src/basic/rlimit-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4
   5 #include "alloc-util.h"
   6 #include "extract-word.h"
   7 #include "fd-util.h"
   8 #include "format-util.h"
   9 #include "macro.h"
  10 #include "missing_resource.h"
  11 #include "rlimit-util.h"
  12 #include "string-table.h"
  13 #include "time-util.h"
  14
  15 int setrlimit_closest(int resource, const struct rlimit *rlim) {
  16         struct rlimit highest, fixed;
  17
  18         assert(rlim);
  19
  20         if (setrlimit(resource, rlim) >= 0)
  21                 return 0;
  22
  23         if (errno != EPERM)
  24                 return -errno;
  25
  26         /* So we failed to set the desired setrlimit, then let's try
  27          * to get as close as we can */
  28         if (getrlimit(resource, &highest) < 0)
  29                 return -errno;
  30
  31         /* If the hard limit is unbounded anyway, then the EPERM had other reasons, let's propagate the original EPERM
  32          * then */
  33         if (highest.rlim_max == RLIM_INFINITY)
  34                 return -EPERM;
  35
  36         fixed = (struct rlimit) {
  37                 .rlim_cur = MIN(rlim->rlim_cur, highest.rlim_max),
  38                 .rlim_max = MIN(rlim->rlim_max, highest.rlim_max),
  39         };
  40
  41         /* Shortcut things if we wouldn't change anything. */
  42         if (fixed.rlim_cur == highest.rlim_cur &&
  43             fixed.rlim_max == highest.rlim_max)
  44                 return 0;
  45
  46         log_debug("Failed at setting rlimit " RLIM_FMT " for resource RLIMIT_%s. Will attempt setting value " RLIM_FMT " instead.", rlim->rlim_max, rlimit_to_string(resource), fixed.rlim_max);
  47
  48         if (setrlimit(resource, &fixed) < 0)
  49                 return -errno;
  50
  51         return 0;
  52 }
  53
  54 int setrlimit_closest_all(const struct rlimit *const *rlim, int *which_failed) {
  55         int r;
  56
  57         assert(rlim);
  58
  59         /* On failure returns the limit's index that failed in *which_failed, but only if non-NULL */
  60
  61         for (int i = 0; i < _RLIMIT_MAX; i++) {
  62                 if (!rlim[i])
  63                         continue;
  64
  65                 r = setrlimit_closest(i, rlim[i]);
  66                 if (r < 0) {
  67                         if (which_failed)
  68                                 *which_failed = i;
  69
  70                         return r;
  71                 }
  72         }
  73
  74         if (which_failed)
  75                 *which_failed = -1;
  76
  77         return 0;
  78 }
  79
  80 static int rlimit_parse_u64(const char *val, rlim_t *ret) {
  81         uint64_t u;
  82         int r;
  83
  84         assert(val);
  85         assert(ret);
  86
  87         if (streq(val, "infinity")) {
  88                 *ret = RLIM_INFINITY;
  89                 return 0;
  90         }
  91
  92         /* setrlimit(2) suggests rlim_t is always 64bit on Linux. */
  93         assert_cc(sizeof(rlim_t) == sizeof(uint64_t));
  94
  95         r = safe_atou64(val, &u);
  96         if (r < 0)
  97                 return r;
  98         if (u >= (uint64_t) RLIM_INFINITY)
  99                 return -ERANGE;
 100
 101         *ret = (rlim_t) u;
 102         return 0;
 103 }
 104
 105 static int rlimit_parse_size(const char *val, rlim_t *ret) {
 106         uint64_t u;
 107         int r;
 108
 109         assert(val);
 110         assert(ret);
 111
 112         if (streq(val, "infinity")) {
 113                 *ret = RLIM_INFINITY;
 114                 return 0;
 115         }
 116
 117         r = parse_size(val, 1024, &u);
 118         if (r < 0)
 119                 return r;
 120         if (u >= (uint64_t) RLIM_INFINITY)
 121                 return -ERANGE;
 122
 123         *ret = (rlim_t) u;
 124         return 0;
 125 }
 126
 127 static int rlimit_parse_sec(const char *val, rlim_t *ret) {
 128         uint64_t u;
 129         usec_t t;
 130         int r;
 131
 132         assert(val);
 133         assert(ret);
 134
 135         if (streq(val, "infinity")) {
 136                 *ret = RLIM_INFINITY;
 137                 return 0;
 138         }
 139
 140         r = parse_sec(val, &t);
 141         if (r < 0)
 142                 return r;
 143         if (t == USEC_INFINITY) {
 144                 *ret = RLIM_INFINITY;
 145                 return 0;
 146         }
 147
 148         u = (uint64_t) DIV_ROUND_UP(t, USEC_PER_SEC);
 149         if (u >= (uint64_t) RLIM_INFINITY)
 150                 return -ERANGE;
 151
 152         *ret = (rlim_t) u;
 153         return 0;
 154 }
 155
 156 static int rlimit_parse_usec(const char *val, rlim_t *ret) {
 157         usec_t t;
 158         int r;
 159
 160         assert(val);
 161         assert(ret);
 162
 163         if (streq(val, "infinity")) {
 164                 *ret = RLIM_INFINITY;
 165                 return 0;
 166         }
 167
 168         r = parse_time(val, &t, 1);
 169         if (r < 0)
 170                 return r;
 171         if (t == USEC_INFINITY) {
 172                 *ret = RLIM_INFINITY;
 173                 return 0;
 174         }
 175
 176         *ret = (rlim_t) t;
 177         return 0;
 178 }
 179
 180 static int rlimit_parse_nice(const char *val, rlim_t *ret) {
 181         uint64_t rl;
 182         int r;
 183
 184         /* So, Linux is weird. The range for RLIMIT_NICE is 40..1, mapping to the nice levels -20..19. However, the
 185          * RLIMIT_NICE limit defaults to 0 by the kernel, i.e. a value that maps to nice level 20, which of course is
 186          * bogus and does not exist. In order to permit parsing the RLIMIT_NICE of 0 here we hence implement a slight
 187          * asymmetry: when parsing as positive nice level we permit 0..19. When parsing as negative nice level, we
 188          * permit -20..0. But when parsing as raw resource limit value then we also allow the special value 0.
