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-rw-r--r--src/timeout.c163
1 files changed, 134 insertions, 29 deletions
diff --git a/src/timeout.c b/src/timeout.c
index 1fe0354..ca4a7cd 100644
--- a/src/timeout.c
+++ b/src/timeout.c
@@ -2,9 +2,9 @@
* timout.c Advanced timeout handling for file system calls
* to avoid deadlocks on remote file shares.
*
- * Version: 0.1 07-Sep-2011 Fink
+ * Version: 0.2 11-Dec-2012 Fink
*
- * Copyright 2011 Werner Fink, 2011 SUSE LINUX Products GmbH, Germany.
+ * Copyright 2011,2012 Werner Fink, 2011,2012 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
@@ -18,26 +18,29 @@
# define _GNU_SOURCE
#endif
-#ifndef USE_SOCKETPAIR
-# define USE_SOCKETPAIR 1
-#endif
-
#ifdef _FEATURES_H
# error Include local config.h before any system header file
#endif
-#include "config.h" /* For _FILE_OFFSET_BITS */
+#include "config.h"
+
+#ifndef WITH_TIMEOUT_STAT
+# define WITH_TIMEOUT_STAT 0
+#endif
+
+#ifndef USE_SOCKETPAIR
+# define USE_SOCKETPAIR 1
+#endif
#include <errno.h>
-#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/mman.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/select.h>
#include <sys/stat.h>
-
#include <unistd.h>
#if USE_SOCKETPAIR
# include <sys/socket.h>
@@ -86,6 +89,15 @@
# define strcpy(d,s) __builtin_strcpy((d),(s)) /* Without boundary check please */
#endif
+#if WITH_TIMEOUT_STAT
+static sigjmp_buf jenv;
+static void sigjump(int sig attribute((unused)))
+{
+ siglongjmp(jenv, 1);
+}
+#endif
+
+#if WITH_TIMEOUT_STAT == 2
/*
* The structure used for communication between the processes
*/
@@ -106,7 +118,8 @@ typedef struct _handle {
static volatile pid_t active;
static int pipes[4] = {-1, -1, -1, -1};
-static char buf[PATH_MAX + sizeof(handle_t) + 1];
+static handle_t *restrict handle;
+static const size_t buflen = PATH_MAX+sizeof(handle_t)+1;
static void sigchild(int sig attribute((unused)))
{
@@ -122,6 +135,7 @@ static void attribute((constructor)) start(void)
{
sigset_t sigset, oldset;
struct sigaction act;
+ char sync[1];
ssize_t in;
if (pipes[1] >= 0) close(pipes[1]);
@@ -138,6 +152,12 @@ static void attribute((constructor)) start(void)
act.sa_handler = sigchild;
sigaction(SIGCHLD, &act, 0);
+ if (!handle)
+ handle = mmap(NULL, buflen, PROT_READ|PROT_WRITE,
+ MAP_ANONYMOUS|MAP_SHARED, -1, 0);
+ if (handle == MAP_FAILED)
+ goto error;
+
if ((active = fork()) < 0)
goto error;
@@ -164,16 +184,22 @@ static void attribute((constructor)) start(void)
pipes[1] = pipes[2] = -1;
pipes[0] = pipes[3] = -1;
- {
- handle_t *restrict handle = (void*)&buf[0];
-
- while ((in = read(STDIN_FILENO, handle, sizeof(buf))) > sizeof(handle_t)) {
- if (handle->function(handle->path, &handle->argument) < 0)
- handle->errcode = errno;
- write(STDOUT_FILENO, &handle->errcode, sizeof(handle->errcode)+sizeof(handle->argument));
- memset(handle, 0, sizeof(handle_t));
+ while ((in = read(STDIN_FILENO, &sync, sizeof(sync))) != 0) {
+ ssize_t out;
+ if (in < 0) {
+ if (errno == EINTR)
+ continue;
+ break;
}
+ if (!handle)
+ break;
+ if (handle->function(handle->path, &handle->argument) < 0)
+ handle->errcode = errno;
+ do
+ out = write(STDOUT_FILENO, &sync, sizeof(sync));
+ while (out < 0 && errno == EINTR);
}
+
sigprocmask(SIG_SETMASK, &oldset, NULL);
exit(0);
error:
@@ -181,6 +207,9 @@ error:
if (pipes[1] >= 0) close(pipes[1]);
if (pipes[2] >= 0) close(pipes[2]);
if (pipes[3] >= 0) close(pipes[3]);
+ if (handle && handle != MAP_FAILED)
+ munmap(handle, buflen);
+ handle = NULL;
}
static void /* attribute((destructor)) */ stop(void)
@@ -189,24 +218,24 @@ static void /* attribute((destructor)) */ stop(void)
kill(active, SIGKILL);
}
-static sigjmp_buf jenv;
-static void sigjump(int sig attribute((unused)))
-{
- siglongjmp(jenv, 1);
-}
-
/*
* External routine
+ *
+ * Execute stat(2) system call with timeout to avoid deadlock
+ * on network based file systems.
