mirror of
git://sourceware.org/git/lvm2.git
synced 2024-12-21 13:34:40 +03:00
libdaemon: implement daemon_close_stray_fds
Refactor existing code from tools/lvmcmdline.c to libdaemon/server/daemon-stray.h daemon_close_stray_fds() used to close stray descriptors above some specified Fd. This is code parses content of /proc dir to minimize 'blind' closing of all possible descriptors within rlimits range. As we have the same code in few other places in it's more 'trivial' version - these were actually sensitive to high amount of descriptors, which might be configured on some system. With this patch we effectively resolve this reported gitlab issue: https://gitlab.com/lvmteam/lvm2/-/issues/5 TODO: Current placement might not be ideal - however considering existing code base constrains it's not so simple. ATM it uses lib/misc/lvm-file.h for custom_fds declaration and rest of functinality is included in daemon header file.
This commit is contained in:
Zdenek Kabelac
parent
ecb8399005
commit
79cdfc8ca6
@ -14,6 +14,7 @@
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#include "daemon-server.h"
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#include "daemon-log.h"
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#include "daemon-stray.h"
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#include "libdaemon/client/daemon-io.h"
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#include <dlfcn.h>
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@ -326,11 +327,14 @@ static void _remove_lockfile(const char *file)
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static void _daemonise(daemon_state s)
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{
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int child_status;
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int fd, ffd;
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int fd;
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pid_t pid;
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struct rlimit rlim;
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struct timeval tval;
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sigset_t my_sigset;
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struct custom_fds custom_fds = {
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/* Do not close fds preloaded by systemd! */
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.out = (_systemd_activation) ? SD_FD_SOCKET_SERVER : -1
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};
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if ((fd = open("/dev/null", O_RDWR)) == -1) {
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fprintf(stderr, "Unable to open /dev/null.\n");
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@ -392,20 +396,7 @@ static void _daemonise(daemon_state s)
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exit(3);
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}
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/* Switch to sysconf(_SC_OPEN_MAX) ?? */
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if (getrlimit(RLIMIT_NOFILE, &rlim) < 0)
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ffd = 256; /* just have to guess */
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else
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ffd = rlim.rlim_cur;
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for (--ffd; ffd > STDERR_FILENO; ffd--) {
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#ifdef __linux__
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/* Do not close fds preloaded by systemd! */
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if (_systemd_activation && ffd == SD_FD_SOCKET_SERVER)
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continue;
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#endif
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(void) close(ffd);
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}
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daemon_close_stray_fds(s.name, 0, STDERR_FILENO, &custom_fds);
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setsid();
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169
libdaemon/server/daemon-stray.h
Normal file
169
libdaemon/server/daemon-stray.h
Normal file
@ -0,0 +1,169 @@
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/*
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* Copyright (C) 2024 Red Hat, Inc.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _LVM_DAEMON_STRAY_H
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#define _LVM_DAEMON_STRAY_H
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/*
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* needs dm -> #include "device_mapper/all.h"
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* needs logging -> #include "libdm/misc/dmlib.h"
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*/
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#include "lib/misc/lvm-file.h"
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/*
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* When compiling with valgrind pool support, skip closing descriptors
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* as there is couple more of them being held by valgrind itself.
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*/
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#ifndef VALGRIND_POOL
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/syscall.h>
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#include <sys/resource.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <limits.h>
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#ifdef HAVE_VALGRIND
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#include <valgrind.h>
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#endif
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static void _daemon_get_cmdline(pid_t pid, char *cmdline, size_t size)
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{
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char buf[sizeof(DEFAULT_PROC_DIR) + 32];
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int fd, n = 0;
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snprintf(buf, sizeof(buf), DEFAULT_PROC_DIR "/%u/cmdline", pid);
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/* FIXME Use generic read code. */
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if ((fd = open(buf, O_RDONLY)) >= 0) {
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if ((n = read(fd, cmdline, size - 1)) < 0) {
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//perror("read", buf);
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n = 0;
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}
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(void) close(fd);
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}
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cmdline[n] = '\0';
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}
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static void _daemon_get_filename(int fd, char *filename, size_t size)
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{
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char buf[sizeof(DEFAULT_PROC_DIR) + 32];
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ssize_t lsize;
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snprintf(buf, sizeof(buf), DEFAULT_PROC_DIR "/self/fd/%u", fd);
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if ((lsize = readlink(buf, filename, sizeof(filename) - 1)) == -1)
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filename[0] = '\0';
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else
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filename[lsize] = '\0';
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}
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static void _daemon_close_descriptor(int fd, unsigned suppress_warnings,
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const char *command, pid_t ppid,
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const char *parent_cmdline)
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{
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char filename[PATH_MAX];
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int r;
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/* Ignore bad file descriptors */
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if (!is_valid_fd(fd))
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return;
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if (!suppress_warnings)
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_daemon_get_filename(fd, filename, sizeof(filename));
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r = close(fd);
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if ((fd <= STDERR_FILENO) || suppress_warnings)
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return;
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if (!r)
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fprintf(stderr, "File descriptor %d (%s) leaked on "
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"%s invocation.", fd, filename, command);
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else if (errno == EBADF)
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return;
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else
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fprintf(stderr, "Close failed on stray file descriptor "
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"%d (%s): %s", fd, filename, strerror(errno));
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fprintf(stderr, " Parent PID %d: %s\n", (int)ppid, parent_cmdline);
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}
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#endif /* VALGRIND_POOL */
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/* Close all stray descriptor except custom fds.
