(do_link, usage): Improve quality of ln's diagnostics.

(do_link): Don't use alloca on a buffer of unbounded size.

diff --git a/src/ln.c b/src/ln.c
index 996ec99f74d8462a690ec49d9c26246584adf51d..49a385c3d3eb30c2385d0707286d3c6d7d991648 100644 (file)
--- a/src/ln.c
+++ b/src/ln.c
@@ -138,6 +138,8 @@ do_link (const char *source, const char *dest)
   struct stat dest_stats;
   char *dest_backup = NULL;
   bool lstat_ok = false;
+  bool source_is_dir = false;
+  bool ok;
 
   /* Use stat here instead of lstat.
      On SVR4, link does not follow symlinks, so this check disallows
@@ -159,11 +161,15 @@ do_link (const char *source, const char *dest)
                 quote (source));
        }
 
-      if (!hard_dir_link && S_ISDIR (source_stats.st_mode))
+      if (S_ISDIR (source_stats.st_mode))
        {
-         error (0, 0, _("%s: hard link not allowed for directory"),
-                quote (source));
-         return false;
+         source_is_dir = true;
+         if (! hard_dir_link)
+           {
+             error (0, 0, _("%s: hard link not allowed for directory"),
+                    quote (source));
+             return false;
+           }
        }
     }
 
@@ -220,37 +226,22 @@ do_link (const char *source, const char *dest)
 
       if (backup_type != no_backups)
        {
-         char *tmp_backup = find_backup_file_name (dest, backup_type);
-         size_t buf_len = strlen (tmp_backup) + 1;
-         dest_backup = alloca (buf_len);
-         memcpy (dest_backup, tmp_backup, buf_len);
-         free (tmp_backup);
-         if (rename (dest, dest_backup))
+         dest_backup = find_backup_file_name (dest, backup_type);
+         if (rename (dest, dest_backup) != 0)
            {
-             if (errno != ENOENT)
+             int rename_errno = errno;
+             free (dest_backup);
+             dest_backup = NULL;
+             if (rename_errno != ENOENT)
                {
-                 error (0, errno, _("cannot backup %s"), quote (dest));
+                 error (0, rename_errno, _("cannot backup %s"), quote (dest));
                  return false;
                }
-             else
-               dest_backup = NULL;
            }
        }
     }
 
-  if (verbose)
-    {
-      printf ((symbolic_link
-              ? _("create symbolic link %s to %s")
-              : _("create hard link %s to %s")),
-             quote_n (0, dest), quote_n (1, source));
-      if (dest_backup)
-       printf (_(" (backup: %s)"), quote (dest_backup));
-      putchar ('\n');
-    }
-
-  if ((*linkfunc) (source, dest) == 0)
-    return true;
+  ok = (linkfunc (source, dest) == 0);
 
   /* If the attempt to create a link failed and we are removing or
      backing up destinations, unlink the destination and try again.
@@ -270,30 +261,52 @@ do_link (const char *source, const char *dest)
      If we didn't remove DEST in that case, the subsequent LINKFUNC
      call would fail.  */
 
-  if (errno == EEXIST && (remove_existing_files || dest_backup))
+  if (!ok && errno == EEXIST && (remove_existing_files || dest_backup))
     {
       if (unlink (dest) != 0)
        {
          error (0, errno, _("cannot remove %s"), quote (dest));
+         free (dest_backup);
          return false;
        }
 
-      if (linkfunc (source, dest) == 0)
-       return true;
+      ok = (linkfunc (source, dest) == 0);
     }
 
-  error (0, errno,
-        (symbolic_link
-         ? _("creating symbolic link %s to %s")
-         : _("creating hard link %s to %s")),
-        quote_n (0, dest), quote_n (1, source));
-
-  if (dest_backup)
+  if (ok)
     {
-      if (rename (dest_backup, dest))
-       error (0, errno, _("cannot un-backup %s"), quote (dest));
+      if (verbose)
+       {
+         if (dest_backup)
+           printf ("%s ~ ", quote (dest_backup));
+         printf ("%s %c> %s\n", quote_n (0, dest), (symbolic_link ? '-' : '='),
+                 quote_n (1, source));
+       }
+    }
+  else
+    {
+      error (0, errno,
+            (symbolic_link
+             ? (errno != ENAMETOOLONG && *source
+                ? _("creating symbolic link %s")
+                : _("creating symbolic link %s -> %s"))
+             : (errno == EMLINK && !source_is_dir
+                ? _("creating hard link to %.0s%s")
+                : (errno == EDQUOT || errno == EEXIST || errno == ENOSPC
+                   || errno == EROFS)
+                ? _("creating hard link %s")
+                : _("creating hard link %s => %s"))),
+            quote_n (0, dest), quote_n (1, source));
+
+      if (dest_backup)
+       {
+         if (rename (dest_backup, dest) != 0)
+           error (0, errno, _("cannot un-backup %s"), quote (dest));
+       }
     }
-  return false;
+
+  free (dest_backup);
+  return ok;
 }
 
 void
@@ -341,7 +354,7 @@ Mandatory arguments to long options are mandatory for short options too.\n\
   -t, --target-directory=DIRECTORY  specify the DIRECTORY in which to create\n\
                                 the links\n\
   -T, --no-target-directory   treat LINK_NAME as a normal file\n\
-  -v, --verbose               print name of each file before linking\n\
+  -v, --verbose               print name of each linked file\n\
 "), stdout);
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);