./move.sh

1 files changed, 1148 insertions, 0 deletions

diff --git a/src/systemd-coredump/coredump.c b/src/systemd-coredump/coredump.c
new file mode 100644
index 0000000000..64ce54d97f
--- /dev/null
+++ b/src/systemd-coredump/coredump.c
@@ -0,0 +1,1148 @@
+/***
+  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 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 <errno.h>
+#include <stdio.h>
+#include <sys/prctl.h>
+#include <sys/xattr.h>
+#include <unistd.h>
+
+#ifdef HAVE_ELFUTILS
+#include <dwarf.h>
+#include <elfutils/libdwfl.h>
+#endif
+
+#include <systemd/sd-journal.h>
+#include <systemd/sd-login.h>
+#include <systemd/sd-daemon.h>
+
+#include "acl-util.h"
+#include "alloc-util.h"
+#include "capability-util.h"
+#include "cgroup-util.h"
+#include "compress.h"
+#include "conf-parser.h"
+#include "copy.h"
+#include "coredump-vacuum.h"
+#include "dirent-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "io-util.h"
+#include "journald-native.h"
+#include "log.h"
+#include "macro.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "process-util.h"
+#include "socket-util.h"
+#include "special.h"
+#include "stacktrace.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+#include "util.h"
+
+/* The maximum size up to which we process coredumps */
+#define PROCESS_SIZE_MAX ((uint64_t) (2LLU*1024LLU*1024LLU*1024LLU))
+
+/* The maximum size up to which we leave the coredump around on disk */
+#define EXTERNAL_SIZE_MAX PROCESS_SIZE_MAX
+
+/* The maximum size up to which we store the coredump in the journal */
+#define JOURNAL_SIZE_MAX ((size_t) (767LU*1024LU*1024LU))
+
+/* Make sure to not make this larger than the maximum journal entry
+ * size. See DATA_SIZE_MAX in journald-native.c. */
+assert_cc(JOURNAL_SIZE_MAX <= DATA_SIZE_MAX);
+
+enum {
+        /* We use this as array indexes for a couple of special fields we use for naming coredumping files, and
+         * attaching xattrs */
+        CONTEXT_PID,
+        CONTEXT_UID,
+        CONTEXT_GID,
+        CONTEXT_SIGNAL,
+        CONTEXT_TIMESTAMP,
+        CONTEXT_RLIMIT,
+        CONTEXT_COMM,
+        CONTEXT_EXE,
+        _CONTEXT_MAX
+};
+
+typedef enum CoredumpStorage {
+        COREDUMP_STORAGE_NONE,
+        COREDUMP_STORAGE_EXTERNAL,
+        COREDUMP_STORAGE_JOURNAL,
+        COREDUMP_STORAGE_BOTH,
+        _COREDUMP_STORAGE_MAX,
+        _COREDUMP_STORAGE_INVALID = -1
+} CoredumpStorage;
+
+static const char* const coredump_storage_table[_COREDUMP_STORAGE_MAX] = {
+        [COREDUMP_STORAGE_NONE] = "none",
+        [COREDUMP_STORAGE_EXTERNAL] = "external",
+        [COREDUMP_STORAGE_JOURNAL] = "journal",
+        [COREDUMP_STORAGE_BOTH] = "both",
+};
+
+DEFINE_PRIVATE_STRING_TABLE_LOOKUP(coredump_storage, CoredumpStorage);
+static DEFINE_CONFIG_PARSE_ENUM(config_parse_coredump_storage, coredump_storage, CoredumpStorage, "Failed to parse storage setting");
+
+static CoredumpStorage arg_storage = COREDUMP_STORAGE_EXTERNAL;
+static bool arg_compress = true;
+static uint64_t arg_process_size_max = PROCESS_SIZE_MAX;
+static uint64_t arg_external_size_max = EXTERNAL_SIZE_MAX;
+static size_t arg_journal_size_max = JOURNAL_SIZE_MAX;
+static uint64_t arg_keep_free = (uint64_t) -1;
+static uint64_t arg_max_use = (uint64_t) -1;
+
+static int parse_config(void) {
+        static const ConfigTableItem items[] = {
+                { "Coredump", "Storage",          config_parse_coredump_storage,  0, &arg_storage           },
+                { "Coredump", "Compress",         config_parse_bool,              0, &arg_compress          },
+                { "Coredump", "ProcessSizeMax",   config_parse_iec_uint64,        0, &arg_process_size_max  },
+                { "Coredump", "ExternalSizeMax",  config_parse_iec_uint64,        0, &arg_external_size_max },
+                { "Coredump", "JournalSizeMax",   config_parse_iec_size,          0, &arg_journal_size_max  },
+                { "Coredump", "KeepFree",         config_parse_iec_uint64,        0, &arg_keep_free         },
+                { "Coredump", "MaxUse",           config_parse_iec_uint64,        0, &arg_max_use           },
+                {}
+        };
+
+        return config_parse_many(PKGSYSCONFDIR "/coredump.conf",
+                                 CONF_PATHS_NULSTR("systemd/coredump.conf.d"),
+                                 "Coredump\0",
+                                 config_item_table_lookup, items,
