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psmisc/psmisc-22.15-timeout.patch
Dr. Werner Fink 54e950fece . 
OBS-URL: https://build.opensuse.org/package/show/Base:System/psmisc?expand=0&rev=38
2011-09-12 15:50:38 +00:00

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diff --git a/configure.ac b/configure.ac
index 6177975..d54f0ad 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,12 +26,12 @@ AC_SUBST([SELINUX_LIB])
dnl Call fork before all stat calls to stop hanging on NFS mounts
AC_SUBST([WITH_TIMEOUT_STAT])
-AC_ARG_ENABLE([TIMEOUT_STAT],
+AC_ARG_ENABLE([timeout_stat],
[AS_HELP_STRING([--enable-timeout-stat], [Use a timeout on stat calls])],
[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])
+ AC_DEFINE([WITH_TIMEOUT_STAT], [1], [Use timeout on stat calls])
fi
dnl ipv4 only option
diff --git a/src/Makefile.am b/src/Makefile.am
index 4398631..bbe9170 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -23,7 +23,7 @@ if WANT_PEEKFD_MIPS
AM_CFLAGS += -DMIPS
endif
-fuser_SOURCES = fuser.c comm.h signals.c signals.h i18n.h fuser.h lists.h
+fuser_SOURCES = fuser.c comm.h signals.c signals.h timeout.c i18n.h fuser.h lists.h timeout.h
fuser_LDADD = @LIBINTL@
diff --git a/src/fuser.c b/src/fuser.c
index 476fdf1..374a17d 100644
--- a/src/fuser.c
+++ b/src/fuser.c
@@ -111,9 +111,8 @@ static dev_t device(const char *path);
#endif
static char *expandpath(const char *path);
-typedef int (*stat_t)(const char*, struct stat*);
#ifdef WITH_TIMEOUT_STAT
-static int timeout(stat_t func, const char *path, struct stat *buf, unsigned int seconds);
+#include "timeout.h"
#else
#define timeout(func,path,buf,dummy) (func)((path),(buf))
#endif /* WITH_TIMEOUT_STAT */
@@ -1779,70 +1778,6 @@ scan_swaps(struct names *names_head, struct inode_list *ino_head,
fclose(fp);
}
-/*
- * Execute stat(2) system call with timeout to avoid deadlock
- * on network based file systems.
- */
-static sigjmp_buf jenv;
-
-static void
-sigalarm(int sig)
-{
- if (sig == SIGALRM)
- siglongjmp(jenv, 1);
-}
-
-#ifdef HAVE_TIMEOUT_STAT
-static int
-timeout(stat_t func, const char *path, struct stat *buf, unsigned int seconds)
-{
- pid_t pid = 0;
- int ret = 0, pipes[4];
- ssize_t len;
-
- if (pipe(&pipes[0]) < 0)
- goto err;
- switch ((pid = fork ())) {
- case -1:
- close(pipes[0]);
- close(pipes[1]);
- goto err;
- case 0:
- (void) signal(SIGALRM, SIG_DFL);
- close(pipes[0]);
- if ((ret = func(path, buf)) == 0)
- do len = write(pipes[1], buf, sizeof(struct stat));
- while (len < 0 && errno == EINTR);
- close(pipes[1]);
- exit(ret);
- default:
- close(pipes[1]);
- if (sigsetjmp(jenv, 1)) {
- (void) alarm(0);
- (void) signal(SIGALRM, SIG_DFL);
- if (waitpid(0, (int*)0, WNOHANG) == 0)
- kill(pid, SIGKILL);
- errno = ETIMEDOUT;
- seconds = 1;
- goto err;
- }
- (void) signal(SIGALRM, sigalarm);
- (void) alarm(seconds);
- if (read(pipes[0], buf, sizeof(struct stat)) == 0) {
- errno = EFAULT;
- ret = -1;
- }
- (void) alarm(0);
- (void) signal(SIGALRM, SIG_DFL);
- close(pipes[0]);
- break;
- }
- return ret;
-err:
- return -1;
-}
-#endif /* HAVE_TIMEOUT_STAT */
-
#ifdef _LISTS_H
/*
* Use /proc/self/mountinfo of modern linux system to determine
diff --git a/src/timeout.c b/src/timeout.c
index e69de29..3b582a3 100644
--- a/src/timeout.c
+++ b/src/timeout.c
@@ -0,0 +1,208 @@
+/*
+ * timout.c Advanced timeout handling for file system calls
+ * to avoid deadlocks on remote file shares.
+ *
+ * Version: 0.1 07-Sep-2011 Fink
+ *
+ * Copyright 2011 Werner Fink, 2011 SUSE LINUX Products GmbH, Germany.
+ *
+ * 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.
+ *
+ * Author: Werner Fink <werner@suse.de>, 2011
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <errno.h>
+#include <pthread.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <wait.h>
+
+#include <stdio.h>
+#include "timeout.h"
+
+#if !defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L)
+# ifndef destructor
+# define destructor __destructor__
+# endif
+# ifndef constructor
+# define constructor __constructor__
+# endif
+# ifndef inline
+# define inline __inline__
+# endif
+# ifndef unused
+# define unused __unused__
+# endif
+# ifndef volatile
+# define volatile __volatile__
+# endif
+#endif
+#ifndef attribute
+# define attribute(attr) __attribute__(attr)
+#endif
+
+/*
+ * The structure used for communication between the processes
+ */
+
+typedef struct _handle {
+ size_t len;
+ int errcode;
+ struct stat argument;
+ stat_t function;
+ char *path;
+} handle_t;
+
+static volatile handle_t handle;
+
+/*
+ * Using a forked process for doing e.g. stat(2) system call as this
+ * allows us to send e.g. SIGKILL to this process if it hangs in `D'
+ * state on a file share due a stalled NFS server. This does not work
+ * with (p)threads as SIGKILL would kill all threads including main.
