journal: add tool to extract coredumps

'systemd-coredumpctl' will list available coredumps:
   PID   UID   GID sig exe
 32452  500  500  11 /home/zbyszek/systemd/build/journalctl
 32666  500  500  11 /usr/lib64/valgrind/memcheck-amd64-linux
...

'systemd-coredumpctl dump PID' will write the coredump
to specified file or stdout.

1 files changed, 393 insertions, 0 deletions

diff --git a/src/journal/coredumpctl.c b/src/journal/coredumpctl.c
new file mode 100644
index 0000000000..5c442ffe9b
--- /dev/null
+++ b/src/journal/coredumpctl.c
@@ -0,0 +1,393 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2012 Zbigniew Jędrzejewski-Szmek
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdio.h>
+#include <string.h>
+#include <getopt.h>
+
+#include <systemd/sd-journal.h>
+
+#include "build.h"
+#include "set.h"
+#include "util.h"
+#include "log.h"
+#include "path-util.h"
+#include "pager.h"
+
+static enum {
+        ACTION_NONE,
+        ACTION_LIST,
+        ACTION_DUMP,
+} arg_action = ACTION_LIST;
+
+Set *matches;
+FILE* output;
+
+int arg_no_pager;
+
+static Set *new_matches(void) {
+        Set *set;
+        char *tmp;
+        int r;
+
+        set = set_new(trivial_hash_func, trivial_compare_func);
+        if (!set) {
+                log_oom();
+                return NULL;
+        }
+
+        tmp = strdup("MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1");
+        if (!tmp) {
+                log_oom();
+                set_clear_free(set);
+                return NULL;
+        }
+
+        r = set_put(set, tmp);
+        if (r < 0) {
+                log_error("failed to add to set: %s", strerror(-r));
+                free(tmp);
+                set_clear_free(set);
+                return NULL;
+        }
+
+        return set;
+}
+
+static int help(void) {
+        printf("%s [OPTIONS...] [MATCHES...]\n\n"
+               "List or retrieve coredumps from the journal.\n\n"
+               "Flags:\n"
+               "  -o --output=FILE  Write output to FILE\n"
+               "     --no-pager     Do not pipe output into a pager\n"
+
+               "Commands:\n"
+               "  -h --help         Show this help\n"
+               "  --version         Print version string\n"
+               "  list              List available coredumps\n"
+               "  dump PID          Print coredump to stdout\n"
+               "  dump PATH         Print coredump to stdout\n"
+               , program_invocation_short_name);
+
+        return 0;
+}
+
+static int add_match(Set *set, const char *match) {
+        int r = -ENOMEM;
+        unsigned pid;
+        const char* prefix;
+        char *pattern = NULL;
+        char _cleanup_free_ *p = NULL;
+
+        if (strchr(match, '='))
+                prefix = "";
+        else if (strchr(match, '/')) {
+                p = path_make_absolute_cwd(match);
+                if (!p)
+                        goto fail;
+
+                match = p;
+                prefix = "COREDUMP_EXE=";
+        }
+        else if (safe_atou(match, &pid) == 0)
+                prefix = "COREDUMP_PID=";
+        else
+                prefix = "COREDUMP_COMM=";
+
+        pattern = strjoin(prefix, match, NULL);
+        if (!pattern)
+                goto fail;
+
+        r = set_put(set, pattern);
+        if (r < 0) {
+                log_error("failed to add pattern '%s': %s",
+                          pattern, strerror(-r));
+                goto fail;
+        }
+        log_debug("Added pattern: %s", pattern);
+
+        return 0;
+fail:
+        free(pattern);
+        log_error("failed to add match: %s", strerror(-r));
+        return r;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_NO_PAGER,
+        };
+
+        int r, c;
+
+        static const struct option options[] = {
+                { "help",         no_argument,       NULL, 'h'              },
+                { "version" ,     no_argument,       NULL, ARG_VERSION      },
+                { "no-pager",     no_argument,       NULL, ARG_NO_PAGER     },
+                { "output",       required_argument, NULL, 'o'              },
+        };
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "ho:", options, NULL)) >= 0)
+                switch(c) {
+                case 'h':
+                        help();
+                        arg_action = ACTION_NONE;
+                        return 0;
+
+                case ARG_VERSION:
+                        puts(PACKAGE_STRING);
+                        puts(DISTRIBUTION);
+                        puts(SYSTEMD_FEATURES);
+                        arg_action = ACTION_NONE;
+                        return 0;
+
+                case ARG_NO_PAGER:
+                        arg_no_pager = true;
+                        break;
+
+                case 'o':
+                        if (output) {
+                                log_error("cannot set output more than once");
+                                return -EINVAL;
+                        }
+
+                        output = fopen(optarg, "we");
+                        if (!output) {
+                                log_error("writing to '%s': %m", optarg);
+                                return -errno;
+                        }
+
+                        break;
+                default:
+                        log_error("Unknown option code %c", c);
+                        return -EINVAL;
+                }
+
+        if (optind < argc) {
+                const char *cmd = argv[optind++];