+                                 false, NULL);
+}
+
+static int fix_acl(int fd, uid_t uid) {
+
+#ifdef HAVE_ACL
+        _cleanup_(acl_freep) acl_t acl = NULL;
+        acl_entry_t entry;
+        acl_permset_t permset;
+        int r;
+
+        assert(fd >= 0);
+
+        if (uid <= SYSTEM_UID_MAX)
+                return 0;
+
+        /* Make sure normal users can read (but not write or delete)
+         * their own coredumps */
+
+        acl = acl_get_fd(fd);
+        if (!acl)
+                return log_error_errno(errno, "Failed to get ACL: %m");
+
+        if (acl_create_entry(&acl, &entry) < 0 ||
+            acl_set_tag_type(entry, ACL_USER) < 0 ||
+            acl_set_qualifier(entry, &uid) < 0) {
+                log_error_errno(errno, "Failed to patch ACL: %m");
+                return -errno;
+        }
+
+        if (acl_get_permset(entry, &permset) < 0 ||
+            acl_add_perm(permset, ACL_READ) < 0)
+                return log_warning_errno(errno, "Failed to patch ACL: %m");
+
+        r = calc_acl_mask_if_needed(&acl);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to patch ACL: %m");
+
+        if (acl_set_fd(fd, acl) < 0)
+                return log_error_errno(errno, "Failed to apply ACL: %m");
+#endif
+
+        return 0;
+}
+
+static int fix_xattr(int fd, const char *context[_CONTEXT_MAX]) {
+
+        static const char * const xattrs[_CONTEXT_MAX] = {
+                [CONTEXT_PID] = "user.coredump.pid",
+                [CONTEXT_UID] = "user.coredump.uid",
+                [CONTEXT_GID] = "user.coredump.gid",
+                [CONTEXT_SIGNAL] = "user.coredump.signal",
+                [CONTEXT_TIMESTAMP] = "user.coredump.timestamp",
+                [CONTEXT_COMM] = "user.coredump.comm",
+                [CONTEXT_EXE] = "user.coredump.exe",
+        };
+
+        int r = 0;
+        unsigned i;
+
+        assert(fd >= 0);
+
+        /* Attach some metadata to coredumps via extended
+         * attributes. Just because we can. */
+
+        for (i = 0; i < _CONTEXT_MAX; i++) {
+                int k;
+
+                if (isempty(context[i]) || !xattrs[i])
+                        continue;
+
+                k = fsetxattr(fd, xattrs[i], context[i], strlen(context[i]), XATTR_CREATE);
+                if (k < 0 && r == 0)
+                        r = -errno;
+        }
+
+        return r;
+}
+
+#define filename_escape(s) xescape((s), "./ ")
+
+static int fix_permissions(
+                int fd,
+                const char *filename,
+                const char *target,
+                const char *context[_CONTEXT_MAX],
+                uid_t uid) {
+
+        assert(fd >= 0);
+        assert(filename);
+        assert(target);
+        assert(context);
+
+        /* Ignore errors on these */
+        (void) fchmod(fd, 0640);
+        (void) fix_acl(fd, uid);
+        (void) fix_xattr(fd, context);
+
+        if (fsync(fd) < 0)
+                return log_error_errno(errno, "Failed to sync coredump %s: %m", filename);
+
+        if (rename(filename, target) < 0)
+                return log_error_errno(errno, "Failed to rename coredump %s -> %s: %m", filename, target);
+
+        return 0;
+}
+
+static int maybe_remove_external_coredump(const char *filename, uint64_t size) {
+
+        /* Returns 1 if might remove, 0 if will not remove, < 0 on error. */
+
+        if (IN_SET(arg_storage, COREDUMP_STORAGE_EXTERNAL, COREDUMP_STORAGE_BOTH) &&
+            size <= arg_external_size_max)
+                return 0;
+
+        if (!filename)
+                return 1;
+
+        if (unlink(filename) < 0 && errno != ENOENT)
+                return log_error_errno(errno, "Failed to unlink %s: %m", filename);
+
+        return 1;
+}
+
+static int make_filename(const char *context[_CONTEXT_MAX], char **ret) {
+        _cleanup_free_ char *c = NULL, *u = NULL, *p = NULL, *t = NULL;
+        sd_id128_t boot = {};
+        int r;
+
+        assert(context);
+
+        c = filename_escape(context[CONTEXT_COMM]);
+        if (!c)
+                return -ENOMEM;
+
+        u = filename_escape(context[CONTEXT_UID]);
+        if (!u)
+                return -ENOMEM;
+
+        r = sd_id128_get_boot(&boot);
+        if (r < 0)
+                return r;
+
+        p = filename_escape(context[CONTEXT_PID]);
+        if (!p)
+                return -ENOMEM;
+
+        t = filename_escape(context[CONTEXT_TIMESTAMP]);
+        if (!t)
+                return -ENOMEM;