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* Note: when 'from_fd' is set to -1, unused 'custom_fds' must use same value!
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*
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* command: print command name with warning message
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* suppress_warning: whether to print warning messages
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* above_fd: close all descriptors above this descriptor
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* custom_fds: preserve descriptors from this set of descriptors
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*/
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static int daemon_close_stray_fds(const char *command, int suppress_warning,
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int from_fd, const struct custom_fds *custom_fds)
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{
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#ifndef VALGRIND_POOL
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struct rlimit rlim;
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int fd;
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unsigned suppress_warnings = 0;
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pid_t ppid = getppid();
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char parent_cmdline[64];
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static const char _fd_dir[] = DEFAULT_PROC_DIR "/self/fd";
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struct dirent *dirent;
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DIR *d;
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#ifdef HAVE_VALGRIND
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if (RUNNING_ON_VALGRIND)
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/* Skipping close of descriptors within valgrind execution. */
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return 1;
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#endif /* HAVE_VALGRIND */
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_daemon_get_cmdline(ppid, parent_cmdline, sizeof(parent_cmdline));
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if ((d = opendir(_fd_dir))) {
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/* Discover openned descriptors from /proc/self/fd listing */
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while ((dirent = readdir(d))) {
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fd = atoi(dirent->d_name);
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if ((fd > from_fd) &&
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(fd != dirfd(d)) &&
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(fd != custom_fds->out) &&
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(fd != custom_fds->err) &&
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(fd != custom_fds->report))
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_daemon_close_descriptor(fd, suppress_warnings,
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command, ppid, parent_cmdline);
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}
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(void) closedir(d);
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} else if (errno == ENOENT) {
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/* Path does not exist, use the old way */
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if (getrlimit(RLIMIT_NOFILE, &rlim) < 0)
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fd = 256; /* just have to guess */
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else if ((fd = (int)rlim.rlim_cur) > 65536)
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fd = 65536; /* do not bother with more then 64K fds */
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while (--fd > from_fd) {
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if ((fd != custom_fds->out) &&
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(fd != custom_fds->err) &&
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(fd != custom_fds->report))
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_daemon_close_descriptor(fd, suppress_warnings, command,
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ppid, parent_cmdline);
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}
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} else
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return 0; /* broken system */
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#endif /* VALGRIND_POOL */
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return 1;
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}
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#endif
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@ -21,6 +21,7 @@
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#include "lvm-version.h"
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#include "lib/locking/lvmlockd.h"
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#include "lib/datastruct/str_list.h"
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#include "libdaemon/server/daemon-stray.h"
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/* coverity[unnecessary_header] */
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#include "stub.h"
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@ -34,10 +35,6 @@
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#include <locale.h>
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#include <langinfo.h>
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#ifdef HAVE_VALGRIND
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#include <valgrind.h>
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#endif
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#ifdef HAVE_GETOPTLONG
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# include <getopt.h>
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# define GETOPTLONG_FN(a, b, c, d, e) getopt_long((a), (b), (c), (d), (e))
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@ -3502,137 +3499,6 @@ static int _get_custom_fds(struct custom_fds *custom_fds)
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_do_get_custom_fd(LVM_REPORT_FD_ENV_VAR_NAME, &custom_fds->report);
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}
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static const char *_get_cmdline(pid_t pid)
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{
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static char _proc_cmdline[32];
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char buf[256];
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int fd, n = 0;
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snprintf(buf, sizeof(buf), DEFAULT_PROC_DIR "/%u/cmdline", pid);
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/* FIXME Use generic read code. */
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if ((fd = open(buf, O_RDONLY)) >= 0) {
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if ((n = read(fd, _proc_cmdline, sizeof(_proc_cmdline) - 1)) < 0) {
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log_sys_error("read", buf);
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n = 0;
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}
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if (close(fd))
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log_sys_error("close", buf);
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}
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_proc_cmdline[n] = '\0';
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return _proc_cmdline;
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}
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static const char *_get_filename(int fd)
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{
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static char filename[PATH_MAX];
