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qemu/io/channel.c
Anthony Harivel 95fa0c79a0 qio: add support for SO_PEERCRED for socket channel 
The function qio_channel_get_peercred() returns a pointer to the
credentials of the peer process connected to this socket.

This credentials structure is defined in <sys/socket.h> as follows:

struct ucred {
	pid_t pid;    /* Process ID of the sending process */
	uid_t uid;    /* User ID of the sending process */
	gid_t gid;    /* Group ID of the sending process */
};

The use of this function is possible only for connected AF_UNIX stream
sockets and for AF_UNIX stream and datagram socket pairs.

On platform other than Linux, the function return 0.

Signed-off-by: Anthony Harivel <aharivel@redhat.com>
Link: https://lore.kernel.org/r/20240522153453.1230389-2-aharivel@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-07-22 13:47:41 +02:00

809 lines
23 KiB
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/*
* QEMU I/O channels
*
* Copyright (c) 2015 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "block/aio-wait.h"
#include "io/channel.h"
#include "qapi/error.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "qemu/iov.h"
bool qio_channel_has_feature(QIOChannel *ioc,
QIOChannelFeature feature)
{
return ioc->features & (1 << feature);
}
void qio_channel_set_feature(QIOChannel *ioc,
QIOChannelFeature feature)
{
ioc->features |= (1 << feature);
}
void qio_channel_set_name(QIOChannel *ioc,
const char *name)
{
g_free(ioc->name);
ioc->name = g_strdup(name);
}
ssize_t qio_channel_readv_full(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds,
size_t *nfds,
int flags,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if ((fds || nfds) &&
!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
error_setg_errno(errp, EINVAL,
"Channel does not support file descriptor passing");
return -1;
}
if ((flags & QIO_CHANNEL_READ_FLAG_MSG_PEEK) &&
!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_READ_MSG_PEEK)) {
error_setg_errno(errp, EINVAL,
"Channel does not support peek read");
return -1;
}
return klass->io_readv(ioc, iov, niov, fds, nfds, flags, errp);
}
ssize_t qio_channel_writev_full(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds,
size_t nfds,
int flags,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (fds || nfds) {
if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
error_setg_errno(errp, EINVAL,
"Channel does not support file descriptor passing");
return -1;
}
if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) {
error_setg_errno(errp, EINVAL,
"Zero Copy does not support file descriptor passing");
return -1;
}
}
if ((flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) &&
!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY)) {
error_setg_errno(errp, EINVAL,
"Requested Zero Copy feature is not available");
return -1;
}
return klass->io_writev(ioc, iov, niov, fds, nfds, flags, errp);
}
int coroutine_mixed_fn qio_channel_readv_all_eof(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp)
{
return qio_channel_readv_full_all_eof(ioc, iov, niov, NULL, NULL, errp);
}
int coroutine_mixed_fn qio_channel_readv_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp)
{
return qio_channel_readv_full_all(ioc, iov, niov, NULL, NULL, errp);
}
int coroutine_mixed_fn qio_channel_readv_full_all_eof(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds, size_t *nfds,
Error **errp)
{
int ret = -1;
struct iovec *local_iov = g_new(struct iovec, niov);
struct iovec *local_iov_head = local_iov;
unsigned int nlocal_iov = niov;
int **local_fds = fds;
size_t *local_nfds = nfds;
bool partial = false;
if (nfds) {
*nfds = 0;
}
if (fds) {
*fds = NULL;
}
nlocal_iov = iov_copy(local_iov, nlocal_iov,
iov, niov,
0, iov_size(iov, niov));
while ((nlocal_iov > 0) || local_fds) {
ssize_t len;
len = qio_channel_readv_full(ioc, local_iov, nlocal_iov, local_fds,
local_nfds, 0, errp);
if (len == QIO_CHANNEL_ERR_BLOCK) {
if (qemu_in_coroutine()) {
qio_channel_yield(ioc, G_IO_IN);
} else {
qio_channel_wait(ioc, G_IO_IN);
}
continue;
}
if (len == 0) {
if (local_nfds && *local_nfds) {
/*
* Got some FDs, but no data yet. This isn't an EOF
* scenario (yet), so carry on to try to read data
* on next loop iteration
*/
goto next_iter;
} else if (!partial) {
/* No fds and no data - EOF before any data read */
ret = 0;
goto cleanup;
} else {
len = -1;
error_setg(errp,
"Unexpected end-of-file before all data were read");
/* Fallthrough into len < 0 handling */
