daemon: Implement a growable strings buffer type.

Previously a lot of daemon code used three variables (a string list,
'int size' and 'int alloc') to track growable strings buffers.  This
commit implements a simple struct containing the same variables, but
using size_t instead of int:

  struct stringsbuf {
    char **argv;
    size_t size;
    size_t alloc;
  };

Use it like this:

  DECLARE_STRINGSBUF (ret);
//...
  if (add_string (&ret, str) == -1)
    return NULL;
//...
  if (end_stringsbuf (&ret) == -1)
    return NULL;
  return ret.argv;

1 files changed, 24 insertions, 24 deletions

diff --git a/daemon/mount.c b/daemon/mount.c
index 0c393f7a..5e74ce8f 100644
--- a/daemon/mount.c
+++ b/daemon/mount.c
@@ -224,8 +224,7 @@ mounts_or_mountpoints (int mp)
 {
   FILE *fp;
   struct mntent *m;
-  char **ret = NULL;
-  int size = 0, alloc = 0;
+  DECLARE_STRINGSBUF (ret);
   size_t i;
   int r;
 
@@ -241,42 +240,43 @@ mounts_or_mountpoints (int mp)
   while ((m = getmntent (fp)) != NULL) {
     /* Allow a mount directory like "/sysroot". */
     if (sysroot_len > 0 && STREQ (m->mnt_dir, sysroot)) {
-      if (add_string (&ret, &size, &alloc, m->mnt_fsname) == -1) {
+      if (add_string (&ret, m->mnt_fsname) == -1) {
       error:
         endmntent (fp);
         return NULL;
       }
       if (mp &&
-          add_string (&ret, &size, &alloc, "/") == -1)
+          add_string (&ret, "/") == -1)
         goto error;
     }
     /* Or allow a mount directory like "/sysroot/...". */
     if (STRPREFIX (m->mnt_dir, sysroot) && m->mnt_dir[sysroot_len] == '/') {
-      if (add_string (&ret, &size, &alloc, m->mnt_fsname) == -1)
+      if (add_string (&ret, m->mnt_fsname) == -1)
         goto error;
       if (mp &&
-          add_string (&ret, &size, &alloc, &m->mnt_dir[sysroot_len]) == -1)
+          add_string (&ret, &m->mnt_dir[sysroot_len]) == -1)
         goto error;
     }
   }
 
   endmntent (fp);
 
-  if (add_string (&ret, &size, &alloc, NULL) == -1)
+  if (end_stringsbuf (&ret) == -1)
     return NULL;
 
   /* Convert /dev/mapper LV paths into canonical paths (RHBZ#646432). */
-  for (i = 0; ret[i] != NULL; i += mp ? 2 : 1) {
-    if (STRPREFIX (ret[i], "/dev/mapper/") || STRPREFIX (ret[i], "/dev/dm-")) {
+  for (i = 0; ret.argv[i] != NULL; i += mp ? 2 : 1) {
+    if (STRPREFIX (ret.argv[i], "/dev/mapper/") ||
+        STRPREFIX (ret.argv[i], "/dev/dm-")) {
       char *canonical;
-      r = lv_canonical (ret[i], &canonical);
+      r = lv_canonical (ret.argv[i], &canonical);
       if (r == -1) {
-        free_strings (ret);
+        free_stringslen (ret.argv, ret.size);
         return NULL;
       }
       if (r == 1) {
-        free (ret[i]);
-        ret[i] = canonical;
+        free (ret.argv[i]);
+        ret.argv[i] = canonical;
       }
       /* Ignore the case where r == 0.  This might happen where
        * eg. a LUKS /dev/mapper device is mounted, but that won't
@@ -285,7 +285,7 @@ mounts_or_mountpoints (int mp)
     }
   }
 
-  return ret;
+  return ret.argv;
 }
 
 char **
@@ -325,8 +325,7 @@ do_umount_all (void)
 {
   FILE *fp;
   struct mntent *m;
-  char **mounts = NULL;
-  int size = 0, alloc = 0;
+  DECLARE_STRINGSBUF (mounts);
   char *err;
   int i, r;
 
@@ -342,14 +341,14 @@ do_umount_all (void)
   while ((m = getmntent (fp)) != NULL) {
     /* Allow a mount directory like "/sysroot". */
     if (sysroot_len > 0 && STREQ (m->mnt_dir, sysroot)) {
-      if (add_string (&mounts, &size, &alloc, m->mnt_dir) == -1) {
+      if (add_string (&mounts, m->mnt_dir) == -1) {
         endmntent (fp);
         return -1;
       }
     }
     /* Or allow a mount directory like "/sysroot/...". */
     if (STRPREFIX (m->mnt_dir, sysroot) && m->mnt_dir[sysroot_len] == '/') {
-      if (add_string (&mounts, &size, &alloc, m->mnt_dir) == -1) {
+      if (add_string (&mounts, m->mnt_dir) == -1) {
         endmntent (fp);
         return -1;
       }
@@ -358,21 +357,22 @@ do_umount_all (void)
 
   endmntent (fp);
 
-  qsort (mounts, size, sizeof (char *), compare_longest_first);
+  if (mounts.size > 0)
+    qsort (mounts.argv, mounts.size, sizeof (char *), compare_longest_first);
 
   /* Unmount them. */
-  for (i = 0; i < size; ++i) {
-    r = command (NULL, &err, "umount", mounts[i], NULL);
+  for (i = 0; i < mounts.size; ++i) {
+    r = command (NULL, &err, "umount", mounts.argv[i], NULL);
     if (r == -1) {
-      reply_with_error ("umount: %s: %s", mounts[i], err);
+      reply_with_error ("umount: %s: %s", mounts.argv[i], err);
       free (err);
-      free_stringslen (mounts, size);
+      free_stringslen (mounts.argv, mounts.size);
       return -1;
     }
     free (err);
   }
 
-  free_stringslen (mounts, size);
+  free_stringslen (mounts.argv, mounts.size);
 
   return 0;
 }