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Systemd/src/coredump/coredump.c

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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
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 <stdio_ext.h>
#include <sys/prctl.h>
#include <sys/xattr.h>
#include <unistd.h>
#if HAVE_ELFUTILS
#include <dwarf.h>
#include <elfutils/libdwfl.h>
#endif
#include "sd-daemon.h"
#include "sd-journal.h"
#include "sd-login.h"
#include "sd-messages.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 "journal-importer.h"
#include "log.h"
#include "macro.h"
#include "missing.h"
#include "mkdir.h"
#include "parse-util.h"
#include "process-util.h"
#include "signal-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 coredump files, and attaching xattrs, and for indexing argv[].
* Our pattern for man:systectl(1) kernel.core_pattern is such that the
* kernel passes fields until CONTEXT_RLIMIT as arguments in argv[]. After
* that it gets complicated: the kernel passes "comm" as one or more fields
* starting at index CONTEXT_COMM (in other words, full "comm" is under index
* CONTEXT_COMM when it does not contain spaces, which is the common
* case). This mapping is not reversible, so we prefer to retrieve "comm"
* from /proc. We only fall back to argv[CONTEXT_COMM...] when that fails.
*
* In the internal context[] array, fields before CONTEXT_COMM are the
* strings from argv[], so they should not be freed. The strings at indices
* CONTEXT_COMM and higher are allocated by us and should be freed at the
* end.
*/
CONTEXT_PID,
CONTEXT_UID,
CONTEXT_GID,
CONTEXT_SIGNAL,
CONTEXT_TIMESTAMP,
CONTEXT_RLIMIT,
CONTEXT_HOSTNAME,
CONTEXT_COMM,
CONTEXT_EXE,
CONTEXT_UNIT,
_CONTEXT_MAX
};
typedef enum CoredumpStorage {
COREDUMP_STORAGE_NONE,
COREDUMP_STORAGE_EXTERNAL,
COREDUMP_STORAGE_JOURNAL,
_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",
};
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 uint64_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_nulstr(PKGSYSCONFDIR "/coredump.conf",
CONF_PATHS_NULSTR("systemd/coredump.conf.d"),
"Coredump\0",
config_item_table_lookup, items,
CONFIG_PARSE_WARN, NULL);
}
static inline uint64_t storage_size_max(void) {
return arg_storage == COREDUMP_STORAGE_EXTERNAL ? arg_external_size_max : arg_journal_size_max;
}
static int fix_acl(int fd, uid_t uid) {
#if HAVE_ACL
_cleanup_(acl_freep) acl_t acl = NULL;
acl_entry_t entry;
acl_permset_t permset;
int r;
assert(fd >= 0);
if (uid_is_system(uid) || uid_is_dynamic(uid) || uid == UID_NOBODY)
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)
return log_error_errno(errno, "Failed to patch ACL: %m");
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_RLIMIT] = "user.coredump.rlimit",
[CONTEXT_HOSTNAME] = "user.coredump.hostname",
[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 inline const char *coredump_tmpfile_name(const char *s) {
return s ? s : "(unnamed temporary file)";
}
static int fix_permissions(
int fd,
const char *filename,
const char *target,
const char *context[_CONTEXT_MAX],
uid_t uid) {
int r;
assert(fd >= 0);
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", coredump_tmpfile_name(filename));
(void) fsync_directory_of_file(fd);
r = link_tmpfile(fd, filename, target);
if (r < 0)
return log_error_errno(r, "Failed to move coredump %s into place: %m", 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 (arg_storage == COREDUMP_STORAGE_EXTERNAL &&
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,
bool *ret_truncated) {
_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 < page_size()) {
/* Is coredumping disabled? Then don't bother saving/processing the coredump.
