/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #include #include #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 "bus-error.h" #include "capability-util.h" #include "cgroup-util.h" #include "compress.h" #include "conf-parser.h" #include "copy.h" #include "coredump-util.h" #include "coredump-vacuum.h" #include "dirent-util.h" #include "elf-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 "journal-send.h" #include "log.h" #include "macro.h" #include "main-func.h" #include "memory-util.h" #include "mkdir-label.h" #include "parse-util.h" #include "process-util.h" #include "signal-util.h" #include "socket-util.h" #include "special.h" #include "stat-util.h" #include "string-table.h" #include "string-util.h" #include "strv.h" #include "sync-util.h" #include "tmpfile-util.h" #include "uid-alloc-range.h" #include "user-util.h" /* The maximum size up to which we process coredumps. We use 1G on 32bit systems, and 32G on 64bit systems */ #if __SIZEOF_POINTER__ == 4 #define PROCESS_SIZE_MAX ((uint64_t) (1LLU*1024LLU*1024LLU*1024LLU)) #elif __SIZEOF_POINTER__ == 8 #define PROCESS_SIZE_MAX ((uint64_t) (32LLU*1024LLU*1024LLU*1024LLU)) #else #error "Unexpected pointer size" #endif /* 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 */ #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION #define JOURNAL_SIZE_MAX ((size_t) (767LU*1024LU*1024LU)) #else /* oss-fuzz limits memory usage. */ #define JOURNAL_SIZE_MAX ((size_t) (10LU*1024LU*1024LU)) #endif /* When checking for available memory and setting lower limits, don't * go below 4MB for writing core files to storage. */ #define PROCESS_SIZE_MIN (4U*1024U*1024U) /* Make sure to not make this larger than the maximum journal entry * size. See DATA_SIZE_MAX in journal-importer.h. */ assert_cc(JOURNAL_SIZE_MAX <= DATA_SIZE_MAX); enum { /* We use these as array indexes for our process metadata cache. * * The first indices of the cache stores the same metadata as the ones passed by * the kernel via argv[], ie the strings array passed by the kernel according to * our pattern defined in /proc/sys/kernel/core_pattern (see man:core(5)). */ META_ARGV_PID, /* %P: as seen in the initial pid namespace */ META_ARGV_UID, /* %u: as seen in the initial user namespace */ META_ARGV_GID, /* %g: as seen in the initial user namespace */ META_ARGV_SIGNAL, /* %s: number of signal causing dump */ META_ARGV_TIMESTAMP, /* %t: time of dump, expressed as seconds since the Epoch (we expand this to µs granularity) */ META_ARGV_RLIMIT, /* %c: core file size soft resource limit */ META_ARGV_HOSTNAME, /* %h: hostname */ _META_ARGV_MAX, /* The following indexes are cached for a couple of special fields we use (and * thereby need to be retrieved quickly) for naming coredump files, and attaching * xattrs. Unlike the previous ones they are retrieved from the runtime * environment. */ META_COMM = _META_ARGV_MAX, _META_MANDATORY_MAX, /* The rest are similar to the previous ones except that we won't fail if one of * them is missing. */ META_EXE = _META_MANDATORY_MAX, META_UNIT, META_PROC_AUXV, _META_MAX }; static const char * const meta_field_names[_META_MAX] = { [META_ARGV_PID] = "COREDUMP_PID=", [META_ARGV_UID] = "COREDUMP_UID=", [META_ARGV_GID] = "COREDUMP_GID=", [META_ARGV_SIGNAL] = "COREDUMP_SIGNAL=", [META_ARGV_TIMESTAMP] = "COREDUMP_TIMESTAMP=", [META_ARGV_RLIMIT] = "COREDUMP_RLIMIT=", [META_ARGV_HOSTNAME] = "COREDUMP_HOSTNAME=", [META_COMM] = "COREDUMP_COMM=", [META_EXE] = "COREDUMP_EXE=", [META_UNIT] = "COREDUMP_UNIT=", [META_PROC_AUXV] = "COREDUMP_PROC_AUXV=", }; typedef struct Context { const char *meta[_META_MAX]; size_t meta_size[_META_MAX]; pid_t pid; bool is_pid1; bool is_journald; } Context; typedef enum CoredumpStorage { COREDUMP_STORAGE_NONE, COREDUMP_STORAGE_EXTERNAL, COREDUMP_STORAGE_JOURNAL, _COREDUMP_STORAGE_MAX, _COREDUMP_STORAGE_INVALID = -EINVAL, } 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_MAX; static uint64_t arg_max_use = UINT64_MAX; 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_infinity, 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_config_file("coredump.conf", "Coredump\0", config_item_table_lookup, items, CONFIG_PARSE_WARN, NULL); } static uint64_t storage_size_max(void) { if (arg_storage == COREDUMP_STORAGE_EXTERNAL) return arg_external_size_max; if (arg_storage == COREDUMP_STORAGE_JOURNAL) return arg_journal_size_max; assert(arg_storage == COREDUMP_STORAGE_NONE); return 0; } static int fix_acl(int fd, uid_t uid, bool allow_user) { assert(fd >= 0); assert(uid_is_valid(uid)); #if HAVE_ACL int r; /* We don't allow users to read coredumps if the uid or capabilities were changed. */ if (!allow_user) return 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 */ r = fd_add_uid_acl_permission(fd, uid, ACL_READ); if (r < 0) return log_error_errno(r, "Failed to adjust ACL of the coredump: %m"); #endif return 0; } static int fix_xattr(int fd, const Context *context) { static const char * const xattrs[_META_MAX] = { [META_ARGV_PID] = "user.coredump.pid", [META_ARGV_UID] = "user.coredump.uid", [META_ARGV_GID] = "user.coredump.gid", [META_ARGV_SIGNAL] = "user.coredump.signal", [META_ARGV_TIMESTAMP] = "user.coredump.timestamp", [META_ARGV_RLIMIT] = "user.coredump.rlimit", [META_ARGV_HOSTNAME] = "user.coredump.hostname", [META_COMM] = "user.coredump.comm", [META_EXE] = "user.coredump.exe", }; int r = 0; assert(fd >= 0); /* Attach some metadata to coredumps via extended * attributes. Just because we can. */ for (unsigned i = 0; i < _META_MAX; i++) { int k; if (isempty(context->meta[i]) || !xattrs[i]) continue; k = fsetxattr(fd, xattrs[i], context->meta[i], strlen(context->meta[i]), XATTR_CREATE); if (k < 0 && r == 0) r = -errno; } return r; } #define filename_escape(s) xescape((s), "./ ") static const char *coredump_tmpfile_name(const char *s) { return s ?: "(unnamed temporary file)"; } static int fix_permissions( int fd, const char *filename, const char *target, const Context *context, uid_t uid, bool allow_user) { int r; assert(fd >= 0); assert(target); assert(context); /* Ignore errors on these */ (void) fchmod(fd, 0640); (void) fix_acl(fd, uid, allow_user); (void) fix_xattr(fd, context); r = fsync_full(fd); if (r < 0) return log_error_errno(r, "Failed to sync coredump %s: %m", coredump_tmpfile_name(filename)); r = link_tmpfile(fd, filename, target, /* replace= */ false); 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 Context *context, 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->meta[META_COMM]); if (!c) return -ENOMEM; u = filename_escape(context->meta[META_ARGV_UID]); if (!u) return -ENOMEM; r = sd_id128_get_boot(&boot); if (r < 0) return r; p = filename_escape(context->meta[META_ARGV_PID]); if (!p) return -ENOMEM; t = filename_escape(context->meta[META_ARGV_TIMESTAMP]); if (!t) return -ENOMEM; if (asprintf(ret, "/var/lib/systemd/coredump/core.%s.%s." SD_ID128_FORMAT_STR ".%s.%s", c, u, SD_ID128_FORMAT_VAL(boot), p, t) < 0) return -ENOMEM; return 0; } static int grant_user_access(int core_fd, const Context *context) { int at_secure = -1; uid_t uid = UID_INVALID, euid = UID_INVALID; uid_t gid = GID_INVALID, egid = GID_INVALID; int r; assert(core_fd >= 0); assert(context); if (!context->meta[META_PROC_AUXV]) return log_warning_errno(SYNTHETIC_ERRNO(ENODATA), "No auxv data, not adjusting permissions."); uint8_t elf[EI_NIDENT]; errno = 0; if (pread(core_fd, &elf, sizeof(elf), 0) != sizeof(elf)) return log_warning_errno(errno_or_else(EIO), "Failed to pread from coredump fd: %s", STRERROR_OR_EOF(errno)); if (elf[EI_MAG0] != ELFMAG0 || elf[EI_MAG1] != ELFMAG1 || elf[EI_MAG2] != ELFMAG2 || elf[EI_MAG3] != ELFMAG3 || elf[EI_VERSION] != EV_CURRENT) return log_info_errno(SYNTHETIC_ERRNO(EUCLEAN), "Core file does not have ELF header, not adjusting permissions."); if (!IN_SET(elf[EI_CLASS], ELFCLASS32, ELFCLASS64) || !IN_SET(elf[EI_DATA], ELFDATA2LSB, ELFDATA2MSB)) return log_info_errno(SYNTHETIC_ERRNO(EUCLEAN), "Core file has strange ELF class, not adjusting permissions."); if ((elf[EI_DATA] == ELFDATA2LSB) != (__BYTE_ORDER == __LITTLE_ENDIAN)) return log_info_errno(SYNTHETIC_ERRNO(EUCLEAN), "Core file has non-native endianness, not adjusting permissions."); r = parse_auxv(LOG_WARNING, /* elf_class= */ elf[EI_CLASS], context->meta[META_PROC_AUXV], context->meta_size[META_PROC_AUXV], &at_secure, &uid, &euid, &gid, &egid); if (r < 0) return r; /* We allow access if we got all the data and at_secure is not set and * the uid/gid matches euid/egid. */ bool ret = at_secure == 0 && uid != UID_INVALID && euid != UID_INVALID && uid == euid && gid != GID_INVALID && egid != GID_INVALID && gid == egid; log_debug("Will %s access (uid="UID_FMT " euid="UID_FMT " gid="GID_FMT " egid="GID_FMT " at_secure=%s)", ret ? "permit" : "restrict", uid, euid, gid, egid, yes_no(at_secure)); return ret; } static int save_external_coredump( const Context *context, int input_fd, char **ret_filename, int *ret_node_fd, int *ret_data_fd, uint64_t *ret_size, uint64_t *ret_compressed_size, bool *ret_truncated) { _cleanup_(unlink_and_freep) char *tmp = NULL; _cleanup_free_ char *fn = NULL; _cleanup_close_ int fd = -EBADF; uint64_t rlimit, process_limit, max_size; bool truncated, storage_on_tmpfs; struct stat st; uid_t uid; int r; assert(context); assert(ret_filename); assert(ret_node_fd); assert(ret_data_fd); assert(ret_size); assert(ret_compressed_size); assert(ret_truncated); r = parse_uid(context->meta[META_ARGV_UID], &uid); if (r < 0) return log_error_errno(r, "Failed to parse UID: %m"); r = safe_atou64(context->meta[META_ARGV_RLIMIT], &rlimit); if (r < 0) return log_error_errno(r, "Failed to parse resource limit '%s': %m", context->meta[META_ARGV_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. */ return log_info_errno(SYNTHETIC_ERRNO(EBADSLT), "Resource limits disable core dumping for process %s (%s).", context->meta[META_ARGV_PID], context->meta[META_COMM]); process_limit = MAX(arg_process_size_max, storage_size_max()); if (process_limit == 0) return log_debug_errno(SYNTHETIC_ERRNO(EBADSLT), "Limits for coredump processing and storage are both 0, not dumping core."); /* Never store more than the process configured, or than we actually shall keep or process */ max_size = MIN(rlimit, process_limit); r = make_filename(context, &fn); if (r < 0) return log_error_errno(r, "Failed to determine coredump file name: %m"); (void) mkdir_parents_label(fn, 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); /* If storage is on tmpfs, the kernel oomd might kill us if there's MemoryMax set on * the service or the slice it belongs to. This is common on low-resources systems, * to avoid crashing processes to take away too many system resources. * Check the cgroup settings, and set max_size to a bit less than half of the * available memory left to the process. * Then, attempt to write the core file uncompressed first - if the write gets * interrupted, we know we won't be able to write it all, so instead compress what * was written so far, delete the uncompressed truncated core, and then continue * compressing from STDIN. Given the compressed core cannot be larger than the * uncompressed one, and 1KB for metadata is accounted for in the calculation, we * should be able to at least store the full compressed core file. */ storage_on_tmpfs = fd_is_temporary_fs(fd) > 0; if (storage_on_tmpfs && arg_compress) { _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL; uint64_t cgroup_limit = UINT64_MAX; struct statvfs sv; /* If we can't get the cgroup limit, just ignore it, but don't fail, * try anyway with the config settings. */ r = sd_bus_default_system(&bus); if (r < 0) log_info_errno(r, "Failed to connect to system bus, skipping MemoryAvailable check: %m"); else { _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; r = sd_bus_get_property_trivial( bus, "org.freedesktop.systemd1", "/org/freedesktop/systemd1/unit/self", "org.freedesktop.systemd1.Service", "MemoryAvailable", &error, 't', &cgroup_limit); if (r < 0) log_warning_errno(r, "Failed to query MemoryAvailable for current unit, " "falling back to static config settings: %s", bus_error_message(&error, r)); } max_size = MIN(cgroup_limit, max_size); max_size = LESS_BY(max_size, 1024U) / 2; /* Account for 1KB metadata overhead for compressing */ max_size = MAX(PROCESS_SIZE_MIN, max_size); /* Impose a lower minimum */ /* tmpfs might get full quickly, so check the available space too. * But don't worry about errors here, failing to access the storage * location will be better logged when writing to it. */ if (fstatvfs(fd, &sv) >= 0) max_size = MIN((uint64_t)sv.f_frsize * (uint64_t)sv.f_bfree, max_size); log_debug("Limiting core file size to %" PRIu64 " bytes due to cgroup memory limits.", max_size); } r = copy_bytes(input_fd, fd, max_size, 0); if (r < 0) return log_error_errno(r, "Cannot store coredump of %s (%s): %m", context->meta[META_ARGV_PID], context->meta[META_COMM]); truncated = r == 1; bool allow_user = grant_user_access(fd, context) > 0; #if HAVE_COMPRESSION if (arg_compress) { _cleanup_(unlink_and_freep) char *tmp_compressed = NULL; _cleanup_free_ char *fn_compressed = NULL; _cleanup_close_ int