src/binfmt/binfmt.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <getopt.h>
  22 #include <limits.h>
  23 #include <stdbool.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #include "alloc-util.h"
  29 #include "conf-files.h"
  30 #include "def.h"
  31 #include "fd-util.h"
  32 #include "fileio.h"
  33 #include "log.h"
  34 #include "string-util.h"
  35 #include "strv.h"
  36 #include "util.h"
  37
  38 static const char conf_file_dirs[] = CONF_PATHS_NULSTR("binfmt.d");
  39
  40 static int delete_rule(const char *rule) {
  41         _cleanup_free_ char *x = NULL, *fn = NULL;
  42         char *e;
  43
  44         assert(rule[0]);
  45
  46         x = strdup(rule);
  47         if (!x)
  48                 return log_oom();
  49
  50         e = strchrnul(x+1, x[0]);
  51         *e = 0;
  52
  53         fn = strappend("/proc/sys/fs/binfmt_misc/", x+1);
  54         if (!fn)
  55                 return log_oom();
  56
  57         return write_string_file(fn, "-1", 0);
  58 }
  59
  60 static int apply_rule(const char *rule) {
  61         int r;
  62
  63         delete_rule(rule);
  64
  65         r = write_string_file("/proc/sys/fs/binfmt_misc/register", rule, 0);
  66         if (r < 0)
  67                 return log_error_errno(r, "Failed to add binary format: %m");
  68
  69         return 0;
  70 }
  71
  72 static int apply_file(const char *path, bool ignore_enoent) {
  73         _cleanup_fclose_ FILE *f = NULL;
  74         int r;
  75
  76         assert(path);
  77
  78         r = search_and_fopen_nulstr(path, "re", NULL, conf_file_dirs, &f);
  79         if (r < 0) {
  80                 if (ignore_enoent && r == -ENOENT)
  81                         return 0;
  82
  83                 return log_error_errno(r, "Failed to open file '%s', ignoring: %m", path);
  84         }
  85
  86         log_debug("apply: %s", path);
  87         for (;;) {
  88                 char l[LINE_MAX], *p;
  89                 int k;
  90
  91                 if (!fgets(l, sizeof(l), f)) {
  92                         if (feof(f))
  93                                 break;
  94
  95                         return log_error_errno(errno, "Failed to read file '%s', ignoring: %m", path);
  96                 }
  97
  98                 p = strstrip(l);
  99                 if (!*p)
 100                         continue;
 101                 if (strchr(COMMENTS "\n", *p))
 102                         continue;
 103
 104                 k = apply_rule(p);
 105                 if (k < 0 && r == 0)
 106                         r = k;
 107         }
 108
 109         return r;
 110 }
 111
 112 static void help(void) {
 113         printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
 114                "Registers binary formats.\n\n"
 115                "  -h --help             Show this help\n"
 116                "     --version          Show package version\n"
 117                , program_invocation_short_name);
 118 }
 119
 120 static int parse_argv(int argc, char *argv[]) {
 121
 122         enum {
 123                 ARG_VERSION = 0x100,
 124         };
 125
 126         static const struct option options[] = {
 127                 { "help",      no_argument,       NULL, 'h'           },
 128                 { "version",   no_argument,       NULL, ARG_VERSION   },
 129                 {}
 130         };
 131
 132         int c;
 133
 134         assert(argc >= 0);
 135         assert(argv);
 136
 137         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
 138
 139                 switch (c) {
 140
 141                 case 'h':
 142                         help();
 143                         return 0;
 144
 145                 case ARG_VERSION:
 146                         return version();
 147
 148                 case '?':
 149                         return -EINVAL;
 150
 151                 default:
 152                         assert_not_reached("Unhandled option");
 153                 }
 154
 155         return 1;
 156 }
 157
 158 int main(int argc, char *argv[]) {
 159         int r, k;
 160
 161         r = parse_argv(argc, argv);
 162         if (r <= 0)
 163                 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 164
 165         log_set_target(LOG_TARGET_AUTO);
 166         log_parse_environment();
 167         log_open();
 168
 169         umask(0022);
 170
 171         r = 0;
 172
 173         if (argc > optind) {
 174                 int i;
 175
 176                 for (i = optind; i < argc; i++) {
 177                         k = apply_file(argv[i], false);
 178                         if (k < 0 && r == 0)
 179                                 r = k;
 180                 }
 181         } else {
 182                 _cleanup_strv_free_ char **files = NULL;
 183                 char **f;
 184
 185                 r = conf_files_list_nulstr(&files, ".conf", NULL, 0, conf_file_dirs);
 186                 if (r < 0) {
 187                         log_error_errno(r, "Failed to enumerate binfmt.d files: %m");
 188                         goto finish;
 189                 }
 190
 191                 /* Flush out all rules */
 192                 write_string_file("/proc/sys/fs/binfmt_misc/status", "-1", 0);
 193
 194                 STRV_FOREACH(f, files) {
 195                         k = apply_file(*f, true);
 196                         if (k < 0 && r == 0)
 197                                 r = k;
 198                 }
 199         }
 200
 201 finish:
 202         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 203 }