debianutils/which.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Which implementation for busybox
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  *
   7  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   8  *
   9  * Based on which from debianutils
  10  */
  11
  12 #include "busybox.h"
  13 #include <string.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <unistd.h>
  17 #include <sys/stat.h>
  18
  19
  20 static int is_executable_file(char *a, struct stat *b)
  21 {
  22         return (!access(a,X_OK) && !stat(a, b) && S_ISREG(b->st_mode));
  23 }
  24
  25 int which_main(int argc, char **argv)
  26 {
  27         int status;
  28         size_t i, count;
  29         char *path_list, *p;
  30
  31         if (argc <= 1 || argv[1][0] == '-') {
  32                 bb_show_usage();
  33         }
  34         argc--;
  35
  36         path_list = getenv("PATH");
  37         if (path_list != NULL) {
  38                 count = 1;
  39                 p = path_list;
  40                 while ((p = strchr(p, ':')) != NULL) {
  41                         *p++ = 0;
  42                         count++;
  43                 }
  44         } else {
  45                 path_list = "/bin\0/sbin\0/usr/bin\0/usr/sbin\0/usr/local/bin";
  46                 count = 5;
  47         }
  48
  49         status = EXIT_SUCCESS;
  50         while (argc-- > 0) {
  51                 struct stat stat_b;
  52                 char *buf;
  53
  54                 argv++;
  55                 buf = argv[0];
  56
  57                 /* If filename is either absolute or contains slashes,
  58                  * stat it */
  59                 if (strchr(buf, '/')) {
  60                         if (is_executable_file(buf, &stat_b)) {
  61                                 puts(buf);
  62                                 goto next;
  63                         }
  64                 } else {
  65                         /* File doesn't contain slashes */
  66                         p = path_list;
  67                         for (i = 0; i < count; i++) {
  68                                 /* Empty component in PATH is treated as . */
  69                                 buf = concat_path_file(p[0] ? p : ".", argv[0]);
  70                                 if (is_executable_file(buf, &stat_b)) {
  71                                         puts(buf);
  72                                         free(buf);
  73                                         goto next;
  74                                 }
  75                                 free(buf);
  76                                 p += strlen(p) + 1;
  77                         }
  78                 }
  79                 status = EXIT_FAILURE;
  80  next:          /* nothing */;
  81         }
  82         bb_fflush_stdout_and_exit(status);
  83 }