diff options
Diffstat (limited to 'src/sysctl')
| -rw-r--r-- | src/sysctl/meson.build | 9 | ||||
| -rw-r--r-- | src/sysctl/sysctl.c | 490 |
2 files changed, 499 insertions, 0 deletions
diff --git a/src/sysctl/meson.build b/src/sysctl/meson.build new file mode 100644 index 0000000..1fb85c2 --- /dev/null +++ b/src/sysctl/meson.build @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: LGPL-2.1-or-later + +executables += [ + libexec_template + { + 'name' : 'systemd-sysctl', + 'public' : true, + 'sources' : files('sysctl.c'), + }, +] diff --git a/src/sysctl/sysctl.c b/src/sysctl/sysctl.c new file mode 100644 index 0000000..aac965f --- /dev/null +++ b/src/sysctl/sysctl.c @@ -0,0 +1,490 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <errno.h> +#include <getopt.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/stat.h> +#include <sys/types.h> + +#include "build.h" +#include "conf-files.h" +#include "constants.h" +#include "creds-util.h" +#include "errno-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "glob-util.h" +#include "hashmap.h" +#include "log.h" +#include "main-func.h" +#include "pager.h" +#include "path-util.h" +#include "pretty-print.h" +#include "string-util.h" +#include "strv.h" +#include "sysctl-util.h" + +static char **arg_prefixes = NULL; +static CatFlags arg_cat_flags = CAT_CONFIG_OFF; +static bool arg_strict = false; +static PagerFlags arg_pager_flags = 0; + +STATIC_DESTRUCTOR_REGISTER(arg_prefixes, strv_freep); + +typedef struct Option { + char *key; + char *value; + bool ignore_failure; +} Option; + +static Option *option_free(Option *o) { + if (!o) + return NULL; + + free(o->key); + free(o->value); + + return mfree(o); +} + +DEFINE_TRIVIAL_CLEANUP_FUNC(Option*, option_free); +DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(option_hash_ops, char, string_hash_func, string_compare_func, Option, option_free); + +static bool test_prefix(const char *p) { + if (strv_isempty(arg_prefixes)) + return true; + + return path_startswith_strv(p, arg_prefixes); +} + +static Option *option_new( + const char *key, + const char *value, + bool ignore_failure) { + + _cleanup_(option_freep) Option *o = NULL; + + assert(key); + + o = new(Option, 1); + if (!o) + return NULL; + + *o = (Option) { + .key = strdup(key), + .value = value ? strdup(value) : NULL, + .ignore_failure = ignore_failure, + }; + + if (!o->key) + return NULL; + if (value && !o->value) + return NULL; + + return TAKE_PTR(o); +} + +static int sysctl_write_or_warn(const char *key, const char *value, bool ignore_failure, bool ignore_enoent) { + int r; + + r = sysctl_write(key, value); + if (r < 0) { + /* Proceed without failing if ignore_failure is true. + * If the sysctl is not available in the kernel or we are running with reduced privileges and + * cannot write it, then log about the issue, and proceed without failing. Unless strict mode + * (arg_strict = true) is enabled, in which case we should fail. (EROFS is treated as a + * permission problem here, since that's how container managers usually protected their + * sysctls.) + * In all other cases log an error and make the tool fail. */ + if (ignore_failure || (!arg_strict && (r == -EROFS || ERRNO_IS_PRIVILEGE(r)))) + log_debug_errno(r, "Couldn't write '%s' to '%s', ignoring: %m", value, key); + else if (ignore_enoent && r == -ENOENT) + log_warning_errno(r, "Couldn't write '%s' to '%s', ignoring: %m", value, key); + else + return log_error_errno(r, "Couldn't write '%s' to '%s': %m", value, key); + } + + return 0; +} + +static int apply_glob_option_with_prefix(OrderedHashmap *sysctl_options, Option *option, const char *prefix) { + _cleanup_strv_free_ char **paths = NULL; + _cleanup_free_ char *pattern = NULL; + int r; + + assert(sysctl_options); + assert(option); + + if (prefix) { + _cleanup_free_ char *key = NULL; + + r = path_glob_can_match(option->key, prefix, &key); + if (r < 0) + return log_error_errno(r, "Failed to check if the glob '%s' matches prefix '%s': %m", + option->key, prefix); + if (r == 0) { + log_debug("The glob '%s' does not match prefix '%s'.", option->key, prefix); + return 0; + } + + log_debug("The glob '%s' is prefixed with '%s': '%s'", option->key, prefix, key); + + if (!string_is_glob(key)) { + /* The prefixed pattern is not glob anymore. Let's skip to call glob(). */ + if (ordered_hashmap_contains(sysctl_options, key)) { + log_debug("Not setting %s (explicit setting exists).", key); + return 0; + } + + return sysctl_write_or_warn(key, option->value, + /* ignore_failure = */ option->ignore_failure, + /* ignore_enoent = */ true); + } + + pattern = path_join("/proc/sys", key); + } else + pattern = path_join("/proc/sys", option->key); + if (!pattern) + return log_oom(); + + r = glob_extend(&paths, pattern, GLOB_NOCHECK); + if (r < 0) { + if (r == -ENOENT) { + log_debug("No match for glob: %s", option->key); + return 0; + } + if (option->ignore_failure || ERRNO_IS_PRIVILEGE(r)) { + log_debug_errno(r, "Failed to resolve glob '%s', ignoring: %m", option->key); + return 0; + } else + return log_error_errno(r, "Couldn't resolve glob '%s': %m", option->key); + } + + STRV_FOREACH(s, paths) { + const char *key; + + assert_se(key = path_startswith(*s, "/proc/sys")); + + if (ordered_hashmap_contains(sysctl_options, key)) { + log_debug("Not setting %s (explicit setting exists).", key); + continue; + } + + RET_GATHER(r, + sysctl_write_or_warn(key, option->value, + /* ignore_failure = */ option->ignore_failure, + /* ignore_enoent = */ !arg_strict)); + } + + return r; +} + +static int apply_glob_option(OrderedHashmap *sysctl_options, Option *option) { + int r = 0; + + if (strv_isempty(arg_prefixes)) + return apply_glob_option_with_prefix(sysctl_options, option, NULL); + + STRV_FOREACH(i, arg_prefixes) + RET_GATHER(r, apply_glob_option_with_prefix(sysctl_options, option, *i)); + return r; +} + +static int apply_all(OrderedHashmap *sysctl_options) { + Option *option; + int r = 0; + + ORDERED_HASHMAP_FOREACH(option, sysctl_options) { + int k; + + /* Ignore "negative match" options, they are there only to exclude stuff from globs. */ + if (!option->value) + continue; + + if (string_is_glob(option->key)) + k = apply_glob_option(sysctl_options, option); + else + k = sysctl_write_or_warn(option->key, option->value, + /* ignore_failure = */ option->ignore_failure, + /* ignore_enoent = */ !arg_strict); + RET_GATHER(r, k); + } + + return r; +} + +static int parse_file(OrderedHashmap **sysctl_options, const char *path, bool ignore_enoent) { + _cleanup_fclose_ FILE *f = NULL; + _cleanup_free_ char *pp = NULL; + unsigned c = 0; + int r; + + assert(path); + + r = search_and_fopen(path, "re", NULL, (const char**) CONF_PATHS_STRV("sysctl.d"), &f, &pp); + if (r < 0) { + if (ignore_enoent && r == -ENOENT) + return 0; + + return log_error_errno(r, "Failed to open file '%s', ignoring: %m", path); + } + + log_debug("Parsing %s", pp); + for (;;) { + _cleanup_(option_freep) Option *new_option = NULL; + _cleanup_free_ char *l = NULL; + bool ignore_failure = false; + Option *existing; + char *value; + int k; + + k = read_stripped_line(f, LONG_LINE_MAX, &l); + if (k == 0) + break; + if (k < 0) + return log_error_errno(k, "Failed to read file '%s', ignoring: %m", pp); + + c++; + + if (isempty(l)) + continue; + if (strchr(COMMENTS, l[0])) + continue; + + char *p = l; + value = strchr(p, '='); + if (value) { + if (p[0] == '-') { + ignore_failure = true; + p++; + } + + *value = 0; + value++; + value = strstrip(value); + + } else { + if (p[0] == '-') + /* We have a "negative match" option. Let's continue with value==NULL. */ + p++; + else { + log_syntax(NULL, LOG_WARNING, pp, c, 0, + "Line is not an assignment, ignoring: %s", p); + if (r == 0) + r = -EINVAL; + continue; + } + } + + p = strstrip(p); + p = sysctl_normalize(p); + + /* We can't filter out globs at this point, we'll need to do that later. */ + if (!string_is_glob(p) && + !test_prefix(p)) + continue; + + existing = ordered_hashmap_get(*sysctl_options, p); + if (existing) { + if (streq_ptr(value, existing->value)) { + existing->ignore_failure = existing->ignore_failure || ignore_failure; + continue; + } + + log_debug("Overwriting earlier assignment of %s at '%s:%u'.", p, pp, c); + option_free(ordered_hashmap_remove(*sysctl_options, p)); + } + + new_option = option_new(p, value, ignore_failure); + if (!new_option) + return log_oom(); + + k = ordered_hashmap_ensure_put(sysctl_options, &option_hash_ops, new_option->key, new_option); + if (k < 0) + return log_error_errno(k, "Failed to add sysctl variable %s to hashmap: %m", p); + + TAKE_PTR(new_option); + } + + return r; +} + +static int read_credential_lines(OrderedHashmap **sysctl_options) { + _cleanup_free_ char *j = NULL; + const char *d; + int r; + + r = get_credentials_dir(&d); + if (r == -ENXIO) + return 0; + if (r < 0) + return log_error_errno(r, "Failed to get credentials directory: %m"); + + j = path_join(d, "sysctl.extra"); + if (!j) + return log_oom(); + + (void) parse_file(sysctl_options, j, /* ignore_enoent= */ true); + return 0; +} + +static int cat_config(char **files) { + pager_open(arg_pager_flags); + + return cat_files(NULL, files, arg_cat_flags); +} + +static int help(void) { + _cleanup_free_ char *link = NULL; + int r; + + r = terminal_urlify_man("systemd-sysctl.service", "8", &link); + if (r < 0) + return log_oom(); + + printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n" + "Applies kernel sysctl settings.\n\n" + " -h --help Show this help\n" + " --version Show package version\n" + " --cat-config Show configuration files\n" + " --tldr Show non-comment parts of configuration\n" + " --prefix=PATH Only apply rules with the specified prefix\n" + " --no-pager Do not pipe output into a pager\n" + "\nSee the %s for details.\n", + program_invocation_short_name, + link); + + return 0; +} + +static int parse_argv(int argc, char *argv[]) { + + enum { + ARG_VERSION = 0x100, + ARG_CAT_CONFIG, + ARG_TLDR, + ARG_PREFIX, + ARG_NO_PAGER, + ARG_STRICT, + }; + + static const struct option options[] = { + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + { "cat-config", no_argument, NULL, ARG_CAT_CONFIG }, + { "tldr", no_argument, NULL, ARG_TLDR }, + { "prefix", required_argument, NULL, ARG_PREFIX }, + { "no-pager", no_argument, NULL, ARG_NO_PAGER }, + { "strict", no_argument, NULL, ARG_STRICT }, + {} + }; + + int c; + + assert(argc >= 0); + assert(argv); + + while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) + + switch (c) { + + case 'h': + return help(); + + case ARG_VERSION: + return version(); + + case ARG_CAT_CONFIG: + arg_cat_flags = CAT_CONFIG_ON; + break; + + case ARG_TLDR: + arg_cat_flags = CAT_TLDR; + break; + + case ARG_PREFIX: { + const char *s; + char *p; + + /* We used to require people to specify absolute paths + * in /proc/sys in the past. This is kinda useless, but + * we need to keep compatibility. We now support any + * sysctl name available. */ + sysctl_normalize(optarg); + + s = path_startswith(optarg, "/proc/sys"); + p = strdup(s ?: optarg); + if (!p) + return log_oom(); + + if (strv_consume(&arg_prefixes, p) < 0) + return log_oom(); + + break; + } + + case ARG_NO_PAGER: + arg_pager_flags |= PAGER_DISABLE; + break; + + case ARG_STRICT: + arg_strict = true; + break; + + case '?': + return -EINVAL; + + default: + assert_not_reached(); + } + + if (arg_cat_flags != CAT_CONFIG_OFF && argc > optind) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Positional arguments are not allowed with --cat-config/--tldr."); + + return 1; +} + +static int run(int argc, char *argv[]) { + _cleanup_ordered_hashmap_free_ OrderedHashmap *sysctl_options = NULL; + int r; + + r = parse_argv(argc, argv); + if (r <= 0) + return r; + + log_setup(); + + umask(0022); + + if (argc > optind) { + r = 0; + + for (int i = optind; i < argc; i++) + RET_GATHER(r, parse_file(&sysctl_options, argv[i], false)); + + } else { + _cleanup_strv_free_ char **files = NULL; + + r = conf_files_list_strv(&files, ".conf", NULL, 0, (const char**) CONF_PATHS_STRV("sysctl.d")); + if (r < 0) + return log_error_errno(r, "Failed to enumerate sysctl.d files: %m"); + + if (arg_cat_flags != CAT_CONFIG_OFF) + return cat_config(files); + + STRV_FOREACH(f, files) + RET_GATHER(r, parse_file(&sysctl_options, *f, true)); + + RET_GATHER(r, read_credential_lines(&sysctl_options)); + } + + RET_GATHER(r, apply_all(sysctl_options)); + + return r; +} + +DEFINE_MAIN_FUNCTION(run); |