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v261
src/basic/rlimit-util.c
539 строк
16 KB
Michael Vogt
basic: make check-pointer-deref clean
31 мар 2026, 19:30
31 мар 2026, 19:30
18e70ee
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include "alloc-util.h" #include "errno-util.h" #include "extract-word.h" #include "fd-util.h" #include "fileio.h" #include "format-util.h" #include "log.h" #include "parse-util.h" #include "process-util.h" #include "rlimit-util.h" #include "string-table.h" #include "strv.h" #include "time-util.h" int setrlimit_closest(int resource, const struct rlimit *rlim) { struct rlimit highest, fixed; assert(rlim); if (setrlimit(resource, rlim) >= 0) return 0; if (errno != EPERM) return -errno; /* So we failed to set the desired setrlimit, then let's try * to get as close as we can */ if (getrlimit(resource, &highest) < 0) return -errno; /* If the hard limit is unbounded anyway, then the EPERM had other reasons, let's propagate the original EPERM * then */ if (highest.rlim_max == RLIM_INFINITY) return -EPERM; fixed = (struct rlimit) { .rlim_cur = MIN(rlim->rlim_cur, highest.rlim_max), .rlim_max = MIN(rlim->rlim_max, highest.rlim_max), }; /* Shortcut things if we wouldn't change anything. */ if (fixed.rlim_cur == highest.rlim_cur && fixed.rlim_max == highest.rlim_max) return 0; 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); return RET_NERRNO(setrlimit(resource, &fixed)); } int setrlimit_closest_all(const struct rlimit *const *rlim, int *which_failed) { int r; assert(rlim); /* On failure returns the limit's index that failed in *which_failed, but only if non-NULL */ for (int i = 0; i < _RLIMIT_MAX; i++) { if (!rlim[i]) continue; r = setrlimit_closest(i, rlim[i]); if (r < 0) { if (which_failed) *which_failed = i; return r; } } if (which_failed) *which_failed = -1; return 0; } static int rlimit_parse_u64(const char *val, rlim_t *ret) { uint64_t u; int r; assert(val); assert(ret); if (streq(val, "infinity")) { *ret = RLIM_INFINITY; return 0; } /* setrlimit(2) suggests rlim_t is always 64-bit on Linux. */ assert_cc(sizeof(rlim_t) == sizeof(uint64_t)); r = safe_atou64(val, &u); if (r < 0) return r; if (u >= (uint64_t) RLIM_INFINITY) return -ERANGE; *ret = (rlim_t) u; return 0; } static int rlimit_parse_size(const char *val, rlim_t *ret) { uint64_t u; int r; assert(val); assert(ret); if (streq(val, "infinity")) { *ret = RLIM_INFINITY; return 0; } r = parse_size(val, 1024, &u); if (r < 0) return r; if (u >= (uint64_t) RLIM_INFINITY) return -ERANGE; *ret = (rlim_t) u; return 0; } static int rlimit_parse_sec(const char *val, rlim_t *ret) { uint64_t u; usec_t t; int r; assert(val); assert(ret); r = parse_sec(val, &t); if (r < 0) return r; if (t == USEC_INFINITY) { *ret = RLIM_INFINITY; return 0; } u = (uint64_t) DIV_ROUND_UP(t, USEC_PER_SEC); if (u >= (uint64_t) RLIM_INFINITY) return -ERANGE; *ret = (rlim_t) u; return 0; } static int rlimit_parse_usec(const char *val, rlim_t *ret) { usec_t t; int r; assert(val); assert(ret); r = parse_time(val, &t, 1); if (r < 0) return r; if (t == USEC_INFINITY) { *ret = RLIM_INFINITY; return 0; } *ret = (rlim_t) t; return 0; } static int rlimit_parse_nice(const char *val, rlim_t *ret) { uint64_t rl; int r; assert(val); assert(ret); /* So, Linux is weird. The range for RLIMIT_NICE is 40..1, mapping to the nice levels -20..19. However, the * RLIMIT_NICE limit defaults to 0 by the kernel, i.e. a value that maps to nice level 20, which of course is * bogus and does not exist. In order to permit parsing the RLIMIT_NICE of 0 here we hence implement a slight * asymmetry: when parsing as positive nice level we permit 0..19. When parsing as negative nice level, we * permit -20..0. But when parsing as raw resource limit value then we also allow the special value 0. * * Yeah, Linux is quality engineering sometimes... */ if (val[0] == '+') { /* Prefixed with "+": Parse as positive user-friendly nice value */ r = safe_atou64(val + 1, &rl); if (r < 0) return r; if (rl >= PRIO_MAX) return -ERANGE; rl = 20 - rl; } else if (val[0] == '-') { /* Prefixed with "-": Parse as negative user-friendly nice value */ r = safe_atou64(val + 1, &rl); if (r < 0) return r; if (rl > (uint64_t) (-PRIO_MIN)) return -ERANGE; rl = 20 + rl; } else { /* Not prefixed: parse as raw resource limit value */ r = safe_atou64(val, &rl); if (r < 0) return r; if (rl > (uint64_t) (20 - PRIO_MIN)) return -ERANGE; } *ret = (rlim_t) rl; return 0; } static int (*const rlimit_parse_table[_RLIMIT_MAX])(const char *val, rlim_t *ret) = { [RLIMIT_CPU] = rlimit_parse_sec, [RLIMIT_FSIZE] = rlimit_parse_size, [RLIMIT_DATA] = rlimit_parse_size, [RLIMIT_STACK] = rlimit_parse_size, [RLIMIT_CORE] = rlimit_parse_size, [RLIMIT_RSS] = rlimit_parse_size, [RLIMIT_NOFILE] = rlimit_parse_u64, [RLIMIT_AS] = rlimit_parse_size, [RLIMIT_NPROC] = rlimit_parse_u64, [RLIMIT_MEMLOCK] = rlimit_parse_size, [RLIMIT_LOCKS] = rlimit_parse_u64, [RLIMIT_SIGPENDING] = rlimit_parse_u64, [RLIMIT_MSGQUEUE] = rlimit_parse_size, [RLIMIT_NICE] = rlimit_parse_nice, [RLIMIT_RTPRIO] = rlimit_parse_u64, [RLIMIT_RTTIME] = rlimit_parse_usec, }; int rlimit_parse_one(int resource, const char *val, rlim_t *ret) { assert(val); assert(ret); if (resource < 0) return -EINVAL; if (resource >= _RLIMIT_MAX) return -EINVAL; return rlimit_parse_table[resource](val, ret); } int rlimit_parse(int resource, const char *val, struct rlimit *ret) { _cleanup_free_ char *hard = NULL, *soft = NULL; rlim_t hl, sl; int r; assert(val); assert(ret); r = extract_first_word(&val, &soft, ":", EXTRACT_DONT_COALESCE_SEPARATORS); if (r < 0) return r; if (r == 0) return -EINVAL; r = rlimit_parse_one(resource, soft, &sl); if (r < 0) return r; r = extract_first_word(&val, &hard, ":", EXTRACT_DONT_COALESCE_SEPARATORS); if (r < 0) return r; if (!isempty(val)) return -EINVAL; if (r == 0) hl = sl; else { r = rlimit_parse_one(resource, hard, &hl); if (r < 0) return r; if (sl > hl) return -EILSEQ; } *ret = (struct rlimit) { .rlim_cur = sl, .rlim_max = hl, }; return 0; } int rlimit_format(const struct rlimit *rl, char **ret) { char *s; assert(rl); assert(ret); if (rl->rlim_cur >= RLIM_INFINITY && rl->rlim_max >= RLIM_INFINITY) s = strdup("infinity"); else if (rl->rlim_cur >= RLIM_INFINITY) s = asprintf_safe("infinity:" RLIM_FMT, rl->rlim_max); else if (rl->rlim_max >= RLIM_INFINITY) s = asprintf_safe(RLIM_FMT ":infinity", rl->rlim_cur); else if (rl->rlim_cur == rl->rlim_max) s = asprintf_safe(RLIM_FMT, rl->rlim_cur); else s = asprintf_safe(RLIM_FMT ":" RLIM_FMT, rl->rlim_cur, rl->rlim_max); if (!s) return -ENOMEM; *ret = s; return 0; } static const char* const rlimit_table[_RLIMIT_MAX] = { [RLIMIT_AS] = "AS", [RLIMIT_CORE] = "CORE", [RLIMIT_CPU] = "CPU", [RLIMIT_DATA] = "DATA", [RLIMIT_FSIZE] = "FSIZE", [RLIMIT_LOCKS] = "LOCKS", [RLIMIT_MEMLOCK] = "MEMLOCK", [RLIMIT_MSGQUEUE] = "MSGQUEUE", [RLIMIT_NICE] = "NICE", [RLIMIT_NOFILE] = "NOFILE", [RLIMIT_NPROC] = "NPROC", [RLIMIT_RSS] = "RSS", [RLIMIT_RTPRIO] = "RTPRIO", [RLIMIT_RTTIME] = "RTTIME", [RLIMIT_SIGPENDING] = "SIGPENDING", [RLIMIT_STACK] = "STACK", }; DEFINE_STRING_TABLE_LOOKUP(rlimit, int); void rlimits_list(const char *prefix) { FOREACH_ELEMENT(field, rlimit_table) printf("%s%s\n", strempty(prefix), *field); } int rlimit_from_string_harder(const char *s) { const char *suffix; /* The official prefix */ suffix = startswith(s, "RLIMIT_"); if (suffix) return rlimit_from_string(suffix); /* Our own unit file setting prefix */ suffix = startswith(s, "Limit"); if (suffix) return rlimit_from_string(suffix); return rlimit_from_string(s); } void rlimit_free_all(struct rlimit **rl) { free_many((void**) rl, _RLIMIT_MAX); } int rlimit_copy_all(struct rlimit* target[static _RLIMIT_MAX], struct rlimit* const source[static _RLIMIT_MAX]) { struct rlimit* copy[_RLIMIT_MAX] = {}; assert(target); assert(source); for (int i = 0; i < _RLIMIT_MAX; i++) { if (!source[i]) continue; copy[i] = newdup(struct rlimit, source[i], 