qemu/monitor/fds.c
Markus Armbruster 7ef88b5334 monitor: Split file descriptor passing stuff off misc.c
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230124121946.1139465-27-armbru@redhat.com>
2023-02-04 07:56:54 +01:00

469 lines
13 KiB
C

/*
* QEMU monitor file descriptor passing
*
* Copyright (c) 2003-2004 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 "qemu/osdep.h"
#include "monitor-internal.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-misc.h"
#include "qapi/qmp/qerror.h"
#include "qemu/ctype.h"
#include "qemu/cutils.h"
#include "sysemu/runstate.h"
/* file descriptors passed via SCM_RIGHTS */
typedef struct mon_fd_t mon_fd_t;
struct mon_fd_t {
char *name;
int fd;
QLIST_ENTRY(mon_fd_t) next;
};
/* file descriptor associated with a file descriptor set */
typedef struct MonFdsetFd MonFdsetFd;
struct MonFdsetFd {
int fd;
bool removed;
char *opaque;
QLIST_ENTRY(MonFdsetFd) next;
};
/* file descriptor set containing fds passed via SCM_RIGHTS */
typedef struct MonFdset MonFdset;
struct MonFdset {
int64_t id;
QLIST_HEAD(, MonFdsetFd) fds;
QLIST_HEAD(, MonFdsetFd) dup_fds;
QLIST_ENTRY(MonFdset) next;
};
/* Protects mon_fdsets */
static QemuMutex mon_fdsets_lock;
static QLIST_HEAD(, MonFdset) mon_fdsets;
void qmp_getfd(const char *fdname, Error **errp)
{
Monitor *cur_mon = monitor_cur();
mon_fd_t *monfd;
int fd, tmp_fd;
fd = qemu_chr_fe_get_msgfd(&cur_mon->chr);
if (fd == -1) {
error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
return;
}
if (qemu_isdigit(fdname[0])) {
close(fd);
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "fdname",
"a name not starting with a digit");
return;
}
QEMU_LOCK_GUARD(&cur_mon->mon_lock);
QLIST_FOREACH(monfd, &cur_mon->fds, next) {
if (strcmp(monfd->name, fdname) != 0) {
continue;
}
tmp_fd = monfd->fd;
monfd->fd = fd;
/* Make sure close() is outside critical section */
close(tmp_fd);
return;
}
monfd = g_new0(mon_fd_t, 1);
monfd->name = g_strdup(fdname);
monfd->fd = fd;
QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next);
}
void qmp_closefd(const char *fdname, Error **errp)
{
Monitor *cur_mon = monitor_cur();
mon_fd_t *monfd;
int tmp_fd;
qemu_mutex_lock(&cur_mon->mon_lock);
QLIST_FOREACH(monfd, &cur_mon->fds, next) {
if (strcmp(monfd->name, fdname) != 0) {
continue;
}
QLIST_REMOVE(monfd, next);
tmp_fd = monfd->fd;
g_free(monfd->name);
g_free(monfd);
qemu_mutex_unlock(&cur_mon->mon_lock);
/* Make sure close() is outside critical section */
close(tmp_fd);
return;
}
qemu_mutex_unlock(&cur_mon->mon_lock);
error_setg(errp, "File descriptor named '%s' not found", fdname);
}
int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp)
{
mon_fd_t *monfd;
QEMU_LOCK_GUARD(&mon->mon_lock);
QLIST_FOREACH(monfd, &mon->fds, next) {
int fd;
if (strcmp(monfd->name, fdname) != 0) {
continue;
}
fd = monfd->fd;
assert(fd >= 0);
/* caller takes ownership of fd */
QLIST_REMOVE(monfd, next);
g_free(monfd->name);
g_free(monfd);
return fd;
}
error_setg(errp, "File descriptor named '%s' has not been found", fdname);
return -1;
}
static void monitor_fdset_cleanup(MonFdset *mon_fdset)
{
MonFdsetFd *mon_fdset_fd;
MonFdsetFd *mon_fdset_fd_next;
