src/basic/proc-cmdline.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 <stdbool.h>
  21 #include <stddef.h>
  22 #include <string.h>
  23
  24 #include "alloc-util.h"
  25 #include "extract-word.h"
  26 #include "fileio.h"
  27 #include "macro.h"
  28 #include "parse-util.h"
  29 #include "proc-cmdline.h"
  30 #include "process-util.h"
  31 #include "special.h"
  32 #include "string-util.h"
  33 #include "util.h"
  34 #include "virt.h"
  35
  36 int proc_cmdline(char **ret) {
  37         const char *e;
  38         assert(ret);
  39
  40         /* For testing purposes it is sometimes useful to be able to override what we consider /proc/cmdline to be */
  41         e = secure_getenv("SYSTEMD_PROC_CMDLINE");
  42         if (e) {
  43                 char *m;
  44
  45                 m = strdup(e);
  46                 if (!m)
  47                         return -ENOMEM;
  48
  49                 *ret = m;
  50                 return 0;
  51         }
  52
  53         if (detect_container() > 0)
  54                 return get_process_cmdline(1, 0, false, ret);
  55         else
  56                 return read_one_line_file("/proc/cmdline", ret);
  57 }
  58
  59 int proc_cmdline_parse(proc_cmdline_parse_t parse_item, void *data, unsigned flags) {
  60
  61         _cleanup_free_ char *line = NULL;
  62         const char *p;
  63         int r;
  64
  65         assert(parse_item);
  66
  67         r = proc_cmdline(&line);
  68         if (r < 0)
  69                 return r;
  70
  71         p = line;
  72         for (;;) {
  73                 _cleanup_free_ char *word = NULL;
  74                 char *value, *key, *q;
  75
  76                 r = extract_first_word(&p, &word, NULL, EXTRACT_QUOTES|EXTRACT_RELAX);
  77                 if (r < 0)
  78                         return r;
  79                 if (r == 0)
  80                         break;
  81
  82                 key = word;
  83
  84                 /* Filter out arguments that are intended only for the initrd */
  85                 q = startswith(word, "rd.");
  86                 if (q) {
  87                         if (!in_initrd())
  88                                 continue;
  89
  90                         if (flags & PROC_CMDLINE_STRIP_RD_PREFIX)
  91                                 key = q;
  92                 }
  93
  94                 value = strchr(key, '=');
  95                 if (value)
  96                         *(value++) = 0;
  97
  98                 r = parse_item(key, value, data);
  99                 if (r < 0)
 100                         return r;
 101         }
 102
 103         return 0;
 104 }
 105
 106 static bool relaxed_equal_char(char a, char b) {
 107
 108         return a == b ||
 109                 (a == '_' && b == '-') ||
 110                 (a == '-' && b == '_');
 111 }
 112
 113 char *proc_cmdline_key_startswith(const char *s, const char *prefix) {
 114
 115         assert(s);
 116         assert(prefix);
 117
 118         /* Much like startswith(), but considers "-" and "_" the same */
 119
 120         for (; *prefix != 0; s++, prefix++)
 121                 if (!relaxed_equal_char(*s, *prefix))
 122                         return NULL;
 123
 124         return (char*) s;
 125 }
 126
 127 bool proc_cmdline_key_streq(const char *x, const char *y) {
 128         assert(x);
 129         assert(y);
 130
 131         /* Much like streq(), but considers "-" and "_" the same */
 132
 133         for (; *x != 0 || *y != 0; x++, y++)
 134                 if (!relaxed_equal_char(*x, *y))
 135                         return false;
 136
 137         return true;
 138 }
 139
 140 int proc_cmdline_get_key(const char *key, unsigned flags, char **value) {
 141         _cleanup_free_ char *line = NULL, *ret = NULL;
 142         bool found = false;
 143         const char *p;
 144         int r;
 145
 146         /* Looks for a specific key on the kernel command line. Supports two modes:
 147          *
 148          * a) The "value" parameter is used. In this case a parameter beginning with the "key" string followed by "="
 149          *    is searched, and the value following this is returned in "value".
 150          *
 151          * b) as above, but the PROC_CMDLINE_VALUE_OPTIONAL flag is set. In this case if the key is found as a
 152          *    separate word (i.e. not followed by "=" but instead by whitespace or the end of the command line), then
 153          *    this is also accepted, and "value" is returned as NULL.
 154          *
 155          * c) The "value" parameter is NULL. In this case a search for the exact "key" parameter is performed.
