static void setup_complete_callback(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_tagstruct *t, void *userdata) {
pa_context *c = userdata;
pa_assert(pd);
pa_assert(c);
pa_assert(c->state == PA_CONTEXT_AUTHORIZING || c->state == PA_CONTEXT_SETTING_NAME);
pa_context_ref(c);
if (command != PA_COMMAND_REPLY) {
pa_context_handle_error(c, command, t, true);
goto finish;
}
switch(c->state) {
case PA_CONTEXT_AUTHORIZING: {
pa_tagstruct *reply;
bool shm_on_remote = false;
bool memfd_on_remote = false;
if (pa_tagstruct_getu32(t, &c->version) < 0 ||
!pa_tagstruct_eof(t)) {
pa_context_fail(c, PA_ERR_PROTOCOL);
goto finish;
}
/* Minimum supported version */
if (c->version < 8) {
pa_context_fail(c, PA_ERR_VERSION);
goto finish;
}
/* Starting with protocol version 13 the MSB of the version
tag reflects if shm is available for this connection or
not. */
if (c->version >= 13) {
shm_on_remote = !!(c->version & 0x80000000U);
/* Starting with protocol version 31, the second MSB of the version
* tag reflects whether memfd is supported on the other PA end. */
if (c->version >= 31)
memfd_on_remote = !!(c->version & 0x40000000U);
/* Reserve the two most-significant _bytes_ of the version tag
* for flags. */
c->version &= 0x0000FFFFU;
}
pa_log_debug("Protocol version: remote %u, local %u", c->version, PA_PROTOCOL_VERSION);
/* Enable shared memory support if possible */
if (c->do_shm)
if (c->version < 10 || (c->version >= 13 && !shm_on_remote))
c->do_shm = false;
if (c->do_shm) {
/* Only enable SHM if both sides are owned by the same
* user. This is a security measure because otherwise
* data private to the user might leak. */
#ifdef HAVE_CREDS
const pa_creds *creds;
if (!(creds = pa_pdispatch_creds(pd)) || getuid() != creds->uid)
c->do_shm = false;
#endif
}
pa_log_debug("Negotiated SHM: %s", pa_yes_no(c->do_shm));
pa_pstream_enable_shm(c->pstream, c->do_shm);
c->shm_type = PA_MEM_TYPE_PRIVATE;
if (c->do_shm) {
if (c->version >= 31 && memfd_on_remote && c->memfd_on_local) {
const char *reason;
pa_pstream_enable_memfd(c->pstream);
if (pa_mempool_is_memfd_backed(c->mempool))
if (pa_pstream_register_memfd_mempool(c->pstream, c->mempool, &reason))
pa_log("Failed to regester memfd mempool. Reason: %s", reason);
/* Even if memfd pool registration fails, the negotiated SHM type
* shall remain memfd as both endpoints claim to support it. */
c->shm_type = PA_MEM_TYPE_SHARED_MEMFD;
} else
c->shm_type = PA_MEM_TYPE_SHARED_POSIX;
}
pa_log_debug("Memfd possible: %s", pa_yes_no(c->memfd_on_local));
pa_log_debug("Negotiated SHM type: %s", pa_mem_type_to_string(c->shm_type));
reply = pa_tagstruct_command(c, PA_COMMAND_SET_CLIENT_NAME, &tag);
if (c->version >= 13) {
pa_init_proplist(c->proplist);
pa_tagstruct_put_proplist(reply, c->proplist);
} else
pa_tagstruct_puts(reply, pa_proplist_gets(c->proplist, PA_PROP_APPLICATION_NAME));
pa_pstream_send_tagstruct(c->pstream, reply);
pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT, setup_complete_callback, c, NULL);
pa_context_set_state(c, PA_CONTEXT_SETTING_NAME);
break;
}
case PA_CONTEXT_SETTING_NAME :
if ((c->version >= 13 && (pa_tagstruct_getu32(t, &c->client_index) < 0 ||
c->client_index == PA_INVALID_INDEX)) ||
!pa_tagstruct_eof(t)) {
pa_context_fail(c, PA_ERR_PROTOCOL);
goto finish;
}
pa_context_set_state(c, PA_CONTEXT_READY);
break;
default:
pa_assert_not_reached();
}
finish:
pa_context_unref(c);
}
static int sharedmem_create(pa_shm *m, pa_mem_type_t type, size_t size, mode_t mode) {
#if defined(HAVE_SHM_OPEN) || defined(HAVE_MEMFD)
char fn[32];
int fd = -1;
struct shm_marker *marker;
bool do_unlink = false;
/* Each time we create a new SHM area, let's first drop all stale
* ones */
pa_shm_cleanup();
pa_random(&m->id, sizeof(m->id));
switch (type) {
#ifdef HAVE_SHM_OPEN
case PA_MEM_TYPE_SHARED_POSIX:
segment_name(fn, sizeof(fn), m->id);
fd = shm_open(fn, O_RDWR|O_CREAT|O_EXCL, mode);
do_unlink = true;
break;
#endif
#ifdef HAVE_MEMFD
case PA_MEM_TYPE_SHARED_MEMFD:
fd = memfd_create("pulseaudio", MFD_ALLOW_SEALING);
break;
#endif
default:
goto fail;
}
if (fd < 0) {
pa_log("%s open() failed: %s", pa_mem_type_to_string(type), pa_cstrerror(errno));
goto fail;
}
m->type = type;
m->size = size + shm_marker_size(type);
m->do_unlink = do_unlink;
if (ftruncate(fd, (off_t) m->size) < 0) {
pa_log("ftruncate() failed: %s", pa_cstrerror(errno));
goto fail;
}
#ifndef MAP_NORESERVE
#define MAP_NORESERVE 0
#endif
if ((m->ptr = mmap(NULL, PA_PAGE_ALIGN(m->size), PROT_READ|PROT_WRITE, MAP_SHARED|MAP_NORESERVE, fd, (off_t) 0)) == MAP_FAILED) {
pa_log("mmap() failed: %s", pa_cstrerror(errno));
goto fail;
}
if (type == PA_MEM_TYPE_SHARED_POSIX) {
/* We store our PID at the end of the shm block, so that we
* can check for dead shm segments later */
marker = (struct shm_marker*) ((uint8_t*) m->ptr + m->size - shm_marker_size(type));
pa_atomic_store(&marker->pid, (int) getpid());
pa_atomic_store(&marker->marker, SHM_MARKER);
}
/* For memfds, we keep the fd open until we pass it
* to the other PA endpoint over unix domain socket. */
if (type == PA_MEM_TYPE_SHARED_MEMFD)
m->fd = fd;
else {
pa_assert_se(pa_close(fd) == 0);
m->fd = -1;
}
return 0;
fail:
if (fd >= 0) {
#ifdef HAVE_SHM_OPEN
if (type == PA_MEM_TYPE_SHARED_POSIX)
shm_unlink(fn);
#endif
pa_close(fd);
}
#endif /* defined(HAVE_SHM_OPEN) || defined(HAVE_MEMFD) */
return -1;
}
