1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2012 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
25 #include <sys/prctl.h>
27 #include <systemd/sd-journal.h>
28 #include <systemd/sd-login.h>
34 #define COREDUMP_MAX (24*1024*1024)
46 static int divert_coredump(void) {
50 log_info("Detected coredump of the journal daemon itself, diverting coredump to /var/lib/systemd/coredump/.");
52 mkdir_p("/var/lib/systemd/coredump", 0755);
54 f = fopen("/var/lib/systemd/coredump/core.systemd-journald", "we");
56 log_error("Failed to create coredump file: %m");
64 l = fread(buffer, 1, sizeof(buffer), stdin);
67 log_error("Failed to read coredump: %m");
76 q = fwrite(buffer, 1, l, f);
78 log_error("Failed to write coredump: %m");
87 log_error("Failed to write coredump: %m");
96 int main(int argc, char* argv[]) {
103 struct iovec iovec[14];
104 char *core_pid = NULL, *core_uid = NULL, *core_gid = NULL, *core_signal = NULL,
105 *core_timestamp = NULL, *core_comm = NULL, *core_exe = NULL, *core_unit = NULL,
106 *core_session = NULL, *core_message = NULL, *core_cmdline = NULL, *t;
108 prctl(PR_SET_DUMPABLE, 0);
110 if (argc != _ARG_MAX) {
111 log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
114 log_error("Invalid number of arguments passed from kernel.");
119 r = parse_pid(argv[ARG_PID], &pid);
121 log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
124 log_error("Failed to parse PID.");
128 if (sd_pid_get_unit(pid, &t) >= 0) {
130 if (streq(t, SPECIAL_JOURNALD_SERVICE)) {
131 /* Make sure we don't make use of the journal,
132 * if it's the journal which is crashing */
133 log_set_target(LOG_TARGET_KMSG);
136 r = divert_coredump();
140 core_unit = strappend("COREDUMP_UNIT=", t);
144 IOVEC_SET_STRING(iovec[j++], core_unit);
147 /* OK, now we know it's not the journal, hence make use of
149 log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
152 r = parse_uid(argv[ARG_UID], &uid);
154 log_error("Failed to parse UID.");
158 r = parse_gid(argv[ARG_GID], &gid);
160 log_error("Failed to parse GID.");
164 core_pid = strappend("COREDUMP_PID=", argv[ARG_PID]);
166 IOVEC_SET_STRING(iovec[j++], core_pid);
168 core_uid = strappend("COREDUMP_UID=", argv[ARG_UID]);
170 IOVEC_SET_STRING(iovec[j++], core_uid);
172 core_gid = strappend("COREDUMP_GID=", argv[ARG_GID]);
174 IOVEC_SET_STRING(iovec[j++], core_gid);
176 core_signal = strappend("COREDUMP_SIGNAL=", argv[ARG_SIGNAL]);
178 IOVEC_SET_STRING(iovec[j++], core_signal);
180 core_comm = strappend("COREDUMP_COMM=", argv[ARG_COMM]);
182 IOVEC_SET_STRING(iovec[j++], core_comm);
184 if (sd_pid_get_session(pid, &t) >= 0) {
185 core_session = strappend("COREDUMP_SESSION=", t);
189 IOVEC_SET_STRING(iovec[j++], core_session);
192 if (get_process_exe(pid, &t) >= 0) {
193 core_exe = strappend("COREDUMP_EXE=", t);
197 IOVEC_SET_STRING(iovec[j++], core_exe);
200 if (get_process_cmdline(pid, LINE_MAX, false, &t) >= 0) {
201 core_cmdline = strappend("COREDUMP_CMDLINE=", t);
205 IOVEC_SET_STRING(iovec[j++], core_cmdline);
208 core_timestamp = join("COREDUMP_TIMESTAMP=", argv[ARG_TIMESTAMP], "000000", NULL);
210 IOVEC_SET_STRING(iovec[j++], core_timestamp);
212 IOVEC_SET_STRING(iovec[j++], "MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1");
213 IOVEC_SET_STRING(iovec[j++], "PRIORITY=2");
215 core_message = join("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") dumped core.", NULL);
217 IOVEC_SET_STRING(iovec[j++], core_message);
219 /* Now, let's drop privileges to become the user who owns the
220 * segfaulted process and allocate the coredump memory under
221 * his uid. This also ensures that the credentials journald
222 * will see are the ones of the coredumping user, thus making
223 * sure the user himself gets access to the core dump. */
225 if (setresgid(gid, gid, gid) < 0 ||
226 setresuid(uid, uid, uid) < 0) {
227 log_error("Failed to drop privileges: %m");
232 p = malloc(9 + COREDUMP_MAX);
234 log_error("Out of memory");
239 memcpy(p, "COREDUMP=", 9);
241 n = loop_read(STDIN_FILENO, p + 9, COREDUMP_MAX, false);
243 log_error("Failed to read core dump data: %s", strerror(-n));
248 iovec[j].iov_base = p;
249 iovec[j].iov_len = 9 + n;
252 r = sd_journal_sendv(iovec, j);
254 log_error("Failed to send coredump: %s", strerror(-r));
262 free(core_timestamp);
270 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;