From 9f3910df62bcc1f726b8e84f9ffc40c4d7916eac Mon Sep 17 00:00:00 2001 From: Werner Fink Date: Thu, 14 Jan 2021 11:37:46 +0100 Subject: [PATCH] Use new statx(2) system call to avoid hangs on NFS Signed-off-by: Werner Fink --- Makefile.am | 4 - configure.ac | 38 +++++---------- src/fuser.c | 98 +++++++++----------------------------- src/statx.c | 149 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ src/statx.h | 68 ++++++++++++++++++++++++++ 5 files changed, 258 insertions(+), 99 deletions(-) --- Makefile.am +++ Makefile.am 2021-01-14 11:29:22.011223930 +0000 @@ -64,8 +64,8 @@ src_fuser_SOURCES = \ src/fuser.h \ src/lists.h -if WANT_TIMEOUT_STAT -src_fuser_SOURCES += src/timeout.c src/timeout.h +if HAVE_SYSCALL_STATX +src_fuser_SOURCES += src/statx.c src/statx.h endif src_fuser_LDADD = @LIBINTL@ src_killall_SOURCES = src/killall.c src/comm.h src/signals.c src/signals.h src/i18n.h --- configure.ac +++ configure.ac 2021-01-14 11:29:22.011223930 +0000 @@ -30,20 +30,6 @@ if test "$enable_selinux" = "yes"; then fi AC_SUBST([SELINUX_LIB]) -# Call fork before all stat calls to stop hanging on NFS mounts -AC_SUBST([WITH_TIMEOUT_STAT]) -AC_ARG_ENABLE([timeout_stat], - [AS_HELP_STRING([--enable-timeout-stat], [Use a timeout on stat calls (optional with argument "static" for a static background process)])], - [enable_timeout_stat=$enableval], - [enable_timeout_stat="no"]) -if test "$enable_timeout_stat" = "yes"; then - AC_DEFINE([WITH_TIMEOUT_STAT], [1], [Use timeout on stat calls]) -fi -if test "$enable_timeout_stat" = "static"; then - AC_DEFINE([WITH_TIMEOUT_STAT], [2], [Use timeout on stat calls]) -fi -AM_CONDITIONAL([WANT_TIMEOUT_STAT], [test "$enable_timeout_stat" = "static"]) - # Use /proc/self/mountinfo if available if test -e /proc/self/mountinfo ; then AC_DEFINE([HAS_MOUNTINFO], [1], [System has /proc/self/mountinfo which can used instead /proc(/self)/mounts]) @@ -57,16 +43,20 @@ fi AC_CHECK_FUNC([name_to_handle_at],[ AC_DEFINE([HAS_NAME_TO_HANDLE_AT], [1], [System has name_to_handle_at(2) system call])]) -# Use string search for network based file systems but only if the system -# has /proc/self/mountinfo -AC_SUBST([WITH_MOUNTINFO_LIST]) -AC_ARG_ENABLE([mountinfo_list], - [AS_HELP_STRING([--enable-mountinfo-list], [Use the list in /proc/self/mountinfo to replace stat(2) syscall on network file systems shares])], - [enable_mountinfo_list="yes"], - [enable_mountinfo_list="no"]) -if test "$enable_mountinfo_list" = "yes" -a -e /proc/self/mountinfo ; then - AC_DEFINE([WITH_MOUNTINFO_LIST], [1], [Use list in /proc/self/mountinfo to replace stat calls]) -fi +AC_CHECK_HEADERS([sys/syscall.h]) +AC_CHECK_DECLS([SYS_statx], + [has_syscall_statx="yes"], + [has_syscall_statx="no"], + [[#include ]] +) +AC_CHECK_FUNCS([statx]) +# Check for linux specific statx(2) system call +AC_SUBST([HAS_SYSCALL_STATX]) +AC_ARG_ENABLE([disable_statx], + [AS_HELP_STRING([--disable-statx], [Do not use linux specific statx(2) system call as replacement for stat(2), lstat(2), and fstat(2)])], + [enable_syscall_statx="no"], + [enable_syscall_statx=$has_syscall_statx]) +AM_CONDITIONAL([HAVE_SYSCALL_STATX], [test "$enable_syscall_statx" = "yes"]) # Enable hardened compile and link flags