+
+        if (asprintf(ret,
+                     "/var/lib/systemd/coredump/core.%s.%s." SD_ID128_FORMAT_STR ".%s.%s000000",
+                     c,
+                     u,
+                     SD_ID128_FORMAT_VAL(boot),
+                     p,
+                     t) < 0)
+                return -ENOMEM;
+
+        return 0;
+}
+
+static int save_external_coredump(
+                const char *context[_CONTEXT_MAX],
+                int input_fd,
+                char **ret_filename,
+                int *ret_node_fd,
+                int *ret_data_fd,
+                uint64_t *ret_size) {
+
+        _cleanup_free_ char *fn = NULL, *tmp = NULL;
+        _cleanup_close_ int fd = -1;
+        uint64_t rlimit, max_size;
+        struct stat st;
+        uid_t uid;
+        int r;
+
+        assert(context);
+        assert(ret_filename);
+        assert(ret_node_fd);
+        assert(ret_data_fd);
+        assert(ret_size);
+
+        r = parse_uid(context[CONTEXT_UID], &uid);
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse UID: %m");
+
+        r = safe_atou64(context[CONTEXT_RLIMIT], &rlimit);
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse resource limit: %s", context[CONTEXT_RLIMIT]);
+        if (rlimit <= 0) {
+                /* Is coredumping disabled? Then don't bother saving/processing the coredump */
+                log_info("Core Dumping has been disabled for process %s (%s).", context[CONTEXT_PID], context[CONTEXT_COMM]);
+                return -EBADSLT;
+        }
+
+        /* Never store more than the process configured, or than we actually shall keep or process */
+        max_size = MIN(rlimit, MAX(arg_process_size_max, arg_external_size_max));
+
+        r = make_filename(context, &fn);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine coredump file name: %m");
+
+        r = tempfn_random(fn, NULL, &tmp);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine temporary file name: %m");
+
+        mkdir_p_label("/var/lib/systemd/coredump", 0755);
+
+        fd = open(tmp, O_CREAT|O_EXCL|O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0640);
+        if (fd < 0)
+                return log_error_errno(errno, "Failed to create coredump file %s: %m", tmp);
+
+        r = copy_bytes(input_fd, fd, max_size, false);
+        if (r == -EFBIG) {
+                log_error("Coredump of %s (%s) is larger than configured processing limit, refusing.", context[CONTEXT_PID], context[CONTEXT_COMM]);
+                goto fail;
+        } else if (IN_SET(r, -EDQUOT, -ENOSPC)) {
+                log_error("Not enough disk space for coredump of %s (%s), refusing.", context[CONTEXT_PID], context[CONTEXT_COMM]);
+                goto fail;
+        } else if (r < 0) {
+                log_error_errno(r, "Failed to dump coredump to file: %m");
+                goto fail;
+        }
+
+        if (fstat(fd, &st) < 0) {
+                log_error_errno(errno, "Failed to fstat coredump %s: %m", tmp);
+                goto fail;
+        }
+
+        if (lseek(fd, 0, SEEK_SET) == (off_t) -1) {
+                log_error_errno(errno, "Failed to seek on %s: %m", tmp);
+                goto fail;
+        }
+
+#if defined(HAVE_XZ) || defined(HAVE_LZ4)
+        /* If we will remove the coredump anyway, do not compress. */
+        if (maybe_remove_external_coredump(NULL, st.st_size) == 0
+            && arg_compress) {
+
+                _cleanup_free_ char *fn_compressed = NULL, *tmp_compressed = NULL;
+                _cleanup_close_ int fd_compressed = -1;
+
+                fn_compressed = strappend(fn, COMPRESSED_EXT);
+                if (!fn_compressed) {
+                        log_oom();
+                        goto uncompressed;
+                }
+
+                r = tempfn_random(fn_compressed, NULL, &tmp_compressed);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to determine temporary file name for %s: %m", fn_compressed);
+                        goto uncompressed;
+                }
+
+                fd_compressed = open(tmp_compressed, O_CREAT|O_EXCL|O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0640);
+                if (fd_compressed < 0) {
+                        log_error_errno(errno, "Failed to create file %s: %m", tmp_compressed);
+                        goto uncompressed;
+                }
+
+                r = compress_stream(fd, fd_compressed, -1);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to compress %s: %m", tmp_compressed);
