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 1e9d276fd831f28db18af64dd38793663fdf107c..4d206ab294bc5b85cb08f7e6fa93c3379ed5781d 100644 (file)
--- a/debianutils/which.c
+++ b/debianutils/which.c
@@ -2,38 +2,25 @@
 /*
  * 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
  */
 
-
 #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)
 {
+       int status = EXIT_SUCCESS;
+       size_t i, count;
        char *path_list;
-       int i, count=1, status = EXIT_SUCCESS;
 
        if (argc <= 1 || **(argv + 1) == '-') {
                bb_show_usage();
@@ -42,10 +29,33 @@ extern int which_main(int argc, char **argv)
 
        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 {
@@ -53,29 +63,32 @@ extern int which_main(int argc, char **argv)
                count = 5;
        }
 
-       while (argc-- > 0) { 
+       while (argc-- > 0) {
+               struct stat stat_b;
                char *buf;
                char *path_n;
-               argv++;
                char found = 0;
+#define is_executable_file(a, b) (!access(a,X_OK) && !stat(a, &b) && \
+               S_ISREG(b.st_mode))
 
-               /*
-                * Check if we were given the full path, first.
-                * Otherwise see if the file exists in our $PATH.
-                */
+               argv++;
                path_n = path_list;
                buf = *argv;
-               if (access(buf, X_OK) == 0) {
+
+               /* 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 (access(buf, X_OK) == 0) {
+                               if (is_executable_file(buf, stat_b)) {
                                        found = 1;
                                        break;
                                }
                                free(buf);
-                               path_n += (strlen(path_n) + 1);
+                               path_n += (bb_strlen(path_n) + 1);
                        }
                }
                if (found) {
@@ -84,7 +97,7 @@ extern int which_main(int argc, char **argv)
                        status = EXIT_FAILURE;
                }
        }
-       return status;
+       bb_fflush_stdout_and_exit(status);
 }
 
 /*