Introduce a new global big lock for mon_fdsets. Take it where needed. The monitor_fdset_get_fd() handling is a bit tricky: now we need to call qemu_mutex_unlock() which might pollute errno, so we need to make sure the correct errno be passed up to the callers. To make things simpler, we let monitor_fdset_get_fd() return the -errno directly when error happens, then in qemu_open() we move it back into errno. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180608035511.7439-8-peterx@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
564 lines
12 KiB
C
564 lines
12 KiB
C
/*
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* QEMU low level functions
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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/* Needed early for CONFIG_BSD etc. */
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#ifdef CONFIG_SOLARIS
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#include <sys/statvfs.h>
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/* See MySQL bug #7156 (http://bugs.mysql.com/bug.php?id=7156) for
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discussion about Solaris header problems */
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extern int madvise(caddr_t, size_t, int);
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#endif
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#include "qemu-common.h"
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#include "qemu/cutils.h"
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#include "qemu/sockets.h"
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#include "qemu/error-report.h"
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#include "monitor/monitor.h"
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static bool fips_enabled = false;
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static const char *hw_version = QEMU_HW_VERSION;
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int socket_set_cork(int fd, int v)
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{
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#if defined(SOL_TCP) && defined(TCP_CORK)
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return qemu_setsockopt(fd, SOL_TCP, TCP_CORK, &v, sizeof(v));
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#else
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return 0;
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#endif
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}
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int socket_set_nodelay(int fd)
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{
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int v = 1;
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return qemu_setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &v, sizeof(v));
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}
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int qemu_madvise(void *addr, size_t len, int advice)
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{
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if (advice == QEMU_MADV_INVALID) {
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errno = EINVAL;
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return -1;
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}
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#if defined(CONFIG_MADVISE)
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return madvise(addr, len, advice);
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#elif defined(CONFIG_POSIX_MADVISE)
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return posix_madvise(addr, len, advice);
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#else
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errno = EINVAL;
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return -1;
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#endif
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}
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static int qemu_mprotect__osdep(void *addr, size_t size, int prot)
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{
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g_assert(!((uintptr_t)addr & ~qemu_real_host_page_mask));
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g_assert(!(size & ~qemu_real_host_page_mask));
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#ifdef _WIN32
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DWORD old_protect;
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if (!VirtualProtect(addr, size, prot, &old_protect)) {
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error_report("%s: VirtualProtect failed with error code %ld",
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__func__, GetLastError());
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return -1;
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}
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return 0;
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#else
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if (mprotect(addr, size, prot)) {
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error_report("%s: mprotect failed: %s", __func__, strerror(errno));
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return -1;
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}
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return 0;
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#endif
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}
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int qemu_mprotect_rwx(void *addr, size_t size)
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{
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#ifdef _WIN32
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return qemu_mprotect__osdep(addr, size, PAGE_EXECUTE_READWRITE);
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#else
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return qemu_mprotect__osdep(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC);
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#endif
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}
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int qemu_mprotect_none(void *addr, size_t size)
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{
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#ifdef _WIN32
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return qemu_mprotect__osdep(addr, size, PAGE_NOACCESS);
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#else
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return qemu_mprotect__osdep(addr, size, PROT_NONE);
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#endif
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}
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#ifndef _WIN32
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static int fcntl_op_setlk = -1;
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static int fcntl_op_getlk = -1;
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/*
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* Dups an fd and sets the flags
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*/
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static int qemu_dup_flags(int fd, int flags)
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{
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int ret;
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int serrno;
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int dup_flags;
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ret = qemu_dup(fd);
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if (ret == -1) {
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goto fail;
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}
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dup_flags = fcntl(ret, F_GETFL);
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if (dup_flags == -1) {
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goto fail;
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}
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if ((flags & O_SYNC) != (dup_flags & O_SYNC)) {
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errno = EINVAL;
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goto fail;
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}
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/* Set/unset flags that we can with fcntl */
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if (fcntl(ret, F_SETFL, flags) == -1) {
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goto fail;
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}
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/* Truncate the file in the cases that open() would truncate it */
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if (flags & O_TRUNC ||
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((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))) {
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if (ftruncate(ret, 0) == -1) {
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goto fail;
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}
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}
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return ret;
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fail:
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serrno = errno;
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if (ret != -1) {
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close(ret);
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}
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errno = serrno;
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return -1;
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}
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int qemu_dup(int fd)
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{
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int ret;
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#ifdef F_DUPFD_CLOEXEC
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ret = fcntl(fd, F_DUPFD_CLOEXEC, 0);
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#else
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ret = dup(fd);
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if (ret != -1) {
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qemu_set_cloexec(ret);
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}
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#endif
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return ret;
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}
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static int qemu_parse_fdset(const char *param)
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{
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return qemu_parse_fd(param);
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}
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static void qemu_probe_lock_ops(void)
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{
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if (fcntl_op_setlk == -1) {
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#ifdef F_OFD_SETLK