* Anything below PAGE_SIZE cannot give a readable coredump (the kernel uses
* ELF_EXEC_PAGESIZE which is not easily accessible, but is usually the same as PAGE_SIZE. */
log_info("Resource limits disable core dumping 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, storage_size_max()));
r = make_filename(context, &fn);
if (r < 0)
return log_error_errno(r, "Failed to determine coredump file name: %m");
mkdir_p_label("/var/lib/systemd/coredump", 0755);
fd = open_tmpfile_linkable(fn, O_RDWR|O_CLOEXEC, &tmp);
if (fd < 0)
return log_error_errno(fd, "Failed to create temporary file for coredump %s: %m", fn);
r = copy_bytes(input_fd, fd, max_size, 0);
if (r < 0) {
log_error_errno(r, "Cannot store coredump of %s (%s): %m", context[CONTEXT_PID], context[CONTEXT_COMM]);
goto fail;
}
*ret_truncated = r == 1;
if (*ret_truncated)
log_struct(LOG_INFO,
LOG_MESSAGE("Core file was truncated to %zu bytes.", max_size),
"SIZE_LIMIT=%zu", max_size,
"MESSAGE_ID=" SD_MESSAGE_TRUNCATED_CORE_STR,
NULL);
if (fstat(fd, &st) < 0) {
log_error_errno(errno, "Failed to fstat core file %s: %m", coredump_tmpfile_name(tmp));
goto fail;
}
if (lseek(fd, 0, SEEK_SET) == (off_t) -1) {
log_error_errno(errno, "Failed to seek on %s: %m", coredump_tmpfile_name(tmp));
goto fail;
}
#if HAVE_XZ || HAVE_LZ4
/* If we will remove the coredump anyway, do not compress. */
if (arg_compress && !maybe_remove_external_coredump(NULL, st.st_size)) {
_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;
}
fd_compressed = open_tmpfile_linkable(fn_compressed, O_RDWR|O_CLOEXEC, &tmp_compressed);
if (fd_compressed < 0) {
log_error_errno(fd_compressed, "Failed to create temporary file for coredump %s: %m", fn_compressed);
goto uncompressed;
}
r = compress_stream(fd, fd_compressed, -1);
if (r < 0) {
log_error_errno(r, "Failed to compress %s: %m", coredump_tmpfile_name(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 */
if (tmp)
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:
if (tmp_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:
if (tmp)
(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;
(void) __fsetlocking(stream, FSETLOCKING_BYCALLER);
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) {
safe_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 = TAKE_PTR(buffer);
return 0;
}
static int get_process_ns(pid_t pid, const char *namespace, ino_t *ns) {
const char *p;
struct stat stbuf;
_cleanup_close_ int proc_ns_dir_fd;
p = procfs_file_alloca(pid, "ns");
proc_ns_dir_fd = open(p, O_DIRECTORY | O_CLOEXEC | O_RDONLY);
if (proc_ns_dir_fd < 0)
return -errno;
if (fstatat(proc_ns_dir_fd, namespace, &stbuf, /* flags */0) < 0)
return -errno;
*ns = stbuf.st_ino;
return 0;
}
static int get_mount_namespace_leader(pid_t pid, pid_t *container_pid) {
pid_t cpid = pid, ppid = 0;
ino_t proc_mntns;
int r = 0;
r = get_process_ns(pid, "mnt", &proc_mntns);
if (r < 0)
return r;
for (;;) {
ino_t parent_mntns;
r = get_process_ppid(cpid, &ppid);
if (r < 0)
return r;
r = get_process_ns(ppid, "mnt", &parent_mntns);
if (r < 0)
return r;
if (proc_mntns != parent_mntns)
break;
if (ppid == 1)
return -ENOENT;
cpid = ppid;
}
*container_pid = ppid;
return 0;
}
/* Returns 1 if the parent was found.
* Returns 0 if there is not a process we can call the pid's
* container parent (the pid's process isn't 'containerized').
* Returns a negative number on errors.