+ */
+
+static volatile pid_t active;
+static int pipes[4] = {-1, -1, -1, -1};
+
+static void attribute((constructor)) start(void)
+{
+ sigset_t sigset, oldset;
+ handle_t handle;
+ ssize_t in;
+
+ if (pipe(&pipes[0]))
+ goto error;
+ if (pipe(&pipes[2]))
+ goto error;
+ if ((active = fork()) < 0)
+ goto error;
+ if (active) {
+ close(pipes[0]);
+ close(pipes[3]);
+ pipes[0] = pipes[3] = -1;
+ return;
+ }
+ sigemptyset(&sigset);
+ sigaddset(&sigset, SIGALRM);
+ sigprocmask(SIG_BLOCK, &sigset, &oldset);
+
+ close(pipes[1]);
+ close(pipes[2]);
+ dup2(pipes[0], 0);
+ dup2(pipes[3], 1);
+ close(pipes[0]);
+ close(pipes[3]);
+ pipes[1] = pipes[2] = -1;
+ pipes[0] = pipes[3] = -1;
+
+ while ((in = read(0, &handle, sizeof(handle_t))) == sizeof(handle_t) &&
+ (handle.path = (char*)malloc(handle.len)) &&
+ (in = read(0, handle.path, handle.len)) == handle.len) {
+ if (handle.function(handle.path, &handle.argument) < 0)
+ handle.errcode = errno;
+ write(1, &handle.errcode, sizeof(handle.errcode)+sizeof(handle.argument));
+ free(handle.path);
+ }
+ sigprocmask(SIG_SETMASK, &oldset, NULL);
+ exit(0);
+error:
+ if (pipes[0] >= 0) close(pipes[0]);
+ if (pipes[1] >= 0) close(pipes[1]);
+ if (pipes[2] >= 0) close(pipes[2]);
+ if (pipes[3] >= 0) close(pipes[3]);
+}
+
+static void /* attribute((destructor)) */ stop(void)
+{
+ if (active <= 0)
+ return;
+ if (waitpid(active, NULL, WNOHANG) == 0)
+ kill(active, SIGKILL);
+ active = 0;
+}
+
+static sigjmp_buf jenv;
+static void sigalarm(int sig attribute((unused)))
+{
+ siglongjmp(jenv, 1);
+}
+
+/*
+ * External routine
+ */
+
+int timeout(stat_t function, const char *path, struct stat *restrict argument, time_t seconds)
+{
+ struct sigaction old_act, new_act;
+ sigset_t sigset, oldset;
+ handle_t handle;
+
+ if (active <= 0) { /* Oops, last one failed therefore clear status and restart */
+ int status;
+ waitpid(-1, &status, WNOHANG);
+ start();
+ }
+
+ handle.len = strlen(path) + 1;
+ handle.errcode = 0;
+ handle.argument = *argument;
+ handle.function = function;
+ handle.path = (char*)0;
+
+ sigemptyset(&sigset);
+ sigaddset(&sigset, SIGALRM);
+ sigprocmask(SIG_UNBLOCK, &sigset, &oldset);
+
+ memset(&new_act, 0, sizeof(new_act));
+ sigemptyset(&new_act.sa_mask);
+ new_act.sa_flags = SA_RESETHAND;
+ new_act.sa_handler = sigalarm;
+
+ if (sigsetjmp(jenv, 1))
+ goto timed;
+
+ sigaction(SIGALRM, &new_act, &old_act);
+ alarm(seconds);
+
+ write(pipes[1], &handle, sizeof(handle_t));
+ write(pipes[1], path, handle.len);
+ sched_yield();
+ read(pipes[2], &handle.errcode, sizeof(handle.errcode)+sizeof(handle.argument));
+
+ alarm(0);
+ sigaction(SIGALRM, &old_act, NULL);
+
+ if (handle.errcode) {
+ errno = handle.errcode;
+ goto error;
+ }
+ *argument = handle.argument;
+ sigprocmask(SIG_SETMASK, &oldset, NULL);
+ return 0;
+timed:
+ (void) alarm(0);
+ sigprocmask(SIG_SETMASK, &oldset, NULL);
+ stop();
+ errno = ETIMEDOUT;
+error:
+ return -1;
+}
+
+/*
+ * End of timeout.c
+ */
diff --git a/src/timeout.h b/src/timeout.h
index e69de29..50dd135 100644
--- a/src/timeout.h
+++ b/src/timeout.h
@@ -0,0 +1,33 @@
+/*
+ * timout.h Advanced timeout handling for file system calls
+ * to avoid deadlocks on remote file shares.
+ *
+ * Version: 0.1 07-Sep-2011 Fink
+ *
+ * Copyright 2011 Werner Fink, 2011 SUSE LINUX Products GmbH, Germany.
+ *
+ * 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.
+ *
+ * Author: Werner Fink <werner@suse.de>, 2011
+ */
+
+#ifndef _TIMEOUT_H
+#define _TIMEOUT_H
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <time.h>
+
+#if !defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L)
+# ifndef restrict
+# define restrict __restrict__
+# endif
+#endif
+
+typedef int (*stat_t)(const char *, struct stat *restrict);
+extern int timeout(stat_t, const char *, struct stat *restrict, time_t);
+
+#endif
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