diff options
Diffstat (limited to 'src/sysctl')
| -rw-r--r-- | src/sysctl/sysctl.c | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/src/sysctl/sysctl.c b/src/sysctl/sysctl.c new file mode 100644 index 0000000..c67d790 --- /dev/null +++ b/src/sysctl/sysctl.c @@ -0,0 +1,320 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <getopt.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "conf-files.h" +#include "def.h" +#include "fd-util.h" +#include "fileio.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" +#include "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); + +static int apply_all(OrderedHashmap *sysctl_options) { + char *property, *value; + Iterator i; + int r = 0; + + ORDERED_HASHMAP_FOREACH_KEY(value, property, sysctl_options, i) { + int k; + + k = sysctl_write(property, value); + if (k < 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 at LOG_NOTICE level, 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 (IN_SET(k, -EPERM, -EACCES, -EROFS, -ENOENT)) + log_notice_errno(k, "Couldn't write '%s' to '%s', ignoring: %m", value, property); + else { + log_error_errno(k, "Couldn't write '%s' to '%s': %m", value, property); + if (r == 0) + r = k; + } + } + } + + return r; +} + +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 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 (;;) { + char *p, *value, *new_value, *property, *existing; + _cleanup_free_ char *l = NULL; + void *v; + 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) { + log_error("Line is not an assignment at '%s:%u': %s", path, c, p); + + if (r == 0) + r = -EINVAL; + continue; + } + + *value = 0; + value++; + + p = sysctl_normalize(strstrip(p)); + value = strstrip(value); + + if (!test_prefix(p)) + continue; + + existing = ordered_hashmap_get2(sysctl_options, p, &v); + if (existing) { + if (streq(value, existing)) + continue; + + log_debug("Overwriting earlier assignment of %s at '%s:%u'.", p, path, c); + free(ordered_hashmap_remove(sysctl_options, p)); + free(v); + } + + property = strdup(p); + if (!property) + return log_oom(); + + new_value = strdup(value); + if (!new_value) { + free(property); + return log_oom(); + } + + k = ordered_hashmap_put(sysctl_options, property, new_value); + if (k < 0) { + log_error_errno(k, "Failed to add sysctl variable %s to hashmap: %m", property); + free(property); + free(new_value); + return k; + } + } + + 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 = strappend("/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_free_free_freep) OrderedHashmap *sysctl_options = NULL; + int r, k; + + r = parse_argv(argc, argv); + if (r <= 0) + return r; + + log_setup_service(); + + umask(0022); + + sysctl_options = ordered_hashmap_new(&path_hash_ops); + if (!sysctl_options) + return log_oom(); + + r = 0; + + if (argc > optind) { + int i; + + 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); |