src/basic/rlimit-util.c

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