Systemd/src/sysctl/sysctl.c
Lennart Poettering 544e146b0e journalctl,elsewhere: make sure --file=foo fails with sane error msg if foo is not readable
It annoyed me for quite a while that running "journalctl --file=…" on a
file that is not readable failed with a "File not found" error instead
of a permission error. Let's fix that.

We make this work by using the GLOB_NOCHECK flag for glob() which means
that files are not accessible will be returned in the array as they are
instead of being filtered away. This then means that our later attemps
to open the files will fail cleanly with a good error message.
2020-05-19 15:26:51 +02:00

434 lines
14 KiB
C

/* 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 <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;
Iterator i;
int r = 0;
ORDERED_HASHMAP_FOREACH(option, sysctl_options, i) {
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);