Re: coreutils-6.3: c89 patch insufficent

[Paul Eggert]

Matthew Woehlke <address@hidden> writes:

> For some reason, I also appear to need the following on NSK/OSS, but
> not on any of the other platforms that lacked c99 compilers.

Thanks for reporting that.  In looking at the code, I found
some other problems (notably, errno was sometimes mishandled)
and installed the following more-general patch into gnulib.

2006-10-11  Paul Eggert  <address@hidden>

        * lib/rename-dest-slash.c: Include stdbool.h but not string.h.
        (has_trailing_slash): Omit size arg; all callers changed.
        Omit 'inline', since it doesn't help performance and we'd
        need to configure it.
        Don't count //, ///, etc. as having a trailing slash.
        As a side effect, this removes a C99ism reported by Matthew Woehlke.
        (rpl_rename_dest_slash): On failure, use rename's errno rather
        than (in some cases) an incorrect or junk errno.
        Simplify code by removing need to compute length; this does
        cause it to make two passes instead of one over the file name,
        but it's worth it.

--- lib/rename-dest-slash.c     15 Sep 2006 18:48:09 -0000      1.2
+++ lib/rename-dest-slash.c     12 Oct 2006 05:36:05 -0000
@@ -31,22 +31,27 @@
 #include <sys/stat.h>
 #include <errno.h>

+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>

 #include "dirname.h"
 #include "xalloc.h"

-static inline bool
-has_trailing_slash (char const *file, size_t len)
+static bool
+has_trailing_slash (char const *file)
 {
-  /* Don't count "/" as having a trailing slash.  */
-  if (len <= FILE_SYSTEM_PREFIX_LEN (file) + 1)
-    return false;
+  /* Don't count "/", "//", etc., as having a trailing slash.  */
+  bool has_non_slash = false;
+  bool ends_in_slash = false;
+
+  for (file += FILE_SYSTEM_PREFIX_LEN (file); *file; file++)
+    {
+      ends_in_slash = ISSLASH (*file);
+      has_non_slash |= ~ ends_in_slash;
+    }

-  char last = file[len - 1];
-  return ISSLASH (last);
+  return has_non_slash & ends_in_slash;
 }

 /* This is a rename wrapper for systems where the rename syscall
@@ -59,31 +64,25 @@
 int
 rpl_rename_dest_slash (char const *src, char const *dst)
 {
-  size_t d_len;
   int ret_val = rename (src, dst);
-  if (ret_val == 0 || errno != ENOENT)
-    return ret_val;

-  /* Don't call rename again if there are no trailing slashes.  */
-  d_len = strlen (dst);
-  if ( ! has_trailing_slash (dst, d_len))
-    return ret_val;
-
-  {
-    /* Fail now, unless SRC is a directory.  */
-    struct stat sb;
-    if (lstat (src, &sb) != 0 || ! S_ISDIR (sb.st_mode))
-      return ret_val;
-  }
-
-  {
-    char *dst_temp;
-    dst_temp = xmemdup (dst, d_len + 1);
-    strip_trailing_slashes (dst_temp);
-
-    ret_val = rename (src, dst_temp);
-    free (dst_temp);
-  }
+  if (ret_val != 0 && errno == ENOENT && has_trailing_slash (dst))
+    {
+      int rename_errno = ENOENT;
+
+      /* Fail now, unless SRC is a directory.  */
+      struct stat sb;
+      if (lstat (src, &sb) == 0 && S_ISDIR (sb.st_mode))
+       {
+         char *dst_temp = xstrdup (dst);
+         strip_trailing_slashes (dst_temp);
+         ret_val = rename (src, dst_temp);
+         rename_errno = errno;
+         free (dst_temp);
+       }
+
+      errno = rename_errno;
+    }

   return ret_val;
 }