示例#1
0
int main(int argc, char* argv[]) {

        /* The small core field we allocate on the stack, to keep things simple */
        char
                *core_pid = NULL, *core_uid = NULL, *core_gid = NULL, *core_signal = NULL,
                *core_session = NULL, *core_exe = NULL, *core_comm = NULL, *core_cmdline = NULL,
                *core_cgroup = NULL, *core_cwd = NULL, *core_root = NULL, *core_unit = NULL,
                *core_slice = NULL;

        /* The larger ones we allocate on the heap */
        _cleanup_free_ char
                *core_timestamp = NULL,  *core_message = NULL, *coredump_data = NULL, *core_owner_uid = NULL,
                *core_open_fds = NULL, *core_proc_status = NULL, *core_proc_maps = NULL, *core_proc_limits = NULL,
                *core_proc_cgroup = NULL, *core_environ = NULL;

        _cleanup_free_ char *exe = NULL, *comm = NULL, *filename = NULL;
        const char *info[_INFO_LEN];

        _cleanup_close_ int coredump_fd = -1;

        struct iovec iovec[26];
        uint64_t coredump_size;
        int r, j = 0;
        uid_t uid, owner_uid;
        gid_t gid;
        pid_t pid;
        char *t;
        const char *p;

        /* Make sure we never enter a loop */
        prctl(PR_SET_DUMPABLE, 0);

        /* First, log to a safe place, since we don't know what
         * crashed and it might be journald which we'd rather not log
         * to then. */
        log_set_target(LOG_TARGET_KMSG);
        log_open();

        if (argc < INFO_COMM + 1) {
                log_error("Not enough arguments passed from kernel (%d, expected %d).",
                          argc - 1, INFO_COMM + 1 - 1);
                r = -EINVAL;
                goto finish;
        }

        /* Ignore all parse errors */
        parse_config();

        log_debug("Selected storage '%s'.", coredump_storage_to_string(arg_storage));
        log_debug("Selected compression %s.", yes_no(arg_compress));

        r = parse_uid(argv[INFO_UID + 1], &uid);
        if (r < 0) {
                log_error("Failed to parse UID.");
                goto finish;
        }

        r = parse_pid(argv[INFO_PID + 1], &pid);
        if (r < 0) {
                log_error("Failed to parse PID.");
                goto finish;
        }

        r = parse_gid(argv[INFO_GID + 1], &gid);
        if (r < 0) {
                log_error("Failed to parse GID.");
                goto finish;
        }

        if (get_process_comm(pid, &comm) < 0) {
                log_warning("Failed to get COMM, falling back to the command line.");
                comm = strv_join(argv + INFO_COMM + 1, " ");
        }

        if (get_process_exe(pid, &exe) < 0)
                log_warning("Failed to get EXE.");

        info[INFO_PID] = argv[INFO_PID + 1];
        info[INFO_UID] = argv[INFO_UID + 1];
        info[INFO_GID] = argv[INFO_GID + 1];
        info[INFO_SIGNAL] = argv[INFO_SIGNAL + 1];
        info[INFO_TIMESTAMP] = argv[INFO_TIMESTAMP + 1];
        info[INFO_COMM] = comm;
        info[INFO_EXE] = exe;

        if (cg_pid_get_unit(pid, &t) >= 0) {

                if (streq(t, SPECIAL_JOURNALD_SERVICE)) {
                        free(t);

                        /* If we are journald, we cut things short,
                         * don't write to the journal, but still
                         * create a coredump. */

                        if (arg_storage != COREDUMP_STORAGE_NONE)
                                arg_storage = COREDUMP_STORAGE_EXTERNAL;

                        r = save_external_coredump(info, uid, &filename, &coredump_fd, &coredump_size);
                        if (r < 0)
                                goto finish;

                        r = maybe_remove_external_coredump(filename, coredump_size);
                        if (r < 0)
                                goto finish;

                        log_info("Detected coredump of the journal daemon itself, diverted to %s.", filename);
                        goto finish;
                }

                core_unit = strjoina("COREDUMP_UNIT=", t);
                free(t);

        } else if (cg_pid_get_user_unit(pid, &t) >= 0) {
                core_unit = strjoina("COREDUMP_USER_UNIT=", t);
                free(t);
        }

        if (core_unit)
                IOVEC_SET_STRING(iovec[j++], core_unit);

        /* OK, now we know it's not the journal, hence we can make use
         * of it now. */
        log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
        log_open();

        core_pid = strjoina("COREDUMP_PID=", info[INFO_PID]);
        IOVEC_SET_STRING(iovec[j++], core_pid);

        core_uid = strjoina("COREDUMP_UID=", info[INFO_UID]);
        IOVEC_SET_STRING(iovec[j++], core_uid);

        core_gid = strjoina("COREDUMP_GID=", info[INFO_GID]);
        IOVEC_SET_STRING(iovec[j++], core_gid);

        core_signal = strjoina("COREDUMP_SIGNAL=", info[INFO_SIGNAL]);
        IOVEC_SET_STRING(iovec[j++], core_signal);

        if (sd_pid_get_session(pid, &t) >= 0) {
                core_session = strjoina("COREDUMP_SESSION=", t);
                free(t);