fd_compressed = -EBADF; uint64_t uncompressed_size = 0; if (lseek(fd, 0, SEEK_SET) == (off_t) -1) return log_error_errno(errno, "Failed to seek on coredump %s: %m", fn); fn_compressed = strjoin(fn, default_compression_extension()); if (!fn_compressed) return log_oom(); fd_compressed = open_tmpfile_linkable(fn_compressed, O_RDWR|O_CLOEXEC, &tmp_compressed); if (fd_compressed < 0) return log_error_errno(fd_compressed, "Failed to create temporary file for coredump %s: %m", fn_compressed); r = compress_stream(fd, fd_compressed, max_size, &uncompressed_size); if (r < 0) return log_error_errno(r, "Failed to compress %s: %m", coredump_tmpfile_name(tmp_compressed)); if (truncated && storage_on_tmpfs) { uint64_t partial_uncompressed_size = 0; /* Uncompressed write was truncated and we are writing to tmpfs: delete * the uncompressed core, and compress the remaining part from STDIN. */ tmp = unlink_and_free(tmp); fd = safe_close(fd); r = compress_stream(input_fd, fd_compressed, max_size, &partial_uncompressed_size); if (r < 0) return log_error_errno(r, "Failed to compress %s: %m", coredump_tmpfile_name(tmp_compressed)); uncompressed_size += partial_uncompressed_size; } r = fix_permissions(fd_compressed, tmp_compressed, fn_compressed, context, uid, allow_user); if (r < 0) return r; if (fstat(fd_compressed, &st) < 0) return log_error_errno(errno, "Failed to fstat core file %s: %m", coredump_tmpfile_name(tmp_compressed)); *ret_filename = TAKE_PTR(fn_compressed); /* compressed */ *ret_node_fd = TAKE_FD(fd_compressed); /* compressed */ *ret_compressed_size = (uint64_t) st.st_size; /* compressed */ *ret_data_fd = TAKE_FD(fd); *ret_size = uncompressed_size; *ret_truncated = truncated; tmp_compressed = mfree(tmp_compressed); return 0; } #endif if (truncated) log_struct(LOG_INFO, LOG_MESSAGE("Core file was truncated to %"PRIu64" bytes.", max_size), "SIZE_LIMIT=%"PRIu64, max_size, "MESSAGE_ID=" SD_MESSAGE_TRUNCATED_CORE_STR); r = fix_permissions(fd, tmp, fn, context, uid, allow_user); if (r < 0) return log_error_errno(r, "Failed to fix permissions and finalize coredump %s into %s: %m", coredump_tmpfile_name(tmp), fn); if (fstat(fd, &st) < 0) return log_error_errno(errno, "Failed to fstat core file %s: %m", coredump_tmpfile_name(tmp)); if (lseek(fd, 0, SEEK_SET) == (off_t) -1) return log_error_errno(errno, "Failed to seek on coredump %s: %m", fn); *ret_filename = TAKE_PTR(fn); *ret_data_fd = TAKE_FD(fd); *ret_size = (uint64_t) st.st_size; *ret_truncated = truncated; return 0; } 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) return log_error_errno(SYNTHETIC_ERRNO(EIO), "Core data too short."); *ret = TAKE_PTR(field); *ret_size = size + 9; 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 = -EBADF; _cleanup_free_ char *buffer = NULL; _cleanup_fclose_ FILE *stream = NULL; const char *fddelim = "", *path; size_t size = 0; int r; 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_unlocked(&buffer, &size); if (!stream) return -ENOMEM; FOREACH_DIRENT(de, proc_fd_dir, return -errno) { _cleanup_fclose_ FILE *fdinfo = NULL; _cleanup_free_ char *fdname = NULL; _cleanup_close_ int fd = -EBADF; r = readlinkat_malloc(dirfd(proc_fd_dir), de->d_name, &fdname); if (r < 0) return r; fprintf(stream, "%s%s:%s\n", fddelim, de->d_name, fdname); fddelim = "\n"; /* Use the directory entry from /proc/[pid]/fd with /proc/[pid]/fdinfo */ fd = openat(proc_fdinfo_fd, de->d_name, O_NOFOLLOW|O_CLOEXEC|O_RDONLY); if (fd < 0) continue; fdinfo = take_fdopen(&fd, "r"); if (!fdinfo) continue; for (;;) { _cleanup_free_ char *line = NULL; r = read_line(fdinfo, LONG_LINE_MAX, &line); if (r < 0) return r; if (r == 0) break; fputs(line, stream); 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 = -EBADF; 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 *ret) { ino_t proc_mntns; int r; r = get_process_ns(pid, "mnt", &proc_mntns); if (r < 0) return r; for (;;) { ino_t parent_mntns; pid_t ppid; r = get_process_ppid(pid, &ppid); if (r == -EADDRNOTAVAIL) /* Reached the top (i.e. typically PID 1, but could also be a process * whose parent is not in our pidns) */ return -ENOENT; if (r < 0) return r; r = get_process_ns(ppid, "mnt", &parent_mntns); if (r < 0) return r; if (proc_mntns != parent_mntns) { *ret = ppid; return 0; } pid = ppid; } } /* 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) { pid_t container_pid; const char *proc_root_path; struct stat root_stat, proc_root_stat; int r; /* 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 (stat_inode_same(&proc_root_stat, &root_stat)) { *cmdline = NULL; return 0; } r = get_mount_namespace_leader(pid, &container_pid); if (r < 0) return r; r = get_process_cmdline(container_pid, SIZE_MAX, PROCESS_CMDLINE_QUOTE_POSIX, cmdline); if (r < 0) return r; return 1; } static int change_uid_gid(const Context *context) { uid_t uid; gid_t gid; int r; r = parse_uid(context->meta[META_ARGV_UID], &uid); if (r < 0) return r; if (uid_is_system(uid)) { const char *user = "systemd-coredump"; r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0); 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->meta[META_ARGV_GID], &gid); if (r < 0) return r; } return drop_privileges(uid, gid, 0); } static int submit_coredump( const Context *context, struct iovec_wrapper *iovw, int input_fd) { _cleanup_(json_variant_unrefp) JsonVariant *json_metadata = NULL; _cleanup_close_ int coredump_fd = -EBADF, coredump_node_fd = -EBADF; _cleanup_free_ char *filename = NULL, *coredump_data = NULL; _cleanup_free_ char *stacktrace = NULL; char *core_message; const char *module_name; uint64_t coredump_size = UINT64_MAX, coredump_compressed_size = UINT64_MAX; bool truncated = false; JsonVariant *module_json; int r; assert(context); assert(iovw); 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, &coredump_compressed_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_node_fd >= 0 ? coredump_compressed_size : coredump_size); if (r < 0) return r; if (r == 0) (void) iovw_put_string_field(iovw, "COREDUMP_FILENAME=", 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_node_fd >= 0 ? coredump_compressed_size : 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"); /* Try to get a stack trace if we can */ if (coredump_size > arg_process_size_max) log_debug("Not generating stack trace: core size %"PRIu64" is greater " "than %"PRIu64" (the configured maximum)", coredump_size, arg_process_size_max); else if (coredump_fd >= 0) { bool skip = startswith(context->meta[META_COMM], "systemd-coredum"); /* COMM is 16 bytes usually */ (void) parse_elf_object(coredump_fd, context->meta[META_EXE], /* fork_disable_dump= */ skip, /* avoid loops */ &stacktrace, &json_metadata); } log: core_message = strjoina("Process ", context->meta[META_ARGV_PID], " (", context->meta[META_COMM], ") of user ", context->meta[META_ARGV_UID], " dumped core.", context->is_journald && filename ? "\nCoredump diverted to " : NULL, context->is_journald && filename ? filename : NULL); core_message = strjoina(core_message, stacktrace ? "\n\n" : NULL, stacktrace); if (context->is_journald) /* We might not be able to log to the journal, so let's always print the message to another * log target. The target was set previously to something safe. */ log_dispatch(LOG_ERR, 0, core_message); (void) iovw_put_string_field(iovw, "MESSAGE=", core_message); if (truncated) (void) iovw_put_string_field(iovw, "COREDUMP_TRUNCATED=", "1"); /* If we managed to parse any ELF metadata (build-id, ELF package meta), * attach it as journal metadata. */ if (json_metadata) { _cleanup_free_ char *formatted_json = NULL; r = json_variant_format(json_metadata, 0, &formatted_json); if (r < 0) return log_error_errno(r, "Failed to format JSON package metadata: %m"); (void) iovw_put_string_field(iovw, "COREDUMP_PACKAGE_JSON=", formatted_json); } /* In the unlikely scenario that context->meta[META_EXE] is not available, * let's avoid guessing the module name and skip the loop. */ if (context->meta[META_EXE]) JSON_VARIANT_OBJECT_FOREACH(module_name, module_json, json_metadata) { JsonVariant *t; /* We only add structured fields for the 'main' ELF module, and only if we can identify it. */ if (!path_equal_filename(module_name, context->meta[META_EXE])) continue; t = json_variant_by_key(module_json, "name"); if (t) (void) iovw_put_string_field(iovw, "COREDUMP_PACKAGE_NAME=", json_variant_string(t)); t = json_variant_by_key(module_json, "version"); if (t) (void) iovw_put_string_field(iovw, "COREDUMP_PACKAGE_VERSION=", json_variant_string(t)); } /* Optionally store the entire coredump in the journal */ if (arg_storage == COREDUMP_STORAGE_JOURNAL && coredump_fd >= 0) { 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) { if (iovw_put(iovw, coredump_data, sz) >= 0) TAKE_PTR(coredump_data); } 