*/
static int get_process_container_parent_cmdline(pid_t pid, char** cmdline) {
int r = 0;
pid_t container_pid;
const char *proc_root_path;
struct stat root_stat, proc_root_stat;
/* To compare inodes of / and /proc/[pid]/root */
if (stat("/", &root_stat) < 0)
return -errno;
proc_root_path = procfs_file_alloca(pid, "root");
if (stat(proc_root_path, &proc_root_stat) < 0)
return -errno;
/* The process uses system root. */
if (proc_root_stat.st_ino == root_stat.st_ino) {
*cmdline = NULL;
return 0;
}
r = get_mount_namespace_leader(pid, &container_pid);
if (r < 0)
return r;
r = get_process_cmdline(container_pid, 0, false, cmdline);
if (r < 0)
return r;
return 1;
}
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 bool is_journald_crash(const char *context[_CONTEXT_MAX]) {
assert(context);
return streq_ptr(context[CONTEXT_UNIT], SPECIAL_JOURNALD_SERVICE);
}
static bool is_pid1_crash(const char *context[_CONTEXT_MAX]) {
assert(context);
return streq_ptr(context[CONTEXT_UNIT], SPECIAL_INIT_SCOPE) ||
streq_ptr(context[CONTEXT_PID], "1");
}
#define SUBMIT_COREDUMP_FIELDS 4
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 = UINT64_MAX;
bool truncated = false, journald_crash;
int r;
assert(context);
assert(iovec);
assert(n_iovec_allocated >= n_iovec + SUBMIT_COREDUMP_FIELDS);
assert(input_fd >= 0);
journald_crash = is_journald_crash(context);
/* 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, &truncated);
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[n_iovec++] = IOVEC_MAKE_STRING(coredump_filename);
} else if (arg_storage == COREDUMP_STORAGE_EXTERNAL)
log_info("The core will not be stored: size %"PRIu64" is greater than %"PRIu64" (the configured maximum)",
coredump_size, arg_external_size_max);
/* 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");
#if 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.",
journald_crash ? "\nCoredump diverted to " : "",
journald_crash ? filename : "",
"\n\n", stacktrace);
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");
} else
log_debug("Not generating stack trace: core size %"PRIu64" is greater than %"PRIu64" (the configured maximum)",
coredump_size, arg_process_size_max);
if (!core_message)
#endif
log:
core_message = strjoin("MESSAGE=Process ", context[CONTEXT_PID],
" (", context[CONTEXT_COMM], ") of user ",
context[CONTEXT_UID], " dumped core.",
journald_crash ? "\nCoredump diverted to " : NULL,
journald_crash ? filename : NULL);
if (!core_message)
return log_oom();
if (journald_crash) {
/* We cannot log to the journal, so just print the MESSAGE.
* The target was set previously to something safe. */
log_dispatch(LOG_ERR, 0, core_message);
return 0;
}
iovec[n_iovec++] = IOVEC_MAKE_STRING(core_message);
if (truncated)
iovec[n_iovec++] = IOVEC_MAKE_STRING("COREDUMP_TRUNCATED=1");
/* Optionally store the entire coredump in the journal */
if (arg_storage == COREDUMP_STORAGE_JOURNAL) {
if (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++] = IOVEC_MAKE(coredump_data, sz);
else
log_warning_errno(r, "Failed to attach the core to the journal entry: %m");
} else
log_info("The core will not be stored: size %"PRIu64" is greater than %"PRIu64" (the configured maximum)",
coredump_size, arg_journal_size_max);
}
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_PID] = "COREDUMP_PID=",
[CONTEXT_UID] = "COREDUMP_UID=",
[CONTEXT_GID] = "COREDUMP_GID=",
[CONTEXT_SIGNAL] = "COREDUMP_SIGNAL=",
[CONTEXT_TIMESTAMP] = "COREDUMP_TIMESTAMP=",
[CONTEXT_RLIMIT] = "COREDUMP_RLIMIT=",
[CONTEXT_HOSTNAME] = "COREDUMP_HOSTNAME=",
[CONTEXT_COMM] = "COREDUMP_COMM=",
[CONTEXT_EXE] = "COREDUMP_EXE=",
};
unsigned i;
assert(iovec);
assert(context);
for (i = 0; i < ELEMENTSOF(context_field_names); i++) {
size_t l;
if (!context_field_names[i])
continue;
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_allocated = 0, i, k;
const char *context[_CONTEXT_MAX] = {};
int r;
assert(fd >= 0);
