by: NGautham R Shenoy <ego@in.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Makefile.objs

@@ -35,6 +35,9 @@ net-nested-$(CONFIG_SLIRP) += slirp.o
 net-nested-$(CONFIG_VDE) += vde.o
 net-obj-y += $(addprefix net/, $(net-nested-y))
 
+fsdev-nested-$(CONFIG_LINUX) = qemu-fsdev.o
+fsdev-obj-$(CONFIG_LINUX) += $(addprefix fsdev/, $(fsdev-nested-y))
+
 ######################################################################
 # libqemu_common.a: Target independent part of system emulation. The
 # long term path is to suppress *all* target specific code in case of
@@ -44,8 +47,8 @@ net-obj-y += $(addprefix net/, $(net-nested-y))
 common-obj-y = $(block-obj-y)
 common-obj-y += $(net-obj-y)
 common-obj-y += $(qobject-obj-y)
+common-obj-$(CONFIG_LINUX) += $(fsdev-obj-$(CONFIG_LINUX))
 common-obj-y += readline.o console.o async.o qemu-error.o
-
 common-obj-y += tcg-runtime.o host-utils.o
 common-obj-y += irq.o ioport.o input.o
 common-obj-$(CONFIG_PTIMER) += ptimer.o

configure

@@ -2757,6 +2757,7 @@ done # for target in $targets
 if test "$source_path_used" = "yes" ; then
     DIRS="tests tests/cris slirp audio block net pc-bios/optionrom"
     DIRS="$DIRS roms/seabios roms/vgabios"
+    DIRS="$DIRS fsdev"
     FILES="Makefile tests/Makefile"
     FILES="$FILES tests/cris/Makefile tests/cris/.gdbinit"
     FILES="$FILES tests/test-mmap.c"

fsdev/qemu-fsdev.c

+/*
+ * Virtio 9p
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ *  Gautham R Shenoy <ego@in.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#include <stdio.h>
+#include <string.h>
+#include "qemu-fsdev.h"
+#include "qemu-queue.h"
+#include "osdep.h"
+#include "qemu-common.h"
+
+static QTAILQ_HEAD(FsTypeEntry_head, FsTypeListEntry) fstype_entries =
+    QTAILQ_HEAD_INITIALIZER(fstype_entries);
+
+static FsTypeTable FsTypes[] = {
+    { .name = "local", .ops = NULL},
+};
+
+int qemu_fsdev_add(QemuOpts *opts)
+{
+    struct FsTypeListEntry *fsle;
+    int i;
+
+    if (qemu_opts_id(opts) == NULL) {
+        fprintf(stderr, "fsdev: No id specified\n");
+        return -1;
+    }
+
+     for (i = 0; i < ARRAY_SIZE(FsTypes); i++) {
+        if (strcmp(FsTypes[i].name, qemu_opt_get(opts, "fstype")) == 0) {
+            break;
+        }
+    }
+
+    if (i == ARRAY_SIZE(FsTypes)) {
+        fprintf(stderr, "fsdev: fstype %s not found\n",
+                    qemu_opt_get(opts, "fstype"));
+        return -1;
+    }
+
+    fsle = qemu_malloc(sizeof(*fsle));
+
+    fsle->fse.fsdev_id = qemu_strdup(qemu_opts_id(opts));
+    fsle->fse.path = qemu_strdup(qemu_opt_get(opts, "path"));
+    fsle->fse.ops = FsTypes[i].ops;
+
+    QTAILQ_INSERT_TAIL(&fstype_entries, fsle, next);
+    return 0;
+
+}
+
+FsTypeEntry *get_fsdev_fsentry(char *id)
+{
+    struct FsTypeListEntry *fsle;
+
+    QTAILQ_FOREACH(fsle, &fstype_entries, next) {
+        if (strcmp(fsle->fse.fsdev_id, id) == 0) {
+            return &fsle->fse;
+        }
+    }
+    return NULL;
+}

fsdev/qemu-fsdev.h

+/*
+ * Virtio 9p
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ *  Gautham R Shenoy <ego@in.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#ifndef QEMU_FSDEV_H
+#define QEMU_FSDEV_H
+#include "qemu-option.h"
+#include "hw/file-op-9p.h"
+
+
+/*
+ * A table to store the various file systems and their callback operations.
+ * -----------------
+ * fstype | ops
+ * -----------------
+ *  local | local_ops
+ *  .     |
+ *  .     |
+ *  .     |
+ *  .     |
+ * -----------------
+ *  etc
+ */
+typedef struct FsTypeTable {
+    const char *name;
+    FileOperations *ops;
+} FsTypeTable;
+
+/*
+ * Structure to store the various fsdev's passed through command line.
+ */
+typedef struct FsTypeEntry {
+    char *fsdev_id;
+    char *path;
+    FileOperations *ops;
+} FsTypeEntry;
+
+typedef struct FsTypeListEntry {
+    FsTypeEntry fse;
+    QTAILQ_ENTRY(FsTypeListEntry) next;
+} FsTypeListEntry;
+
+extern int qemu_fsdev_add(QemuOpts *opts);
+extern FsTypeEntry *get_fsdev_fsentry(char *id);
+#endif