+ *
*/
-int timeout(stat_t function, const char *path, struct stat *restrict argument, time_t seconds)
+int
+timeout(stat_t function, const char *path, struct stat *restrict argument, time_t seconds)
{
- handle_t *restrict handle = (void*)&buf[0];
struct sigaction alrm_act, pipe_act, new_act;
sigset_t sigset, oldset;
+ char sync[1] = "x";
if (active <= 0) /* Oops, last one failed therefore clear status and restart */
start();
-
+ if (!handle) /* No shared memory area */
+ return function(path, argument);
memset(handle, 0, sizeof(handle_t));
handle->len = strlen(path) + 1;
if (handle->len >= PATH_MAX) {
@@ -235,8 +264,8 @@ int timeout(stat_t function, const char *path, struct stat *restrict argument, t
sigaction(SIGPIPE, &new_act, &pipe_act);
alarm(seconds);
- write(pipes[1], handle, sizeof(handle_t)+handle->len);
- read(pipes[2], &handle->errcode, sizeof(handle->errcode)+sizeof(handle->argument));
+ write(pipes[1], &sync, sizeof(sync));
+ read(pipes[2], &sync, sizeof(sync));
alarm(0);
sigaction(SIGPIPE, &pipe_act, NULL);
@@ -261,6 +290,82 @@ timed:
error:
return -1;
}
+#elif WITH_TIMEOUT_STAT == 1
+/*
+ * External routine
+ *
+ * Execute stat(2) system call with timeout to avoid deadlock
+ * on network based file systems.
+ *
+ */
+int
+timeout(stat_t function, const char *path, struct stat *restrict argument, time_t seconds)
+{
+ struct sigaction alrm_act, pipe_act, new_act;
+ sigset_t sigset, oldset;
+ int ret = 0, pipes[4];
+ pid_t pid = 0;
+ ssize_t len;
+
+ if (pipe(&pipes[0]) < 0)
+ goto error;
+ switch ((pid = fork())) {
+ case -1:
+ close(pipes[0]);
+ close(pipes[1]);
+ goto error;
+ case 0:
+ new_act.sa_handler = SIG_DFL;
+ sigaction(SIGALRM, &new_act, NULL);
+ close(pipes[0]);
+ if ((ret = function(path, argument)) == 0)
+ do
+ len = write(pipes[1], argument, sizeof(struct stat));
+ while (len < 0 && errno == EINTR);
+ close(pipes[1]);
+ exit(ret);
+ default:
+ close(pipes[1]);
+
+ sigemptyset(&sigset);
+ sigaddset(&sigset, SIGALRM);
+ sigaddset(&sigset, SIGPIPE);
+ sigprocmask(SIG_UNBLOCK, &sigset, &oldset);
+
+ memset(&new_act, 0, sizeof(new_act));
+ sigemptyset(&new_act.sa_mask);
+
+ if (sigsetjmp(jenv, 1))
+ goto timed;
+
+ new_act.sa_handler = sigjump;
+ sigaction(SIGALRM, &new_act, &alrm_act);
+ sigaction(SIGPIPE, &new_act, &pipe_act);
+ alarm(seconds);
+ if (read(pipes[0], argument, sizeof(struct stat)) == 0) {
+ errno = EFAULT;
+ ret = -1;
+ }
+ (void)alarm(0);
+ sigaction(SIGPIPE, &pipe_act, NULL);
+ sigaction(SIGALRM, &alrm_act, NULL);
+
+ close(pipes[0]);
+ waitpid(pid, NULL, 0);
+ break;
+ }
+ return ret;
+timed:
+ (void)alarm(0);
+ sigaction(SIGPIPE, &pipe_act, NULL);
+ sigaction(SIGALRM, &alrm_act, NULL);
+ if (waitpid(0, NULL, WNOHANG) == 0)
+ kill(pid, SIGKILL);
+ errno = ETIMEDOUT;
+error:
+ return -1;
+}
+#endif
/*
* End of timeout.c
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-14 19:05:03 +0000