log_set_target(LOG_TARGET_AUTO);
log_parse_environment();
log_open();
log_debug("Processing coredump received on stdin...");
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;
ssize_t l;
if (!GREEDY_REALLOC(iovec, n_allocated, n_iovec + SUBMIT_COREDUMP_FIELDS)) {
r = log_oom();
goto finish;
}
l = next_datagram_size_fd(fd);
if (l < 0) {
r = log_error_errno(l, "Failed to determine datagram size to read: %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_allocated, n_iovec + SUBMIT_COREDUMP_FIELDS)) {
r = log_oom();
goto finish;
}
/* Make sure 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_HOSTNAME]);
assert(context[CONTEXT_COMM]);
assert(coredump_fd >= 0);
/* Small quirk: the journal fields contain the timestamp padded with six zeroes, so that the kernel-supplied 1s
* granularity timestamps becomes 1µs granularity, i.e. the granularity systemd usually operates in. Since we
* are reconstructing the original kernel context, we chop this off again, here. */
k = strlen(context[CONTEXT_TIMESTAMP]);
if (k > 6)
context[CONTEXT_TIMESTAMP] = strndupa(context[CONTEXT_TIMESTAMP], k - 6);
r = submit_coredump(context, iovec, n_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, SOCKADDR_UN_LEN(sa.un)) < 0)
return log_error_errno(errno, "Failed to connect to coredump service: %m");
for (i = 0; i < n_iovec; i++) {
struct msghdr mh = {
.msg_iov = (struct iovec*) iovec + i,
.msg_iovlen = 1,
};
struct iovec copy[2];
for (;;) {
if (sendmsg(fd, &mh, MSG_NOSIGNAL) >= 0)
break;
if (errno == EMSGSIZE && mh.msg_iov[0].iov_len > 0) {
/* This field didn't fit? That's a pity. Given that this is just metadata,
* let's truncate the field at half, and try again. We append three dots, in
* order to show that this is truncated. */
if (mh.msg_iov != copy) {
/* We don't want to modify the caller's iovec, hence let's create our
* own array, consisting of two new iovecs, where the first is a
* (truncated) copy of what we want to send, and the second one
* contains the trailing dots. */
copy[0] = iovec[i];
copy[1] = (struct iovec) {
.iov_base = (char[]) { '.', '.', '.' },
.iov_len = 3,
};
mh.msg_iov = copy;
mh.msg_iovlen = 2;
}
copy[0].iov_len /= 2; /* halve it, and try again */
continue;
}
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 char* set_iovec_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value) {
char *x;
x = strappend(field, value);
if (x)
iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(x);
return x;
}
static char* set_iovec_field_free(struct iovec *iovec, size_t *n_iovec, const char *field, char *value) {
char *x;
x = set_iovec_field(iovec, n_iovec, field, value);
free(value);
return x;
}
static int gather_pid_metadata(
char* context[_CONTEXT_MAX],
char **comm_fallback,
struct iovec *iovec, size_t *n_iovec) {
/* We need 27 empty slots in iovec!
*
* Note that if we fail on oom later on, we do not roll-back changes to the iovec structure. (It remains valid,
* with the first n_iovec fields initialized.) */
uid_t owner_uid;
pid_t pid;
char *t;
const char *p;
int r, signo;
r = parse_pid(context[CONTEXT_PID], &pid);
if (r < 0)
return log_error_errno(r, "Failed to parse PID \"%s\": %m", context[CONTEXT_PID]);
r = get_process_comm(pid, &context[CONTEXT_COMM]);
if (r < 0) {
log_warning_errno(r, "Failed to get COMM, falling back to the command line: %m");
context[CONTEXT_COMM] = strv_join(comm_fallback, " ");
if (!context[CONTEXT_COMM])
return log_oom();
}
r = get_process_exe(pid, &context[CONTEXT_EXE]);
if (r < 0)
log_warning_errno(r, "Failed to get EXE, ignoring: %m");
if (cg_pid_get_unit(pid, &context[CONTEXT_UNIT]) >= 0) {
if (!is_journald_crash((const char**) context)) {
/* 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 this is PID 1 disable coredump collection, we'll unlikely be able to process it later on. */
if (is_pid1_crash((const char**) context)) {
log_notice("Due to PID 1 having crashed coredump collection will now be turned off.");