 189          *
 190          * Yeah, Linux is quality engineering sometimes... */
 191
 192         if (val[0] == '+') {
 193
 194                 /* Prefixed with "+": Parse as positive user-friendly nice value */
 195                 r = safe_atou64(val + 1, &rl);
 196                 if (r < 0)
 197                         return r;
 198
 199                 if (rl >= PRIO_MAX)
 200                         return -ERANGE;
 201
 202                 rl = 20 - rl;
 203
 204         } else if (val[0] == '-') {
 205
 206                 /* Prefixed with "-": Parse as negative user-friendly nice value */
 207                 r = safe_atou64(val + 1, &rl);
 208                 if (r < 0)
 209                         return r;
 210
 211                 if (rl > (uint64_t) (-PRIO_MIN))
 212                         return -ERANGE;
 213
 214                 rl = 20 + rl;
 215         } else {
 216
 217                 /* Not prefixed: parse as raw resource limit value */
 218                 r = safe_atou64(val, &rl);
 219                 if (r < 0)
 220                         return r;
 221
 222                 if (rl > (uint64_t) (20 - PRIO_MIN))
 223                         return -ERANGE;
 224         }
 225
 226         *ret = (rlim_t) rl;
 227         return 0;
 228 }
 229
 230 static int (*const rlimit_parse_table[_RLIMIT_MAX])(const char *val, rlim_t *ret) = {
 231         [RLIMIT_CPU] = rlimit_parse_sec,
 232         [RLIMIT_FSIZE] = rlimit_parse_size,
 233         [RLIMIT_DATA] = rlimit_parse_size,
 234         [RLIMIT_STACK] = rlimit_parse_size,
 235         [RLIMIT_CORE] = rlimit_parse_size,
 236         [RLIMIT_RSS] = rlimit_parse_size,
 237         [RLIMIT_NOFILE] = rlimit_parse_u64,
 238         [RLIMIT_AS] = rlimit_parse_size,
 239         [RLIMIT_NPROC] = rlimit_parse_u64,
 240         [RLIMIT_MEMLOCK] = rlimit_parse_size,
 241         [RLIMIT_LOCKS] = rlimit_parse_u64,
 242         [RLIMIT_SIGPENDING] = rlimit_parse_u64,
 243         [RLIMIT_MSGQUEUE] = rlimit_parse_size,
 244         [RLIMIT_NICE] = rlimit_parse_nice,
 245         [RLIMIT_RTPRIO] = rlimit_parse_u64,
 246         [RLIMIT_RTTIME] = rlimit_parse_usec,
 247 };
 248
 249 int rlimit_parse_one(int resource, const char *val, rlim_t *ret) {
 250         assert(val);
 251         assert(ret);
 252
 253         if (resource < 0)
 254                 return -EINVAL;
 255         if (resource >= _RLIMIT_MAX)
 256                 return -EINVAL;
 257
 258         return rlimit_parse_table[resource](val, ret);
 259 }
 260
 261 int rlimit_parse(int resource, const char *val, struct rlimit *ret) {
 262         _cleanup_free_ char *hard = NULL, *soft = NULL;
 263         rlim_t hl, sl;
 264         int r;
 265
 266         assert(val);
 267         assert(ret);
 268
 269         r = extract_first_word(&val, &soft, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
 270         if (r < 0)
 271                 return r;
 272         if (r == 0)
 273                 return -EINVAL;
 274
 275         r = rlimit_parse_one(resource, soft, &sl);
 276         if (r < 0)
 277                 return r;
 278
 279         r = extract_first_word(&val, &hard, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
 280         if (r < 0)
 281                 return r;
 282         if (!isempty(val))
 283                 return -EINVAL;
 284         if (r == 0)
 285                 hl = sl;
 286         else {
 287                 r = rlimit_parse_one(resource, hard, &hl);
 288                 if (r < 0)
 289                         return r;
 290                 if (sl > hl)
 291                         return -EILSEQ;
 292         }
 293
 294         *ret = (struct rlimit) {
 295                 .rlim_cur = sl,
 296                 .rlim_max = hl,
 297         };
 298
 299         return 0;
 300 }
 301
 302 int rlimit_format(const struct rlimit *rl, char **ret) {
 303         char *s = NULL;
 304
 305         assert(rl);
