diff options
Diffstat (limited to 'src/basic/rlimit-util.c')
| -rw-r--r-- | src/basic/rlimit-util.c | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/src/basic/rlimit-util.c b/src/basic/rlimit-util.c new file mode 100644 index 0000000..c1f0b2b --- /dev/null +++ b/src/basic/rlimit-util.c @@ -0,0 +1,428 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <errno.h> + +#include "alloc-util.h" +#include "errno-util.h" +#include "extract-word.h" +#include "fd-util.h" +#include "format-util.h" +#include "macro.h" +#include "missing_resource.h" +#include "rlimit-util.h" +#include "string-table.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); + + if (streq(val, "infinity")) { + *ret = RLIM_INFINITY; + return 0; + } + + 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); + + if (streq(val, "infinity")) { + *ret = RLIM_INFINITY; + return 0; + } + + 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; + + /* 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) { + _cleanup_free_ char *s = NULL; + int r; + + assert(rl); + assert(ret); + + if (rl->rlim_cur >= RLIM_INFINITY && rl->rlim_max >= RLIM_INFINITY) + r = free_and_strdup(&s, "infinity"); + else if (rl->rlim_cur >= RLIM_INFINITY) + r = asprintf(&s, "infinity:" RLIM_FMT, rl->rlim_max); + else if (rl->rlim_max >= RLIM_INFINITY) + r = asprintf(&s, RLIM_FMT ":infinity", rl->rlim_cur); + else if (rl->rlim_cur == rl->rlim_max) + r = asprintf(&s, RLIM_FMT, rl->rlim_cur); + else + r = asprintf(&s, RLIM_FMT ":" RLIM_FMT, rl->rlim_cur, rl->rlim_max); + if (r < 0) + return -ENOMEM; + + *ret = TAKE_PTR(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); + +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; +} |