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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ | |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2012 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
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 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <errno.h> | |
23 | #include <unistd.h> | |
24 | #include <stdio.h> | |
25 | #include <sys/prctl.h> | |
26 | ||
27 | #include <systemd/sd-journal.h> | |
28 | ||
29 | #ifdef HAVE_LOGIND | |
30 | #include <systemd/sd-login.h> | |
31 | #endif | |
32 | ||
33 | #include "log.h" | |
34 | #include "util.h" | |
35 | #include "macro.h" | |
36 | #include "mkdir.h" | |
37 | #include "special.h" | |
38 | #include "cgroup-util.h" | |
39 | ||
40 | /* Few programs have less than 3MiB resident */ | |
41 | #define COREDUMP_MIN_START (3*1024*1024) | |
42 | /* Make sure to not make this larger than the maximum journal entry | |
43 | * size. See ENTRY_SIZE_MAX in journald-native.c. */ | |
44 | #define COREDUMP_MAX (768*1024*1024) | |
45 | ||
46 | enum { | |
47 | ARG_PID = 1, | |
48 | ARG_UID, | |
49 | ARG_GID, | |
50 | ARG_SIGNAL, | |
51 | ARG_TIMESTAMP, | |
52 | ARG_COMM, | |
53 | _ARG_MAX | |
54 | }; | |
55 | ||
56 | static int divert_coredump(void) { | |
57 | _cleanup_fclose_ FILE *f = NULL; | |
58 | ||
59 | log_info("Detected coredump of the journal daemon itself, diverting coredump to /var/lib/systemd/coredump/."); | |
60 | ||
61 | mkdir_p_label("/var/lib/systemd/coredump", 0755); | |
62 | ||
63 | f = fopen("/var/lib/systemd/coredump/core.systemd-journald", "we"); | |
64 | if (!f) { | |
65 | log_error("Failed to create coredump file: %m"); | |
66 | return -errno; | |
67 | } | |
68 | ||
69 | for (;;) { | |
70 | uint8_t buffer[4096]; | |
71 | size_t l, q; | |
72 | ||
73 | l = fread(buffer, 1, sizeof(buffer), stdin); | |
74 | if (l <= 0) { | |
75 | if (ferror(f)) { | |
76 | log_error("Failed to read coredump: %m"); | |
77 | return -errno; | |
78 | } | |
79 | ||
80 | break; | |
81 | } | |
82 | ||
83 | q = fwrite(buffer, 1, l, f); | |
84 | if (q != l) { | |
85 | log_error("Failed to write coredump: %m"); | |
86 | return -errno; | |
87 | } | |
88 | } | |
89 | ||
90 | fflush(f); | |
91 | ||
92 | if (ferror(f)) { | |
93 | log_error("Failed to write coredump: %m"); | |
94 | return -errno; | |
95 | } | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | int main(int argc, char* argv[]) { | |
101 | int r, j = 0; | |
102 | char *t; | |
103 | ssize_t n; | |
104 | pid_t pid; | |
105 | uid_t uid; | |
106 | gid_t gid; | |
107 | struct iovec iovec[14]; | |
108 | size_t coredump_bufsize, coredump_size; | |
109 | _cleanup_free_ char *core_pid = NULL, *core_uid = NULL, *core_gid = NULL, *core_signal = NULL, | |
110 | *core_timestamp = NULL, *core_comm = NULL, *core_exe = NULL, *core_unit = NULL, | |
111 | *core_session = NULL, *core_message = NULL, *core_cmdline = NULL, *coredump_data = NULL; | |
112 | ||
113 | prctl(PR_SET_DUMPABLE, 0); | |
114 | ||
115 | if (argc != _ARG_MAX) { | |
116 | log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); | |
117 | log_open(); | |
118 | ||
119 | log_error("Invalid number of arguments passed from kernel."); | |
120 | r = -EINVAL; | |
121 | goto finish; | |
122 | } | |
123 | ||
124 | r = parse_pid(argv[ARG_PID], &pid); | |
125 | if (r < 0) { | |
126 | log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); | |
127 | log_open(); | |
128 | ||
129 | log_error("Failed to parse PID."); | |
130 | goto finish; | |
131 | } | |
132 | ||
133 | if (cg_pid_get_unit(pid, &t) >= 0) { | |
134 | ||
135 | if (streq(t, SPECIAL_JOURNALD_SERVICE)) { | |
136 | /* Make sure we don't make use of the journal, | |
137 | * if it's the journal which is crashing */ | |
138 | log_set_target(LOG_TARGET_KMSG); | |
139 | log_open(); | |
140 | ||
141 | r = divert_coredump(); | |
142 | goto finish; | |
143 | } | |
144 | ||
145 | core_unit = strappend("COREDUMP_UNIT=", t); | |
146 | } else if (cg_pid_get_user_unit(pid, &t) >= 0) | |
147 | core_unit = strappend("COREDUMP_USER_UNIT=", t); | |
148 | ||
149 | if (core_unit) | |
150 | IOVEC_SET_STRING(iovec[j++], core_unit); | |
151 | ||
152 | /* OK, now we know it's not the journal, hence make use of | |
153 | * it */ | |