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int fd;
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int ret;
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struct flock fl = {
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.l_whence = SEEK_SET,
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.l_start = 0,
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.l_len = 0,
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.l_type = F_WRLCK,
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};
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fd = open("/dev/null", O_RDWR);
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if (fd < 0) {
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fprintf(stderr,
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"Failed to open /dev/null for OFD lock probing: %s\n",
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strerror(errno));
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fcntl_op_setlk = F_SETLK;
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fcntl_op_getlk = F_GETLK;
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return;
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}
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ret = fcntl(fd, F_OFD_GETLK, &fl);
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close(fd);
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if (!ret) {
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fcntl_op_setlk = F_OFD_SETLK;
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fcntl_op_getlk = F_OFD_GETLK;
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} else {
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fcntl_op_setlk = F_SETLK;
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fcntl_op_getlk = F_GETLK;
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}
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#else
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fcntl_op_setlk = F_SETLK;
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fcntl_op_getlk = F_GETLK;
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#endif
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}
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}
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bool qemu_has_ofd_lock(void)
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{
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qemu_probe_lock_ops();
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#ifdef F_OFD_SETLK
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return fcntl_op_setlk == F_OFD_SETLK;
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#else
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return false;
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#endif
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}
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static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
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{
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int ret;
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struct flock fl = {
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.l_whence = SEEK_SET,
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.l_start = start,
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.l_len = len,
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.l_type = fl_type,
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};
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qemu_probe_lock_ops();
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do {
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ret = fcntl(fd, fcntl_op_setlk, &fl);
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} while (ret == -1 && errno == EINTR);
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return ret == -1 ? -errno : 0;
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}
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int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive)
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{
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return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK);
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}
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int qemu_unlock_fd(int fd, int64_t start, int64_t len)
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{
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return qemu_lock_fcntl(fd, start, len, F_UNLCK);
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}
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int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
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{
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int ret;
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struct flock fl = {
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.l_whence = SEEK_SET,
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.l_start = start,
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.l_len = len,
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.l_type = exclusive ? F_WRLCK : F_RDLCK,
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};
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qemu_probe_lock_ops();
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ret = fcntl(fd, fcntl_op_getlk, &fl);
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if (ret == -1) {
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return -errno;
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} else {
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return fl.l_type == F_UNLCK ? 0 : -EAGAIN;
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}
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}
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#endif
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/*
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* Opens a file with FD_CLOEXEC set
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*/
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int qemu_open(const char *name, int flags, ...)
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{
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int ret;
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int mode = 0;
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#ifndef _WIN32
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const char *fdset_id_str;
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/* Attempt dup of fd from fd set */
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if (strstart(name, "/dev/fdset/", &fdset_id_str)) {
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int64_t fdset_id;
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int fd, dupfd;
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fdset_id = qemu_parse_fdset(fdset_id_str);
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if (fdset_id == -1) {
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errno = EINVAL;
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return -1;
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}
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fd = monitor_fdset_get_fd(fdset_id, flags);
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if (fd < 0) {
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errno = -fd;
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return -1;
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}
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dupfd = qemu_dup_flags(fd, flags);
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if (dupfd == -1) {
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return -1;
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}
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ret = monitor_fdset_dup_fd_add(fdset_id, dupfd);
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if (ret == -1) {
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close(dupfd);
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errno = EINVAL;
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return -1;
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}
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return dupfd;
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}
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#endif
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if (flags & O_CREAT) {
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va_list ap;
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va_start(ap, flags);
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mode = va_arg(ap, int);
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va_end(ap);
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}
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#ifdef O_CLOEXEC
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ret = open(name, flags | O_CLOEXEC, mode);
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#else
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ret = open(name, flags, mode);
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if (ret >= 0) {
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qemu_set_cloexec(ret);
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}
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#endif
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#ifdef O_DIRECT
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if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
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error_report("file system may not support O_DIRECT");
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errno = EINVAL; /* in case it was clobbered */
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}
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#endif /* O_DIRECT */
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return ret;
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}
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int qemu_close(int fd)
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{
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int64_t fdset_id;
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/* Close fd that was dup'd from an fdset */
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fdset_id = monitor_fdset_dup_fd_find(fd);
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if (fdset_id != -1) {
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int ret;
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ret = close(fd);
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if (ret == 0) {
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monitor_fdset_dup_fd_remove(fd);
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}
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return ret;
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}
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return close(fd);
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}
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/*
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* A variant of write(2) which handles partial write.