AC_ARG_ENABLE([harden_flags], --- src/fuser.c +++ src/fuser.c 2021-01-14 11:30:10.750278604 +0000 @@ -63,7 +63,7 @@ #include "fuser.h" #include "signals.h" #include "i18n.h" -#include "timeout.h" +#include "statx.h" #include "comm.h" //#define DEBUG 1 @@ -118,10 +118,6 @@ static void clear_mntinfo(void) __attrib static void init_mntinfo(void) __attribute__ ((__constructor__)); static int get_fdinfo(const pid_t pid, const char *fd, struct fdinfo *info); static int find_mountpoint(const char *path, mntinfo_t **mountinfo); -#if defined(WITH_MOUNTINFO_LIST) -static int mntstat(const char *path, struct stat *buf); -#endif -static stat_t thestat = stat; static char *expandpath(const char *path); static struct unixsocket_list *unixsockets = NULL; static struct names *names_head = NULL, *names_tail = NULL; @@ -509,7 +505,7 @@ int parse_file(struct names *this_name, free(this_name->filename); this_name->filename = strdup(new); } - if (timeout(thestat, this_name->filename, &(this_name->st), 5) != 0 || + if (statn(this_name->filename, STATX_INO|STATX_TYPE, &(this_name->st)) != 0 || find_mountpoint(this_name->filename, &mountinfo) != 0) { if (errno == ENOENT) fprintf(stderr, @@ -1245,9 +1241,7 @@ int main(int argc, char *argv[]) opts |= OPT_INTERACTIVE; break; case 'I': -#if defined(WITH_MOUNTINFO_LIST) opts |= OPT_ALWAYSSTAT; -#endif break; case 'k': opts |= OPT_KILL; @@ -1313,10 +1307,11 @@ int main(int argc, char *argv[]) continue; } -#if defined(WITH_MOUNTINFO_LIST) - if ((opts & (OPT_MOUNTS|OPT_ALWAYSSTAT)) == OPT_MOUNTS) - thestat = mntstat; +#if defined(HAVE_DECL_SYS_STATX) && HAVE_DECL_SYS_STATX == 1 + if ((opts & OPT_ALWAYSSTAT)) + stat_flags = 0; /* Triggers sync with e.g. remote NFS server even on autofs */ #endif + /* an option */ /* Not an option, must be a file specification */ if ((this_name = malloc(sizeof(struct names))) == NULL) @@ -1636,7 +1631,7 @@ static struct stat *get_pidstat(const pi if ((st = (struct stat *)malloc(sizeof(struct stat))) == NULL) return NULL; snprintf(pathname, 256, "/proc/%d/%s", pid, filename); - if (timeout(thestat, pathname, st, 5) != 0) { + if (statn(pathname, STATX_UID|STATX_INO|STATX_TYPE, st) != 0) { free(st); return NULL; } @@ -1683,7 +1678,7 @@ check_dir(const pid_t pid, const char *d snprintf(filepath, sizeof filepath - 1, "/proc/%d/%s/%s", pid, dirname, direntry->d_name); - if (timeout(thestat, filepath, &st, 5) != 0) { + if (statn(filepath, STATX_INO, &st) != 0) { if (errno != ENOENT && errno != ENOTDIR) { fprintf(stderr, _("Cannot stat file %s: %s\n"), filepath, strerror(errno)); @@ -1740,7 +1735,7 @@ check_dir(const pid_t pid, const char *d if (thedev != ino_tmp->device) continue; if (!st.st_ino - && timeout(thestat, filepath, &st, 5) != 0) { + && statn(filepath, STATX_INO, &st) != 0) { fprintf(stderr, _("Cannot stat file %s: %s\n"), filepath, strerror(errno)); @@ -1838,11 +1833,11 @@ static uid_t getpiduid(const pid_t pid) if (asprintf(&pathname, "/proc/%d", pid) < 0) return 0; - if (timeout(thestat, pathname, &st, 5) != 0) { - free(pathname); + if (statn(pathname, STATX_UID, &st) != 0) { + free(pathname); return 0; - } - free(pathname); + } + free(pathname); return st.st_uid; } @@ -1880,7 +1875,7 @@ void fill_unix_cache(struct unixsocket_l path = scanned_path; if (*scanned_path == '@') scanned_path++; - if (timeout(thestat, scanned_path, &st, 5) < 0) { + if (statn(scanned_path, STATX_INO, &st) < 0) { free(path); continue; } @@ -2015,7 +2010,7 @@ static dev_t find_net_dev(void) fprintf(stderr, _("Cannot open a network socket.\n")); return -1; } - if (fstat(skt, &st) != 0) { + if (fstatn(skt, STATX_INO, &st) != 0) { fprintf(stderr, _("Cannot find socket's device number.\n")); close(skt); return -1; @@ -2052,7 +2047,7 @@ scan_knfsd(struct names *names_head, str if ((find_space = strpbrk(line, " \t")) == NULL) continue; *find_space = '\0'; - if (timeout(thestat, line, &st, 5) != 0) { + if (statn(line, STATX_INO, &st) != 0) { continue; } /* Scan the devices */ @@ -2086,7 +2081,7 @@ scan_mounts(struct names *names_head, st mntinfo_t *mnt = list_entry(ptr, mntinfo_t); const char *find_mountp = mnt->mpoint; - if (timeout(thestat, find_mountp, &st, 5) != 0) + if (statn(find_mountp, STATX_INO, &st) != 0) continue; /* Scan the devices */ @@ -2136,7 +2131,7 @@ scan_swaps(struct names *names_head, str if (*find_space == '\0') continue; } - if (timeout(thestat, line, &st, 5) != 0) { + if (statn(line, STATX_INO, &st) != 0) { continue; } /* Scan the devices */ @@ -2228,10 +2223,10 @@ init_mntinfo(void) &mid, &parid, &maj, &min, &mpoint[0], &type[0], &devname[0]) == 7) { struct stat st; mntinf = add_mntinfo(mpoint, type, mid, parid, makedev(maj, min)); - if (mntinf && strncmp(devname, "/dev/", 5) == 0 && stat(devname, &st) == 0) { + if (mntinf && strncmp(devname, "/dev/", 5) == 0 && statn(devname, 0, &st) == 0) { if (st.st_rdev != 0 && mntinf->dev != st.st_rdev) { mntinf->vol = st.st_rdev; - stat(mpoint, &st); + statn(mpoint, 0, &st); mntinf->dev = st.st_dev; /* stat(2) on binary does not see subvol dev */ } } @@ -2243,7 +2238,7 @@ init_mntinfo(void) parid = -1; while (fscanf (mnt, "%s %s %s %*[^\n]", &devname[0], &mpoint[0], &type[0]) == 3) { struct stat st; - if (stat(mpoint, &st) != 0) { + if (statn(mpoint, 0, &st) != 0) { if (errno != EACCES) { fprintf(stderr, _("Cannot stat %s: %s\n"), mpoint, strerror(errno)); @@ -2252,7 +2247,7 @@ init_mntinfo(void) st.st_dev = (dev_t)-1; } mntinf = add_mntinfo(mpoint, type, mid++, parid, st.st_dev); - if (mntinf && strncmp(devname, "/dev/", 5) == 0 && stat(devname, &st) == 0) { + if (mntinf && strncmp(devname, "/dev/", 5) == 0 && statn(devname, 0, &st) == 0) { if (st.st_rdev != 0 && mntinf->dev != st.st_rdev) mntinf->vol = st.st_rdev; } @@ -2302,7 +2297,7 @@ out: struct stat lst; snprintf(pathname, 256, "/proc/%d/fd/%s", pid, fd); - if (!flags && lstat(pathname, &lst) == 0) { + if (!flags && lstatn(pathname, STATX_MODE, &lst) == 0) { if (lst.st_mode & S_IWUSR) info->flags |= O_WRONLY; ret++; @@ -2375,7 +2370,7 @@ find_mountpoint(const char *path, mntinf /* could be a chroot or a container */ - if (stat(path, &st) != 0) { + if (statn(path, 0, &st) != 0) { if (errno != EACCES) { fprintf(stderr, _("Cannot stat %s: %s\n"), path, strerror(errno)); @@ -2407,7 +2402,7 @@ find_mountpoint(const char *path, mntinf /* could be a chroot or a container */ - if (stat(use, &st) != 0) { + if (statn(use, 0, &st) != 0) { if (errno != EACCES) { fprintf(stderr, _("Cannot stat %s: %s\n"), use, strerror(errno)); @@ -2445,49 +2440,6 @@ out: return ret; } -#if defined(WITH_MOUNTINFO_LIST) -/* - * Determine device of links below /proc/ - */ -static int mntstat(const char *path, struct stat *buf) -{ - char name[PATH_MAX + 1]; - const char *use; - mntinfo_t *mnt; - - if ((use = realpath(path, name)) == NULL || *use != '/') - { - if (errno == ENOENT) - return -1; - /* - * Could be a special file (socket, pipe, inotify) - */ - errno = 0; - return stat(path, buf); - } - if (strncmp("/dev/", use, 5) == 0) { - /* - * Could be a special file (socket, pipe, inotify) - */ - errno = 0; - return stat(path, buf); - } - - if (find_mountpoint(use, &mnt) < 0) { - errno = ENOENT; - return -1; - } - - if (mnt->isremote) { - buf->st_dev = mnt->dev; - buf->st_ino = mnt->id; /* inode substitute */ - return 0; /* found on NFS */ - } - - return stat(path, buf); -} -#endif /* WITH_MOUNTINFO_LIST */ - /* * Somehow the realpath(3) glibc function call, nevertheless * it avoids lstat(2) system calls. --- src/statx.c +++ src/statx.c 2021-01-14 11:29:22.015223853 +0000 @@ -0,0 +1,149 @@ +/* + * statx.c - Map modern statx(2) system call to older stat(2), lstat(2), + * and fstat(2) replacements named {,l,f}statn() + * + * Copyright (C) 2018 Werner Fink + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif + +#ifdef HAVE_CONFIG_H +#include +#endif + +#ifndef HAVE_STATX +# define _ASM_GENERIC_FCNTL_H /* Avoid collisions between asm/fcntl.h and bits/fcntl.h ! */ +# include /* Definition of AT_* and AT_STATX_* constants ! */ +#endif +#include /* Definition of AT_* constants */ +#include +#ifndef HAVE_STATX +# ifndef STATX_TYPE +# include /* Provides 'struct statx' and STATX_* ! */ +# endif +#endif +#include +#include +#include +#include + +int stat_flags = AT_NO_AUTOMOUNT|AT_STATX_DONT_SYNC; + +int statn(const char *pathname, unsigned int mask, struct stat *st) +{ + int flags = stat_flags; + int dirfd = pathname && *pathname == '/' ? 0 : AT_FDCWD; + int ret; + struct statx stx; + +#ifndef HAVE_STATX + ret = syscall(SYS_statx, dirfd, pathname, flags, mask, &stx); +#else + ret = statx(dirfd, pathname, flags, mask, &stx); +#endif + if (ret >= 0) { + st->st_dev = makedev(stx.stx_dev_major, stx.stx_dev_minor); + st->st_rdev = makedev(stx.stx_rdev_major, stx.stx_rdev_minor); + + st->st_ino = stx.stx_ino; + st->st_mode = stx.stx_mode; + st->st_nlink = stx.stx_nlink; + st->st_uid = stx.stx_uid; + st->st_gid = stx.stx_gid; + st->st_size = stx.stx_size; + st->st_blksize = stx.stx_blksize; + st->st_blocks = stx.stx_blocks; + + st->st_atim.tv_sec = stx.stx_atime.tv_sec; + st->st_atim.tv_nsec = stx.stx_atime.tv_nsec; + st->st_mtim.tv_sec = stx.stx_mtime.tv_sec; + st->st_mtim.tv_nsec = stx.stx_mtime.tv_nsec; + st->st_ctim.tv_sec = stx.stx_ctime.tv_sec; + st->st_ctim.tv_nsec = stx.stx_ctime.tv_nsec; + } + return ret; +} + +int fstatn(int fd, unsigned int mask, struct stat *st) +{ + int flags = AT_EMPTY_PATH|stat_flags; + int ret; + struct statx stx; + +#ifndef HAVE_STATX + ret = syscall(SYS_statx, fd, "", flags, mask, &stx); +#else + ret = statx(fd, "", flags, mask, &stx); +#endif + if (ret >= 0) { + st->st_dev = makedev(stx.stx_dev_major, stx.stx_dev_minor); + st->st_rdev = makedev(stx.stx_rdev_major, stx.stx_rdev_minor); + + st->st_ino = stx.stx_ino; + st->st_mode = stx.stx_mode; + st->st_nlink = stx.stx_nlink; + st->st_uid = stx.stx_uid; + st->st_gid = stx.stx_gid; + st->st_size = stx.stx_size; + st->st_blksize = stx.stx_blksize; + st->st_blocks = stx.stx_blocks; + + st->st_atim.tv_sec = stx.stx_atime.tv_sec; + st->st_atim.tv_nsec = stx.stx_atime.tv_nsec; + st->st_mtim.tv_sec = stx.stx_mtime.tv_sec; + st->st_mtim.tv_nsec = stx.stx_mtime.tv_nsec; + st->st_ctim.tv_sec = stx.stx_ctime.tv_sec; + st->st_ctim.tv_nsec = stx.stx_ctime.tv_nsec; + } + return ret; +} + +int lstatn(const char *pathname, unsigned int mask, struct stat *st) +{ + int flags = AT_SYMLINK_NOFOLLOW|stat_flags; + int dirfd = pathname && *pathname == '/' ? 0 : AT_FDCWD; + int ret; + struct statx stx; + +#ifndef HAVE_STATX + ret = syscall(SYS_statx, dirfd, pathname, flags, mask, &stx); +#else + ret = statx(dirfd, pathname, flags, mask, &stx); +#endif + if (ret >= 0) { + st->st_dev = makedev(stx.stx_dev_major, stx.stx_dev_minor); + st->st_rdev = makedev(stx.stx_rdev_major, stx.stx_rdev_minor); + + st->st_ino = stx.stx_ino; + st->st_mode = stx.stx_mode; + st->st_nlink = stx.stx_nlink; + st->st_uid = stx.stx_uid; + st->st_gid = stx.stx_gid; + st->st_size = stx.stx_size; + st->st_blksize = stx.stx_blksize; + st->st_blocks = stx.stx_blocks; + + st->st_atim.tv_sec = stx.stx_atime.tv_sec; + st->st_atim.tv_nsec = stx.stx_atime.tv_nsec; + st->st_mtim.tv_sec = stx.stx_mtime.tv_sec; + st->st_mtim.tv_nsec = stx.stx_mtime.tv_nsec; + st->st_ctim.tv_sec = stx.stx_ctime.tv_sec; + st->st_ctim.tv_nsec = stx.stx_ctime.tv_nsec; + } + return ret; +} --- src/statx.h +++ src/statx.h 2021-01-14 11:29:22.019223776 +0000 @@ -0,0 +1,68 @@ +/* + * statx.h - Map modern statx(2) system call to older stat(2), lstat(2), + * and fstat(2) replacements named {,l,f}statn() + * + * Copyright (C) 2018 Werner Fink + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef _STATX_H +#define _STATX_H + +extern int stat_flags; +#if defined(HAVE_DECL_SYS_STATX) && HAVE_DECL_SYS_STATX == 1 +# ifndef HAVE_STATX +# define _ASM_GENERIC_FCNTL_H /* Avoid collisions between asm/fcntl.h and bits/fcntl.h ! */ +# include /* Definition of AT_* and AT_STATX_* constants ! */ +# ifndef STATX_TYPE +# include /* Provides 'struct statx' and STATX_* ! */ +# endif +# endif +extern int statn(const char*, unsigned int, struct stat*); +extern int fstatn(int, unsigned int, struct stat*); +extern int lstatn(const char*, unsigned int, struct stat*); +#else +extern inline int +statn(const char *path, unsigned int mask __attribute__((unused)), struct stat *st) +{ + return stat(path, st); +} +extern inline int +fstatn(int fd, unsigned int mask __attribute__((unused)), struct stat *st) +{ + return fstat(fd, st); +} +extern inline int +lstatn(const char *path, unsigned int mask __attribute__((unused)), struct stat *st) +{ + return lstat(path, st); +} +#define STATX_TYPE 0 +#define STATX_MODE 0 +#define STATX_NLINK 0 +#define STATX_UID 0 +#define STATX_GID 0 +#define STATX_ATIME 0 +#define STATX_MTIME 0 +#define STATX_CTIME 0 +#define STATX_INO 0 +#define STATX_SIZE 0 +#define STATX_BLOCKS 0 +#define STATX_BASIC_STATS 0 +#define STATX_BTIME 0 +#define STATX_ALL 0 +#endif +#endif