/* `ln' program to create links between files. Copyright (C) 1986, 1989, 1990, 1991, 1995 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 #include #include #include #include "system.h" #include "backupfile.h" #include "version.h" #include "error.h" int link (const char *, const char *); /* Some systems don't declare this anywhere. */ #ifdef S_ISLNK int symlink (const char *, const char *); #endif /* Construct a string NEW_DEST by concatenating DEST, a slash, and basename(SOURCE) in alloca'd memory. Don't modify DEST or SOURCE. */ #define PATH_BASENAME_CONCAT(new_dest, dest, source) \ do \ { \ char *source_base; \ char *tmp_source; \ \ tmp_source = (char *) alloca (strlen ((source)) + 1); \ strcpy (tmp_source, (source)); \ strip_trailing_slashes (tmp_source); \ source_base = basename (tmp_source); \ \ (new_dest) = (char *) alloca (strlen ((dest)) + 1 \ + strlen (source_base) + 1); \ stpcpy (stpcpy (stpcpy ((new_dest), (dest)), "/"), source_base);\ } \ while (0) char *basename (char *); enum backup_type get_version (); int isdir (); int yesno (); void strip_trailing_slashes (); char *stpcpy (); static void usage (int status); static int do_link (char *source, char *dest); /* The name by which the program was run, for error messages. */ char *program_name; /* A pointer to the function used to make links. This will point to either `link' or `symlink'. */ static int (*linkfunc) (); /* If nonzero, make symbolic links; otherwise, make hard links. */ static int symbolic_link; /* If nonzero, ask the user before removing existing files. */ static int interactive; /* If nonzero, remove existing files unconditionally. */ static int remove_existing_files; /* If nonzero, list each file as it is moved. */ static int verbose; /* If nonzero, allow the superuser to make hard links to directories. */ static int hard_dir_link; /* If nonzero, and the specified destination is a symbolic link to a directory, treat it just as if it were a directory. Otherwise, the command `ln --force --no-dereference file symlink-to-dir' deletes symlink-to-dir before creating the new link. */ static int dereference_dest_dir_symlinks = 1; /* If non-zero, display usage information and exit. */ static int show_help; /* If non-zero, print the version on standard output and exit. */ static int show_version; static struct option const long_options[] = { {"backup", no_argument, NULL, 'b'}, {"directory", no_argument, &hard_dir_link, 1}, {"no-dereference", no_argument, NULL, 'n'}, {"force", no_argument, NULL, 'f'}, {"interactive", no_argument, NULL, 'i'}, {"suffix", required_argument, NULL, 'S'}, {"symbolic", no_argument, &symbolic_link, 1}, {"verbose", no_argument, &verbose, 1}, {"version-control", required_argument, NULL, 'V'}, {"help", no_argument, &show_help, 1}, {"version", no_argument, &show_version, 1}, {NULL, 0, NULL, 0} }; void main (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, "bdfinsvFS: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 'n': dereference_dest_dir_symlinks = 0; break; case 's': #ifdef S_ISLNK symbolic_link = 1; #else error (1, 0, "symbolic links are not supported on this system"); #endif break; case 'v': verbose = 1; break; case 'S': simple_backup_suffix = optarg; break; case 'V': version = optarg; break; default: usage (1); break; } } if (show_version) { printf ("ln - %s\n", version_string); exit (0); } if (show_help) usage (0); if (optind == argc) { error (0, 0, "missing file argument"); usage (1); } 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) { struct stat source_stats; char *source; char *dest; char *new_dest; source = argv[optind]; dest = argv[optind + 1]; /* When the destination is specified with a trailing slash and the source exists but is not a directory, convert the user's command `ln source dest/' to `ln source dest/basename(source)'. */ if (dest[strlen (dest) - 1] == '/' && lstat (source, &source_stats) == 0 && !S_ISDIR (source_stats.st_mode)) { PATH_BASENAME_CONCAT (new_dest, dest, source); } else { new_dest = dest; } errors = do_link (source, new_dest); } 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 the (usually) existing file SOURCE. Symbolic links to nonexistent files are allowed. If DEST is a directory, put the link to SOURCE in that directory. Return 1 if there is an error, otherwise 0. */ static int do_link (char *source, char *dest) { struct stat dest_stats; char *dest_backup = NULL; int lstat_status; /* Use stat here 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) { struct stat source_stats; if (stat (source, &source_stats) != 0) { error (0, errno, "%s", source); return 1; } if (!hard_dir_link && S_ISDIR (source_stats.st_mode)) { error (0, 0, "%s: hard link not allowed for directory", source); return 1; } } if (lstat (dest, &dest_stats) != 0 && errno != ENOENT) { error (0, errno, "%s", dest); return 1; } /* If the destination is a directory or (it is a symlink to a directory and the user has not specified --no-dereference), then form the actual destination name by appending basename (source) to the specified destination directory. */ lstat_status = lstat (dest, &dest_stats); if (lstat_status != 0 && errno != ENOENT) { error (0, errno, "%s", dest); return 1; } if ((lstat_status == 0 && S_ISDIR (dest_stats.st_mode)) #ifdef S_ISLNK || (dereference_dest_dir_symlinks && (S_ISLNK (dest_stats.st_mode) && isdir (dest))) #endif ) { /* Target is a directory; build the full filename. */ char *new_dest; PATH_BASENAME_CONCAT (new_dest, dest, source); dest = new_dest; /* Set this to non-zero to force another call to lstat with the new destination. */ lstat_status = 1; } if (lstat_status == 0 || 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 = (char *) 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 `%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 symbolic_link ? "symbolic " : "", #else "", #endif source, dest); if (dest_backup) { if (rename (dest_backup, dest)) error (0, errno, "cannot un-backup `%s'", dest); } return 1; } static void usage (int status) { if (status != 0) fprintf (stderr, "Try `%s --help' for more information.\n", program_name); else { printf ("\ Usage: %s [OPTION]... SOURCE [DEST]\n\ or: %s [OPTION]... SOURCE... DIRECTORY\n\ ", program_name, program_name); printf ("\ Link SOURCE to DEST (. by default), or multiple SOURCE(s) to DIRECTORY.\n\ Makes hard links by default, symbolic links with -s.\n\ \n\ -b, --backup make backups for removed files\n\ -d, -F, --directory hard link directories (super-user only)\n\ -f, --force remove existing destinations\n\ -n, --no-dereference with --force, remove destination that is a\n\ symlink to a directory\n\ -i, --interactive prompt whether to remove destinations\n\ -s, --symbolic make symbolic links instead of hard links\n\ -v, --verbose print name of each file before linking\n\ -S, --suffix=SUFFIX override the usual backup suffix\n\ -V, --version-control=WORD override the usual version control\n\ --help display this help and exit\n\ --version output version information and exit\n\ \n\ The backup suffix is ~, unless set with SIMPLE_BACKUP_SUFFIX. The\n\ version control may be set with VERSION_CONTROL, values are:\n\ \n\ t, numbered make numbered backups\n\ nil, existing numbered if numbered backups exist, simple otherwise\n\ never, simple always make simple backups\n"); } exit (status); }