+                        goto fail_compressed;
+                }
+
+                r = fix_permissions(fd_compressed, tmp_compressed, fn_compressed, context, uid);
+                if (r < 0)
+                        goto fail_compressed;
+
+                /* OK, this worked, we can get rid of the uncompressed version now */
+                unlink_noerrno(tmp);
+
+                *ret_filename = fn_compressed;     /* compressed */
+                *ret_node_fd = fd_compressed;      /* compressed */
+                *ret_data_fd = fd;                 /* uncompressed */
+                *ret_size = (uint64_t) st.st_size; /* uncompressed */
+
+                fn_compressed = NULL;
+                fd = fd_compressed = -1;
+
+                return 0;
+
+        fail_compressed:
+                (void) unlink(tmp_compressed);
+        }
+
+uncompressed:
+#endif
+
+        r = fix_permissions(fd, tmp, fn, context, uid);
+        if (r < 0)
+                goto fail;
+
+        *ret_filename = fn;
+        *ret_data_fd = fd;
+        *ret_node_fd = -1;
+        *ret_size = (uint64_t) st.st_size;
+
+        fn = NULL;
+        fd = -1;
+
+        return 0;
+
+fail:
+        (void) unlink(tmp);
+        return r;
+}
+
+static int allocate_journal_field(int fd, size_t size, char **ret, size_t *ret_size) {
+        _cleanup_free_ char *field = NULL;
+        ssize_t n;
+
+        assert(fd >= 0);
+        assert(ret);
+        assert(ret_size);
+
+        if (lseek(fd, 0, SEEK_SET) == (off_t) -1)
+                return log_warning_errno(errno, "Failed to seek: %m");
+
+        field = malloc(9 + size);
+        if (!field) {
+                log_warning("Failed to allocate memory for coredump, coredump will not be stored.");
+                return -ENOMEM;
+        }
+
+        memcpy(field, "COREDUMP=", 9);
+
+        n = read(fd, field + 9, size);
+        if (n < 0)
+                return log_error_errno((int) n, "Failed to read core data: %m");
+        if ((size_t) n < size) {
+                log_error("Core data too short.");
+                return -EIO;
+        }
+
+        *ret = field;
+        *ret_size = size + 9;
+
+        field = NULL;
+
+        return 0;
+}
+
+/* Joins /proc/[pid]/fd/ and /proc/[pid]/fdinfo/ into the following lines:
+ * 0:/dev/pts/23
+ * pos:    0
+ * flags:  0100002
+ *
+ * 1:/dev/pts/23
+ * pos:    0
+ * flags:  0100002
+ *
+ * 2:/dev/pts/23
+ * pos:    0
+ * flags:  0100002
+ * EOF
+ */
+static int compose_open_fds(pid_t pid, char **open_fds) {
+        _cleanup_closedir_ DIR *proc_fd_dir = NULL;
+        _cleanup_close_ int proc_fdinfo_fd = -1;
+        _cleanup_free_ char *buffer = NULL;
+        _cleanup_fclose_ FILE *stream = NULL;
+        const char *fddelim = "", *path;
+        struct dirent *dent = NULL;
+        size_t size = 0;
+        int r = 0;
+
+        assert(pid >= 0);
+        assert(open_fds != NULL);
+
+        path = procfs_file_alloca(pid, "fd");
+        proc_fd_dir = opendir(path);
+        if (!proc_fd_dir)
+                return -errno;
+
+        proc_fdinfo_fd = openat(dirfd(proc_fd_dir), "../fdinfo", O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC|O_PATH);
+        if (proc_fdinfo_fd < 0)
+                return -errno;
+
+        stream = open_memstream(&buffer, &size);
+        if (!stream)
+                return -ENOMEM;
+
+        FOREACH_DIRENT(dent, proc_fd_dir, return -errno) {
+                _cleanup_fclose_ FILE *fdinfo = NULL;
+                _cleanup_free_ char *fdname = NULL;
+                char line[LINE_MAX];
+                int fd;
+
+                r = readlinkat_malloc(dirfd(proc_fd_dir), dent->d_name, &fdname);
+                if (r < 0)
+                        return r;
+
+                fprintf(stream, "%s%s:%s\n", fddelim, dent->d_name, fdname);
+                fddelim = "\n";
+
+                /* Use the directory entry from /proc/[pid]/fd with /proc/[pid]/fdinfo */
+                fd = openat(proc_fdinfo_fd, dent->d_name, O_NOFOLLOW|O_CLOEXEC|O_RDONLY);
+                if (fd < 0)
+                        continue;
+
+                fdinfo = fdopen(fd, "re");
+                if (fdinfo == NULL) {
+                        close(fd);
+                        continue;
+                }
+
+                FOREACH_LINE(line, fdinfo, break) {
+                        fputs(line, stream);
