src/binfmt.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <stdlib.h>
  23 #include <stdbool.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27 #include <limits.h>
  28
  29 #include "log.h"
  30 #include "util.h"
  31
  32 static int delete_rule(const char *rule) {
  33         char *x, *fn, *e;
  34         int r;
  35
  36         assert(rule[0]);
  37
  38         if (!(x = strdup(rule)))
  39                 return -ENOMEM;
  40
  41         e = strchrnul(x+1, x[0]);
  42         *e = 0;
  43
  44         asprintf(&fn, "/proc/sys/fs/binfmt_misc/%s", x+1);
  45         free(x);
  46
  47         if (!fn)
  48                 return -ENOMEM;
  49
  50         r = write_one_line_file(fn, "-1");
  51         free(fn);
  52
  53         return r;
  54 }
  55
  56 static int apply_rule(const char *rule) {
  57         int r;
  58
  59         delete_rule(rule);
  60
  61         if ((r = write_one_line_file("/proc/sys/fs/binfmt_misc/register", rule)) < 0) {
  62                 log_error("Failed to add binary format: %s", strerror(-r));
  63                 return r;
  64         }
  65
  66         return 0;
  67 }
  68
  69 static int apply_file(const char *path, bool ignore_enoent) {
  70         FILE *f;
  71         int r = 0;
  72
  73         assert(path);
  74
  75         if (!(f = fopen(path, "re"))) {
  76                 if (ignore_enoent && errno == ENOENT)
  77                         return 0;
  78
  79                 log_error("Failed to open file '%s', ignoring: %m", path);
  80                 return -errno;
  81         }
  82
  83         while (!feof(f)) {
  84                 char l[LINE_MAX], *p;
  85                 int k;
  86
  87                 if (!fgets(l, sizeof(l), f)) {
  88                         if (feof(f))
  89                                 break;
  90
  91                         log_error("Failed to read file '%s', ignoring: %m", path);
  92                         r = -errno;
  93                         goto finish;
  94                 }
  95
  96                 p = strstrip(l);
  97
  98                 if (!*p)
  99                         continue;
 100
 101                 if (strchr(COMMENTS, *p))
 102                         continue;
 103
 104                 if ((k = apply_rule(p)) < 0 && r == 0)
 105                         r = k;
 106         }
 107
 108 finish:
 109         fclose(f);
 110
 111         return r;
 112 }
 113
 114 static int scandir_filter(const struct dirent *d) {
 115         assert(d);
 116
 117         if (ignore_file(d->d_name))
 118                 return 0;
 119
 120         if (d->d_type != DT_REG &&
 121             d->d_type != DT_LNK &&
 122             d->d_type != DT_UNKNOWN)
 123                 return 0;
 124
 125         return endswith(d->d_name, ".conf");
 126 }
 127
 128 static int apply_tree(const char *path) {
 129         struct dirent **de = NULL;
 130         int n, i, r = 0;
 131
 132         if ((n = scandir(path, &de, scandir_filter, alphasort)) < 0) {
 133
 134                 if (errno == ENOENT)
 135                         return 0;
 136
 137                 log_error("Failed to enumerate %s files: %m", path);
 138                 return -errno;
 139         }
 140
 141         for (i = 0; i < n; i++) {
 142                 char *fn;
 143                 int k;
 144
 145                 k = asprintf(&fn, "%s/%s", path, de[i]->d_name);
 146                 free(de[i]);
 147
 148                 if (k < 0) {
 149                         log_error("Failed to allocate file name.");
 150
 151                         if (r == 0)
 152                                 r = -ENOMEM;
 153                         continue;
 154                 }
 155
 156                 if ((k = apply_file(fn, true)) < 0 && r == 0)
 157                         r = k;
 158         }
 159
 160         free(de);
 161
 162         return r;
 163 }
 164
 165 int main(int argc, char *argv[]) {
 166         int r = 0;
 167
 168         if (argc > 2) {
 169                 log_error("This program expects one or no arguments.");
 170                 return EXIT_FAILURE;
 171         }
 172
 173         log_set_target(LOG_TARGET_AUTO);
 174         log_parse_environment();
 175         log_open();
 176
 177         if (argc > 1)
 178                 r = apply_file(argv[1], false);
 179         else {
 180                 /* Flush out all rules */
 181                 write_one_line_file("/proc/sys/fs/binfmt_misc/status", "-1");
 182
 183                 r = apply_tree("/etc/binfmt.d");
 184         }
 185
 186         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 187 }