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); } /* If journald is coredumping, we have to be careful that we don't deadlock when trying to write the * coredump to the journal, so we put the journal socket in nonblocking mode before trying to write * the coredump to the socket. */ if (context->is_journald) { r = journal_fd_nonblock(true); if (r < 0) return log_error_errno(r, "Failed to make journal socket non-blocking: %m"); } r = sd_journal_sendv(iovw->iovec, iovw->count); if (context->is_journald) { int k; k = journal_fd_nonblock(false); if (k < 0) return log_error_errno(k, "Failed to make journal socket blocking: %m"); } if (r == -EAGAIN && context->is_journald) log_warning_errno(r, "Failed to log journal coredump, ignoring: %m"); else if (r < 0) return log_error_errno(r, "Failed to log coredump: %m"); return 0; } static int save_context(Context *context, const struct iovec_wrapper *iovw) { const char *unit; int r; assert(context); assert(iovw); assert(iovw->count >= _META_ARGV_MAX); /* The context does not allocate any memory on its own */ for (size_t n = 0; n < iovw->count; n++) { struct iovec *iovec = iovw->iovec + n; for (size_t i = 0; i < ELEMENTSOF(meta_field_names); i++) { /* 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 process_socket() and gather_pid_metadata_*()) */ assert(((char*) iovec->iov_base)[iovec->iov_len] == 0); const char *p = startswith(iovec->iov_base, meta_field_names[i]); if (p) { context->meta[i] = p; context->meta_size[i] = iovec->iov_len - strlen(meta_field_names[i]); break; } } } if (!context->meta[META_ARGV_PID]) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to find the PID of crashing process"); r = parse_pid(context->meta[META_ARGV_PID], &context->pid); if (r < 0) return log_error_errno(r, "Failed to parse PID \"%s\": %m", context->meta[META_ARGV_PID]); unit = context->meta[META_UNIT]; context->is_pid1 = streq(context->meta[META_ARGV_PID], "1") || streq_ptr(unit, SPECIAL_INIT_SCOPE); context->is_journald = streq_ptr(unit, SPECIAL_JOURNALD_SERVICE); return 0; } static int process_socket(int fd) { _cleanup_close_ int input_fd = -EBADF; Context context = {}; struct iovec_wrapper iovw = {}; struct iovec iovec; int r; assert(fd >= 0); log_setup(); log_debug("Processing coredump received on stdin..."); for (;;) { CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control; struct msghdr mh = { .msg_control = &control, .msg_controllen = sizeof(control), .msg_iovlen = 1, }; ssize_t n; ssize_t l; l = next_datagram_size_fd(fd); if (l < 0) { r = log_error_errno(l, "Failed to determine datagram size to read: %m"); goto finish; } iovec.iov_len = l; iovec.iov_base = malloc(l + 1); if (!iovec.iov_base) { r = log_oom(); goto finish; } mh.msg_iov = &iovec; n = recvmsg_safe(fd, &mh, MSG_CMSG_CLOEXEC); if (n < 0) { free(iovec.iov_base); r = log_error_errno(n, "Failed to receive datagram: %m"); goto finish; } /* The final zero-length datagram carries the file descriptor and tells us * that we're done. */ if (n == 0) { struct cmsghdr *found; free(iovec.iov_base); found = cmsg_find(&mh, SOL_SOCKET, SCM_RIGHTS, CMSG_LEN(sizeof(int))); if (!found) { cmsg_close_all(&mh); r = log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Coredump file descriptor missing."); goto finish; } assert(input_fd < 0); input_fd = *CMSG_TYPED_DATA(found, int); break; } else cmsg_close_all(&mh); /* Add trailing NUL byte, in case these are strings */ ((char*) iovec.iov_base)[n] = 0; iovec.iov_len = (size_t) n; r = iovw_put(&iovw, iovec.iov_base, iovec.iov_len); if (r < 0) goto finish; } /* Make sure we got all data we really need */ assert(input_fd >= 0); r = save_context(&context, &iovw); if (r < 0) goto finish; /* Make sure we received at least all fields we need. */ for (int i = 0; i < _META_MANDATORY_MAX; i++) if (!context.meta[i]) { r = log_error_errno(SYNTHETIC_ERRNO(EINVAL), "A mandatory argument (%i) has not been sent, aborting.", i); goto finish; } r = submit_coredump(&context, &iovw, input_fd); finish: iovw_free_contents(&iovw, true); return r; } static int send_iovec(const struct iovec_wrapper *iovw, int input_fd) { _cleanup_close_ int fd = -EBADF; int r; assert(iovw); 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"); r = connect_unix_path(fd, AT_FDCWD, "/run/systemd/coredump"); if (r < 0) return log_error_errno(r, "Failed to connect to coredump service: %m"); for (size_t i = 0; i < iovw->count; i++) { struct msghdr mh = { .msg_iov = iovw->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] = iovw->iovec[i]; copy[1] = IOVEC_MAKE(((char[]){'.', '.', '.'