+                        if (!endswith(line, "\n"))
+                                fputc('\n', stream);
+                }
+        }
+
+        errno = 0;
+        stream = safe_fclose(stream);
+
+        if (errno > 0)
+                return -errno;
+
+        *open_fds = buffer;
+        buffer = NULL;
+
+        return 0;
+}
+
+static int change_uid_gid(const char *context[]) {
+        uid_t uid;
+        gid_t gid;
+        int r;
+
+        r = parse_uid(context[CONTEXT_UID], &uid);
+        if (r < 0)
+                return r;
+
+        if (uid <= SYSTEM_UID_MAX) {
+                const char *user = "systemd-coredump";
+
+                r = get_user_creds(&user, &uid, &gid, NULL, NULL);
+                if (r < 0) {
+                        log_warning_errno(r, "Cannot resolve %s user. Proceeding to dump core as root: %m", user);
+                        uid = gid = 0;
+                }
+        } else {
+                r = parse_gid(context[CONTEXT_GID], &gid);
+                if (r < 0)
+                        return r;
+        }
+
+        return drop_privileges(uid, gid, 0);
+}
+
+static int submit_coredump(
+                const char *context[_CONTEXT_MAX],
+                struct iovec *iovec,
+                size_t n_iovec_allocated,
+                size_t n_iovec,
+                int input_fd) {
+
+        _cleanup_close_ int coredump_fd = -1, coredump_node_fd = -1;
+        _cleanup_free_ char *core_message = NULL, *filename = NULL, *coredump_data = NULL;
+        uint64_t coredump_size;
+        int r;
+
+        assert(context);
+        assert(iovec);
+        assert(n_iovec_allocated >= n_iovec + 3);
+        assert(input_fd >= 0);
+
+        /* Vacuum before we write anything again */
+        (void) coredump_vacuum(-1, arg_keep_free, arg_max_use);
+
+        /* Always stream the coredump to disk, if that's possible */
+        r = save_external_coredump(context, input_fd, &filename, &coredump_node_fd, &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)
+                return r;
+        if (r == 0) {
+                const char *coredump_filename;
+
+                coredump_filename = strjoina("COREDUMP_FILENAME=", filename);
+                IOVEC_SET_STRING(iovec[n_iovec++], coredump_filename);
+        }
+
+        /* Vacuum again, but exclude the coredump we just created */
+        (void) coredump_vacuum(coredump_node_fd >= 0 ? coredump_node_fd : 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 = change_uid_gid(context);
+        if (r < 0)
+                return log_error_errno(r, "Failed to drop privileges: %m");
+
+#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, context[CONTEXT_EXE], &stacktrace);
+                if (r >= 0)
+                        core_message = strjoin("MESSAGE=Process ", context[CONTEXT_PID], " (", context[CONTEXT_COMM], ") of user ", context[CONTEXT_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 ", context[CONTEXT_PID], " (", context[CONTEXT_COMM], ") of user ", context[CONTEXT_UID], " dumped core.", NULL);
+        if (core_message)
+                IOVEC_SET_STRING(iovec[n_iovec++], 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[n_iovec].iov_base = coredump_data;
+                        iovec[n_iovec].iov_len = sz;
+                        n_iovec++;
+                }
+        }
+
+        assert(n_iovec <= n_iovec_allocated);
+
+        r = sd_journal_sendv(iovec, n_iovec);
+        if (r < 0)
+                return log_error_errno(r, "Failed to log coredump: %m");
+
+        return 0;
+}
+
+static void map_context_fields(const struct iovec *iovec, const char *context[]) {
+
+        static const char * const context_field_names[_CONTEXT_MAX] = {
+                [CONTEXT_PID] = "COREDUMP_PID=",
+                [CONTEXT_UID] = "COREDUMP_UID=",
+                [CONTEXT_GID] = "COREDUMP_GID=",
+                [CONTEXT_SIGNAL] = "COREDUMP_SIGNAL=",
+                [CONTEXT_TIMESTAMP] = "COREDUMP_TIMESTAMP=",
+                [CONTEXT_COMM] = "COREDUMP_COMM=",
+                [CONTEXT_EXE] = "COREDUMP_EXE=",
+                [CONTEXT_RLIMIT] = "COREDUMP_RLIMIT=",
+        };
+
+        unsigned i;
+
+        assert(iovec);
+        assert(context);
+
+        for (i = 0; i < _CONTEXT_MAX; i++) {
+                size_t l;
+
+                l = strlen(context_field_names[i]);
+                if (iovec->iov_len < l)