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*
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* Return the number of bytes transferred.
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* Set errno if fewer than `count' bytes are written.
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*
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* This function don't work with non-blocking fd's.
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* Any of the possibilities with non-bloking fd's is bad:
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* - return a short write (then name is wrong)
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* - busy wait adding (errno == EAGAIN) to the loop
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*/
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ssize_t qemu_write_full(int fd, const void *buf, size_t count)
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{
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ssize_t ret = 0;
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ssize_t total = 0;
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while (count) {
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ret = write(fd, buf, count);
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if (ret < 0) {
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if (errno == EINTR)
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continue;
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break;
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}
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count -= ret;
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buf += ret;
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total += ret;
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}
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return total;
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}
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/*
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* Opens a socket with FD_CLOEXEC set
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*/
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int qemu_socket(int domain, int type, int protocol)
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{
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int ret;
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#ifdef SOCK_CLOEXEC
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ret = socket(domain, type | SOCK_CLOEXEC, protocol);
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if (ret != -1 || errno != EINVAL) {
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return ret;
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}
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#endif
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ret = socket(domain, type, protocol);
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if (ret >= 0) {
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qemu_set_cloexec(ret);
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}
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return ret;
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}
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/*
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* Accept a connection and set FD_CLOEXEC
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*/
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int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
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{
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int ret;
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#ifdef CONFIG_ACCEPT4
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ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
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if (ret != -1 || errno != ENOSYS) {
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return ret;
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}
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#endif
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ret = accept(s, addr, addrlen);
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if (ret >= 0) {
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qemu_set_cloexec(ret);
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}
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return ret;
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}
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void qemu_set_hw_version(const char *version)
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{
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hw_version = version;
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}
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const char *qemu_hw_version(void)
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{
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return hw_version;
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}
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void fips_set_state(bool requested)
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{
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#ifdef __linux__
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if (requested) {
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FILE *fds = fopen("/proc/sys/crypto/fips_enabled", "r");
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if (fds != NULL) {
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fips_enabled = (fgetc(fds) == '1');
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fclose(fds);
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}
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}
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#else
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fips_enabled = false;
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#endif /* __linux__ */
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#ifdef _FIPS_DEBUG
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fprintf(stderr, "FIPS mode %s (requested %s)\n",
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(fips_enabled ? "enabled" : "disabled"),
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(requested ? "enabled" : "disabled"));
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#endif
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}
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bool fips_get_state(void)
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{
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return fips_enabled;
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}
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#ifdef _WIN32
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static void socket_cleanup(void)
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{
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WSACleanup();
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}
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#endif
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int socket_init(void)
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{
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#ifdef _WIN32
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WSADATA Data;
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int ret, err;
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ret = WSAStartup(MAKEWORD(2, 2), &Data);
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if (ret != 0) {
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err = WSAGetLastError();
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fprintf(stderr, "WSAStartup: %d\n", err);
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return -1;
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}
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atexit(socket_cleanup);
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#endif
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return 0;
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}
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#if !GLIB_CHECK_VERSION(2, 31, 0)
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|
/* Ensure that glib is running in multi-threaded mode
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|
* Old versions of glib require explicit initialization. Failure to do
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|
* this results in the single-threaded code paths being taken inside
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|
* glib. For example, the g_slice allocator will not be thread-safe
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|
* and cause crashes.
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|
*/
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|
static void __attribute__((constructor)) thread_init(void)
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|
{
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|
if (!g_thread_supported()) {
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|
g_thread_init(NULL);
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|
}
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|
}
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|
#endif
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|
|
#ifndef CONFIG_IOVEC
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|
/* helper function for iov_send_recv() */
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|
static ssize_t
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readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write)
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|
{
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|
unsigned i = 0;
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|
ssize_t ret = 0;
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|
while (i < iov_cnt) {
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ssize_t r = do_write
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? write(fd, iov[i].iov_base, iov[i].iov_len)
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|
: read(fd, iov[i].iov_base, iov[i].iov_len);
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|
if (r > 0) {
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ret += r;
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|
} else if (!r) {
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break;
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} else if (errno == EINTR) {
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|
continue;
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} else {
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|
/* else it is some "other" error,
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|
* only return if there was no data processed. */
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|
if (ret == 0) {
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ret = -1;
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}
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break;
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}
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i++;
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}
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|
return ret;
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}
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|
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
|