Initial revision

1 files changed, 293 insertions, 0 deletions

diff --git a/src/ln.c b/src/ln.c
new file mode 100644
index 000000000..781a55d8b
--- /dev/null
+++ b/src/ln.c
@@ -0,0 +1,293 @@
+/* `ln' program to create links between files.
+   Copyright (C) 1986, 1989, 1990, 1991 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* Written by Mike Parker and David MacKenzie. */
+
+#ifdef _AIX
+ #pragma alloca
+#endif
+#include <stdio.h>
+#include <sys/types.h>
+#include <getopt.h>
+#include "system.h"
+#include "backupfile.h"
+
+int link ();			/* Some systems don't declare this anywhere. */
+
+#ifdef S_ISLNK
+int symlink ();
+#endif
+
+char *basename ();
+enum backup_type get_version ();
+int do_link ();
+int isdir ();
+int yesno ();
+void error ();
+void usage ();
+
+/* A pointer to the function used to make links.  This will point to either
+   `link' or `symlink'. */
+int (*linkfunc) ();
+
+/* If nonzero, make symbolic links; otherwise, make hard links.  */
+int symbolic_link;
+
+/* If nonzero, ask the user before removing existing files.  */
+int interactive;
+
+/* If nonzero, remove existing files unconditionally.  */
+int remove_existing_files;
+
+/* If nonzero, list each file as it is moved. */
+int verbose;
+
+/* If nonzero, allow the superuser to make hard links to directories. */
+int hard_dir_link;
+
+/* The name by which the program was run, for error messages.  */
+char *program_name;
+
+struct option long_options[] = 
+{
+  {"backup", 0, NULL, 'b'},
+  {"directory", 0, &hard_dir_link, 1},
+  {"force", 0, NULL, 'f'},
+  {"interactive", 0, NULL, 'i'},
+  {"suffix", 1, NULL, 'S'},
+  {"symbolic", 0, &symbolic_link, 1},
+  {"verbose", 0, &verbose, 1},
+  {"version-control", 1, NULL, 'V'},
+  {NULL, 0, NULL, 0}
+};
+
+void
+main (argc, argv)
+     int argc;
+     char **argv;
+{
+  int c;
+  int errors;
+  int make_backups = 0;
+  char *version;
+
+  version = getenv ("SIMPLE_BACKUP_SUFFIX");
+  if (version)
+    simple_backup_suffix = version;
+  version = getenv ("VERSION_CONTROL");
+  program_name = argv[0];
+  linkfunc = link;
+  symbolic_link = remove_existing_files = interactive = verbose
+    = hard_dir_link = 0;
+  errors = 0;
+
+  while ((c = getopt_long (argc, argv, "bdfisvFS:V:", long_options, (int *) 0))
+	 != EOF)
+    {
+      switch (c)
+	{
+	case 0:			/* Long-named option. */
+ 	  break;
+	case 'b':
+	  make_backups = 1;
+	  break;
+	case 'd':
+	case 'F':
+	  hard_dir_link = 1;
+	  break;
+	case 'f':
+	  remove_existing_files = 1;
+	  interactive = 0;
+	  break;
+	case 'i':
+	  remove_existing_files = 0;
+	  interactive = 1;
+	  break;
+	case 's':
+#ifdef S_ISLNK
+	  symbolic_link = 1;
+#else
+	  error (0, 0, "symbolic links not supported; making hard links");
+#endif
+	  break;
+	case 'v':
+	  verbose = 1;
+	  break;
+	case 'S':
+	  simple_backup_suffix = optarg;
+	  break;
+	case 'V':
+	  version = optarg;
+	  break;
+	default:
+	  usage ();
+	  break;
+	}
+    }
+  if (optind == argc)
+    usage ();
+
+  if (make_backups)
+    backup_type = get_version (version);
+
+#ifdef S_ISLNK
+  if (symbolic_link)
+    linkfunc = symlink;
+#endif
+
+  if (optind == argc - 1)
+    errors = do_link (argv[optind], ".");
+  else if (optind == argc - 2)
+    {
+      errors = do_link (argv[optind], argv[optind + 1]);
+    }
+  else
+    {
+      char *to;
+
+      to = argv[argc - 1];
+      if (!isdir (to))
+	error (1, 0, "when making multiple links, last argument must be a directory");
+      for (; optind < argc - 1; ++optind)
+	errors += do_link (argv[optind], to);
+    }
+
+  exit (errors != 0);
+}
+
+/* Make a link DEST to existing file SOURCE.
