Notes on portability, and on when #include <linux/blah> is appropriate.

[oweals/busybox.git] / debianutils / which.c

diff --git a/debianutils/which.c b/debianutils/which.c
index 79a89c4ebea2e3426535d6126be45f0df0e8a6cb..4d206ab294bc5b85cb08f7e6fa93c3379ed5781d 100644 (file)
--- a/debianutils/which.c
+++ b/debianutils/which.c
@@ -2,73 +2,102 @@
 /*
  * Which implementation for busybox
  *
- * Copyright (C) 1999-2003 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
- * 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 of the License, 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Licensed under the GPL v2, see the file LICENSE in this tarball.
  *
+ * Based on which from debianutils
  */
 
-/* getopt not needed */
 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
+#include <sys/stat.h>
 #include "busybox.h"
 
-extern int which_main(int argc, char **argv)
+int which_main(int argc, char **argv)
 {
-       char *path_list, *path_n;
-       struct stat filestat;
-       int i, count=1, found, status = EXIT_SUCCESS;
+       int status = EXIT_SUCCESS;
+       size_t i, count;
+       char *path_list;
 
-       if (argc <= 1 || **(argv + 1) == '-')
+       if (argc <= 1 || **(argv + 1) == '-') {
                bb_show_usage();
+       }
        argc--;
 
        path_list = getenv("PATH");
        if (path_list != NULL) {
-               for(i=strlen(path_list); i > 0; i--)
-                       if (path_list[i]==':') {
-                               path_list[i]=0;
+               size_t path_len = bb_strlen(path_list);
+               char *new_list = NULL;
+               count = 1;
+
+               for (i = 0; i <= path_len; i++) {
+                       char *this_i = &path_list[i];
+                       if (*this_i == ':') {
+                               /* ^::[^:] == \.: */
+                               if (!i && (*(this_i + 1) == ':')) {
+                                       *this_i = '.';
+                                       continue;
+                               }
+                               *this_i = 0;
                                count++;
+                               /* ^:[^:] == \.0 and [^:]::[^:] == 0\.0 and [^:]:$ == 0\.0 */
+                               if (!i || (*(this_i + 1) == ':') || (i == path_len-1)) {
+                                       new_list = xrealloc(new_list, path_len += 1);
+                                       if (i) {
+                                               memmove(&new_list[i+2], &path_list[i+1], path_len-i);
+                                               new_list[i+1] = '.';
+                                               memmove(new_list, path_list, i);
+                                       } else {
+                                               memmove(&new_list[i+1], &path_list[i], path_len-i);
+                                               new_list[i] = '.';
+                                       }
+                                       path_list = new_list;
+                               }
                        }
+               }
        } else {
                path_list = "/bin\0/sbin\0/usr/bin\0/usr/sbin\0/usr/local/bin";
                count = 5;
        }
 
-       while(argc-- > 0) { 
-               path_n = path_list;
+       while (argc-- > 0) {
+               struct stat stat_b;
+               char *buf;
+               char *path_n;
+               char found = 0;
+#define is_executable_file(a, b) (!access(a,X_OK) && !stat(a, &b) && \
+               S_ISREG(b.st_mode))
+
                argv++;
-               found = 0;
-               for (i = 0; i < count; i++) {
-                       char *buf;
-                       buf = concat_path_file(path_n, *argv);
-                       if (stat (buf, &filestat) == 0
-                           && filestat.st_mode & S_IXUSR)
-                       {
-                               puts(buf);
-                               found = 1;
-                               break;
+               path_n = path_list;
+               buf = *argv;
+
+               /* if filename is either absolute or contains slashes,
+                * stat it */
+               if (strchr(buf, '/') != NULL && is_executable_file(buf, stat_b)) {
+                       found = 1;
+               } else {
+                       /* Couldn't access file and file doesn't contain slashes */
+                       for (i = 0; i < count; i++) {
+                               buf = concat_path_file(path_n, *argv);
+                               if (is_executable_file(buf, stat_b)) {
+                                       found = 1;
+                                       break;
+                               }
+                               free(buf);
+                               path_n += (bb_strlen(path_n) + 1);
                        }
-                       free(buf);
-                       path_n += (strlen(path_n) + 1);
                }
-               if (!found)
+               if (found) {
+                       puts(buf);
+               } else {
                        status = EXIT_FAILURE;
+               }
        }
-       return status;
+       bb_fflush_stdout_and_exit(status);
 }
 
 /*