Re: EMC Celerra: opendir bug? [Re: in ls.c, should check errno after readdir

[Jim Meyering]

Ok.  The Solaris5.8 man page for readdir suggests the same thing,
so I've changed remove.c and ls.c to check for readdir failures:

        * src/remove.c (remove_cwd_entries): Use closedir (not CLOSEDIR)
        when ignoring any return value.

        * src/remove.c (remove_cwd_entries): Detect and diagnose readdir
        failures.  On some systems (at least EMC Celerra and Solaris5.8),
        this appears to be necessary.
        (is_empty_dir): Likewise.  Also, always close directory handle.
        * src/ls.c (print_dir): Likewise.
        (print_dir): Rename local variable: reading -> dirp.
        Reported by Mike Coleman.

There remain three files in lib/ that need similar changes.

Thanks again for the report and follow-up.

Index: ls.c
===================================================================
RCS file: /fetish/cu/src/ls.c,v
retrieving revision 1.304
retrieving revision 1.306
diff -u -p -u -r1.304 -r1.306
--- ls.c        8 Jul 2002 09:12:48 -0000       1.304
+++ ls.c        29 Aug 2002 10:16:00 -0000      1.306
@@ -2030,14 +2030,14 @@ queue_directory (const char *name, const
 static void
 print_dir (const char *name, const char *realname)
 {
-  register DIR *reading;
+  register DIR *dirp;
   register struct dirent *next;
   register uintmax_t total_blocks = 0;
   static int first = 1;
 
   errno = 0;
-  reading = opendir (name);
-  if (!reading)
+  dirp = opendir (name);
+  if (!dirp)
     {
       error (0, errno, "%s", quotearg_colon (name));
       exit_status = 1;
@@ -2047,7 +2047,7 @@ print_dir (const char *name, const char 
   if (LOOP_DETECT)
     {
       struct stat dir_stat;
-      int fd = dirfd (reading);
+      int fd = dirfd (dirp);
 
       /* If dirfd failed, endure the overhead of using stat.  */
       if ((0 <= fd
@@ -2077,23 +2077,43 @@ print_dir (const char *name, const char 
 
   clear_files ();
 
-  while ((next = readdir (reading)) != NULL)
-    if (file_interesting (next))
-      {
-       enum filetype type = unknown;
+  while (1)
+    {
+      /* Set errno to zero so we can distinguish between a readdir failure
+        and when readdir simply finds that there are no more entries.  */
+      errno = 0;
+      if ((next = readdir (dirp)) == NULL)
+       {
+         if (errno)
+           {
+             /* Save/restore errno across closedir call.  */
+             int e = errno;
+             closedir (dirp);
+             errno = e;
+
+             /* Arrange to give a diagnostic after exiting this loop.  */
+             dirp = NULL;
+           }
+         break;
+       }
+
+      if (file_interesting (next))
+       {
+         enum filetype type = unknown;
 
 #if HAVE_STRUCT_DIRENT_D_TYPE
-       if (next->d_type == DT_DIR || next->d_type == DT_CHR
-           || next->d_type == DT_BLK || next->d_type == DT_SOCK
-           || next->d_type == DT_FIFO)
-         type = next->d_type;
+         if (next->d_type == DT_DIR || next->d_type == DT_CHR
+             || next->d_type == DT_BLK || next->d_type == DT_SOCK
+             || next->d_type == DT_FIFO)
+           type = next->d_type;
 #endif
-       total_blocks += gobble_file (next->d_name, type, 0, name);
-      }
+         total_blocks += gobble_file (next->d_name, type, 0, name);
+       }
+    }
 
-  if (CLOSEDIR (reading))
+  if (dirp == NULL || CLOSEDIR (dirp))
     {
-      error (0, errno, "%s", quotearg_colon (name));
+      error (0, errno, _("reading directory %s"), quotearg_colon (name));
       exit_status = 1;
       /* Don't return; print whatever we got. */
     }

Index: remove.c
===================================================================
RCS file: /fetish/cu/src/remove.c,v
retrieving revision 1.59
retrieving revision 1.63
diff -u -p -u -r1.59 -r1.63
--- remove.c    22 Jul 2002 06:59:26 -0000      1.59
+++ remove.c    29 Aug 2002 10:42:12 -0000      1.63
@@ -522,19 +522,30 @@ is_empty_dir (char const *dir)
 {
   DIR *dirp = opendir (dir);
   if (dirp == NULL)
-    return false;
+    {
+      closedir (dirp);
+      return false;
+    }
 
   while (1)
     {
-      struct dirent *dp = readdir (dirp);
+      struct dirent *dp;
       const char *f;
 
+      errno = 0;
+      dp = readdir (dirp);
       if (dp == NULL)
-       return true;
+       {
+         closedir (dirp);
+         return errno == 0 ? true : false;
+       }
 
       f = dp->d_name;
       if ( ! DOT_OR_DOTDOT (f))
-       return false;
+       {
+         closedir (dirp);
+         return false;
+       }
     }
 }
 
@@ -810,12 +821,27 @@ remove_cwd_entries (char **subdir, struc
 
   while (1)
     {
-      struct dirent *dp = readdir (dirp);
+      struct dirent *dp;
       enum RM_status tmp_status;
       const char *f;
 
-      if (dp == NULL)
-       break;
+      /* Set errno to zero so we can distinguish between a readdir failure
+        and when readdir simply finds that there are no more entries.  */
+      errno = 0;
+      if ((dp = readdir (dirp)) == NULL)
+       {
+         if (errno)
+           {
+             /* Save/restore errno across closedir call.  */
+             int e = errno;
+             closedir (dirp);
+             errno = e;
+
+             /* Arrange to give a diagnostic after exiting this loop.  */
+             dirp = NULL;
+           }
+         break;
+       }
 
       f = dp->d_name;
       if (DOT_OR_DOTDOT (f))
@@ -871,7 +897,13 @@ remove_cwd_entries (char **subdir, struc
        break;
     }
 
-  closedir (dirp);
+  if (dirp == NULL || CLOSEDIR (dirp) != 0)
+    {
+      /* Note that this diagnostic serves for both readdir
+        and closedir failures.  */
+      error (0, errno, _("reading directory %s"), quote (full_filename (".")));
+      status = RM_ERROR;
+    }
 
   return status;
 }