btrfs-progs: Fix the receive code pathing

The receive code was not distinguishing properly between the mount root
and the directory to create the received subvolume in.
Also make sure the find_mount_root reports an error if it cannot find
a match at all.

Reported-by: Robert Buhren <robert@robertbuhren.de>
Reported-by: Rory Campbell-Lange <rory@campbell-lange.net>
Reported-by: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Signed-off-by: Alex Lyakas <alex.btrfs@zadarastorage.com>
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>

diff --git a/cmds-receive.c b/cmds-receive.c
index 937db1c..c2fa2e1 100644 (file)
--- a/cmds-receive.c
+++ b/cmds-receive.c
@@ -56,11 +56,13 @@ static int g_verbose = 0;
 struct btrfs_receive
 {
        int mnt_fd;
+       int dest_dir_fd;
 
        int write_fd;
        char *write_path;
 
        char *root_path;
+       char *dest_dir_path; /* relative to root_path */
        char *full_subvol_path;
 
        struct subvol_info *cur_subvol;
@@ -154,9 +156,12 @@ static int process_subvol(const char *path, const u8 *uuid, u64 ctransid,
 
        r->cur_subvol = calloc(1, sizeof(*r->cur_subvol));
 
-       r->cur_subvol->path = strdup(path);
+       if (strlen(r->dest_dir_path) == 0)
+               r->cur_subvol->path = strdup(path);
+       else
+               r->cur_subvol->path = path_cat(r->dest_dir_path, path);
        free(r->full_subvol_path);
-       r->full_subvol_path = path_cat(r->root_path, path);
+       r->full_subvol_path = path_cat3(r->root_path, r->dest_dir_path, path);
 
        fprintf(stderr, "At subvol %s\n", path);
 
@@ -172,7 +177,7 @@ static int process_subvol(const char *path, const u8 *uuid, u64 ctransid,
 
        memset(&args_v1, 0, sizeof(args_v1));
        strncpy_null(args_v1.name, path);
-       ret = ioctl(r->mnt_fd, BTRFS_IOC_SUBVOL_CREATE, &args_v1);
+       ret = ioctl(r->dest_dir_fd, BTRFS_IOC_SUBVOL_CREATE, &args_v1);
        if (ret < 0) {
                ret = -errno;
                fprintf(stderr, "ERROR: creating subvolume %s failed. "
@@ -200,9 +205,12 @@ static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid,
 
        r->cur_subvol = calloc(1, sizeof(*r->cur_subvol));
 
-       r->cur_subvol->path = strdup(path);
+       if (strlen(r->dest_dir_path) == 0)
+               r->cur_subvol->path = strdup(path);
+       else
+               r->cur_subvol->path = path_cat(r->dest_dir_path, path);
        free(r->full_subvol_path);
-       r->full_subvol_path = path_cat(r->root_path, path);
+       r->full_subvol_path = path_cat3(r->root_path, r->dest_dir_path, path);
 
        fprintf(stderr, "At snapshot %s\n", path);
 
@@ -249,7 +257,7 @@ static int process_snapshot(const char *path, const u8 *uuid, u64 ctransid,
                goto out;
        }
 
-       ret = ioctl(r->mnt_fd, BTRFS_IOC_SNAP_CREATE_V2, &args_v2);
+       ret = ioctl(r->dest_dir_fd, BTRFS_IOC_SNAP_CREATE_V2, &args_v2);
        close(args_v2.fd);
        if (ret < 0) {
                ret = -errno;
@@ -796,17 +804,49 @@ struct btrfs_send_ops send_ops = {
 int do_receive(struct btrfs_receive *r, const char *tomnt, int r_fd)
 {
        int ret;
+       char *dest_dir_full_path;
        int end = 0;
 
-       r->root_path = strdup(tomnt);
-       r->mnt_fd = open(tomnt, O_RDONLY | O_NOATIME);
+       dest_dir_full_path = realpath(tomnt, NULL);
+       if (!dest_dir_full_path) {
+               ret = -errno;
+               fprintf(stderr, "ERROR: realpath(%s) failed. %s\n", tomnt,
+                       strerror(-ret));
+               goto out;
+       }
+       r->dest_dir_fd = open(dest_dir_full_path, O_RDONLY | O_NOATIME);
+       if (r->dest_dir_fd < 0) {
+               ret = -errno;
+               fprintf(stderr,
+                       "ERROR: failed to open destination directory %s. %s\n",
+                       dest_dir_full_path, strerror(-ret));
+               goto out;
+       }
+
+       ret = find_mount_root(dest_dir_full_path, &r->root_path);
+       if (ret < 0) {
+               ret = -EINVAL;
+               fprintf(stderr, "ERROR: failed to determine mount point "
+                       "for %s\n", dest_dir_full_path);
+               goto out;
+       }
+       r->mnt_fd = open(r->root_path, O_RDONLY | O_NOATIME);
        if (r->mnt_fd < 0) {
                ret = -errno;
-               fprintf(stderr, "ERROR: failed to open %s. %s\n", tomnt,
-                               strerror(-ret));
+               fprintf(stderr, "ERROR: failed to open %s. %s\n", r->root_path,
+                       strerror(-ret));
                goto out;
        }
 
+       /*
+        * find_mount_root returns a root_path that is a subpath of
+        * dest_dir_full_path. Now get the other part of root_path,
+        * which is the destination dir relative to root_path.
+        */
+       r->dest_dir_path = dest_dir_full_path + strlen(r->root_path);
+       while (r->dest_dir_path[0] == '/')
+               r->dest_dir_path++;
+
        ret = subvol_uuid_search_init(r->mnt_fd, &r->sus);
        if (ret < 0)
                goto out;
@@ -839,6 +879,8 @@ out:
        r->write_path = NULL;
        free(r->full_subvol_path);
        r->full_subvol_path = NULL;
+       r->dest_dir_path = NULL;
+       free(dest_dir_full_path);
        if (r->cur_subvol) {
                free(r->cur_subvol->path);
                free(r->cur_subvol);
@@ -849,6 +891,10 @@ out:
                close(r->mnt_fd);
                r->mnt_fd = -1;
        }
+       if (r->dest_dir_fd != -1) {
+               close(r->dest_dir_fd);
+               r->dest_dir_fd = -1;
+       }
        return ret;
 }
 
@@ -865,6 +911,7 @@ static int do_cmd_receive(int argc, char **argv)
        memset(&r, 0, sizeof(r));
        r.mnt_fd = -1;
        r.write_fd = -1;
+       r.dest_dir_fd = -1;
 
        while ((c = getopt(argc, argv, "evf:")) != -1) {
                switch (c) {

diff --git a/cmds-send.c b/cmds-send.c
index fcde74c..9bb4206 100644 (file)
--- a/cmds-send.c
+++ b/cmds-send.c
@@ -84,6 +84,13 @@ int find_mount_root(const char *path, char **mount_root)
        }
        fclose(mnttab);
 
+       if (!longest_match) {
+               fprintf(stderr,
+                       "ERROR: Failed to find mount root for path %s.\n",
+                       path);
+               return -ENOENT;
+       }
+
        *mount_root = realpath(longest_match, NULL);
        free(longest_match);