1); if (!copy[i]) { rlimit_free_all(copy); return -ENOMEM; } } memcpy(target, copy, sizeof(struct rlimit*) * _RLIMIT_MAX); return 0; } int rlimit_nofile_bump(int limit) { int r; /* Bumps the (soft) RLIMIT_NOFILE resource limit as close as possible to the specified limit. If a negative * limit is specified, bumps it to the maximum the kernel and the hard resource limit allows. This call should * be used by all our programs that might need a lot of fds, and that know how to deal with high fd numbers * (i.e. do not use select() — which chokes on fds >= 1024) */ if (limit < 0) limit = read_nr_open(); if (limit < 3) limit = 3; r = setrlimit_closest(RLIMIT_NOFILE, &RLIMIT_MAKE_CONST(limit)); if (r < 0) return log_debug_errno(r, "Failed to set RLIMIT_NOFILE: %m"); return 0; } int rlimit_nofile_safe(void) { struct rlimit rl; /* Resets RLIMIT_NOFILE's soft limit FD_SETSIZE (i.e. 1024), for compatibility with software still using * select() */ if (getrlimit(RLIMIT_NOFILE, &rl) < 0) return log_debug_errno(errno, "Failed to query RLIMIT_NOFILE: %m"); if (rl.rlim_cur <= FD_SETSIZE) return 0; /* So we might have inherited a hard limit that's larger than the kernel's maximum limit as stored in * /proc/sys/fs/nr_open. If we pass this hard limit unmodified to setrlimit(), we'll get EPERM. To * make sure that doesn't happen, let's limit our hard limit to the value from nr_open. */ rl.rlim_max = MIN(rl.rlim_max, (rlim_t) read_nr_open()); rl.rlim_cur = MIN((rlim_t) FD_SETSIZE, rl.rlim_max); if (setrlimit(RLIMIT_NOFILE, &rl) < 0) return log_debug_errno(errno, "Failed to lower RLIMIT_NOFILE's soft limit to " RLIM_FMT ": %m", rl.rlim_cur); return 1; } int pid_getrlimit(pid_t pid, int resource, struct rlimit *ret) { static const char * const prefix_table[_RLIMIT_MAX] = { [RLIMIT_CPU] = "Max cpu time", [RLIMIT_FSIZE] = "Max file size", [RLIMIT_DATA] = "Max data size", [RLIMIT_STACK] = "Max stack size", [RLIMIT_CORE] = "Max core file size", [RLIMIT_RSS] = "Max resident set", [RLIMIT_NPROC] = "Max processes", [RLIMIT_NOFILE] = "Max open files", [RLIMIT_MEMLOCK] = "Max locked memory", [RLIMIT_AS] = "Max address space", [RLIMIT_LOCKS] = "Max file locks", [RLIMIT_SIGPENDING] = "Max pending signals", [RLIMIT_MSGQUEUE] = "Max msgqueue size", [RLIMIT_NICE] = "Max nice priority", [RLIMIT_RTPRIO] = "Max realtime priority", [RLIMIT_RTTIME] = "Max realtime timeout", }; int r; assert(resource >= 0); assert(resource < _RLIMIT_MAX); assert(pid >= 0); assert(ret); if (pid == 0 || pid == getpid_cached()) return RET_NERRNO(getrlimit(resource, ret)); r = RET_NERRNO(prlimit(pid, resource, /* new_limit= */ NULL, ret)); if (!ERRNO_IS_NEG_PRIVILEGE(r)) return r; /* We don't have access? Then try to go via /proc/$PID/limits. Weirdly that's world readable in * contrast to querying the data via prlimit() */ const char *p = procfs_file_alloca(pid, "limits"); _cleanup_free_ char *limits = NULL; r = read_full_file(p, &limits, /* ret_size= */ NULL); if (r < 0) return -EPERM; /* propagate original permission error if we can't access the limits file */ _cleanup_strv_free_ char **l = NULL; l = strv_split_newlines(limits); if (!l) return -ENOMEM; STRV_FOREACH(i, strv_skip(l, 1)) { _cleanup_free_ char *soft = NULL, *hard = NULL; uint64_t sv, hv; const char *e; e = startswith(*i, prefix_table[resource]); if (!e) continue; if (*e != ' ') continue; e += strspn(e, WHITESPACE); size_t n; n = strcspn(e, WHITESPACE); if (n == 0) continue; soft = strndup(e, n); if (!soft) return -ENOMEM; e += n; if (*e != ' ') continue; e += strspn(e, WHITESPACE); n = strcspn(e, WHITESPACE); if (n == 0) continue; hard = strndup(e, n); if (!hard) return -ENOMEM; if (streq(soft, "unlimited")) sv = RLIM_INFINITY; else { r = safe_atou64(soft, &sv); if (r < 0) return r; } if (streq(hard, "unlimited")) hv = RLIM_INFINITY; else { r = safe_atou64(hard, &hv); if (r < 0) return r; } *ret = (struct rlimit) { .rlim_cur = sv, .rlim_max = hv, }; return 0; } return -ENOTRECOVERABLE; }