+   If DEST is a directory, put the link to SOURCE in that directory.
+   Return 1 if there is an error, otherwise 0.  */
+
+int
+do_link (source, dest)
+     char *source;
+     char *dest;
+{
+  struct stat dest_stats;
+  char *dest_backup = NULL;
+
+  /* isdir uses stat instead of lstat.
+     On SVR4, link does not follow symlinks, so this check disallows
+     making hard links to symlinks that point to directories.  Big deal.
+     On other systems, link follows symlinks, so this check is right.  */
+  if (!symbolic_link && !hard_dir_link && isdir (source))
+    {
+      error (0, 0, "%s: hard link not allowed for directory", source);
+      return 1;
+    }
+  if (isdir (dest))
+    {
+      /* Target is a directory; build the full filename. */
+      char *new_dest;
+      char *source_base;
+
+      source_base = basename (source);
+      new_dest = (char *)
+	alloca (strlen (source_base) + 1 + strlen (dest) + 1);
+      sprintf (new_dest, "%s/%s", dest, source_base);
+      dest = new_dest;
+    }
+
+  if (lstat (dest, &dest_stats) == 0)
+    {
+      if (S_ISDIR (dest_stats.st_mode))
+	{
+	  error (0, 0, "%s: cannot overwrite directory", dest);
+	  return 1;
+	}
+      if (interactive)
+	{
+	  fprintf (stderr, "%s: replace `%s'? ", program_name, dest);
+	  if (!yesno ())
+	    return 0;
+	}
+      else if (!remove_existing_files)
+	{
+	  error (0, 0, "%s: File exists", dest);
+	  return 1;
+	}
+
+      if (backup_type != none)
+	{
+	  char *tmp_backup = find_backup_file_name (dest);
+	  if (tmp_backup == NULL)
+	    error (1, 0, "virtual memory exhausted");
+	  dest_backup = alloca (strlen (tmp_backup) + 1);
+	  strcpy (dest_backup, tmp_backup);
+	  free (tmp_backup);
+	  if (rename (dest, dest_backup))
+	    {
+	      if (errno != ENOENT)
+		{
+		  error (0, errno, "cannot backup `%s'", dest);
+		  return 1;
+		}
+	      else
+		dest_backup = NULL;
+	    }
+	}
+      else if (unlink (dest) && errno != ENOENT)
+	{
+	  error (0, errno, "cannot remove old link to `%s'", dest);
+	  return 1;
+	}
+    }
+  else if (errno != ENOENT)
+    {
+      error (0, errno, "%s", dest);
+      return 1;
+    }
+       
+  if (verbose)
+    printf ("%s -> %s\n", source, dest);
+
+  if ((*linkfunc) (source, dest) == 0)
+    {
+      return 0;
+    }
+
+  error (0, errno, "cannot %slink `%s' to `%s'",
+#ifdef S_ISLNK
+	     linkfunc == symlink ? "symbolic " : "",
+#else
+	     "",
+#endif
+	     source, dest);
+
+  if (dest_backup)
+    {
+      if (rename (dest_backup, dest))
+	error (0, errno, "cannot un-backup `%s'", dest);
+    }
+  return 1;
+}
+
+void
+usage ()
+{
+  fprintf (stderr, "\
+Usage: %s [options] source [dest]\n\
+       %s [options] source... directory\n\
+Options:\n\
+       [-bdfisvF] [-S backup-suffix] [-V {numbered,existing,simple}]\n\
+       [--version-control={numbered,existing,simple}] [--backup] [--directory]\n\
+       [--force] [--interactive] [--symbolic] [--verbose]\n\
+       [--suffix=backup-suffix]\n",
+	   program_name, program_name);
+  exit (1);
+}