}
}
if (len < 0) {
/* Close any FDs we previously received */
if (nfds && fds) {
size_t i;
for (i = 0; i < (*nfds); i++) {
close((*fds)[i]);
}
g_free(*fds);
*fds = NULL;
*nfds = 0;
}
goto cleanup;
}
if (nlocal_iov) {
iov_discard_front(&local_iov, &nlocal_iov, len);
}
next_iter:
partial = true;
local_fds = NULL;
local_nfds = NULL;
}
ret = 1;
cleanup:
g_free(local_iov_head);
return ret;
}
int coroutine_mixed_fn qio_channel_readv_full_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds, size_t *nfds,
Error **errp)
{
int ret = qio_channel_readv_full_all_eof(ioc, iov, niov, fds, nfds, errp);
if (ret == 0) {
error_setg(errp, "Unexpected end-of-file before all data were read");
return -1;
}
if (ret == 1) {
return 0;
}
return ret;
}
int coroutine_mixed_fn qio_channel_writev_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp)
{
return qio_channel_writev_full_all(ioc, iov, niov, NULL, 0, 0, errp);
}
int coroutine_mixed_fn qio_channel_writev_full_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds, size_t nfds,
int flags, Error **errp)
{
int ret = -1;
struct iovec *local_iov = g_new(struct iovec, niov);
struct iovec *local_iov_head = local_iov;
unsigned int nlocal_iov = niov;
nlocal_iov = iov_copy(local_iov, nlocal_iov,
iov, niov,
0, iov_size(iov, niov));
while (nlocal_iov > 0) {
ssize_t len;
len = qio_channel_writev_full(ioc, local_iov, nlocal_iov, fds,
nfds, flags, errp);
if (len == QIO_CHANNEL_ERR_BLOCK) {
if (qemu_in_coroutine()) {
qio_channel_yield(ioc, G_IO_OUT);
} else {
qio_channel_wait(ioc, G_IO_OUT);
}
continue;
}
if (len < 0) {
goto cleanup;
}
iov_discard_front(&local_iov, &nlocal_iov, len);
fds = NULL;
nfds = 0;
}
ret = 0;
cleanup:
g_free(local_iov_head);
return ret;
}
ssize_t qio_channel_readv(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp)
{
return qio_channel_readv_full(ioc, iov, niov, NULL, NULL, 0, errp);
}
ssize_t qio_channel_writev(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp)
{
return qio_channel_writev_full(ioc, iov, niov, NULL, 0, 0, errp);
}
ssize_t qio_channel_read(QIOChannel *ioc,
char *buf,
size_t buflen,
Error **errp)
{
struct iovec iov = { .iov_base = buf, .iov_len = buflen };
return qio_channel_readv_full(ioc, &iov, 1, NULL, NULL, 0, errp);
}
ssize_t qio_channel_write(QIOChannel *ioc,
const char *buf,
size_t buflen,
Error **errp)
{
struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
return qio_channel_writev_full(ioc, &iov, 1, NULL, 0, 0, errp);
}
int coroutine_mixed_fn qio_channel_read_all_eof(QIOChannel *ioc,
char *buf,
size_t buflen,
Error **errp)
{
struct iovec iov = { .iov_base = buf, .iov_len = buflen };
return qio_channel_readv_all_eof(ioc, &iov, 1, errp);
}
int coroutine_mixed_fn qio_channel_read_all(QIOChannel *ioc,
char *buf,
size_t buflen,
Error **errp)
{
struct iovec iov = { .iov_base = buf, .iov_len = buflen };
return qio_channel_readv_all(ioc, &iov, 1, errp);
}
int coroutine_mixed_fn qio_channel_write_all(QIOChannel *ioc,
const char *buf,
size_t buflen,
Error **errp)
{
struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
return qio_channel_writev_all(ioc, &iov, 1, errp);
}
int qio_channel_set_blocking(QIOChannel *ioc,
bool enabled,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
return klass->io_set_blocking(ioc, enabled, errp);
}
void qio_channel_set_follow_coroutine_ctx(QIOChannel *ioc, bool enabled)
{
ioc->follow_coroutine_ctx = enabled;
}
int qio_channel_close(QIOChannel *ioc,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
return klass->io_close(ioc, errp);
}
GSource *qio_channel_create_watch(QIOChannel *ioc,
GIOCondition condition)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
GSource *ret = klass->io_create_watch(ioc, condition);
if (ioc->name) {
g_source_set_name(ret, ioc->name);
}
return ret;
}
void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
AioContext *read_ctx,
IOHandler *io_read,
AioContext *write_ctx,
IOHandler *io_write,
void *opaque)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
klass->io_set_aio_fd_handler(ioc, read_ctx, io_read, write_ctx, io_write,
opaque);
}
guint qio_channel_add_watch_full(QIOChannel *ioc,
GIOCondition condition,
QIOChannelFunc func,
gpointer user_data,
GDestroyNotify notify,
GMainContext *context)
{
GSource *source;
guint id;
source = qio_channel_create_watch(ioc, condition);
g_source_set_callback(source, (GSourceFunc)func, user_data, notify);
id = g_source_attach(source, context);
g_source_unref(source);
return id;
}
guint qio_channel_add_watch(QIOChannel *ioc,