}), 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 int gather_pid_metadata_from_argv( struct iovec_wrapper *iovw, Context *context, int argc, char **argv) { _cleanup_free_ char *free_timestamp = NULL; int r, signo; char *t; /* We gather all metadata that were passed via argv[] into an array of iovecs that * we'll forward to the socket unit */ if (argc < _META_ARGV_MAX) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Not enough arguments passed by the kernel (%i, expected %i).", argc, _META_ARGV_MAX); for (int i = 0; i < _META_ARGV_MAX; i++) { t = argv[i]; switch (i) { case META_ARGV_TIMESTAMP: /* 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. */ t = free_timestamp = strjoin(argv[i], "000000"); if (!t) return log_oom(); break; case META_ARGV_SIGNAL: /* For signal, record its pretty name too */ if (safe_atoi(argv[i], &signo) >= 0 && SIGNAL_VALID(signo)) (void) iovw_put_string_field(iovw, "COREDUMP_SIGNAL_NAME=SIG", signal_to_string(signo)); break; default: break; } r = iovw_put_string_field(iovw, meta_field_names[i], t); if (r < 0) return r; } /* Cache some of the process metadata we collected so far and that we'll need to * access soon */ return save_context(context, iovw); } static int gather_pid_metadata(struct iovec_wrapper *iovw, Context *context) { uid_t owner_uid; pid_t pid; char *t; size_t size; const char *p; int r; /* 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 iovec fields initialized.) */ pid = context->pid; /* The following is mandatory */ r = get_process_comm(pid, &t); if (r < 0) return log_error_errno(r, "Failed to get COMM: %m"); r = iovw_put_string_field_free(iovw, "COREDUMP_COMM=", t); if (r < 0) return r; /* The following are optional, but we use them if present. */ r = get_process_exe(pid, &t); if (r >= 0) r = iovw_put_string_field_free(iovw, "COREDUMP_EXE=", t); if (r < 0) log_warning_errno(r, "Failed to get EXE, ignoring: %m"); if (cg_pid_get_unit(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_UNIT=", t); if (cg_pid_get_user_unit(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_USER_UNIT=", t); if (sd_pid_get_session(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_SESSION=", t); if (sd_pid_get_owner_uid(pid, &owner_uid) >= 0) { r = asprintf(&t, UID_FMT, owner_uid); if (r > 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_OWNER_UID=", t); } if (sd_pid_get_slice(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_SLICE=", t); if (get_process_cmdline(pid, SIZE_MAX, PROCESS_CMDLINE_QUOTE_POSIX, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_CMDLINE=", t); if (cg_pid_get_path_shifted(pid, NULL, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_CGROUP=", t); if (compose_open_fds(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_OPEN_FDS=", t); p = procfs_file_alloca(pid, "status"); if (read_full_virtual_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_STATUS=", t); p = procfs_file_alloca(pid, "maps"); if (read_full_virtual_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_MAPS=", t); p = procfs_file_alloca(pid, "limits"); if (read_full_virtual_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_LIMITS=", t); p = procfs_file_alloca(pid, "cgroup"); if (read_full_virtual_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_CGROUP=", t); p = procfs_file_alloca(pid, "mountinfo"); if (read_full_virtual_file(p, &t, NULL) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_PROC_MOUNTINFO=", t); /* We attach /proc/auxv here. ELF coredumps also contain a note for this (NT_AUXV), see elf(5). */ p = procfs_file_alloca(pid, "auxv"); if (read_full_virtual_file(p, &t, &size) >= 0) { char *buf = malloc(strlen("COREDUMP_PROC_AUXV=") + size + 1); if (buf) { /* Add a dummy terminator to make save_context() happy. */ *((uint8_t*) mempcpy(stpcpy(buf, "COREDUMP_PROC_AUXV="), t, size)) = '\0'; (void) iovw_consume(iovw, buf, size + strlen("COREDUMP_PROC_AUXV=")); } free(t); } if (get_process_cwd(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_CWD=", t); if (get_process_root(pid, &t) >= 0) { bool proc_self_root_is_slash; proc_self_root_is_slash = strcmp(t, "/") == 