/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2012 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <errno.h> #include <unistd.h> #include <stdio.h> #include <sys/prctl.h> #include <systemd/sd-journal.h> #include <systemd/sd-login.h> #include "log.h" #include "util.h" #include "special.h" #define COREDUMP_MAX (24*1024*1024) enum { ARG_PID = 1, ARG_UID, ARG_GID, ARG_SIGNAL, ARG_TIMESTAMP, ARG_COMM, _ARG_MAX }; static int divert_coredump(void) { FILE *f; int r; log_info("Detected coredump of the journal daemon itself, diverting coredump to /var/lib/systemd/coredump/."); mkdir_p("/var/lib/systemd/coredump", 0755); f = fopen("/var/lib/systemd/coredump/core.systemd-journald", "we"); if (!f) { log_error("Failed to create coredump file: %m"); return -errno; } for (;;) { uint8_t buffer[4096]; size_t l, q; l = fread(buffer, 1, sizeof(buffer), stdin); if (l <= 0) { if (ferror(f)) { log_error("Failed to read coredump: %m"); r = -errno; goto finish; } r = 0; break; } q = fwrite(buffer, 1, l, f); if (q != l) { log_error("Failed to write coredump: %m"); r = -errno; goto finish; } } fflush(f); if (ferror(f)) { log_error("Failed to write coredump: %m"); r = -errno; } finish: fclose(f); return r; } int main(int argc, char* argv[]) { int r, j = 0; char *p = NULL; ssize_t n; pid_t pid; uid_t uid; gid_t gid; struct iovec iovec[14]; char *core_pid = NULL, *core_uid = NULL, *core_gid = NULL, *core_signal = NULL, *core_timestamp = NULL, *core_comm = NULL, *core_exe = NULL, *core_unit = NULL, *core_session = NULL, *core_message = NULL, *core_cmdline = NULL, *t; prctl(PR_SET_DUMPABLE, 0); if (argc != _ARG_MAX) { log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); log_open(); log_error("Invalid number of arguments passed from kernel."); r = -EINVAL; goto finish; } r = parse_pid(argv[ARG_PID], &pid); if (r < 0) { log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); log_open(); log_error("Failed to parse PID."); goto finish; } if (sd_pid_get_unit(pid, &t) >= 0) { if (streq(t, SPECIAL_JOURNALD_SERVICE)) { /* Make sure we don't make use of the journal, * if it's the journal which is crashing */ log_set_target(LOG_TARGET_KMSG); log_open(); r = divert_coredump(); goto finish; } core_unit = strappend("COREDUMP_UNIT=", t); free(t); if (core_unit) IOVEC_SET_STRING(iovec[j++], core_unit); } /* OK, now we know it's not the journal, hence make use of * it */ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); log_open(); r = parse_uid(argv[ARG_UID], &uid); if (r < 0) { log_error("Failed to parse UID."); goto finish; } r = parse_gid(argv[ARG_GID], &gid); if (r < 0) { log_error("Failed to parse GID."); goto finish; } core_pid = strappend("COREDUMP_PID=", argv[ARG_PID]); if (core_pid) IOVEC_SET_STRING(iovec[j++], core_pid); core_uid = strappend("COREDUMP_UID=", argv[ARG_UID]); if (core_uid) IOVEC_SET_STRING(iovec[j++], core_uid); core_gid = strappend("COREDUMP_GID=", argv[ARG_GID]); if (core_gid) IOVEC_SET_STRING(iovec[j++], core_gid); core_signal = strappend("COREDUMP_SIGNAL=", argv[ARG_SIGNAL]); if (core_signal) IOVEC_SET_STRING(iovec[j++], core_signal); core_comm = strappend("COREDUMP_COMM=", argv[ARG_COMM]); if (core_comm) IOVEC_SET_STRING(iovec[j++], core_comm); if (sd_pid_get_session(pid, &t) >= 0) { core_session = strappend("COREDUMP_SESSION=", t); free(t); if (core_session) IOVEC_SET_STRING(iovec[j++], core_session); } if (get_process_exe(pid, &t) >= 0) { core_exe = strappend("COREDUMP_EXE=", t); free(t); if (core_exe) IOVEC_SET_STRING(iovec[j++], core_exe); } if (get_process_cmdline(pid, LINE_MAX, false, &t) >= 0) { core_cmdline = strappend("COREDUMP_CMDLINE=", t); free(t); if (core_cmdline) IOVEC_SET_STRING(iovec[j++], core_cmdline); } core_timestamp = join("COREDUMP_TIMESTAMP=", argv[ARG_TIMESTAMP], "000000", NULL); if (core_timestamp) IOVEC_SET_STRING(iovec[j++], core_timestamp); IOVEC_SET_STRING(iovec[j++], "MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1"); IOVEC_SET_STRING(iovec[j++], "PRIORITY=2"); core_message = join("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") dumped core.", NULL); if (core_message) IOVEC_SET_STRING(iovec[j++], core_message); /* Now, let's drop privileges to become the user who owns the * segfaulted process and allocate the coredump memory under * his uid. This also ensures that the credentials journald * will see are the ones of the coredumping user, thus making * sure the user himself gets access to the core dump. */ if (setresgid(gid, gid, gid) < 0 || setresuid(uid, uid, uid) < 0) { log_error("Failed to drop privileges: %m"); r = -errno; goto finish; } p = malloc(9 + COREDUMP_MAX); if (!p) { log_error("Out of memory"); r = -ENOMEM; goto finish; } memcpy(p, "COREDUMP=", 9); n = loop_read(STDIN_FILENO, p + 9, COREDUMP_MAX, false); if (n < 0) { log_error("Failed to read core dump data: %s", strerror(-n)); r = (int) n; goto finish; } iovec[j].iov_base = p; iovec[j].iov_len = 9 + n; j++; r = sd_journal_sendv(iovec, j); if (r < 0) log_error("Failed to send coredump: %s", strerror(-r)); finish: free(p); free(core_pid); free(core_uid); free(core_gid); free(core_signal); free(core_timestamp); free(core_comm); free(core_exe); free(core_cmdline); free(core_unit); free(core_session); free(core_message); return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; }