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char buf[32]; /* Assumes short DEFAULT_PROC_DIR */
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int size;
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snprintf(buf, sizeof(buf), DEFAULT_PROC_DIR "/self/fd/%u", fd);
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if ((size = readlink(buf, filename, sizeof(filename) - 1)) == -1)
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filename[0] = '\0';
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else
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filename[size] = '\0';
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return filename;
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}
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static void _close_descriptor(int fd, unsigned suppress_warnings,
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const char *command, pid_t ppid,
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const char *parent_cmdline)
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{
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int r;
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const char *filename;
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/* Ignore bad file descriptors */
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if (!is_valid_fd(fd))
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return;
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if (!suppress_warnings)
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filename = _get_filename(fd);
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r = close(fd);
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if (suppress_warnings)
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return;
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if (!r)
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fprintf(stderr, "File descriptor %d (%s) leaked on "
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"%s invocation.", fd, filename, command);
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else if (errno == EBADF)
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return;
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else
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fprintf(stderr, "Close failed on stray file descriptor "
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"%d (%s): %s", fd, filename, strerror(errno));
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fprintf(stderr, " Parent PID %" PRIpid_t ": %s\n", ppid, parent_cmdline);
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}
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static int _close_stray_fds(const char *command, struct custom_fds *custom_fds)
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{
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#ifndef VALGRIND_POOL
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struct rlimit rlim;
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int fd;
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unsigned suppress_warnings = 0;
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pid_t ppid = getppid();
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const char *parent_cmdline = _get_cmdline(ppid);
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static const char _fd_dir[] = DEFAULT_PROC_DIR "/self/fd";
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struct dirent *dirent;
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DIR *d;
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#ifdef HAVE_VALGRIND
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if (RUNNING_ON_VALGRIND) {
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log_debug("Skipping close of descriptors within valgrind execution.");
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return 1;
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}
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#endif
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if (getenv("LVM_SUPPRESS_FD_WARNINGS"))
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suppress_warnings = 1;
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if (!(d = opendir(_fd_dir))) {
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if (errno != ENOENT) {
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log_sys_error("opendir", _fd_dir);
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return 0; /* broken system */
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}
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/* Path does not exist, use the old way */
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if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
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log_sys_error("getrlimit", "RLIMIT_NOFILE");
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return 1;
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}
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for (fd = 3; fd < (int)rlim.rlim_cur; fd++) {
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if ((fd != custom_fds->out) &&
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(fd != custom_fds->err) &&
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(fd != custom_fds->report)) {
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_close_descriptor(fd, suppress_warnings, command, ppid,
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parent_cmdline);
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}
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}
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return 1;
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}
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while ((dirent = readdir(d))) {
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fd = atoi(dirent->d_name);
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if ((fd > 2) &&
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(fd != dirfd(d)) &&
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(fd != custom_fds->out) &&
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(fd != custom_fds->err) &&
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(fd != custom_fds->report)) {
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_close_descriptor(fd, suppress_warnings,
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command, ppid, parent_cmdline);
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}
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}
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if (closedir(d))
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log_sys_debug("closedir", _fd_dir);
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#endif
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return 1;
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}
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struct cmd_context *init_lvm(unsigned set_connections,
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unsigned set_filters,
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unsigned threaded)
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@ -3761,7 +3627,8 @@ int lvm2_main(int argc, char **argv)
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if (!_get_custom_fds(&custom_fds))
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return EINIT_FAILED;
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if (!_close_stray_fds(base, &custom_fds))
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if (!daemon_close_stray_fds(base, getenv("LVM_SUPPRESS_FD_WARNINGS") ? 1 : 0,
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STDERR_FILENO, &custom_fds))
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return EINIT_FAILED;
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if (!init_custom_log_streams(&custom_fds))
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