154 | log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); | |
155 | log_open(); | |
156 | ||
157 | r = parse_uid(argv[ARG_UID], &uid); | |
158 | if (r < 0) { | |
159 | log_error("Failed to parse UID."); | |
160 | goto finish; | |
161 | } | |
162 | ||
163 | r = parse_gid(argv[ARG_GID], &gid); | |
164 | if (r < 0) { | |
165 | log_error("Failed to parse GID."); | |
166 | goto finish; | |
167 | } | |
168 | ||
169 | core_pid = strappend("COREDUMP_PID=", argv[ARG_PID]); | |
170 | if (core_pid) | |
171 | IOVEC_SET_STRING(iovec[j++], core_pid); | |
172 | ||
173 | core_uid = strappend("COREDUMP_UID=", argv[ARG_UID]); | |
174 | if (core_uid) | |
175 | IOVEC_SET_STRING(iovec[j++], core_uid); | |
176 | ||
177 | core_gid = strappend("COREDUMP_GID=", argv[ARG_GID]); | |
178 | if (core_gid) | |
179 | IOVEC_SET_STRING(iovec[j++], core_gid); | |
180 | ||
181 | core_signal = strappend("COREDUMP_SIGNAL=", argv[ARG_SIGNAL]); | |
182 | if (core_signal) | |
183 | IOVEC_SET_STRING(iovec[j++], core_signal); | |
184 | ||
185 | core_comm = strappend("COREDUMP_COMM=", argv[ARG_COMM]); | |
186 | if (core_comm) | |
187 | IOVEC_SET_STRING(iovec[j++], core_comm); | |
188 | ||
189 | #ifdef HAVE_LOGIND | |
190 | if (sd_pid_get_session(pid, &t) >= 0) { | |
191 | core_session = strappend("COREDUMP_SESSION=", t); | |
192 | free(t); | |
193 | ||
194 | if (core_session) | |
195 | IOVEC_SET_STRING(iovec[j++], core_session); | |
196 | } | |
197 | ||
198 | #endif | |
199 | ||
200 | if (get_process_exe(pid, &t) >= 0) { | |
201 | core_exe = strappend("COREDUMP_EXE=", t); | |
202 | free(t); | |
203 | ||
204 | if (core_exe) | |
205 | IOVEC_SET_STRING(iovec[j++], core_exe); | |
206 | } | |
207 | ||
208 | if (get_process_cmdline(pid, 0, false, &t) >= 0) { | |
209 | core_cmdline = strappend("COREDUMP_CMDLINE=", t); | |
210 | free(t); | |
211 | ||
212 | if (core_cmdline) | |
213 | IOVEC_SET_STRING(iovec[j++], core_cmdline); | |
214 | } | |
215 | ||
216 | core_timestamp = strjoin("COREDUMP_TIMESTAMP=", argv[ARG_TIMESTAMP], "000000", NULL); | |
217 | if (core_timestamp) | |
218 | IOVEC_SET_STRING(iovec[j++], core_timestamp); | |
219 | ||
220 | IOVEC_SET_STRING(iovec[j++], "MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1"); | |
221 | IOVEC_SET_STRING(iovec[j++], "PRIORITY=2"); | |
222 | ||
223 | core_message = strjoin("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") dumped core.", NULL); | |
224 | if (core_message) | |
225 | IOVEC_SET_STRING(iovec[j++], core_message); | |
226 | ||
227 | /* Now, let's drop privileges to become the user who owns the | |
228 | * segfaulted process and allocate the coredump memory under | |
229 | * his uid. This also ensures that the credentials journald | |
230 | * will see are the ones of the coredumping user, thus making | |
231 | * sure the user himself gets access to the core dump. */ | |
232 | ||
233 | if (setresgid(gid, gid, gid) < 0 || | |
234 | setresuid(uid, uid, uid) < 0) { | |
235 | log_error("Failed to drop privileges: %m"); | |
236 | r = -errno; | |
237 | goto finish; | |
238 | } | |
239 | ||
240 | coredump_bufsize = COREDUMP_MIN_START; | |
241 | coredump_data = malloc(coredump_bufsize); | |
242 | if (!coredump_data) { | |
243 | r = log_oom(); | |
244 | goto finish; | |
245 | } | |
246 | ||
247 | memcpy(coredump_data, "COREDUMP=", 9); | |
248 | coredump_size = 9; | |
249 | ||
250 | for (;;) { | |
251 | n = loop_read(STDIN_FILENO, coredump_data + coredump_size, | |
252 | coredump_bufsize - coredump_size, false); | |
253 | if (n < 0) { | |
254 | log_error("Failed to read core dump data: %s", strerror(-n)); | |
255 | r = (int) n; | |
256 | goto finish; | |
257 | } else if (n == 0) | |
258 | break; | |
259 | ||
260 | coredump_size += n; | |
261 | if (!GREEDY_REALLOC(coredump_data, coredump_bufsize, coredump_size + 1)) { | |
262 | r = log_oom(); | |
263 | goto finish; | |
264 | } | |
265 | } | |
266 | ||
267 | iovec[j].iov_base = coredump_data; | |
268 | iovec[j].iov_len = coredump_size; | |
269 | j++; | |
270 | ||
271 | r = sd_journal_sendv(iovec, j); | |
272 | if (r < 0) | |
273 | log_error("Failed to send coredump: %s", strerror(-r)); | |
274 | ||
275 | finish: | |
276 | return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; | |
277 | } |