 156          *
 157          * In all three cases, > 0 is returned if the key is found, 0 if not. */
 158
 159         if (isempty(key))
 160                 return -EINVAL;
 161
 162         if ((flags & PROC_CMDLINE_VALUE_OPTIONAL) && !value)
 163                 return -EINVAL;
 164
 165         r = proc_cmdline(&line);
 166         if (r < 0)
 167                 return r;
 168
 169         p = line;
 170         for (;;) {
 171                 _cleanup_free_ char *word = NULL;
 172                 const char *e;
 173
 174                 r = extract_first_word(&p, &word, NULL, EXTRACT_QUOTES|EXTRACT_RELAX);
 175                 if (r < 0)
 176                         return r;
 177                 if (r == 0)
 178                         break;
 179
 180                 /* Automatically filter out arguments that are intended only for the initrd, if we are not in the
 181                  * initrd. */
 182                 if (!in_initrd() && startswith(word, "rd."))
 183                         continue;
 184
 185                 if (value) {
 186                         e = proc_cmdline_key_startswith(word, key);
 187                         if (!e)
 188                                 continue;
 189
 190                         if (*e == '=') {
 191                                 r = free_and_strdup(&ret, e+1);
 192                                 if (r < 0)
 193                                         return r;
 194
 195                                 found = true;
 196
 197                         } else if (*e == 0 && (flags & PROC_CMDLINE_VALUE_OPTIONAL))
 198                                 found = true;
 199
 200                 } else {
 201                         if (streq(word, key))
 202                                 found = true;
 203                 }
 204         }
 205
 206         if (value) {
 207                 *value = ret;
 208                 ret = NULL;
 209         }
 210
 211         return found;
 212 }
 213
 214 int proc_cmdline_get_bool(const char *key, bool *ret) {
 215         _cleanup_free_ char *v = NULL;
 216         int r;
 217
 218         assert(ret);
 219
 220         r = proc_cmdline_get_key(key, PROC_CMDLINE_VALUE_OPTIONAL, &v);
 221         if (r < 0)
 222                 return r;
 223         if (r == 0) {
 224                 *ret = false;
 225                 return 0;
 226         }
 227
 228         if (v) { /* parameter passed */
 229                 r = parse_boolean(v);
 230                 if (r < 0)
 231                         return r;
 232                 *ret = r;
 233         } else /* no parameter passed */
 234                 *ret = true;
 235
 236         return 1;
 237 }
 238
 239 int shall_restore_state(void) {
 240         bool ret;
 241         int r;
 242
 243         r = proc_cmdline_get_bool("systemd.restore_state", &ret);
 244         if (r < 0)
 245                 return r;
 246
 247         return r > 0 ? ret : true;
 248 }
 249
 250 static const char * const rlmap[] = {
 251         "emergency", SPECIAL_EMERGENCY_TARGET,
 252         "-b",        SPECIAL_EMERGENCY_TARGET,
 253         "rescue",    SPECIAL_RESCUE_TARGET,
 254         "single",    SPECIAL_RESCUE_TARGET,
 255         "-s",        SPECIAL_RESCUE_TARGET,
 256         "s",         SPECIAL_RESCUE_TARGET,
 257         "S",         SPECIAL_RESCUE_TARGET,
 258         "1",         SPECIAL_RESCUE_TARGET,
 259         "2",         SPECIAL_MULTI_USER_TARGET,
 260         "3",         SPECIAL_MULTI_USER_TARGET,
 261         "4",         SPECIAL_MULTI_USER_TARGET,
 262         "5",         SPECIAL_GRAPHICAL_TARGET,
 263         NULL
 264 };
 265
 266 static const char * const rlmap_initrd[] = {
 267         "emergency", SPECIAL_EMERGENCY_TARGET,
 268         "rescue",    SPECIAL_RESCUE_TARGET,
 269         NULL
 270 };
 271
 272 const char* runlevel_to_target(const char *word) {
 273         size_t i;
 274         const char * const *rlmap_ptr = in_initrd() ? rlmap_initrd
 275                                                     : rlmap;
 276
 277         if (!word)
 278                 return NULL;
 279
 280         if (in_initrd() && (word = startswith(word, "rd.")) == NULL)
 281                 return NULL;
 282
 283         for (i = 0; rlmap_ptr[i] != NULL; i += 2)
 284                 if (streq(word, rlmap_ptr[i]))
 285                         return rlmap_ptr[i+1];
 286
 287         return NULL;
 288 }