0; (void) iovw_put_string_field_free(iovw, "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) (void) iovw_put_string_field_free(iovw, "COREDUMP_CONTAINER_CMDLINE=", t); } if (get_process_environ(pid, &t) >= 0) (void) iovw_put_string_field_free(iovw, "COREDUMP_ENVIRON=", t); /* we successfully acquired all metadata */ return save_context(context, iovw); } static int process_kernel(int argc, char* argv[]) { Context context = {}; struct iovec_wrapper *iovw; int r; /* When we're invoked by the kernel, stdout/stderr are closed which is dangerous because the fds * could get reallocated. To avoid hard to debug issues, let's instead bind stdout/stderr to * /dev/null. */ r = rearrange_stdio(STDIN_FILENO, -EBADF, -EBADF); if (r < 0) return log_error_errno(r, "Failed to connect stdout/stderr to /dev/null: %m"); log_debug("Processing coredump received from the kernel..."); iovw = iovw_new(); if (!iovw) return log_oom(); (void) iovw_put_string_field(iovw, "MESSAGE_ID=", SD_MESSAGE_COREDUMP_STR); (void) iovw_put_string_field(iovw, "PRIORITY=", STRINGIFY(LOG_CRIT)); /* Collect all process metadata passed by the kernel through argv[] */ r = gather_pid_metadata_from_argv(iovw, &context, argc - 1, argv + 1); if (r < 0) goto finish; /* Collect the rest of the process metadata retrieved from the runtime */ r = gather_pid_metadata(iovw, &context); if (r < 0) goto finish; if (!context.is_journald) /* OK, now we know it's not the journal, hence we can make use of it now. */ log_set_target_and_open(LOG_TARGET_JOURNAL_OR_KMSG); /* If this is PID 1 disable coredump collection, we'll unlikely be able to process * it later on. * * FIXME: maybe we should disable coredumps generation from the beginning and * re-enable it only when we know it's either safe (ie we're not running OOM) or * it's not pid1 ? */ if (context.is_pid1) { log_notice("Due to PID 1 having crashed coredump collection will now be turned off."); disable_coredumps(); } if (context.is_journald || context.is_pid1) r = submit_coredump(&context, iovw, STDIN_FILENO); else r = send_iovec(iovw, STDIN_FILENO); finish: iovw = iovw_free_free(iovw); return r; } static int process_backtrace(int argc, char *argv[]) { Context context = {}; struct iovec_wrapper *iovw; char *message; int r; _cleanup_(journal_importer_cleanup) JournalImporter importer = JOURNAL_IMPORTER_INIT(STDIN_FILENO); log_debug("Processing backtrace on stdin..."); iovw = iovw_new(); if (!iovw) return log_oom(); (void) iovw_put_string_field(iovw, "MESSAGE_ID=", SD_MESSAGE_BACKTRACE_STR); (void) iovw_put_string_field(iovw, "PRIORITY=", STRINGIFY(LOG_CRIT)); /* Collect all process metadata from argv[] by making sure to skip the * '--backtrace' option */ r = gather_pid_metadata_from_argv(iovw, &context, argc - 2, argv + 2); if (r < 0) goto finish; /* Collect the rest of the process metadata retrieved from the runtime */ r = gather_pid_metadata(iovw, &context); if (r < 0) goto finish; 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 (journal_importer_eof(&importer)) { log_warning("Did not receive a full journal entry on stdin, ignoring message sent by reporter"); message = strjoina("Process ", context.meta[META_ARGV_PID], " (", context.meta[META_COMM], ")" " of user ", context.meta[META_ARGV_UID], " failed with ", context.meta[META_ARGV_SIGNAL]); r = iovw_put_string_field(iovw, "MESSAGE=", message); if (r < 0) return r; } else { /* The imported iovecs are not supposed to be freed by us so let's store * them at the end of the array so we can skip them while freeing the * rest. */ for (size_t i = 0; i < importer.iovw.count; i++) { struct iovec *iovec = importer.iovw.iovec + i; iovw_put(iovw, iovec->iov_base, iovec->iov_len); } } r = sd_journal_sendv(iovw->iovec, iovw->count); if (r < 0) log_error_errno(r, "Failed to log backtrace: %m"); finish: iovw->count -= importer.iovw.count; iovw = iovw_free_free(iovw); return r; } static int run(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_and_open(LOG_TARGET_KMSG); /* 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) return log_error_errno(r, "Failed to determine the number of file descriptors: %m"); /* 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")) return process_backtrace(argc, argv); else return process_kernel(argc, argv); } else if (r == 1) return process_socket(SD_LISTEN_FDS_START); return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Received unexpected number of file descriptors."); } DEFINE_MAIN_FUNCTION(run);