QLIST_FOREACH_SAFE(mon_fdset_fd, &mon_fdset->fds, next, mon_fdset_fd_next) {
if ((mon_fdset_fd->removed ||
(QLIST_EMPTY(&mon_fdset->dup_fds) && mon_refcount == 0)) &&
runstate_is_running()) {
close(mon_fdset_fd->fd);
g_free(mon_fdset_fd->opaque);
QLIST_REMOVE(mon_fdset_fd, next);
g_free(mon_fdset_fd);
}
}
if (QLIST_EMPTY(&mon_fdset->fds) && QLIST_EMPTY(&mon_fdset->dup_fds)) {
QLIST_REMOVE(mon_fdset, next);
g_free(mon_fdset);
}
}
void monitor_fdsets_cleanup(void)
{
MonFdset *mon_fdset;
MonFdset *mon_fdset_next;
QEMU_LOCK_GUARD(&mon_fdsets_lock);
QLIST_FOREACH_SAFE(mon_fdset, &mon_fdsets, next, mon_fdset_next) {
monitor_fdset_cleanup(mon_fdset);
}
}
AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id,
const char *opaque, Error **errp)
{
int fd;
Monitor *mon = monitor_cur();
AddfdInfo *fdinfo;
fd = qemu_chr_fe_get_msgfd(&mon->chr);
if (fd == -1) {
error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
goto error;
}
fdinfo = monitor_fdset_add_fd(fd, has_fdset_id, fdset_id, opaque, errp);
if (fdinfo) {
return fdinfo;
}
error:
if (fd != -1) {
close(fd);
}
return NULL;
}
void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t fd, Error **errp)
{
MonFdset *mon_fdset;
MonFdsetFd *mon_fdset_fd;
char fd_str[60];
QEMU_LOCK_GUARD(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
if (mon_fdset->id != fdset_id) {
continue;
}
QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
if (has_fd) {
if (mon_fdset_fd->fd != fd) {
continue;
}
mon_fdset_fd->removed = true;
break;
} else {
mon_fdset_fd->removed = true;
}
}
if (has_fd && !mon_fdset_fd) {
goto error;
}
monitor_fdset_cleanup(mon_fdset);
return;
}
error:
if (has_fd) {
snprintf(fd_str, sizeof(fd_str), "fdset-id:%" PRId64 ", fd:%" PRId64,
fdset_id, fd);
} else {
snprintf(fd_str, sizeof(fd_str), "fdset-id:%" PRId64, fdset_id);
}
error_setg(errp, "File descriptor named '%s' not found", fd_str);
}
FdsetInfoList *qmp_query_fdsets(Error **errp)
{
MonFdset *mon_fdset;
MonFdsetFd *mon_fdset_fd;
FdsetInfoList *fdset_list = NULL;
QEMU_LOCK_GUARD(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
FdsetInfo *fdset_info = g_malloc0(sizeof(*fdset_info));
fdset_info->fdset_id = mon_fdset->id;
QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
FdsetFdInfo *fdsetfd_info;
fdsetfd_info = g_malloc0(sizeof(*fdsetfd_info));
fdsetfd_info->fd = mon_fdset_fd->fd;
fdsetfd_info->opaque = g_strdup(mon_fdset_fd->opaque);
QAPI_LIST_PREPEND(fdset_info->fds, fdsetfd_info);
}
QAPI_LIST_PREPEND(fdset_list, fdset_info);
}
return fdset_list;
}
AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_id, int64_t fdset_id,
const char *opaque, Error **errp)
{
MonFdset *mon_fdset = NULL;
MonFdsetFd *mon_fdset_fd;
AddfdInfo *fdinfo;
QEMU_LOCK_GUARD(&mon_fdsets_lock);
if (has_fdset_id) {
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
/* Break if match found or match impossible due to ordering by ID */
if (fdset_id <= mon_fdset->id) {
if (fdset_id < mon_fdset->id) {
mon_fdset = NULL;
}
break;
}
}
}
if (mon_fdset == NULL) {
int64_t fdset_id_prev = -1;
MonFdset *mon_fdset_cur = QLIST_FIRST(&mon_fdsets);
if (has_fdset_id) {
if (fdset_id < 0) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "fdset-id",
