370 lines
11 KiB
C
370 lines
11 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <dirent.h>
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#include <fcntl.h>
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#include <mqueue.h>
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#include <sys/ipc.h>
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#include <sys/msg.h>
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#include <sys/sem.h>
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#include <sys/shm.h>
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#include <sys/stat.h>
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#include "clean-ipc.h"
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#include "fd-util.h"
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#include "fileio.h"
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#include "formats-util.h"
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#include "string-util.h"
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#include "strv.h"
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#include "util.h"
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#include "dirent-util.h"
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static int clean_sysvipc_shm(uid_t delete_uid) {
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_cleanup_fclose_ FILE *f = NULL;
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char line[LINE_MAX];
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bool first = true;
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int ret = 0;
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f = fopen("/proc/sysvipc/shm", "re");
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if (!f) {
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if (errno == ENOENT)
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return 0;
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log_warning_errno(errno, "Failed to open /proc/sysvipc/shm: %m");
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return -errno;
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}
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FOREACH_LINE(line, f, goto fail) {
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unsigned n_attached;
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pid_t cpid, lpid;
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uid_t uid, cuid;
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gid_t gid, cgid;
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int shmid;
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if (first) {
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first = false;
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continue;
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}
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truncate_nl(line);
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if (sscanf(line, "%*i %i %*o %*u " PID_FMT " " PID_FMT " %u " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
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&shmid, &cpid, &lpid, &n_attached, &uid, &gid, &cuid, &cgid) != 8)
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continue;
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if (n_attached > 0)
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continue;
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if (uid != delete_uid)
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continue;
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if (shmctl(shmid, IPC_RMID, NULL) < 0) {
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/* Ignore entries that are already deleted */
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if (errno == EIDRM || errno == EINVAL)
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continue;
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ret = log_warning_errno(errno,
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"Failed to remove SysV shared memory segment %i: %m",
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shmid);
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}
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}
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return ret;
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fail:
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log_warning_errno(errno, "Failed to read /proc/sysvipc/shm: %m");
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return -errno;
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}
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static int clean_sysvipc_sem(uid_t delete_uid) {
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_cleanup_fclose_ FILE *f = NULL;
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char line[LINE_MAX];
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bool first = true;
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int ret = 0;
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f = fopen("/proc/sysvipc/sem", "re");
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if (!f) {
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if (errno == ENOENT)
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return 0;
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log_warning_errno(errno, "Failed to open /proc/sysvipc/sem: %m");
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return -errno;
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}
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FOREACH_LINE(line, f, goto fail) {
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uid_t uid, cuid;
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gid_t gid, cgid;
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int semid;
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if (first) {
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first = false;
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continue;
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}
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truncate_nl(line);
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if (sscanf(line, "%*i %i %*o %*u " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
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&semid, &uid, &gid, &cuid, &cgid) != 5)
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continue;
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if (uid != delete_uid)
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continue;
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if (semctl(semid, 0, IPC_RMID) < 0) {
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/* Ignore entries that are already deleted */
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if (errno == EIDRM || errno == EINVAL)
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continue;
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ret = log_warning_errno(errno,
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"Failed to remove SysV semaphores object %i: %m",
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semid);
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}
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}
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return ret;
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fail:
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log_warning_errno(errno, "Failed to read /proc/sysvipc/sem: %m");
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return -errno;
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}
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static int clean_sysvipc_msg(uid_t delete_uid) {
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_cleanup_fclose_ FILE *f = NULL;
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char line[LINE_MAX];
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bool first = true;
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int ret = 0;
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f = fopen("/proc/sysvipc/msg", "re");
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if (!f) {
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if (errno == ENOENT)
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return 0;
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log_warning_errno(errno, "Failed to open /proc/sysvipc/msg: %m");
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return -errno;
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}
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FOREACH_LINE(line, f, goto fail) {
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uid_t uid, cuid;
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gid_t gid, cgid;
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pid_t cpid, lpid;
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int msgid;
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if (first) {
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first = false;
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continue;
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}
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truncate_nl(line);
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if (sscanf(line, "%*i %i %*o %*u %*u " PID_FMT " " PID_FMT " " UID_FMT " " GID_FMT " " UID_FMT " " GID_FMT,
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&msgid, &cpid, &lpid, &uid, &gid, &cuid, &cgid) != 7)
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continue;
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if (uid != delete_uid)
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continue;
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if (msgctl(msgid, IPC_RMID, NULL) < 0) {
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/* Ignore entries that are already deleted */
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if (errno == EIDRM || errno == EINVAL)
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continue;
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ret = log_warning_errno(errno,
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"Failed to remove SysV message queue %i: %m",
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msgid);
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}
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}
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return ret;
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fail:
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log_warning_errno(errno, "Failed to read /proc/sysvipc/msg: %m");
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return -errno;
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}
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static int clean_posix_shm_internal(DIR *dir, uid_t uid) {
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struct dirent *de;
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int ret = 0, r;
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assert(dir);
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FOREACH_DIRENT(de, dir, goto fail) {
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struct stat st;
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if (STR_IN_SET(de->d_name, "..", "."))