GIOCondition condition,
QIOChannelFunc func,
gpointer user_data,
GDestroyNotify notify)
{
return qio_channel_add_watch_full(ioc, condition, func,
user_data, notify, NULL);
}
GSource *qio_channel_add_watch_source(QIOChannel *ioc,
GIOCondition condition,
QIOChannelFunc func,
gpointer user_data,
GDestroyNotify notify,
GMainContext *context)
{
GSource *source;
guint id;
id = qio_channel_add_watch_full(ioc, condition, func,
user_data, notify, context);
source = g_main_context_find_source_by_id(context, id);
g_source_ref(source);
return source;
}
ssize_t qio_channel_pwritev(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_pwritev) {
error_setg(errp, "Channel does not support pwritev");
return -1;
}
if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_SEEKABLE)) {
error_setg_errno(errp, EINVAL, "Requested channel is not seekable");
return -1;
}
return klass->io_pwritev(ioc, iov, niov, offset, errp);
}
ssize_t qio_channel_pwrite(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, Error **errp)
{
struct iovec iov = {
.iov_base = buf,
.iov_len = buflen
};
return qio_channel_pwritev(ioc, &iov, 1, offset, errp);
}
ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_preadv) {
error_setg(errp, "Channel does not support preadv");
return -1;
}
if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_SEEKABLE)) {
error_setg_errno(errp, EINVAL, "Requested channel is not seekable");
return -1;
}
return klass->io_preadv(ioc, iov, niov, offset, errp);
}
ssize_t qio_channel_pread(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, Error **errp)
{
struct iovec iov = {
.iov_base = buf,
.iov_len = buflen
};
return qio_channel_preadv(ioc, &iov, 1, offset, errp);
}
int qio_channel_shutdown(QIOChannel *ioc,
QIOChannelShutdown how,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_shutdown) {
error_setg(errp, "Data path shutdown not supported");
return -1;
}
return klass->io_shutdown(ioc, how, errp);
}
void qio_channel_set_delay(QIOChannel *ioc,
bool enabled)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (klass->io_set_delay) {
klass->io_set_delay(ioc, enabled);
}
}
void qio_channel_set_cork(QIOChannel *ioc,
bool enabled)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (klass->io_set_cork) {
klass->io_set_cork(ioc, enabled);
}
}
int qio_channel_get_peerpid(QIOChannel *ioc,
unsigned int *pid,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_peerpid) {
error_setg(errp, "Channel does not support peer pid");
return -1;
}
klass->io_peerpid(ioc, pid, errp);
return 0;
}
off_t qio_channel_io_seek(QIOChannel *ioc,
off_t offset,
int whence,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_seek) {
error_setg(errp, "Channel does not support random access");
return -1;
}
return klass->io_seek(ioc, offset, whence, errp);
}
int qio_channel_flush(QIOChannel *ioc,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_flush ||
!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY)) {
return 0;
}
return klass->io_flush(ioc, errp);
}
static void qio_channel_restart_read(void *opaque)
{
QIOChannel *ioc = opaque;
Coroutine *co = qatomic_xchg(&ioc->read_coroutine, NULL);
if (!co) {
return;
}
/* Assert that aio_co_wake() reenters the coroutine directly */
assert(qemu_get_current_aio_context() ==
qemu_coroutine_get_aio_context(co));
aio_co_wake(co);
}
static void qio_channel_restart_write(void *opaque)
{
QIOChannel *ioc = opaque;
Coroutine *co = qatomic_xchg(&ioc->write_coroutine, NULL);
if (!co) {
return;
}
/* Assert that aio_co_wake() reenters the coroutine directly */
assert(qemu_get_current_aio_context() ==
qemu_coroutine_get_aio_context(co));
aio_co_wake(co);
}
static void coroutine_fn
qio_channel_set_fd_handlers(QIOChannel *ioc, GIOCondition condition)
{
AioContext *ctx = ioc->follow_coroutine_ctx ?
qemu_coroutine_get_aio_context(qemu_coroutine_self()) :
iohandler_get_aio_context();
AioContext *read_ctx = NULL;
IOHandler *io_read = NULL;
AioContext *write_ctx = NULL;
IOHandler *io_write = NULL;
if (condition == G_IO_IN) {
ioc->read_coroutine = qemu_coroutine_self();
ioc->read_ctx = ctx;
read_ctx = ctx;
io_read = qio_channel_restart_read;
/*
* Thread safety: if the other coroutine is set and its AioContext
* matches ours, then there is mutual exclusion between read and write
* because they share a single thread and it's safe to set both read
* and write fd handlers here. If the AioContext does not match ours,
* then both threads may run in parallel but there is no shared state
* to worry about.