disable_coredumps();
}
set_iovec_field(iovec, n_iovec, "COREDUMP_UNIT=", context[CONTEXT_UNIT]);
}
if (cg_pid_get_user_unit(pid, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_USER_UNIT=", t);
/* The next few are mandatory */
if (!set_iovec_field(iovec, n_iovec, "COREDUMP_PID=", context[CONTEXT_PID]))
return log_oom();
if (!set_iovec_field(iovec, n_iovec, "COREDUMP_UID=", context[CONTEXT_UID]))
return log_oom();
if (!set_iovec_field(iovec, n_iovec, "COREDUMP_GID=", context[CONTEXT_GID]))
return log_oom();
if (!set_iovec_field(iovec, n_iovec, "COREDUMP_SIGNAL=", context[CONTEXT_SIGNAL]))
return log_oom();
if (!set_iovec_field(iovec, n_iovec, "COREDUMP_RLIMIT=", context[CONTEXT_RLIMIT]))
return log_oom();
if (!set_iovec_field(iovec, n_iovec, "COREDUMP_HOSTNAME=", context[CONTEXT_HOSTNAME]))
return log_oom();
if (!set_iovec_field(iovec, n_iovec, "COREDUMP_COMM=", context[CONTEXT_COMM]))
return log_oom();
if (context[CONTEXT_EXE] &&
!set_iovec_field(iovec, n_iovec, "COREDUMP_EXE=", context[CONTEXT_EXE]))
return log_oom();
if (sd_pid_get_session(pid, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_SESSION=", t);
if (sd_pid_get_owner_uid(pid, &owner_uid) >= 0) {
r = asprintf(&t, "COREDUMP_OWNER_UID=" UID_FMT, owner_uid);
if (r > 0)
iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(t);
}
if (sd_pid_get_slice(pid, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_SLICE=", t);
if (get_process_cmdline(pid, 0, false, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_CMDLINE=", t);
if (cg_pid_get_path_shifted(pid, NULL, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_CGROUP=", t);
if (compose_open_fds(pid, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_OPEN_FDS=", t);
p = procfs_file_alloca(pid, "status");
if (read_full_file(p, &t, NULL) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_STATUS=", t);
p = procfs_file_alloca(pid, "maps");
if (read_full_file(p, &t, NULL) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_MAPS=", t);
p = procfs_file_alloca(pid, "limits");
if (read_full_file(p, &t, NULL) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_LIMITS=", t);
p = procfs_file_alloca(pid, "cgroup");
if (read_full_file(p, &t, NULL) >=0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_CGROUP=", t);
p = procfs_file_alloca(pid, "mountinfo");
if (read_full_file(p, &t, NULL) >=0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_PROC_MOUNTINFO=", t);
if (get_process_cwd(pid, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_CWD=", t);
if (get_process_root(pid, &t) >= 0) {
bool proc_self_root_is_slash;
proc_self_root_is_slash = strcmp(t, "/") == 0;
set_iovec_field_free(iovec, n_iovec, "COREDUMP_ROOT=", t);
/* If the process' root is "/", then there is a chance it has
* mounted own root and hence being containerized. */
if (proc_self_root_is_slash && get_process_container_parent_cmdline(pid, &t) > 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_CONTAINER_CMDLINE=", t);
}
if (get_process_environ(pid, &t) >= 0)
set_iovec_field_free(iovec, n_iovec, "COREDUMP_ENVIRON=", t);
t = strjoin("COREDUMP_TIMESTAMP=", context[CONTEXT_TIMESTAMP], "000000");
if (t)
iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(t);
if (safe_atoi(context[CONTEXT_SIGNAL], &signo) >= 0 && SIGNAL_VALID(signo))
set_iovec_field(iovec, n_iovec, "COREDUMP_SIGNAL_NAME=SIG", signal_to_string(signo));
return 0; /* we successfully acquired all metadata */
}
static int process_kernel(int argc, char* argv[]) {
char* context[_CONTEXT_MAX] = {};
struct iovec iovec[29 + SUBMIT_COREDUMP_FIELDS];
size_t i, n_iovec, n_to_free = 0;
int r;
log_debug("Processing coredump received from the kernel...");
if (argc < CONTEXT_COMM + 1) {
log_error("Not enough arguments passed by the kernel (%i, expected %i).", argc - 1, CONTEXT_COMM + 1 - 1);
return -EINVAL;
}
context[CONTEXT_PID] = argv[1 + CONTEXT_PID];
