Message queue name calculation

- Use absolute path for directory name instead of base name.  This avoids issues
  with multiple directories with the same name, with trailing slashes on the
  directory name, and with symbolic links.
- Substitute slashes in the directory path with character 0xff to form a valid
  message queue name and avoid possible conflicts with real pathnames.
- Truncate the message queue name if it comes out to more than NAME_MAX bytes.

diff --git a/src/mount.c b/src/mount.c
index c130f618c2777deb6f89f4d6d5db26676b7bfe00..ac56415ecd5906607e69f3e68987df7443a2bfcc 100644 (file)
--- a/src/mount.c
+++ b/src/mount.c
@@ -35,6 +35,7 @@
 #include "xml.h"
 #include "io.h"
 #include "timestamp.h"
+#include <limits.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/wait.h>
@@ -541,72 +542,65 @@ static int delete_staging_dir(struct wimfs_context *ctx)
 }
 
 
-/* Simple function that returns the concatenation of 4 strings. */
-static char *strcat_dup(const char *s1, const char *s2, const char *s3,
-                       const char *s4)
+/* Simple function that returns the concatenation of 2 strings. */
+static char *strcat_dup(const char *s1, const char *s2, size_t max_len)
 {
-       size_t len = strlen(s1) + strlen(s2) + strlen(s3) + strlen(s4) + 1;
-       char *p = MALLOC(len);
+       size_t len = strlen(s1) + strlen(s2);
+       if (len > max_len)
+               len = max_len;
+       char *p = MALLOC(len + 1);
        if (!p)
                return NULL;
-       p = strcpy(p, s1);
-       p = strcat(p, s2);
-       p = strcat(p, s3);
-       return strcat(p, s4);
+       snprintf(p, len + 1, "%s%s", s1, s2);
+       return p;
 }
 
-/* Removes trailing forward slashes in a string. */
-static void remove_trailing_slashes(char *s)
+static int set_message_queue_names(struct wimfs_context *ctx,
+                                  const char *mount_dir)
 {
-       long len = strlen(s);
-       for (long i = len - 1; i >= 1; i--) {
-               if (s[i] == '/')
-                       s[i] = '\0';
-               else
-                       break;
-       }
-}
+       static const char *u2d_prefix = "/wimlib-unmount-to-daemon-mq";
+       static const char *d2u_prefix = "/wimlib-daemon-to-unmount-mq";
+       char *dir_path;
+       char *p;
+       int ret;
 
-/* Changes forward slashes to underscores in a string. */
-static void s_slashes_underscores_g(char *s)
-{
-       while (*s) {
-               if (*s == '/')
-                       *s = '_';
-               s++;
+       dir_path = realpath(mount_dir, NULL);
+       if (!dir_path) {
+               ERROR_WITH_ERRNO("Failed to resolve path \"%s\"", mount_dir);
+               return WIMLIB_ERR_NOTDIR;
        }
-}
 
-static int set_message_queue_names(struct wimfs_context *ctx,
-                                  const char *mount_dir)
-{
-       static const char *slash = "/";
-       static const char *prefix = "wimlib-";
-       static const char *u2d_suffix = "unmount-to-daemon-mq";
-       static const char *d2u_suffix = "daemon-to-unmount-mq";
+       DEBUG("Using absolute dir_path = `%s'", dir_path);
 
-       const char *mount_dir_basename = path_basename(mount_dir);
 
-       ctx->unmount_to_daemon_mq_name = strcat_dup(slash, mount_dir_basename,
-                                                   prefix, u2d_suffix);
+       p = dir_path;
+       while (*p) {
+               if (*p == '/')
+                       *p = 0xff;
+               p++;
+       }
+
+       ctx->unmount_to_daemon_mq_name = strcat_dup(u2d_prefix, dir_path,
+                                                   NAME_MAX);
        if (!ctx->unmount_to_daemon_mq_name) {
-               ERROR("Out of memory");
-               return WIMLIB_ERR_NOMEM;
+               ret = WIMLIB_ERR_NOMEM;
+               goto out_free_dir_path;
        }
-       ctx->daemon_to_unmount_mq_name = strcat_dup(slash, mount_dir_basename,
-                                                   prefix, d2u_suffix);
+       ctx->daemon_to_unmount_mq_name = strcat_dup(d2u_prefix, dir_path,
+                                                   NAME_MAX);
        if (!ctx->daemon_to_unmount_mq_name) {
-               ERROR("Out of memory");
-               FREE(ctx->unmount_to_daemon_mq_name);
-               ctx->unmount_to_daemon_mq_name = NULL;
-               return WIMLIB_ERR_NOMEM;
+               ret = WIMLIB_ERR_NOMEM;
+               goto out_free_unmount_to_daemon_mq_name;
        }
 
-       remove_trailing_slashes(ctx->unmount_to_daemon_mq_name);
-       remove_trailing_slashes(ctx->daemon_to_unmount_mq_name);
-       s_slashes_underscores_g(ctx->unmount_to_daemon_mq_name + 1);
-       s_slashes_underscores_g(ctx->daemon_to_unmount_mq_name + 1);
-       return 0;
+       ret = 0;
+       goto out_free_dir_path;
+out_free_unmount_to_daemon_mq_name:
+       FREE(ctx->unmount_to_daemon_mq_name);
+       ctx->unmount_to_daemon_mq_name = NULL;
+out_free_dir_path:
+       FREE(dir_path);
+       return ret;
 }
 
 static void free_message_queue_names(struct wimfs_context *ctx)
@@ -640,6 +634,7 @@ static int open_message_queues(struct wimfs_context *ctx, bool daemon)
        else
                flags = O_WRONLY | O_CREAT;
 
+       DEBUG("Opening message queue \"%s\"", ctx->unmount_to_daemon_mq_name);
        ctx->unmount_to_daemon_mq = mq_open(ctx->unmount_to_daemon_mq_name,
                                            flags, 0700, NULL);
 
@@ -654,6 +649,7 @@ static int open_message_queues(struct wimfs_context *ctx, bool daemon)
        else
                flags = O_RDONLY | O_CREAT;
 
+       DEBUG("Opening message queue \"%s\"", ctx->daemon_to_unmount_mq_name);
        ctx->daemon_to_unmount_mq = mq_open(ctx->daemon_to_unmount_mq_name,
                                            flags, 0700, NULL);
 
@@ -1919,7 +1915,11 @@ WIMLIBAPI int wimlib_mount(WIMStruct *wim, int image, const char *dir,
        ctx.wim = wim;
        ctx.mount_flags = flags;
 
+       DEBUG("Calling fuse_main()");
+
        ret = fuse_main(argc, argv, &wimfs_operations, &ctx);
+
+       DEBUG("Returned from fuse_main() (ret = %d)", ret);
        if (ret)
                ret = WIMLIB_ERR_FUSE;
 out_free_dir_copy: