diff options
Diffstat (limited to 'src/sysctl/sysctl.c')
| -rw-r--r-- | src/sysctl/sysctl.c | 432 |
1 files changed, 432 insertions, 0 deletions
diff --git a/src/sysctl/sysctl.c b/src/sysctl/sysctl.c new file mode 100644 index 0000000..e263d45 --- /dev/null +++ b/src/sysctl/sysctl.c @@ -0,0 +1,432 @@ +/* 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 "conf-files.h" +#include "def.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 bool arg_cat_config = 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) { + char **i; + + if (strv_isempty(arg_prefixes)) + return true; + + STRV_FOREACH(i, arg_prefixes) { + const char *t; + + t = path_startswith(*i, "/proc/sys/"); + if (!t) + t = *i; + + if (path_startswith(p, t)) + return true; + } + + return false; +} + +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) { + int r; + + r = sysctl_write(key, value); + if (r < 0) { + /* 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. (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 || r == -EROFS || ERRNO_IS_PRIVILEGE(r)) + log_debug_errno(r, "Couldn't write '%s' to '%s', ignoring: %m", value, key); + else if (r == -ENOENT) + log_info_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_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)) { + _cleanup_strv_free_ char **paths = NULL; + _cleanup_free_ char *pattern = NULL; + char **s; + + pattern = path_join("/proc/sys", option->key); + if (!pattern) + return log_oom(); + + k = glob_extend(&paths, pattern, GLOB_NOCHECK); + if (k < 0) { + if (option->ignore_failure || ERRNO_IS_PRIVILEGE(k)) + log_debug_errno(k, "Failed to resolve glob '%s', ignoring: %m", + option->key); + else { + log_error_errno(k, "Couldn't resolve glob '%s': %m", + option->key); + if (r == 0) + r = k; + } + + } else if (strv_isempty(paths)) + log_debug("No match for glob: %s", option->key); + + STRV_FOREACH(s, paths) { + const char *key; + + assert_se(key = path_startswith(*s, "/proc/sys")); + + if (!test_prefix(key)) + continue; + + if (ordered_hashmap_contains(sysctl_options, key)) { + log_info("Not setting %s (explicit setting exists).", key); + continue; + } + + k = sysctl_write_or_warn(key, option->value, option->ignore_failure); + if (r == 0) + r = k; + } + + } else { + k = sysctl_write_or_warn(option->key, option->value, option->ignore_failure); + if (r == 0) + r = k; + } + } + + return r; +} + +static int parse_file(OrderedHashmap **sysctl_options, const char *path, bool ignore_enoent) { + _cleanup_fclose_ FILE *f = NULL; + unsigned c = 0; + int r; + + assert(path); + + r = search_and_fopen(path, "re", NULL, (const char**) CONF_PATHS_STRV("sysctl.d"), &f); + 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", path); + for (;;) { + _cleanup_(option_freep) Option *new_option = NULL; + _cleanup_free_ char *l = NULL; + bool ignore_failure = false; + Option *existing; + char *p, *value; + int k; + + k = read_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", path); + + c++; + + p = strstrip(l); + + if (isempty(p)) + continue; + if (strchr(COMMENTS "\n", *p)) + continue; + + 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, path, 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; + + if (ordered_hashmap_ensure_allocated(sysctl_options, &option_hash_ops) < 0) + return log_oom(); + + 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, path, 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_put(*sysctl_options, 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 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" + " --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_PREFIX, + ARG_NO_PAGER, + }; + + static const struct option options[] = { + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + { "cat-config", no_argument, NULL, ARG_CAT_CONFIG }, + { "prefix", required_argument, NULL, ARG_PREFIX }, + { "no-pager", no_argument, NULL, ARG_NO_PAGER }, + {} + }; + + 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_config = true; + break; + + case ARG_PREFIX: { + 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); + + if (path_startswith(optarg, "/proc/sys")) + p = strdup(optarg); + else + p = path_join("/proc/sys", 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 '?': + return -EINVAL; + + default: + assert_not_reached("Unhandled option"); + } + + if (arg_cat_config && argc > optind) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Positional arguments are not allowed with --cat-config"); + + return 1; +} + +static int run(int argc, char *argv[]) { + _cleanup_(ordered_hashmap_freep) OrderedHashmap *sysctl_options = NULL; + int r, k; + + r = parse_argv(argc, argv); + if (r <= 0) + return r; + + log_setup_service(); + + umask(0022); + + if (argc > optind) { + int i; + + r = 0; + + for (i = optind; i < argc; i++) { + k = parse_file(&sysctl_options, argv[i], false); + if (k < 0 && r == 0) + r = k; + } + } else { + _cleanup_strv_free_ char **files = NULL; + char **f; + + 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_config) { + (void) pager_open(arg_pager_flags); + + return cat_files(NULL, files, 0); + } + + STRV_FOREACH(f, files) { + k = parse_file(&sysctl_options, *f, true); + if (k < 0 && r == 0) + r = k; + } + } + + k = apply_all(sysctl_options); + if (k < 0 && r == 0) + r = k; + + return r; +} + +DEFINE_MAIN_FUNCTION(run); |