context[CONTEXT_UID] = argv[1 + CONTEXT_UID];
context[CONTEXT_GID] = argv[1 + CONTEXT_GID];
context[CONTEXT_SIGNAL] = argv[1 + CONTEXT_SIGNAL];
context[CONTEXT_TIMESTAMP] = argv[1 + CONTEXT_TIMESTAMP];
context[CONTEXT_RLIMIT] = argv[1 + CONTEXT_RLIMIT];
context[CONTEXT_HOSTNAME] = argv[1 + CONTEXT_HOSTNAME];
r = gather_pid_metadata(context, argv + 1 + CONTEXT_COMM, iovec, &n_to_free);
if (r < 0)
goto finish;
n_iovec = n_to_free;
iovec[n_iovec++] = IOVEC_MAKE_STRING("MESSAGE_ID=" SD_MESSAGE_COREDUMP_STR);
assert_cc(2 == LOG_CRIT);
iovec[n_iovec++] = IOVEC_MAKE_STRING("PRIORITY=2");
assert(n_iovec <= ELEMENTSOF(iovec));
if (is_journald_crash((const char**) context) || is_pid1_crash((const char**) context))
r = submit_coredump((const char**) context,
iovec, ELEMENTSOF(iovec), n_iovec,
STDIN_FILENO);
else
r = send_iovec(iovec, n_iovec, STDIN_FILENO);
finish:
for (i = 0; i < n_to_free; i++)
free(iovec[i].iov_base);
/* Those fields are allocated by gather_pid_metadata */
free(context[CONTEXT_COMM]);
free(context[CONTEXT_EXE]);
free(context[CONTEXT_UNIT]);
return r;
}
static int process_backtrace(int argc, char *argv[]) {
char *context[_CONTEXT_MAX] = {};
_cleanup_free_ char *message = NULL;
_cleanup_free_ struct iovec *iovec = NULL;
size_t n_iovec, n_allocated, n_to_free = 0, i;
int r;
JournalImporter importer = {
.fd = STDIN_FILENO,
};
log_debug("Processing backtrace on stdin...");
if (argc < CONTEXT_COMM + 1) {
log_error("Not enough arguments passed (%i, expected %i).", argc - 1, CONTEXT_COMM + 1 - 1);
return -EINVAL;
}
context[CONTEXT_PID] = argv[2 + CONTEXT_PID];
context[CONTEXT_UID] = argv[2 + CONTEXT_UID];
context[CONTEXT_GID] = argv[2 + CONTEXT_GID];
context[CONTEXT_SIGNAL] = argv[2 + CONTEXT_SIGNAL];
context[CONTEXT_TIMESTAMP] = argv[2 + CONTEXT_TIMESTAMP];
context[CONTEXT_RLIMIT] = argv[2 + CONTEXT_RLIMIT];
context[CONTEXT_HOSTNAME] = argv[2 + CONTEXT_HOSTNAME];
n_allocated = 34 + COREDUMP_STORAGE_EXTERNAL;
/* 26 metadata, 2 static, +unknown input, 4 storage, rounded up */
iovec = new(struct iovec, n_allocated);
if (!iovec)
return log_oom();
r = gather_pid_metadata(context, argv + 2 + CONTEXT_COMM, iovec, &n_to_free);
if (r < 0)
goto finish;
if (r > 0) {
/* This was a special crash, and has already been processed. */
r = 0;
goto finish;
}
n_iovec = n_to_free;
for (;;) {
r = journal_importer_process_data(&importer);
if (r < 0) {
log_error_errno(r, "Failed to parse journal entry on stdin: %m");
goto finish;
}
if (r == 1 || /* complete entry */
journal_importer_eof(&importer)) /* end of data */
break;
}
if (!GREEDY_REALLOC(iovec, n_allocated, n_iovec + importer.iovw.count + 2))
return log_oom();
if (journal_importer_eof(&importer)) {
log_warning("Did not receive a full journal entry on stdin, ignoring message sent by reporter");
message = strjoin("MESSAGE=Process ", context[CONTEXT_PID],
" (", context[CONTEXT_COMM], ")"
" of user ", context[CONTEXT_UID],
" failed with ", context[CONTEXT_SIGNAL]);
if (!message) {
r = log_oom();
goto finish;
}
iovec[n_iovec++] = IOVEC_MAKE_STRING(message);
} else {
for (i = 0; i < importer.iovw.count; i++)
iovec[n_iovec++] = importer.iovw.iovec[i];
}
iovec[n_iovec++] = IOVEC_MAKE_STRING("MESSAGE_ID=" SD_MESSAGE_BACKTRACE_STR);
assert_cc(2 == LOG_CRIT);
iovec[n_iovec++] = IOVEC_MAKE_STRING("PRIORITY=2");
assert(n_iovec <= n_allocated);
r = sd_journal_sendv(iovec, n_iovec);
if (r < 0)
log_error_errno(r, "Failed to log backtrace: %m");
finish:
for (i = 0; i < n_to_free; i++)
free(iovec[i].iov_base);
/* Those fields are allocated by gather_pid_metadata */
free(context[CONTEXT_COMM]);
free(context[CONTEXT_EXE]);
free(context[CONTEXT_UNIT]);
return r;
}
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) {
if (streq_ptr(argv[1], "--backtrace"))
r = process_backtrace(argc, argv);
else
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;
}
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