                IOVEC_SET_STRING(iovec[j++], core_session);
        }

        if (sd_pid_get_owner_uid(pid, &owner_uid) >= 0) {
                r = asprintf(&core_owner_uid,
                             "COREDUMP_OWNER_UID=" UID_FMT, owner_uid);
                if (r > 0)
                        IOVEC_SET_STRING(iovec[j++], core_owner_uid);
        }

        if (sd_pid_get_slice(pid, &t) >= 0) {
                core_slice = strjoina("COREDUMP_SLICE=", t);
                free(t);

                IOVEC_SET_STRING(iovec[j++], core_slice);
        }

        if (comm) {
                core_comm = strjoina("COREDUMP_COMM=", comm);
                IOVEC_SET_STRING(iovec[j++], core_comm);
        }

        if (exe) {
                core_exe = strjoina("COREDUMP_EXE=", exe);
                IOVEC_SET_STRING(iovec[j++], core_exe);
        }

        if (get_process_cmdline(pid, 0, false, &t) >= 0) {
                core_cmdline = strjoina("COREDUMP_CMDLINE=", t);
                free(t);

                IOVEC_SET_STRING(iovec[j++], core_cmdline);
        }

        if (cg_pid_get_path_shifted(pid, NULL, &t) >= 0) {
                core_cgroup = strjoina("COREDUMP_CGROUP=", t);
                free(t);

                IOVEC_SET_STRING(iovec[j++], core_cgroup);
        }

        if (compose_open_fds(pid, &t) >= 0) {
                core_open_fds = strappend("COREDUMP_OPEN_FDS=", t);
                free(t);

                if (core_open_fds)
                        IOVEC_SET_STRING(iovec[j++], core_open_fds);
        }

        p = procfs_file_alloca(pid, "status");
        if (read_full_file(p, &t, NULL) >= 0) {
                core_proc_status = strappend("COREDUMP_PROC_STATUS=", t);
                free(t);

                if (core_proc_status)
                        IOVEC_SET_STRING(iovec[j++], core_proc_status);
        }

        p = procfs_file_alloca(pid, "maps");
        if (read_full_file(p, &t, NULL) >= 0) {
                core_proc_maps = strappend("COREDUMP_PROC_MAPS=", t);
                free(t);

                if (core_proc_maps)
                        IOVEC_SET_STRING(iovec[j++], core_proc_maps);
        }

        p = procfs_file_alloca(pid, "limits");
        if (read_full_file(p, &t, NULL) >= 0) {
                core_proc_limits = strappend("COREDUMP_PROC_LIMITS=", t);
                free(t);

                if (core_proc_limits)
                        IOVEC_SET_STRING(iovec[j++], core_proc_limits);
        }

        p = procfs_file_alloca(pid, "cgroup");
        if (read_full_file(p, &t, NULL) >=0) {
                core_proc_cgroup = strappend("COREDUMP_PROC_CGROUP=", t);
                free(t);

                if (core_proc_cgroup)
                        IOVEC_SET_STRING(iovec[j++], core_proc_cgroup);
        }

        if (get_process_cwd(pid, &t) >= 0) {
                core_cwd = strjoina("COREDUMP_CWD=", t);
                free(t);

                IOVEC_SET_STRING(iovec[j++], core_cwd);
        }

        if (get_process_root(pid, &t) >= 0) {
                core_root = strjoina("COREDUMP_ROOT=", t);
                free(t);

                IOVEC_SET_STRING(iovec[j++], core_root);
        }

        if (get_process_environ(pid, &t) >= 0) {
                core_environ = strappend("COREDUMP_ENVIRON=", t);
                free(t);

                if (core_environ)
                        IOVEC_SET_STRING(iovec[j++], core_environ);
        }

        core_timestamp = strjoin("COREDUMP_TIMESTAMP=", info[INFO_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");

        /* Vacuum before we write anything again */
        coredump_vacuum(-1, arg_keep_free, arg_max_use);

        /* Always stream the coredump to disk, if that's possible */
        r = save_external_coredump(info, uid, &filename, &coredump_fd, &coredump_size);
        if (r < 0)
                /* skip whole core dumping part */
                goto log;

        /* If we don't want to keep the coredump on disk, remove it
         * now, as later on we will lack the privileges for
         * it. However, we keep the fd to it, so that we can still
         * process it and log it. */
        r = maybe_remove_external_coredump(filename, coredump_size);
        if (r < 0)
                goto finish;
        if (r == 0) {
                const char *coredump_filename;

                coredump_filename = strjoina("COREDUMP_FILENAME=", filename);
                IOVEC_SET_STRING(iovec[j++], coredump_filename);
        }