+                        continue;
+
+                if (memcmp(iovec->iov_base, context_field_names[i], l) != 0)
+                        continue;
+
+                /* Note that these strings are NUL terminated, because we made sure that a trailing NUL byte is in the
+                 * buffer, though not included in the iov_len count. (see below) */
+                context[i] = (char*) iovec->iov_base + l;
+                break;
+        }
+}
+
+static int process_socket(int fd) {
+        _cleanup_close_ int coredump_fd = -1;
+        struct iovec *iovec = NULL;
+        size_t n_iovec = 0, n_iovec_allocated = 0, i;
+        const char *context[_CONTEXT_MAX] = {};
+        int r;
+
+        assert(fd >= 0);
+
+        log_set_target(LOG_TARGET_AUTO);
+        log_parse_environment();
+        log_open();
+
+        for (;;) {
+                union {
+                        struct cmsghdr cmsghdr;
+                        uint8_t buf[CMSG_SPACE(sizeof(int))];
+                } control = {};
+                struct msghdr mh = {
+                        .msg_control = &control,
+                        .msg_controllen = sizeof(control),
+                        .msg_iovlen = 1,
+                };
+                ssize_t n;
+                int l;
+
+                if (!GREEDY_REALLOC(iovec, n_iovec_allocated, n_iovec + 3)) {
+                        r = log_oom();
+                        goto finish;
+                }
+
+                if (ioctl(fd, FIONREAD, &l) < 0) {
+                        r = log_error_errno(errno, "FIONREAD failed: %m");
+                        goto finish;
+                }
+
+                assert(l >= 0);
+
+                iovec[n_iovec].iov_len = l;
+                iovec[n_iovec].iov_base = malloc(l + 1);
+
+                if (!iovec[n_iovec].iov_base) {
+                        r = log_oom();
+                        goto finish;
+                }
+
+                mh.msg_iov = iovec + n_iovec;
+
+                n = recvmsg(fd, &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
+                if (n < 0)  {
+                        free(iovec[n_iovec].iov_base);
+                        r = log_error_errno(errno, "Failed to receive datagram: %m");
+                        goto finish;
+                }
+
+                if (n == 0) {
+                        struct cmsghdr *cmsg, *found = NULL;
+                        /* The final zero-length datagram carries the file descriptor and tells us that we're done. */
+
+                        free(iovec[n_iovec].iov_base);
+
+                        CMSG_FOREACH(cmsg, &mh) {
+                                if (cmsg->cmsg_level == SOL_SOCKET &&
+                                    cmsg->cmsg_type == SCM_RIGHTS &&
+                                    cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
+                                        assert(!found);
+                                        found = cmsg;
+                                }
+                        }
+
+                        if (!found) {
+                                log_error("Coredump file descriptor missing.");
+                                r = -EBADMSG;
+                                goto finish;
+                        }
+
+                        assert(coredump_fd < 0);
+                        coredump_fd = *(int*) CMSG_DATA(found);
+                        break;
+                }
+
+                /* Add trailing NUL byte, in case these are strings */
+                ((char*) iovec[n_iovec].iov_base)[n] = 0;
+                iovec[n_iovec].iov_len = (size_t) n;
+
+                cmsg_close_all(&mh);
+                map_context_fields(iovec + n_iovec, context);
+                n_iovec++;
+        }
+
+        if (!GREEDY_REALLOC(iovec, n_iovec_allocated, n_iovec + 3)) {
+                r = log_oom();
+                goto finish;
+        }
+
+        /* Make sure we we got all data we really need */
+        assert(context[CONTEXT_PID]);
+        assert(context[CONTEXT_UID]);
+        assert(context[CONTEXT_GID]);
+        assert(context[CONTEXT_SIGNAL]);
+        assert(context[CONTEXT_TIMESTAMP]);
+        assert(context[CONTEXT_RLIMIT]);
+        assert(context[CONTEXT_COMM]);
+        assert(coredump_fd >= 0);
+
+        r = submit_coredump(context, iovec, n_iovec_allocated, n_iovec, coredump_fd);
+
+finish:
+        for (i = 0; i < n_iovec; i++)