+                if(streq(cmd, "list"))
+                        arg_action = ACTION_LIST;
+                else if (streq(cmd, "dump"))
+                        arg_action = ACTION_DUMP;
+                else {
+                        log_error("Unknown action '%s'", cmd);
+                        return -EINVAL;
+                }
+        }
+
+        while (optind < argc) {
+                r = add_match(matches, argv[optind]);
+                if (r != 0)
+                        return r;
+                optind++;
+        }
+
+        return 0;
+}
+
+static int retrieve(sd_journal *j, const char *name, const char **var) {
+        const void *data;
+        size_t len, field;
+        int r;
+
+        r = sd_journal_get_data(j, name, &data, &len);
+        if (r < 0) {
+                log_warning("Failed to retrieve %s", name);
+                return r;
+        }
+
+        field = strlen(name) + 1; // name + "="
+        assert(len >= field);
+
+        *var = strndup((const char*)data + field, len - field);
+        if (!var)
+                return log_oom();
+
+        return 0;
+}
+
+static void print_entry(FILE* file, sd_journal *j, int had_header) {
+        const char _cleanup_free_
+                *pid = NULL, *uid = NULL, *gid = NULL,
+                *sgnl = NULL, *exe = NULL;
+
+        retrieve(j, "COREDUMP_PID", &pid);
+        retrieve(j, "COREDUMP_UID", &uid);
+        retrieve(j, "COREDUMP_GID", &gid);
+        retrieve(j, "COREDUMP_SIGNAL", &sgnl);
+        retrieve(j, "COREDUMP_EXE", &exe);
+        if (!exe)
+                retrieve(j, "COREDUMP_COMM", &exe);
+        if (!exe)
+                retrieve(j, "COREDUMP_CMDLINE", &exe);
+
+        if (!pid && !uid && !gid && !sgnl && !exe) {
+                log_warning("empty coredump log entry");
+                return;
+        }
+
+        if (!had_header)
+                fprintf(file, "%*s %*s %*s %*s %s\n",
+                        6, "PID",
+                        5, "UID",
+                        5, "GID",
+                        3, "sig",
+                        "exe");
+
+        fprintf(file, "%*s %*s %*s %*s %s\n",
+                6, pid,
+                5, uid,
+                5, gid,
+                3, sgnl,
+                exe);
+}
+
+static int dump_list(sd_journal *j) {
+        int found = 0;
+
+        assert(j);
+
+        SD_JOURNAL_FOREACH(j)
+                print_entry(stdout, j, found++);
+
+        if (!found) {
+                log_error("no coredumps found");
+                return -ESRCH;
+        }
+
+        return 0;
+}
+
+static int dump_core(sd_journal* j) {
+        const char *data;
+        size_t len, ret;
+        int r;
+
+        assert(j);
+
+        r = sd_journal_seek_tail(j);
+        if (r == 0)
+                r = sd_journal_previous(j);
+        if (r < 0) {
+                log_error("Failed to search journal: %s", strerror(-r));
+                return r;
+        }
+
+	if (r == 0) {
+		log_error("No match found");
+		return -ESRCH;
+	}
+
+        r = sd_journal_get_data(j, "COREDUMP", (const void**) &data, &len);
+        if (r != 0) {
+                log_error("retrieve COREDUMP field: %s", strerror(-r));
+                return r;
+        }
+
+        print_entry(output ? stdout : stderr, j, false);
+
+        if (on_tty() && !output) {
+                log_error("Refusing to dump core to tty");
+                return -ENOTTY;
+        }
+
+        assert(len >= 9);
+
+        ret = fwrite(data+9, len-9, 1, output ? output : stdout);
+        if (ret != 1) {
+                log_error("dumping coredump: %m (%zu)", ret);
+                return -errno;
+        }
+
+        r = sd_journal_previous(j);
+        if (r >= 0)
+                log_warning("More than one entry matches, ignoring rest.\n");
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        sd_journal *j = NULL;
+        const char* match;
+        Iterator it;
+        int r = 0;
+
+        log_parse_environment();
+        log_open();
+
+        matches = new_matches();
+        if (!matches)
+                goto end;
+
+        if (parse_argv(argc, argv))
+                goto end;
+
+        if (arg_action == ACTION_NONE)
+                goto end;
+
+        r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY);
+        if (r < 0) {
+                log_error("Failed to open journal: %s", strerror(-r));
+                goto end;
+        }
+
+        SET_FOREACH(match, matches, it) {
+                log_info("Matching: %s", match);
+
+                r = sd_journal_add_match(j, match, strlen(match));
+                if (r != 0) {
+                        log_error("Failed to add match '%s': %s",
+                                  match, strerror(-r));
+                        goto end;
+                }
+        }
+
+        switch(arg_action) {
+        case ACTION_LIST:
+                if (!arg_no_pager)
+                        pager_open();
+
+                r = dump_list(j);
+                break;
+        case ACTION_DUMP:
+                r = dump_core(j);
+                break;
+        case ACTION_NONE:
+                assert_not_reached("Shouldn't be here");
+        }
+
+end:
+        if (j)
+                sd_journal_close(j);
+
+        set_free_free(matches);
+
+        pager_close();
+
+        if (output)
+                fclose(output);
+
+        return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}