hw/file-op-9p.h

+/*
+ * Virtio 9p
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#ifndef _FILEOP_H
+#define _FILEOP_H
+#include <sys/types.h>
+#include <dirent.h>
+#include <sys/time.h>
+#include <utime.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+
+typedef struct FsContext
+{
+    char *fs_root;
+    uid_t uid;
+} FsContext;
+
+typedef struct FileOperations
+{
+    void *opaque;
+} FileOperations;
+#endif

qemu-config.c

@@ -151,6 +151,24 @@ QemuOptsList qemu_chardev_opts = {
     },
 };
 
+#ifdef CONFIG_LINUX
+QemuOptsList qemu_fsdev_opts = {
+    .name = "fsdev",
+    .implied_opt_name = "fstype",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_fsdev_opts.head),
+    .desc = {
+        {
+            .name = "fstype",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "path",
+            .type = QEMU_OPT_STRING,
+        },
+        { /*End of list */ }
+    },
+};
+#endif
+
 QemuOptsList qemu_device_opts = {
     .name = "device",
     .implied_opt_name = "driver",

qemu-config.h

@@ -3,6 +3,9 @@
 
 extern QemuOptsList qemu_drive_opts;
 extern QemuOptsList qemu_chardev_opts;
+#ifdef CONFIG_LINUX
+extern QemuOptsList qemu_fsdev_opts;
+#endif
 extern QemuOptsList qemu_device_opts;
 extern QemuOptsList qemu_netdev_opts;
 extern QemuOptsList qemu_net_opts;

qemu-options.hx

@@ -478,6 +478,40 @@ To get a help on possible @var{driver}s, @var{option}s or @var{value}s, use
 @code{-device @var{driver},@var{option}=?}. 
 ETEXI
 
+#ifdef CONFIG_LINUX
+DEFHEADING(File system options:)
+
+DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
+    "-fsdev local,id=id,path=path\n",
+    QEMU_ARCH_ALL)
+
+STEXI
+
+The general form of a File system device option is:
+@table @option
+
+@item -fsdev @var{fstype} ,id=@var{id} [,@var{options}]
+@findex -fsdev
+Fstype is one of:
+@option{local},
+The specific Fstype will determine the applicable options.
+
+Options to each backend are described below.
+
+@item -fsdev local ,id=@var{id} ,path=@var{path}
+
+Create a file-system-"device" for local-filesystem.
+
+@option{local} is only available on Linux.
+
+@option{path} specifies the path to be exported. @option{path} is required.
+
+@end table
+ETEXI
+#endif
+
+DEFHEADING()
+
 DEF("name", HAS_ARG, QEMU_OPTION_name,
     "-name string1[,process=string2]\n"
     "                set the name of the guest\n"

vl.c

@@ -149,6 +149,9 @@ int main(int argc, char **argv)
 #include "qemu-option.h"
 #include "qemu-config.h"
 #include "qemu-objects.h"
+#ifdef CONFIG_LINUX
+#include "fsdev/qemu-fsdev.h"
+#endif
 
 #include "disas.h"
 
@@ -2310,6 +2313,16 @@ static int chardev_init_func(QemuOpts *opts, void *opaque)
     return 0;
 }
 
+#ifdef CONFIG_LINUX
+static int fsdev_init_func(QemuOpts *opts, void *opaque)
+{
+    int ret;
+    ret = qemu_fsdev_add(opts);
+
+    return ret;
+}
+#endif
+
 static int mon_init_func(QemuOpts *opts, void *opaque)
 {
     CharDriverState *chr;
@@ -3081,6 +3094,15 @@ int main(int argc, char **argv, char **envp)
                     exit(1);
                 }
                 break;
+#ifdef CONFIG_LINUX
+            case QEMU_OPTION_fsdev:
+                opts = qemu_opts_parse(&qemu_fsdev_opts, optarg, 1);
+                if (!opts) {
+                    fprintf(stderr, "parse error: %s\n", optarg);
+                    exit(1);
+                }
+                break;
+#endif
             case QEMU_OPTION_serial:
                 add_device_config(DEV_SERIAL, optarg);
                 default_serial = 0;
@@ -3437,6 +3459,11 @@ int main(int argc, char **argv, char **envp)
 
     if (qemu_opts_foreach(&qemu_chardev_opts, chardev_init_func, NULL, 1) != 0)
         exit(1);
+#ifdef CONFIG_LINUX
+    if (qemu_opts_foreach(&qemu_fsdev_opts, fsdev_init_func, NULL, 1) != 0) {
+        exit(1);
+    }
+#endif
 
 #ifndef _WIN32
     if (daemonize) {