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continue;
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if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
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if (errno == ENOENT)
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continue;
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log_warning_errno(errno, "Failed to stat() POSIX shared memory segment %s: %m", de->d_name);
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ret = -errno;
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continue;
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}
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if (st.st_uid != uid)
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continue;
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if (S_ISDIR(st.st_mode)) {
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_cleanup_closedir_ DIR *kid;
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kid = xopendirat(dirfd(dir), de->d_name, O_NOFOLLOW|O_NOATIME);
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if (!kid) {
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if (errno != ENOENT) {
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log_warning_errno(errno, "Failed to enter shared memory directory %s: %m", de->d_name);
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ret = -errno;
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}
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} else {
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r = clean_posix_shm_internal(kid, uid);
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if (r < 0)
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ret = r;
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}
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if (unlinkat(dirfd(dir), de->d_name, AT_REMOVEDIR) < 0) {
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if (errno == ENOENT)
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continue;
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log_warning_errno(errno, "Failed to remove POSIX shared memory directory %s: %m", de->d_name);
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ret = -errno;
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}
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} else {
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if (unlinkat(dirfd(dir), de->d_name, 0) < 0) {
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if (errno == ENOENT)
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continue;
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log_warning_errno(errno, "Failed to remove POSIX shared memory segment %s: %m", de->d_name);
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ret = -errno;
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}
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}
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}
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return ret;
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fail:
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log_warning_errno(errno, "Failed to read /dev/shm: %m");
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return -errno;
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}
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static int clean_posix_shm(uid_t uid) {
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_cleanup_closedir_ DIR *dir = NULL;
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dir = opendir("/dev/shm");
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if (!dir) {
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if (errno == ENOENT)
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return 0;
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log_warning_errno(errno, "Failed to open /dev/shm: %m");
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return -errno;
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}
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return clean_posix_shm_internal(dir, uid);
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}
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static int clean_posix_mq(uid_t uid) {
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_cleanup_closedir_ DIR *dir = NULL;
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struct dirent *de;
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int ret = 0;
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dir = opendir("/dev/mqueue");
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if (!dir) {
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if (errno == ENOENT)
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return 0;
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log_warning_errno(errno, "Failed to open /dev/mqueue: %m");
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return -errno;
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}
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FOREACH_DIRENT(de, dir, goto fail) {
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struct stat st;
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char fn[1+strlen(de->d_name)+1];
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if (STR_IN_SET(de->d_name, "..", "."))
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continue;
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if (fstatat(dirfd(dir), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
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if (errno == ENOENT)
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continue;
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ret = log_warning_errno(errno,
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"Failed to stat() MQ segment %s: %m",
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de->d_name);
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continue;
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}
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if (st.st_uid != uid)
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continue;
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fn[0] = '/';
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strcpy(fn+1, de->d_name);
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if (mq_unlink(fn) < 0) {
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if (errno == ENOENT)
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continue;
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ret = log_warning_errno(errno,
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"Failed to unlink POSIX message queue %s: %m",
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fn);
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}
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}
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return ret;
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fail:
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log_warning_errno(errno, "Failed to read /dev/mqueue: %m");
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return -errno;
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}
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int clean_ipc(uid_t uid) {
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int ret = 0, r;
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/* Refuse to clean IPC of the root and system users */
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if (uid <= SYSTEM_UID_MAX)
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return 0;
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r = clean_sysvipc_shm(uid);
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if (r < 0)
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ret = r;
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r = clean_sysvipc_sem(uid);
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if (r < 0)
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ret = r;
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r = clean_sysvipc_msg(uid);
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if (r < 0)
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ret = r;
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r = clean_posix_shm(uid);
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if (r < 0)
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ret = r;
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r = clean_posix_mq(uid);
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if (r < 0)
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ret = r;
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return ret;
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}
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