*/
if (ioc->write_coroutine && ioc->write_ctx == ctx) {
write_ctx = ctx;
io_write = qio_channel_restart_write;
}
} else if (condition == G_IO_OUT) {
ioc->write_coroutine = qemu_coroutine_self();
ioc->write_ctx = ctx;
write_ctx = ctx;
io_write = qio_channel_restart_write;
if (ioc->read_coroutine && ioc->read_ctx == ctx) {
read_ctx = ctx;
io_read = qio_channel_restart_read;
}
} else {
abort();
}
qio_channel_set_aio_fd_handler(ioc, read_ctx, io_read,
write_ctx, io_write, ioc);
}
static void coroutine_fn
qio_channel_clear_fd_handlers(QIOChannel *ioc, GIOCondition condition)
{
AioContext *read_ctx = NULL;
IOHandler *io_read = NULL;
AioContext *write_ctx = NULL;
IOHandler *io_write = NULL;
AioContext *ctx;
if (condition == G_IO_IN) {
ctx = ioc->read_ctx;
read_ctx = ctx;
io_read = NULL;
if (ioc->write_coroutine && ioc->write_ctx == ctx) {
write_ctx = ctx;
io_write = qio_channel_restart_write;
}
} else if (condition == G_IO_OUT) {
ctx = ioc->write_ctx;
write_ctx = ctx;
io_write = NULL;
if (ioc->read_coroutine && ioc->read_ctx == ctx) {
read_ctx = ctx;
io_read = qio_channel_restart_read;
}
} else {
abort();
}
qio_channel_set_aio_fd_handler(ioc, read_ctx, io_read,
write_ctx, io_write, ioc);
}
void coroutine_fn qio_channel_yield(QIOChannel *ioc,
GIOCondition condition)
{
AioContext *ioc_ctx;
assert(qemu_in_coroutine());
ioc_ctx = qemu_coroutine_get_aio_context(qemu_coroutine_self());
if (condition == G_IO_IN) {
assert(!ioc->read_coroutine);
} else if (condition == G_IO_OUT) {
assert(!ioc->write_coroutine);
} else {
abort();
}
qio_channel_set_fd_handlers(ioc, condition);
qemu_coroutine_yield();
assert(in_aio_context_home_thread(ioc_ctx));
/* Allow interrupting the operation by reentering the coroutine other than
* through the aio_fd_handlers. */
if (condition == G_IO_IN) {
assert(ioc->read_coroutine == NULL);
} else if (condition == G_IO_OUT) {
assert(ioc->write_coroutine == NULL);
}
qio_channel_clear_fd_handlers(ioc, condition);
}
void qio_channel_wake_read(QIOChannel *ioc)
{
Coroutine *co = qatomic_xchg(&ioc->read_coroutine, NULL);
if (co) {
aio_co_wake(co);
}
}
static gboolean qio_channel_wait_complete(QIOChannel *ioc,
GIOCondition condition,
gpointer opaque)
{
GMainLoop *loop = opaque;
g_main_loop_quit(loop);
return FALSE;
}
void qio_channel_wait(QIOChannel *ioc,
GIOCondition condition)
{
GMainContext *ctxt = g_main_context_new();
GMainLoop *loop = g_main_loop_new(ctxt, TRUE);
GSource *source;
source = qio_channel_create_watch(ioc, condition);
g_source_set_callback(source,
(GSourceFunc)qio_channel_wait_complete,
loop,
NULL);
g_source_attach(source, ctxt);
g_main_loop_run(loop);
g_source_unref(source);
g_main_loop_unref(loop);
g_main_context_unref(ctxt);
}
static void qio_channel_finalize(Object *obj)
{
QIOChannel *ioc = QIO_CHANNEL(obj);
/* Must not have coroutines in qio_channel_yield() */
assert(!ioc->read_coroutine);
assert(!ioc->write_coroutine);
g_free(ioc->name);
#ifdef _WIN32
if (ioc->event) {
CloseHandle(ioc->event);
}
#endif
}
static const TypeInfo qio_channel_info = {
.parent = TYPE_OBJECT,
.name = TYPE_QIO_CHANNEL,
.instance_size = sizeof(QIOChannel),
.instance_finalize = qio_channel_finalize,
.abstract = true,
.class_size = sizeof(QIOChannelClass),
};
static void qio_channel_register_types(void)
{
type_register_static(&qio_channel_info);
}
type_init(qio_channel_register_types);
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