contrib/fexists.c

   1 /*
   2     Copyright (C) 2001-2011 Ben Kibbey <bjk@luxsci.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02110-1301  USA
  17 */
  18 /*
  19  * Userinfo module to check file existance in a users home directory. The only
  20  * required flag is -f to specify the filename which only checks for the file
  21  * existance and not mode or type. This module is not chainable. It gets the
  22  * users home directory from the password structure passed from the main
  23  * program.
  24  *
  25  * Compile with: cc -O2 -fPIC -shared -o fexists.so fexists.c
  26  * Run with: ui -O ./fexists.so -f filename --
  27  *
  28  * Ben Kibbey <bjk@luxsci.net>
  29  */
  30 #include <stdio.h>
  31 #include <unistd.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <err.h>
  35 #include <pwd.h>
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <errno.h>
  39
  40 #define F_READ          0x0001
  41 #define F_WRITE         0x0002
  42 #define F_WRITE_W       0x0004
  43 #define F_DIR           0x0008
  44
  45 static struct file_s {
  46     char *name;
  47     unsigned flags;
  48 } *files;
  49
  50 static int idx;
  51 extern void add_string(char ***, const char *);
  52
  53 void ui_module_init(int *chainable)
  54 {
  55     *chainable = 0;
  56 }
  57
  58 void ui_module_exit()
  59 {
  60     int i;
  61
  62     for (i = 0; i < idx; i++)
  63         free(files[i].name);
  64
  65     free(files);
  66     files = NULL;
  67     idx = 0;
  68 }
  69
  70 void ui_module_help()
  71 {
  72     printf("  Check for file existance in a users home directory ([-rwWd] -f <file>).\n");
  73     printf("\t-r  filename is readable by you\n");
  74     printf("\t-w  filename is writeable\n");
  75     printf("\t-W  filename is writeable by you\n");
  76     printf("\t-d  filename is a directory\n\n");
  77 }
  78
  79 char *ui_module_options_init(char **defaults)
  80 {
  81     *defaults = NULL;
  82     return "rwWdf:";
  83 }
  84
  85 int ui_module_options(int argc, char **argv)
  86 {
  87     int opt;
  88     unsigned flags = 0;
  89
  90     while ((opt = getopt(argc, argv, "f:rwWd")) != -1) {
  91         switch (opt) {
  92             case 'r':
  93                 flags |= F_READ;
  94                 break;
  95             case 'w':
  96                 flags |= F_WRITE;
  97                 break;
  98             case 'W':
  99                 flags |= F_WRITE_W;
 100                 break;
 101             case 'd':
 102                 flags |= F_DIR;
 103                 break;
 104             case 'f':
 105                 if (!flags)
 106                     return 1;
 107
 108                 if ((files = realloc(files, (idx + 1) * sizeof(struct file_s))) == NULL) {
 109                     warn("realloc()");
 110                     return 1;
 111                 }
 112
 113                 files[idx].name = strdup(optarg);
 114                 files[idx++].flags = flags;
 115                 flags = 0;
 116                 break;
 117             default:
 118                 return 1;
 119         }
 120     }
 121
 122     return !files ? 1 : 0;
 123 }
 124
 125 int ui_module_exec(char ***results, const struct passwd *pw, const int msep, const int verbose,
 126         const char *tf)
 127 {
 128     char **strings = *results;
 129     char buf[FILENAME_MAX];
 130     struct stat st;
 131     int ret = 0;
 132     int i;
 133
 134     for (i = 0; i < idx; i++) {
 135         ret = 0;
 136         snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, files[i].name);
 137
 138         if (stat(buf, &st) != -1) {
 139             ret = 1;
 140
 141             if (files[i].flags & F_READ) {
 142                 if (access(buf, R_OK) == -1) {
 143                     ret = 0;
 144                     goto done;
 145                 }
 146
 147                 ret = 1;
 148             }
 149
 150             if (files[i].flags & F_WRITE) {
 151                 if (access(buf, W_OK) == -1) {
 152                     ret = 0;
 153                     goto done;
 154                 }
 155
 156                 ret = 1;
 157             }
 158
 159             if (files[i].flags & F_WRITE) {
 160                 if (st.st_mode & S_IWOTH)
 161                     ret = 1;
 162                 else {
 163                     ret = 0;
 164                     goto done;
 165                 }
 166             }
 167
 168             if (files[i].flags & F_DIR) {
 169                 if (S_ISDIR(st.st_mode))
 170                     ret = 1;
 171                 else {
 172                     ret = 0;
 173                     goto done;
 174                 }
 175             }
 176         }
 177         else {
 178             if (errno == EACCES)
 179                 ret = -1;
 180         }
 181
 182 done:
 183         if (ret == -1)
 184             add_string(&strings, "!");
 185         else
 186             add_string(&strings, (ret) ? "1" : "0");
 187     }
 188
 189     *results = strings;
 190     return 0;
 191 }