qemu/util/osdep.c
Stefan Hajnoczi ae2990c259 osdep: initialize glib threads in all QEMU tools
glib versions prior to 2.31.0 require an explicit g_thread_init() call
to enable multi-threading.

Failure to initialize threading causes glib to take single-threaded code
paths without synchronization.  For example, the g_slice allocator will
crash due to race conditions.

Fix this for all QEMU tool programs (qemu-nbd, qemu-io, qemu-img) by
moving the g_thread_init() call from vl.c:main() into a new
osdep.c:thread_init() constructor function.

thread_init() has __attribute__((constructor)) and is automatically
invoked by the runtime during startup.

We can now drop the "simple" trace backend's g_thread_init() call since
thread_init() already called it.

Note that we must keep coroutine-gthread.c's g_thread_init() call which
is located in a constructor function.  There is no guarantee for
constructor function ordering so thread_init() may only be called later.

Reported-by: Mario de Chenno <mario.dechenno@unina2.it>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-25 13:39:31 +01:00

499 lines
11 KiB
C

/*
* QEMU low level functions
*
* Copyright (c) 2003 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
/* Needed early for CONFIG_BSD etc. */
#include "config-host.h"
#if defined(CONFIG_MADVISE) || defined(CONFIG_POSIX_MADVISE)
#include <sys/mman.h>
#endif
#ifdef CONFIG_SOLARIS
#include <sys/types.h>
#include <sys/statvfs.h>
/* See MySQL bug #7156 (http://bugs.mysql.com/bug.php?id=7156) for
discussion about Solaris header problems */
extern int madvise(caddr_t, size_t, int);
#endif
#include "qemu-common.h"
#include "qemu/sockets.h"
#include "monitor/monitor.h"
static bool fips_enabled = false;
static const char *qemu_version = QEMU_VERSION;
int socket_set_cork(int fd, int v)
{
#if defined(SOL_TCP) && defined(TCP_CORK)
return qemu_setsockopt(fd, SOL_TCP, TCP_CORK, &v, sizeof(v));
#else
return 0;
#endif
}
int socket_set_nodelay(int fd)
{
int v = 1;
return qemu_setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v));
}
int qemu_madvise(void *addr, size_t len, int advice)
{
if (advice == QEMU_MADV_INVALID) {
errno = EINVAL;
return -1;
}
#if defined(CONFIG_MADVISE)
return madvise(addr, len, advice);
#elif defined(CONFIG_POSIX_MADVISE)
return posix_madvise(addr, len, advice);
#else
errno = EINVAL;
return -1;
#endif
}
#ifndef _WIN32
/*
* Dups an fd and sets the flags
*/
static int qemu_dup_flags(int fd, int flags)
{
int ret;
int serrno;
int dup_flags;
#ifdef F_DUPFD_CLOEXEC
ret = fcntl(fd, F_DUPFD_CLOEXEC, 0);
#else
ret = dup(fd);
if (ret != -1) {
qemu_set_cloexec(ret);
}
#endif
if (ret == -1) {
goto fail;
}
dup_flags = fcntl(ret, F_GETFL);
if (dup_flags == -1) {
goto fail;
}
if ((flags & O_SYNC) != (dup_flags & O_SYNC)) {
errno = EINVAL;
goto fail;
}
/* Set/unset flags that we can with fcntl */
if (fcntl(ret, F_SETFL, flags) == -1) {
goto fail;
}
/* Truncate the file in the cases that open() would truncate it */
if (flags & O_TRUNC ||
((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) {
if (ftruncate(ret, 0) == -1) {
goto fail;
}
}
return ret;
fail:
serrno = errno;
if (ret != -1) {
close(ret);
}
errno = serrno;
return -1;
}
static int qemu_parse_fdset(const char *param)
{
return qemu_parse_fd(param);
}
#endif
/*
* Opens a file with FD_CLOEXEC set
*/
int qemu_open(const char *name, int flags, ...)
{
int ret;
int mode = 0;
#ifndef _WIN32
const char *fdset_id_str;
/* Attempt dup of fd from fd set */
if (strstart(name, "/dev/fdset/", &fdset_id_str)) {
int64_t fdset_id;
int fd, dupfd;
fdset_id = qemu_parse_fdset(fdset_id_str);
if (fdset_id == -1) {
errno = EINVAL;
return -1;
}
fd = monitor_fdset_get_fd(fdset_id, flags);
if (fd == -1) {
return -1;
}
dupfd = qemu_dup_flags(fd, flags);
if (dupfd == -1) {
return -1;
}
ret = monitor_fdset_dup_fd_add(fdset_id, dupfd);
if (ret == -1) {
close(dupfd);
errno = EINVAL;
return -1;
}
return dupfd;
}
#endif
if (flags & O_CREAT) {
va_list ap;
va_start(ap, flags);
mode = va_arg(ap, int);
va_end(ap);
}
#ifdef O_CLOEXEC
ret = open(name, flags | O_CLOEXEC, mode);
#else
ret = open(name, flags, mode);
if (ret >= 0) {
qemu_set_cloexec(ret);
}
#endif
#ifdef O_DIRECT
if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
error_report("file system may not support O_DIRECT");
errno = EINVAL; /* in case it was clobbered */
}
#endif /* O_DIRECT */
return ret;
}
int qemu_close(int fd)
{
int64_t fdset_id;
/* Close fd that was dup'd from an fdset */
fdset_id = monitor_fdset_dup_fd_find(fd);
if (fdset_id != -1) {
int ret;
ret = close(fd);
if (ret == 0) {
monitor_fdset_dup_fd_remove(fd);
}
return ret;
}
return close(fd);
}
/*
* A variant of write(2) which handles partial write.
*
* Return the number of bytes transferred.
