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-rw-r--r--src/journal/journald-client.c113
1 files changed, 113 insertions, 0 deletions
diff --git a/src/journal/journald-client.c b/src/journal/journald-client.c
new file mode 100644
index 0000000..25970c1
--- /dev/null
+++ b/src/journal/journald-client.c
@@ -0,0 +1,113 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "cgroup-util.h"
+#include "errno-util.h"
+#include "journald-client.h"
+#include "nulstr-util.h"
+#include "pcre2-util.h"
+
+/* This consumes both `allow_list` and `deny_list` arguments. Hence, those arguments are not owned by the
+ * caller anymore and should not be freed. */
+static void client_set_filtering_patterns(ClientContext *c, Set *allow_list, Set *deny_list) {
+ assert(c);
+
+ set_free_and_replace(c->log_filter_allowed_patterns, allow_list);
+ set_free_and_replace(c->log_filter_denied_patterns, deny_list);
+}
+
+static int client_parse_log_filter_nulstr(const char *nulstr, size_t len, Set **ret) {
+ _cleanup_set_free_ Set *s = NULL;
+ _cleanup_strv_free_ char **patterns_strv = NULL;
+ int r;
+
+ assert(nulstr);
+ assert(ret);
+
+ patterns_strv = strv_parse_nulstr(nulstr, len);
+ if (!patterns_strv)
+ return log_oom_debug();
+
+ STRV_FOREACH(pattern, patterns_strv) {
+ _cleanup_(pattern_freep) pcre2_code *compiled_pattern = NULL;
+
+ r = pattern_compile_and_log(*pattern, 0, &compiled_pattern);
+ if (r < 0)
+ return r;
+
+ r = set_ensure_consume(&s, &pcre2_code_hash_ops_free, TAKE_PTR(compiled_pattern));
+ if (r < 0)
+ return log_debug_errno(r, "Failed to insert regex into set: %m");
+ }
+
+ *ret = TAKE_PTR(s);
+
+ return 0;
+}
+
+int client_context_read_log_filter_patterns(ClientContext *c, const char *cgroup) {
+ char *deny_list_xattr, *xattr_end;
+ _cleanup_free_ char *xattr = NULL, *unit_cgroup = NULL;
+ _cleanup_set_free_ Set *allow_list = NULL, *deny_list = NULL;
+ int r;
+
+ assert(c);
+
+ r = cg_path_get_unit_path(cgroup, &unit_cgroup);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to get the unit's cgroup path for %s: %m", cgroup);
+
+ r = cg_get_xattr_malloc(unit_cgroup, "user.journald_log_filter_patterns", &xattr);
+ if (ERRNO_IS_NEG_XATTR_ABSENT(r)) {
+ client_set_filtering_patterns(c, NULL, NULL);
+ return 0;
+ } else if (r < 0)
+ return log_debug_errno(r, "Failed to get user.journald_log_filter_patterns xattr for %s: %m", unit_cgroup);
+
+ xattr_end = xattr + r;
+
+ /* We expect '0xff' to be present in the attribute, even if the lists are empty. We expect the
+ * following:
+ * - Allow list, but no deny list: 0xXX, ...., 0xff
+ * - No allow list, but deny list: 0xff, 0xXX, ....
+ * - Allow list, and deny list: 0xXX, ...., 0xff, 0xXX, ....
+ * This is due to the fact allowed and denied patterns list are two nulstr joined together with '0xff'.
+ * None of the allowed or denied nulstr have a nul-termination character.
+ *
+ * We do not expect both the allow list and deny list to be empty, as this condition is tested
+ * before writing to xattr. */
+ deny_list_xattr = memchr(xattr, (char)0xff, r);
+ if (!deny_list_xattr)
+ return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+ "Missing delimiter in cgroup user.journald_log_filter_patterns attribute: %m");
+
+ r = client_parse_log_filter_nulstr(xattr, deny_list_xattr - xattr, &allow_list);
+ if (r < 0)
+ return r;
+
+ /* Use 'deny_list_xattr + 1' to skip '0xff'. */
+ ++deny_list_xattr;
+ r = client_parse_log_filter_nulstr(deny_list_xattr, xattr_end - deny_list_xattr, &deny_list);
+ if (r < 0)
+ return r;
+
+ client_set_filtering_patterns(c, TAKE_PTR(allow_list), TAKE_PTR(deny_list));
+
+ return 0;
+}
+
+int client_context_check_keep_log(ClientContext *c, const char *message, size_t len) {
+ pcre2_code *regex;
+
+ if (!c || !message)
+ return true;
+
+ SET_FOREACH(regex, c->log_filter_denied_patterns)
+ if (pattern_matches_and_log(regex, message, len, NULL) > 0)
+ return false;
+
+ SET_FOREACH(regex, c->log_filter_allowed_patterns)
+ if (pattern_matches_and_log(regex, message, len, NULL) > 0)
+ return true;
+
+ return set_isempty(c->log_filter_allowed_patterns);
+}