"a non-negative value");
return NULL;
}
/* Use specified fdset ID */
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
mon_fdset_cur = mon_fdset;
if (fdset_id < mon_fdset_cur->id) {
break;
}
}
} else {
/* Use first available fdset ID */
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
mon_fdset_cur = mon_fdset;
if (fdset_id_prev == mon_fdset_cur->id - 1) {
fdset_id_prev = mon_fdset_cur->id;
continue;
}
break;
}
}
mon_fdset = g_malloc0(sizeof(*mon_fdset));
if (has_fdset_id) {
mon_fdset->id = fdset_id;
} else {
mon_fdset->id = fdset_id_prev + 1;
}
/* The fdset list is ordered by fdset ID */
if (!mon_fdset_cur) {
QLIST_INSERT_HEAD(&mon_fdsets, mon_fdset, next);
} else if (mon_fdset->id < mon_fdset_cur->id) {
QLIST_INSERT_BEFORE(mon_fdset_cur, mon_fdset, next);
} else {
QLIST_INSERT_AFTER(mon_fdset_cur, mon_fdset, next);
}
}
mon_fdset_fd = g_malloc0(sizeof(*mon_fdset_fd));
mon_fdset_fd->fd = fd;
mon_fdset_fd->removed = false;
mon_fdset_fd->opaque = g_strdup(opaque);
QLIST_INSERT_HEAD(&mon_fdset->fds, mon_fdset_fd, next);
fdinfo = g_malloc0(sizeof(*fdinfo));
fdinfo->fdset_id = mon_fdset->id;
fdinfo->fd = mon_fdset_fd->fd;
return fdinfo;
}
int monitor_fdset_dup_fd_add(int64_t fdset_id, int flags)
{
#ifdef _WIN32
return -ENOENT;
#else
MonFdset *mon_fdset;
QEMU_LOCK_GUARD(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
MonFdsetFd *mon_fdset_fd;
MonFdsetFd *mon_fdset_fd_dup;
int fd = -1;
int dup_fd;
int mon_fd_flags;
if (mon_fdset->id != fdset_id) {
continue;
}
QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
mon_fd_flags = fcntl(mon_fdset_fd->fd, F_GETFL);
if (mon_fd_flags == -1) {
return -1;
}
if ((flags & O_ACCMODE) == (mon_fd_flags & O_ACCMODE)) {
fd = mon_fdset_fd->fd;
break;
}
}
if (fd == -1) {
errno = EACCES;
return -1;
}
dup_fd = qemu_dup_flags(fd, flags);
if (dup_fd == -1) {
return -1;
}
mon_fdset_fd_dup = g_malloc0(sizeof(*mon_fdset_fd_dup));
mon_fdset_fd_dup->fd = dup_fd;
QLIST_INSERT_HEAD(&mon_fdset->dup_fds, mon_fdset_fd_dup, next);
return dup_fd;
}
errno = ENOENT;
return -1;
#endif
}
static int64_t monitor_fdset_dup_fd_find_remove(int dup_fd, bool remove)
{
MonFdset *mon_fdset;
MonFdsetFd *mon_fdset_fd_dup;
QEMU_LOCK_GUARD(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) {
if (mon_fdset_fd_dup->fd == dup_fd) {
if (remove) {
QLIST_REMOVE(mon_fdset_fd_dup, next);
g_free(mon_fdset_fd_dup);
if (QLIST_EMPTY(&mon_fdset->dup_fds)) {
monitor_fdset_cleanup(mon_fdset);
}
return -1;
} else {
return mon_fdset->id;
}
}
}
}
return -1;
}
int64_t monitor_fdset_dup_fd_find(int dup_fd)
{
return monitor_fdset_dup_fd_find_remove(dup_fd, false);
}
void monitor_fdset_dup_fd_remove(int dup_fd)
{
monitor_fdset_dup_fd_find_remove(dup_fd, true);
}
int monitor_fd_param(Monitor *mon, const char *fdname, Error **errp)
{
int fd;
if (!qemu_isdigit(fdname[0]) && mon) {
fd = monitor_get_fd(mon, fdname, errp);
} else {
fd = qemu_parse_fd(fdname);
if (fd < 0) {
error_setg(errp, "Invalid file descriptor number '%s'",
fdname);
}
}
return fd;
}
static void __attribute__((__constructor__)) monitor_fds_init(void)
{
qemu_mutex_init(&mon_fdsets_lock);
}