* Set errno if fewer than `count' bytes are written.
*
* This function don't work with non-blocking fd's.
* Any of the possibilities with non-bloking fd's is bad:
* - return a short write (then name is wrong)
* - busy wait adding (errno == EAGAIN) to the loop
*/
ssize_t qemu_write_full(int fd, const void *buf, size_t count)
{
ssize_t ret = 0;
ssize_t total = 0;
while (count) {
ret = write(fd, buf, count);
if (ret < 0) {
if (errno == EINTR)
continue;
break;
}
count -= ret;
buf += ret;
total += ret;
}
return total;
}
/*
* Opens a socket with FD_CLOEXEC set
*/
int qemu_socket(int domain, int type, int protocol)
{
int ret;
#ifdef SOCK_CLOEXEC
ret = socket(domain, type | SOCK_CLOEXEC, protocol);
if (ret != -1 || errno != EINVAL) {
return ret;
}
#endif
ret = socket(domain, type, protocol);
if (ret >= 0) {
qemu_set_cloexec(ret);
}
return ret;
}
/*
* Accept a connection and set FD_CLOEXEC
*/
int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
{
int ret;
#ifdef CONFIG_ACCEPT4
ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
if (ret != -1 || errno != ENOSYS) {
return ret;
}
#endif
ret = accept(s, addr, addrlen);
if (ret >= 0) {
qemu_set_cloexec(ret);
}
return ret;
}
/*
* A variant of send(2) which handles partial write.
*
* Return the number of bytes transferred, which is only
* smaller than `count' if there is an error.
*
* This function won't work with non-blocking fd's.
* Any of the possibilities with non-bloking fd's is bad:
* - return a short write (then name is wrong)
* - busy wait adding (errno == EAGAIN) to the loop
*/
ssize_t qemu_send_full(int fd, const void *buf, size_t count, int flags)
{
ssize_t ret = 0;
ssize_t total = 0;
while (count) {
ret = send(fd, buf, count, flags);
if (ret < 0) {
if (errno == EINTR) {
continue;
}
break;
}
count -= ret;
buf += ret;
total += ret;
}
return total;
}
/*
* A variant of recv(2) which handles partial write.
*
* Return the number of bytes transferred, which is only
* smaller than `count' if there is an error.
*
* This function won't work with non-blocking fd's.
* Any of the possibilities with non-bloking fd's is bad:
* - return a short write (then name is wrong)
* - busy wait adding (errno == EAGAIN) to the loop
*/
ssize_t qemu_recv_full(int fd, void *buf, size_t count, int flags)
{
ssize_t ret = 0;
ssize_t total = 0;
while (count) {
ret = qemu_recv(fd, buf, count, flags);
if (ret <= 0) {
if (ret < 0 && errno == EINTR) {
continue;
}
break;
}
count -= ret;
buf += ret;
total += ret;
}
return total;
}
void qemu_set_version(const char *version)
{
qemu_version = version;
}
const char *qemu_get_version(void)
{
return qemu_version;
}
void fips_set_state(bool requested)
{
#ifdef __linux__
if (requested) {
FILE *fds = fopen("/proc/sys/crypto/fips_enabled", "r");
if (fds != NULL) {
fips_enabled = (fgetc(fds) == '1');
fclose(fds);
}
}
#else
fips_enabled = false;
#endif /* __linux__ */
#ifdef _FIPS_DEBUG
fprintf(stderr, "FIPS mode %s (requested %s)\n",
(fips_enabled ? "enabled" : "disabled"),
(requested ? "enabled" : "disabled"));
#endif
}
bool fips_get_state(void)
{
return fips_enabled;
}
#ifdef _WIN32
static void socket_cleanup(void)
{
WSACleanup();
}
#endif
int socket_init(void)
{
#ifdef _WIN32
WSADATA Data;
int ret, err;
ret = WSAStartup(MAKEWORD(2, 2), &Data);
if (ret != 0) {
err = WSAGetLastError();
fprintf(stderr, "WSAStartup: %d\n", err);
return -1;
}
atexit(socket_cleanup);
#endif
return 0;
}
/* Ensure that glib is running in multi-threaded mode */
static void __attribute__((constructor)) thread_init(void)
{
if (!g_thread_supported()) {
#if !GLIB_CHECK_VERSION(2, 31, 0)
/* Old versions of glib require explicit initialization. Failure to do
* this results in the single-threaded code paths being taken inside
* glib. For example, the g_slice allocator will not be thread-safe
* and cause crashes.
*/
g_thread_init(NULL);
#else
fprintf(stderr, "glib threading failed to initialize.\n");
exit(1);
#endif
}
}
#ifndef CONFIG_IOVEC
/* helper function for iov_send_recv() */
static ssize_t
readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write)
{
unsigned i = 0;
ssize_t ret = 0;
while (i < iov_cnt) {
ssize_t r = do_write
? write(fd, iov[i].iov_base, iov[i].iov_len)
: read(fd, iov[i].iov_base, iov[i].iov_len);
if (r > 0) {
ret += r;
} else if (!r) {
break;
} else if (errno == EINTR) {
continue;
} else {
/* else it is some "other" error,
* only return if there was no data processed. */
if (ret == 0) {
ret = -1;
}
break;
}
i++;
}
return ret;
}
ssize_t
readv(int fd, const struct iovec *iov, int iov_cnt)
{
return readv_writev(fd, iov, iov_cnt, false);
}
ssize_t
writev(int fd, const struct iovec *iov, int iov_cnt)
{
return readv_writev(fd, iov, iov_cnt, true);
}
#endif