+                free(iovec[i].iov_base);
+        free(iovec);
+
+        return r;
+}
+
+static int send_iovec(const struct iovec iovec[], size_t n_iovec, int input_fd) {
+
+        static const union sockaddr_union sa = {
+                .un.sun_family = AF_UNIX,
+                .un.sun_path = "/run/systemd/coredump",
+        };
+        _cleanup_close_ int fd = -1;
+        size_t i;
+        int r;
+
+        assert(iovec || n_iovec <= 0);
+        assert(input_fd >= 0);
+
+        fd = socket(AF_UNIX, SOCK_SEQPACKET|SOCK_CLOEXEC, 0);
+        if (fd < 0)
+                return log_error_errno(errno, "Failed to create coredump socket: %m");
+
+        if (connect(fd, &sa.sa, offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path)) < 0)
+                return log_error_errno(errno, "Failed to connect to coredump service: %m");
+
+        for (i = 0; i < n_iovec; i++) {
+                ssize_t n;
+                assert(iovec[i].iov_len > 0);
+
+                n = send(fd, iovec[i].iov_base, iovec[i].iov_len, MSG_NOSIGNAL);
+                if (n < 0)
+                        return log_error_errno(errno, "Failed to send coredump datagram: %m");
+        }
+
+        r = send_one_fd(fd, input_fd, 0);
+        if (r < 0)
+                return log_error_errno(r, "Failed to send coredump fd: %m");
+
+        return 0;
+}
+
+static int process_journald_crash(const char *context[], int input_fd) {
+        _cleanup_close_ int coredump_fd = -1, coredump_node_fd = -1;
+        _cleanup_free_ char *filename = NULL;
+        uint64_t coredump_size;
+        int r;
+
+        assert(context);
+        assert(input_fd >= 0);
+
+        /* 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(context, input_fd, &filename, &coredump_node_fd, &coredump_fd, &coredump_size);
+        if (r < 0)
+                return r;
+
+        r = maybe_remove_external_coredump(filename, coredump_size);
+        if (r < 0)
+                return r;
+
+        log_info("Detected coredump of the journal daemon itself, diverted to %s.", filename);
+        return 0;
+}
+
+static int process_kernel(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_user_unit = NULL, *core_slice = NULL, *core_timestamp = NULL, *core_rlimit = NULL;
+
+        /* The larger ones we allocate on the heap */
+        _cleanup_free_ char
+                *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;
+        const char *context[_CONTEXT_MAX];
+        struct iovec iovec[25];
+        size_t n_iovec = 0;
+        uid_t owner_uid;
+        const char *p;
+        pid_t pid;
+        char *t;
+        int r;
+
+        if (argc < CONTEXT_COMM + 1) {
+                log_error("Not enough arguments passed from kernel (%i, expected %i).", argc - 1, CONTEXT_COMM + 1 - 1);
+                return -EINVAL;
+        }
+
+        r = parse_pid(argv[CONTEXT_PID + 1], &pid);
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse PID.");
+
+        r = get_process_comm(pid, &comm);
+        if (r < 0) {
+                log_warning_errno(r, "Failed to get COMM, falling back to the command line: %m");
+                comm = strv_join(argv + CONTEXT_COMM + 1, " ");
+                if (!comm)
+                        return log_oom();
+        }
+
+        r = get_process_exe(pid, &exe);
+        if (r < 0)
+                log_warning_errno(r, "Failed to get EXE, ignoring: %m");
+
+        context[CONTEXT_PID] = argv[CONTEXT_PID + 1];
+        context[CONTEXT_UID] = argv[CONTEXT_UID + 1];
+        context[CONTEXT_GID] = argv[CONTEXT_GID + 1];
+        context[CONTEXT_SIGNAL] = argv[CONTEXT_SIGNAL + 1];
+        context[CONTEXT_TIMESTAMP] = argv[CONTEXT_TIMESTAMP + 1];
+        context[CONTEXT_RLIMIT] = argv[CONTEXT_RLIMIT + 1];
+        context[CONTEXT_COMM] = comm;
+        context[CONTEXT_EXE] = exe;
+
+        if (cg_pid_get_unit(pid, &t) >= 0) {
+
+                if (streq(t, SPECIAL_JOURNALD_SERVICE)) {
+                        free(t);
+                        return process_journald_crash(context, STDIN_FILENO);
+                }
+
+                core_unit = strjoina("COREDUMP_UNIT=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], 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();
+
+        if (cg_pid_get_user_unit(pid, &t) >= 0) {
+                core_user_unit = strjoina("COREDUMP_USER_UNIT=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], core_user_unit);
+        }
