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.

3 files changed, 588 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index e86e6347ed..42c481ed79 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -482,6 +482,7 @@ MANPAGES = \
 	man/journald.conf.5 \
 	man/systemd-journald.service.8 \
 	man/journalctl.1 \
+	man/systemd-coredumpctl.1 \
 	man/systemd-inhibit.1 \
 	man/systemd-remount-fs.service.8 \
 	man/systemd-update-utmp-runlevel.service.8 \
@@ -2457,6 +2458,13 @@ journalctl_LDADD += \
 	$(QRENCODE_LIBS)
 endif
 
+systemd_coredumpctl_SOURCES = \
+	src/journal/coredumpctl.c
+
+systemd_coredumpctl_LDADD = \
+	libsystemd-shared.la \
+	libsystemd-journal.la
+
 test_journal_SOURCES = \
 	src/journal/test-journal.c
 
@@ -2647,6 +2655,7 @@ rootbin_PROGRAMS += \
 	journalctl
 
 bin_PROGRAMS += \
+	systemd-coredumpctl \
 	systemd-cat
 
 dist_systemunit_DATA += \
diff --git a/man/systemd-coredumpctl.xml b/man/systemd-coredumpctl.xml
new file mode 100644
index 0000000000..378d40fa13
--- /dev/null
+++ b/man/systemd-coredumpctl.xml
@@ -0,0 +1,186 @@
+<?xml version='1.0'?> <!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+        "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+
+<!--
+  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/>.
+-->
+
+<refentry id="systemd-coredumpctl">
+
+        <refentryinfo>
+                <title>systemd-coredumpctl</title>
+                <productname>systemd</productname>
+
+                <authorgroup>
+                        <author>
+                                <contrib>Developer</contrib>
+                                <firstname>Zbigniew</firstname>
+                                <surname>Jędrzejewski-Szmek</surname>
+                                <email>zbyszek@in.waw.pl</email>
+                        </author>
+                </authorgroup>
+        </refentryinfo>
+
+        <refmeta>
+                <refentrytitle>systemd-coredumpctl</refentrytitle>
+                <manvolnum>1</manvolnum>
+        </refmeta>
+
+        <refnamediv>
+                <refname>systemd-coredumpctl</refname>
+                <refpurpose>Retrieve coredumps from the journal</refpurpose>
+        </refnamediv>
+
+        <refsynopsisdiv>
+                <cmdsynopsis>
+                        <command>systemd-coredumpctl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="req">COMMAND</arg> <arg choice="opt" rep="repeat">PID|COMM|EXE|MATCH</arg></command>
+                </cmdsynopsis>
+        </refsynopsisdiv>
+
+        <refsect1>
+                <title>Description</title>
+
+                <para><command>systemd-coredumpctl</command> may be used to
+                retrieve coredumps from
+                <citerefentry><refentrytitle>systemd-journald</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+        </refsect1>
+
+        <refsect1>
+                <title>Options</title>
+
+                <para>The following options are understood:</para>
+
+                <variablelist>
+                        <varlistentry>
+                                <term><option>--help</option></term>
+                                <term><option>-h</option></term>
+
+                                <listitem><para>Print a short help
+                                text and exit.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><option>--version</option></term>
+
+                                <listitem><para>Print a short version
+                                string and exit.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><option>--output=FILE</option></term>
+                                <term><option>-o FILE</option></term>
+
+                                <listitem><para>Write the core to
+                                <option>FILE</option>.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><option>--no-pager</option></term>
+
+                                <listitem><para>Do not pipe output of
+                                <command>list</command> into a
+                                pager.</para></listitem>
+                        </varlistentry>
+
+                </variablelist>
+
+                <para>The following commands are understood:</para>
+
+                <variablelist>
+                        <varlistentry>
+                                <term><command>list</command></term>
+
+                                <listitem><para>List coredumps captured in the journal
+                                matching specified characteristics.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><command>dump</command></term>
+
+                                <listitem><para>Extract the last coredump
+                                matching specified characteristics.
+                                Coredump will be written on stdout, unless
+                                an output file is specified with
+                                <option>-o/--output</option>.
+                                </para></listitem>
+                        </varlistentry>
+
+                </variablelist>
+
+        </refsect1>
+
+        <refsect1>
+                <title>Matching</title>
+
+                <para>Match can be:</para>
+
+                <variablelist>
+                        <varlistentry>
+                                <term><option>PID</option></term>
+
+                                <listitem><para>Process ID of the
+                                process that dumped
+                                core. An integer.</para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><option>COMM</option></term>
+
+                                <listitem><para>Name of the executable
+                                (matches <option>COREDUMP_COMM=</option>).
+                                Must not contain slashes.
+                                </para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><option>EXE</option></term>
+
+                                <listitem><para>Path to the executable
+                                (matches <option>COREDUMP_EXE=</option>).
+                                Must contain at least one slash.
+                                </para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><option>MATCH</option></term>
+
+                                <listitem><para>General journalctl predicates
+                                (see <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>).
+                                Must contain an equals sign.
+                                </para></listitem>
+                        </varlistentry>
+                </variablelist>
+        </refsect1>
+
+        <refsect1>
+                <title>Exit status</title>
+                <para>On success 0 is returned, a non-zero failure
+                code otherwise. Not finding any mathing coredumps is treated
+		as failure.
+		</para>
+        </refsect1>
+
+        <refsect1>
+                <title>See Also</title>
+                <para>
+                        <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                </para>
+        </refsect1>
+
+</refentry>
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;
+}