Re: [Libguestfs] [PATCH 3/3] mountable: Implement Mountable support for all apis which take it

A Mountable is passed from the library to the daemon as a string. The daemon stub parses it into a mountable_t, which it passes to the implementation. Update all implementations which now take a mountable_t. --- daemon/blkid.c | 36 ++++++++++++++++++++++++++++++------ daemon/daemon.h | 39 +++++++++++++++++++++++++++++++++++++++ daemon/ext2.c | 15 ++++++++++++--- daemon/guestfsd.c | 42 ++++++++++++++++++++++++++++++++++++++++++ daemon/labels.c | 19 +++++++++++++++++-- daemon/mount.c | 52 +++++++++++++++++++++++++++++++++++++++++++--------- generator/c.ml | 12 +++++++++++- generator/daemon.ml | 11 ++++++++--- 8 files changed, 202 insertions(+), 24 deletions(-) diff --git a/daemon/blkid.c b/daemon/blkid.c index b6bc22d..429a005 100644 --- a/daemon/blkid.c +++ b/daemon/blkid.c @@ -69,21 +69,45 @@ get_blkid_tag (const char *device, const char *tag) } char * -do_vfs_type (const char *device) +do_vfs_type (const mountable_t *mountable) { - return get_blkid_tag (device, "TYPE"); + switch (mountable->type) { + case MOUNTABLE_DEVICE: + return get_blkid_tag (mountable->desc.device, "TYPE"); + case MOUNTABLE_BTRFSVOL: + return strdup("btrfs");

+ default: + reply_with_error ("Unknown mountable type: %i", mountable->type); + return NULL; + } } char * -do_vfs_label (const char *device) +do_vfs_label (const mountable_t *mountable) { - return get_blkid_tag (device, "LABEL"); + switch (mountable->type) { + case MOUNTABLE_DEVICE: + return get_blkid_tag (mountable->desc.device, "LABEL"); + case MOUNTABLE_BTRFSVOL: + return get_blkid_tag (mountable->desc.btrfsvol.device, "LABEL");

+ default: + reply_with_error ("Unknown mountable type: %i", mountable->type); + return NULL; + } } char * -do_vfs_uuid (const char *device) +do_vfs_uuid (const mountable_t *mountable) { - return get_blkid_tag (device, "UUID"); + switch (mountable->type) { + case MOUNTABLE_DEVICE: + return get_blkid_tag (mountable->desc.device, "UUID"); + case MOUNTABLE_BTRFSVOL: + return get_blkid_tag (mountable->desc.btrfsvol.device, "UUID"); + default: + reply_with_error ("Unknown mountable type: %i", mountable->type); + return NULL; + } } /* RHEL5 blkid doesn't have the -p (low-level probing) option and the diff --git a/daemon/daemon.h b/daemon/daemon.h index df1ba3a..8f5015a 100644 --- a/daemon/daemon.h +++ b/daemon/daemon.h @@ -47,6 +47,24 @@ extern int xwrite (int sock, const void *buf, size_t len) extern int xread (int sock, void *buf, size_t len) __attribute__((__warn_unused_result__)); +/* Mountables */ + +typedef enum { + MOUNTABLE_DEVICE, + MOUNTABLE_BTRFSVOL +} mountable_type_t; + +typedef struct { + mountable_type_t type; + union { + const char *device; + struct { + const char *device; + const char *volume; + } btrfsvol; + } desc; +} mountable_t; + /* Growable strings buffer. */ struct stringsbuf { char **argv; @@ -114,6 +132,8 @@ extern void trim (char *str); extern int device_name_translation (char *device); +extern int parse_btrfsvol (char *desc, mountable_t *mountable); + extern int prog_exists (const char *prog); extern void udev_settle (void); @@ -320,6 +340,25 @@ is_zero (const char *buffer, size_t size) } \ } while (0) +#define RESOLVE_MOUNTABLE(string,mountable,cancel_stmt,fail_stmt) \ + do { \ + if (strncmp ((string), "btrfsvol:", strlen ("btrfsvol:")) == 0) { \ + if (parse_btrfsvol ((string) + strlen ("btrfsvol:"), &(mountable)) == -1)\ + { \ + cancel_stmt; \ + reply_with_error ("%s: %s: expecting a btrfs volume", \ + __func__, (string)); \ + fail_stmt; \ + } \ + } \ + \ + else { \ + mountable.type = MOUNTABLE_DEVICE; \ + mountable.desc.device = (string); \ + RESOLVE_DEVICE((string), cancel_stmt, fail_stmt); \ + } \ + } while (0) + /* Helper for functions which need either an absolute path in the * mounted filesystem, OR a /dev/ device which exists. * diff --git a/daemon/ext2.c b/daemon/ext2.c index ab879db..94e85f0 100644 --- a/daemon/ext2.c +++ b/daemon/ext2.c @@ -127,13 +127,19 @@ do_tune2fs_l (const char *device) int do_set_e2label (const char *device, const char *label) { - return do_set_label (device, label); + mountable_t mountable; + mountable.type = MOUNTABLE_DEVICE; + mountable.desc.device = device; + return do_set_label (&mountable, label); } char * do_get_e2label (const char *device) { - return do_vfs_label (device); + mountable_t mountable; + mountable.type = MOUNTABLE_DEVICE; + mountable.desc.device = device; + return do_vfs_label (&mountable); } int @@ -156,7 +162,10 @@ do_set_e2uuid (const char *device, const char *uuid) char * do_get_e2uuid (const char *device) { - return do_vfs_uuid (device); + mountable_t mountable; + mountable.type = MOUNTABLE_DEVICE; + mountable.desc.device = device; + return do_vfs_uuid (&mountable); } /* If the filesystem is not mounted, run e2fsck -f on it unconditionally. */ diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c index 9c1c028..5016780 100644 --- a/daemon/guestfsd.c +++ b/daemon/guestfsd.c @@ -1165,6 +1165,48 @@ device_name_translation (char *device) return -1; } +/* Parse the mountable descriptor for a btrfs subvolume. Don't call this + * directly - use the RESOLVE_MOUNTABLE macro. + * + * A btrfs subvolume is given as: + * + * btrfsvol:/dev/sda3/root + * + * where /dev/sda3 is a block device containing a btrfs filesystem, and root is + * the name of a subvolume on it. This function is passed the string following + * 'btrfsvol:'. + */ +int +parse_btrfsvol (char *desc, mountable_t *mountable) +{ + mountable->type = MOUNTABLE_BTRFSVOL; + + char *device = desc; + + if (strncmp (device, "/dev/", strlen("/dev/")) == -1) + return -1; + + char *volume = NULL; + char *slash = device + strlen("/dev/") - 1; + while ((slash = strchr (slash + 1, '/'))) { + *slash = '\0'; + + if (!is_root_device(device) && device_name_translation (device) == 0) { + volume = slash + 1; + break; + } + + *slash = '/'; + } + + if (!volume) return -1; + + mountable->desc.btrfsvol.device = device; + mountable->desc.btrfsvol.volume = volume; + + return 0; +} + /* Check program exists and is executable on $PATH. Actually, we * just assume PATH contains the default entries (see main() above). */ diff --git a/daemon/labels.c b/daemon/labels.c index ead6b46..e2f045a 100644 --- a/daemon/labels.c +++ b/daemon/labels.c @@ -75,16 +75,31 @@ ntfslabel (const char *device, const char *label) } int -do_set_label (const char *device, const char *label) +do_set_label (const mountable_t *mountable, const char *label) { char *vfs_type; int r; /* How we set the label depends on the filesystem type. */ - vfs_type = do_vfs_type (device); + vfs_type = do_vfs_type (mountable); if (vfs_type == NULL) return -1; + const char *device; + switch (mountable->type) { + case MOUNTABLE_DEVICE: + device = mountable->desc.device; + break; + + case MOUNTABLE_BTRFSVOL: + device = mountable->desc.btrfsvol.device; + break; + + default: + reply_with_error ("Invalid mountable type %i", mountable->type); + return -1; + } + if (STREQ (vfs_type, "ext2") || STREQ (vfs_type, "ext3") || STREQ (vfs_type, "ext4")) r = e2label (device, label); diff --git a/daemon/mount.c b/daemon/mount.c index c84faaf..d0c321a 100644 --- a/daemon/mount.c +++ b/daemon/mount.c @@ -124,7 +124,7 @@ is_device_mounted (const char *device) int do_mount_vfs (const char *options, const char *vfstype, - const char *device, const char *mountpoint) + const mountable_t *mountable, const char *mountpoint) { int r; char *mp; @@ -151,13 +151,47 @@ do_mount_vfs (const char *options, const char *vfstype, return -1; } + char *options_plus = NULL; + const char *device = NULL; + switch (mountable->type) { + case MOUNTABLE_DEVICE: + device = mountable->desc.device; + break; + + case MOUNTABLE_BTRFSVOL: + device = mountable->desc.btrfsvol.device; + if (options && strlen(options) > 1) { + if (asprintf (&options_plus, "subvol=%s,%s", + mountable->desc.btrfsvol.volume, options) == -1) + { + reply_with_perror ("asprintf"); + return -1; + } + } else { + if (asprintf (&options_plus, "subvol=%s", + mountable->desc.btrfsvol.volume) == -1) + { + reply_with_perror ("asprintf"); + return -1; + } + } + break; + + default: + reply_with_error ("Invalid mountable type %i", mountable->type); + return -1; + } + if (vfstype) r = command (NULL, &error, - str_mount, "-o", options, "-t", vfstype, device, mp, NULL); + str_mount, "-o", options_plus ? options_plus : options, + "-t", vfstype, device, mp, NULL); else r = command (NULL, &error, - str_mount, "-o", options, device, mp, NULL); + str_mount, "-o", options_plus ? options_plus : options, + device, mp, NULL); free (mp); + free (options_plus); if (r == -1) { reply_with_error ("%s on %s (options: '%s'): %s", device, mountpoint, options, error); @@ -170,22 +204,22 @@ do_mount_vfs (const char *options, const char *vfstype, } int -do_mount (const char *device, const char *mountpoint) +do_mount (const mountable_t *mountable, const char *mountpoint) { - return do_mount_vfs ("", NULL, device, mountpoint); + return do_mount_vfs ("", NULL, mountable, mountpoint); } int -do_mount_ro (const char *device, const char *mountpoint) +do_mount_ro (const mountable_t *mountable, const char *mountpoint) { - return do_mount_vfs ("ro", NULL, device, mountpoint); + return do_mount_vfs ("ro", NULL, mountable, mountpoint); } int -do_mount_options (const char *options, const char *device, +do_mount_options (const char *options, const mountable_t *mountable, const char *mountpoint) { - return do_mount_vfs (options, NULL, device, mountpoint); + return do_mount_vfs (options, NULL, mountable, mountpoint); } /* Takes optional arguments, consult optargs_bitmask. */ diff --git a/generator/c.ml b/generator/c.ml index c20f502..e0fc852 100644 --- a/generator/c.ml +++ b/generator/c.ml @@ -109,12 +109,18 @@ let rec generate_prototype ?(extern = true) ?(static = false) List.iter ( function | Pathname n - | Device n | Mountable n | Dev_or_Path n + | Device n | Dev_or_Path n | String n | OptString n | Key n -> next (); pr "const char *%s" n + | Mountable n -> + next(); + if in_daemon then + pr "const mountable_t *%s" n + else + pr "const char *%s" n | StringList n | DeviceList n -> next (); pr "char *const *%s" n @@ -148,6 +154,7 @@ let rec generate_prototype ?(extern = true) ?(static = false) (* Generate C call arguments, eg "(handle, foo, bar)" *) and generate_c_call_args ?handle ?(implicit_size_ptr = "&size") + ?(in_daemon = false) (ret, args, optargs) = pr "("; let comma = ref false in @@ -164,6 +171,9 @@ and generate_c_call_args ?handle ?(implicit_size_ptr = "&size") | BufferIn n -> next (); pr "%s, %s_size" n n + | Mountable n -> + next (); + pr (if in_daemon then "&%s" else "%s") n | arg -> next (); pr "%s" (name_of_argt arg) diff --git a/generator/daemon.ml b/generator/daemon.ml index a7096a1..094fe6d 100644 --- a/generator/daemon.ml +++ b/generator/daemon.ml @@ -38,6 +38,7 @@ let generate_daemon_actions_h () = pr "\n"; pr "#include \"guestfs_protocol.h\"\n"; + pr "#include \"daemon.h\"\n"; pr "\n"; List.iter ( @@ -111,11 +112,12 @@ and generate_daemon_actions () = pr " struct guestfs_%s_args args;\n" name; List.iter ( function - | Device n | Mountable n | Dev_or_Path n + | Device n | Dev_or_Path n | Pathname n | String n | Key n | OptString n -> pr " char *%s;\n" n + | Mountable n -> pr " mountable_t %s;\n" n | StringList n | DeviceList n -> pr " char **%s;\n" n | Bool n -> pr " int %s;\n" n | Int n -> pr " int %s;\n" n @@ -205,10 +207,13 @@ and generate_daemon_actions () = pr_args n; pr " ABS_PATH (%s, %s, goto done);\n" n (if is_filein then "cancel_receive ()" else ""); - | Device n | Mountable n -> + | Device n -> pr_args n; pr " RESOLVE_DEVICE (%s, %s, goto done);\n" n (if is_filein then "cancel_receive ()" else ""); + | Mountable n -> + pr " RESOLVE_MOUNTABLE(args.%s, %s, %s, goto done);\n" + n n (if is_filein then "cancel_receive ()" else ""); | Dev_or_Path n -> pr_args n; pr " REQUIRE_ROOT_OR_RESOLVE_DEVICE (%s, %s, goto done);\n" @@ -257,7 +262,7 @@ and generate_daemon_actions () = (function FileIn _ | FileOut _ -> false | _ -> true) args in let style = ret, args' @ args_of_optargs optargs, [] in pr " r = do_%s " name; - generate_c_call_args style; + generate_c_call_args ~in_daemon:true style; pr ";\n" in (match ret with