+
+        core_pid = strjoina("COREDUMP_PID=", context[CONTEXT_PID]);
+        IOVEC_SET_STRING(iovec[n_iovec++], core_pid);
+
+        core_uid = strjoina("COREDUMP_UID=", context[CONTEXT_UID]);
+        IOVEC_SET_STRING(iovec[n_iovec++], core_uid);
+
+        core_gid = strjoina("COREDUMP_GID=", context[CONTEXT_GID]);
+        IOVEC_SET_STRING(iovec[n_iovec++], core_gid);
+
+        core_signal = strjoina("COREDUMP_SIGNAL=", context[CONTEXT_SIGNAL]);
+        IOVEC_SET_STRING(iovec[n_iovec++], core_signal);
+
+        core_rlimit = strjoina("COREDUMP_RLIMIT=", context[CONTEXT_RLIMIT]);
+        IOVEC_SET_STRING(iovec[n_iovec++], core_rlimit);
+
+        if (sd_pid_get_session(pid, &t) >= 0) {
+                core_session = strjoina("COREDUMP_SESSION=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], 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[n_iovec++], core_owner_uid);
+        }
+
+        if (sd_pid_get_slice(pid, &t) >= 0) {
+                core_slice = strjoina("COREDUMP_SLICE=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], core_slice);
+        }
+
+        if (comm) {
+                core_comm = strjoina("COREDUMP_COMM=", comm);
+                IOVEC_SET_STRING(iovec[n_iovec++], core_comm);
+        }
+
+        if (exe) {
+                core_exe = strjoina("COREDUMP_EXE=", exe);
+                IOVEC_SET_STRING(iovec[n_iovec++], core_exe);
+        }
+
+        if (get_process_cmdline(pid, 0, false, &t) >= 0) {
+                core_cmdline = strjoina("COREDUMP_CMDLINE=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], core_cmdline);
+        }
+
+        if (cg_pid_get_path_shifted(pid, NULL, &t) >= 0) {
+                core_cgroup = strjoina("COREDUMP_CGROUP=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], 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[n_iovec++], 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[n_iovec++], 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[n_iovec++], 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[n_iovec++], 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[n_iovec++], core_proc_cgroup);
+        }
+
+        if (get_process_cwd(pid, &t) >= 0) {
+                core_cwd = strjoina("COREDUMP_CWD=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], core_cwd);
+        }
+
+        if (get_process_root(pid, &t) >= 0) {
+                core_root = strjoina("COREDUMP_ROOT=", t);
+                free(t);
+
+                IOVEC_SET_STRING(iovec[n_iovec++], core_root);
+        }
+
+        if (get_process_environ(pid, &t) >= 0) {
+                core_environ = strappend("COREDUMP_ENVIRON=", t);
+                free(t);
+
+                if (core_environ)
+                        IOVEC_SET_STRING(iovec[n_iovec++], core_environ);
+        }
+
+        core_timestamp = strjoina("COREDUMP_TIMESTAMP=", context[CONTEXT_TIMESTAMP], "000000", NULL);
+        IOVEC_SET_STRING(iovec[n_iovec++], core_timestamp);
+
+        IOVEC_SET_STRING(iovec[n_iovec++], "MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1");
+
+        assert_cc(2 == LOG_CRIT);
+        IOVEC_SET_STRING(iovec[n_iovec++], "PRIORITY=2");
+
+        assert(n_iovec <= ELEMENTSOF(iovec));
+
+        return send_iovec(iovec, n_iovec, STDIN_FILENO);
+}
+
+int main(int argc, char *argv[]) {
+        int r;
+
+        /* 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();
+
+        /* Make sure we never enter a loop */
+        (void) prctl(PR_SET_DUMPABLE, 0);
+
+        /* Ignore all parse errors */
+        (void) parse_config();
+
+        log_debug("Selected storage '%s'.", coredump_storage_to_string(arg_storage));
+        log_debug("Selected compression %s.", yes_no(arg_compress));
+
+        r = sd_listen_fds(false);
+        if (r < 0) {
+                log_error_errno(r, "Failed to determine number of file descriptor: %m");
+                goto finish;
+        }
+
+        /* If we got an fd passed, we are running in coredumpd mode. Otherwise we are invoked from the kernel as
+         * coredump handler */
+        if (r == 0)
+                r = process_kernel(argc, argv);
+        else if (r == 1)
+                r = process_socket(SD_LISTEN_FDS_START);
+        else {
+                log_error("Received unexpected number of file descriptors.");
+                r = -EINVAL;
+        }
+
+finish:
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}