        /* Vacuum again, but exclude the coredump we just created */
        coredump_vacuum(coredump_fd, arg_keep_free, arg_max_use);

        /* Now, let's drop privileges to become the user who owns the
         * segfaulted process and allocate the coredump memory under
         * the user's uid. This also ensures that the credentials
         * journald will see are the ones of the coredumping user,
         * thus making sure the user gets access to the core
         * dump. Let's also get rid of all capabilities, if we run as
         * root, we won't need them anymore. */
        r = drop_privileges(uid, gid, 0);
        if (r < 0) {
                log_error_errno(r, "Failed to drop privileges: %m");
                goto finish;
        }

#ifdef HAVE_ELFUTILS
        /* Try to get a strack trace if we can */
        if (coredump_size <= arg_process_size_max) {
                _cleanup_free_ char *stacktrace = NULL;

                r = coredump_make_stack_trace(coredump_fd, exe, &stacktrace);
                if (r >= 0)
                        core_message = strjoin("MESSAGE=Process ", info[INFO_PID], " (", comm, ") of user ", info[INFO_UID], " dumped core.\n\n", stacktrace, NULL);
                else if (r == -EINVAL)
                        log_warning("Failed to generate stack trace: %s", dwfl_errmsg(dwfl_errno()));
                else
                        log_warning_errno(r, "Failed to generate stack trace: %m");
        }

        if (!core_message)
#endif
log:
        core_message = strjoin("MESSAGE=Process ", info[INFO_PID], " (", comm, ") of user ", info[INFO_UID], " dumped core.", NULL);
        if (core_message)
                IOVEC_SET_STRING(iovec[j++], core_message);

        /* Optionally store the entire coredump in the journal */
        if (IN_SET(arg_storage, COREDUMP_STORAGE_JOURNAL, COREDUMP_STORAGE_BOTH) &&
            coredump_size <= arg_journal_size_max) {
                size_t sz = 0;

                /* Store the coredump itself in the journal */

                r = allocate_journal_field(coredump_fd, (size_t) coredump_size, &coredump_data, &sz);
                if (r >= 0) {
                        iovec[j].iov_base = coredump_data;
                        iovec[j].iov_len = sz;
                        j++;
                }
        }

        r = sd_journal_sendv(iovec, j);
        if (r < 0)
                log_error_errno(r, "Failed to log coredump: %m");

finish:
        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}
static void test_get_process_comm(void) {
        struct stat st;
        _cleanup_free_ char *a = NULL, *c = NULL, *d = NULL, *f = NULL, *i = NULL, *cwd = NULL, *root = NULL;
        _cleanup_free_ char *env = NULL;
        pid_t e;
        uid_t u;
        gid_t g;
        dev_t h;
        int r;
        pid_t me;

        if (stat("/proc/1/comm", &st) == 0) {
                assert_se(get_process_comm(1, &a) >= 0);
                log_info("pid1 comm: '%s'", a);
        } else
                log_warning("/proc/1/comm does not exist.");

        assert_se(get_process_cmdline(1, 0, true, &c) >= 0);
        log_info("pid1 cmdline: '%s'", c);

        assert_se(get_process_cmdline(1, 8, false, &d) >= 0);
        log_info("pid1 cmdline truncated: '%s'", d);

        assert_se(get_process_ppid(1, &e) >= 0);
        log_info("pid1 ppid: "PID_FMT, e);
        assert_se(e == 0);

        assert_se(is_kernel_thread(1) == 0);

        r = get_process_exe(1, &f);
        assert_se(r >= 0 || r == -EACCES);
        log_info("pid1 exe: '%s'", strna(f));

        assert_se(get_process_uid(1, &u) == 0);
        log_info("pid1 uid: "UID_FMT, u);
        assert_se(u == 0);

        assert_se(get_process_gid(1, &g) == 0);
        log_info("pid1 gid: "GID_FMT, g);
        assert_se(g == 0);

        me = getpid();

        r = get_process_cwd(me, &cwd);
        assert_se(r >= 0 || r == -EACCES);
        log_info("pid1 cwd: '%s'", cwd);

        r = get_process_root(me, &root);
        assert_se(r >= 0 || r == -EACCES);
        log_info("pid1 root: '%s'", root);

        r = get_process_environ(me, &env);
        assert_se(r >= 0 || r == -EACCES);
        log_info("self strlen(environ): '%zu'", strlen(env));

        if (!detect_container())
                assert_se(get_ctty_devnr(1, &h) == -ENXIO);

        getenv_for_pid(1, "PATH", &i);
        log_info("pid1 $PATH: '%s'", strna(i));
}