 306         assert(ret);
 307
 308         if (rl->rlim_cur >= RLIM_INFINITY && rl->rlim_max >= RLIM_INFINITY)
 309                 s = strdup("infinity");
 310         else if (rl->rlim_cur >= RLIM_INFINITY)
 311                 (void) asprintf(&s, "infinity:" RLIM_FMT, rl->rlim_max);
 312         else if (rl->rlim_max >= RLIM_INFINITY)
 313                 (void) asprintf(&s, RLIM_FMT ":infinity", rl->rlim_cur);
 314         else if (rl->rlim_cur == rl->rlim_max)
 315                 (void) asprintf(&s, RLIM_FMT, rl->rlim_cur);
 316         else
 317                 (void) asprintf(&s, RLIM_FMT ":" RLIM_FMT, rl->rlim_cur, rl->rlim_max);
 318
 319         if (!s)
 320                 return -ENOMEM;
 321
 322         *ret = s;
 323         return 0;
 324 }
 325
 326 static const char* const rlimit_table[_RLIMIT_MAX] = {
 327         [RLIMIT_AS]         = "AS",
 328         [RLIMIT_CORE]       = "CORE",
 329         [RLIMIT_CPU]        = "CPU",
 330         [RLIMIT_DATA]       = "DATA",
 331         [RLIMIT_FSIZE]      = "FSIZE",
 332         [RLIMIT_LOCKS]      = "LOCKS",
 333         [RLIMIT_MEMLOCK]    = "MEMLOCK",
 334         [RLIMIT_MSGQUEUE]   = "MSGQUEUE",
 335         [RLIMIT_NICE]       = "NICE",
 336         [RLIMIT_NOFILE]     = "NOFILE",
 337         [RLIMIT_NPROC]      = "NPROC",
 338         [RLIMIT_RSS]        = "RSS",
 339         [RLIMIT_RTPRIO]     = "RTPRIO",
 340         [RLIMIT_RTTIME]     = "RTTIME",
 341         [RLIMIT_SIGPENDING] = "SIGPENDING",
 342         [RLIMIT_STACK]      = "STACK",
 343 };
 344
 345 DEFINE_STRING_TABLE_LOOKUP(rlimit, int);
 346
 347 int rlimit_from_string_harder(const char *s) {
 348         const char *suffix;
 349
 350         /* The official prefix */
 351         suffix = startswith(s, "RLIMIT_");
 352         if (suffix)
 353                 return rlimit_from_string(suffix);
 354
 355         /* Our own unit file setting prefix */
 356         suffix = startswith(s, "Limit");
 357         if (suffix)
 358                 return rlimit_from_string(suffix);
 359
 360         return rlimit_from_string(s);
 361 }
 362
 363 void rlimit_free_all(struct rlimit **rl) {
 364         int i;
 365
 366         if (!rl)
 367                 return;
 368
 369         for (i = 0; i < _RLIMIT_MAX; i++)
 370                 rl[i] = mfree(rl[i]);
 371 }
 372
 373 int rlimit_nofile_bump(int limit) {
 374         int r;
 375
 376         /* Bumps the (soft) RLIMIT_NOFILE resource limit as close as possible to the specified limit. If a negative
 377          * limit is specified, bumps it to the maximum the kernel and the hard resource limit allows. This call should
 378          * be used by all our programs that might need a lot of fds, and that know how to deal with high fd numbers
 379          * (i.e. do not use select() — which chokes on fds >= 1024) */
 380
 381         if (limit < 0)
 382                 limit = read_nr_open();
 383
 384         if (limit < 3)
 385                 limit = 3;
 386
 387         r = setrlimit_closest(RLIMIT_NOFILE, &RLIMIT_MAKE_CONST(limit));
 388         if (r < 0)
 389                 return log_debug_errno(r, "Failed to set RLIMIT_NOFILE: %m");
 390
 391         return 0;
 392 }
 393
 394 int rlimit_nofile_safe(void) {
 395         struct rlimit rl;
 396
 397         /* Resets RLIMIT_NOFILE's soft limit FD_SETSIZE (i.e. 1024), for compatibility with software still using
 398          * select() */
 399
 400         if (getrlimit(RLIMIT_NOFILE, &rl) < 0)
 401                 return log_debug_errno(errno, "Failed to query RLIMIT_NOFILE: %m");
 402
 403         if (rl.rlim_cur <= FD_SETSIZE)
 404                 return 0;
 405
 406         rl.rlim_cur = FD_SETSIZE;
 407         if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
 408                 return log_debug_errno(errno, "Failed to lower RLIMIT_NOFILE's soft limit to " RLIM_FMT ": %m", rl.rlim_cur);
 409
 410         return 1;
 411 }