1 /***
2 This file is part of PulseAudio.
3
4 Copyright 2004-2006 Lennart Poettering
5
6 PulseAudio is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
10
11 PulseAudio is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
18 ***/
19
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23
24 #include <pulsecore/core-util.h>
25 #include <pulsecore/macro.h>
26 #include <pulsecore/native-common.h>
27 #include <pulsecore/pstream.h>
28 #include <pulsecore/refcnt.h>
29 #include <pulse/xmalloc.h>
30
31 #include "pstream-util.h"
32
33 #include "log/audio_log.h"
34
35 #define PA_SNPRINTF_COMMAND_STR_LENGTH 256
36
pa_pstream_send_tagstruct_with_ancil_data(pa_pstream * p,pa_tagstruct * t,pa_cmsg_ancil_data * ancil_data)37 static void pa_pstream_send_tagstruct_with_ancil_data(pa_pstream *p, pa_tagstruct *t, pa_cmsg_ancil_data *ancil_data) {
38 size_t length;
39 const uint8_t *data;
40 pa_packet *packet;
41
42 pa_assert(p);
43 pa_assert(t);
44
45 uint32_t command;
46 if (ReadCommand(t, &command) == 0) {
47 char t[PA_SNPRINTF_COMMAND_STR_LENGTH] = {0};
48 pa_snprintf(t, sizeof(t), "PA_SEND_CMD[%u]", p, command);
49 CallStart(t);
50 CallEnd();
51 }
52
53 pa_assert_se(data = pa_tagstruct_data(t, &length));
54 pa_assert_se(packet = pa_packet_new_data(data, length));
55 pa_tagstruct_free(t);
56
57 pa_pstream_send_packet(p, packet, ancil_data);
58 pa_packet_unref(packet);
59 }
60
61 #ifdef HAVE_CREDS
62
pa_pstream_send_tagstruct_with_creds(pa_pstream * p,pa_tagstruct * t,const pa_creds * creds)63 void pa_pstream_send_tagstruct_with_creds(pa_pstream *p, pa_tagstruct *t, const pa_creds *creds) {
64 if (creds) {
65 pa_cmsg_ancil_data a;
66
67 a.nfd = 0;
68 a.creds_valid = true;
69 a.creds = *creds;
70 pa_pstream_send_tagstruct_with_ancil_data(p, t, &a);
71 }
72 else
73 pa_pstream_send_tagstruct_with_ancil_data(p, t, NULL);
74 }
75
76 /* @close_fds: If set then the pstreams code, after invoking a sendmsg(),
77 * will close all passed fds.
78 *
79 * Such fds cannot be closed here as this might lead to freeing them
80 * before they're actually passed to the other end. The internally-used
81 * pa_pstream_send_packet() does not do any actual writes and just
82 * defers write events over the pstream. */
pa_pstream_send_tagstruct_with_fds(pa_pstream * p,pa_tagstruct * t,int nfd,const int * fds,bool close_fds)83 void pa_pstream_send_tagstruct_with_fds(pa_pstream *p, pa_tagstruct *t, int nfd, const int *fds,
84 bool close_fds) {
85 if (nfd > 0) {
86 pa_cmsg_ancil_data a;
87
88 a.nfd = nfd;
89 a.creds_valid = false;
90 a.close_fds_on_cleanup = close_fds;
91 pa_assert(nfd <= MAX_ANCIL_DATA_FDS);
92 memcpy(a.fds, fds, sizeof(int) * nfd);
93 pa_pstream_send_tagstruct_with_ancil_data(p, t, &a);
94 }
95 else
96 pa_pstream_send_tagstruct_with_ancil_data(p, t, NULL);
97 }
98
99 #else
100
pa_pstream_send_tagstruct_with_creds(pa_pstream * p,pa_tagstruct * t,const pa_creds * creds)101 void pa_pstream_send_tagstruct_with_creds(pa_pstream *p, pa_tagstruct *t, const pa_creds *creds) {
102 pa_pstream_send_tagstruct_with_ancil_data(p, t, NULL);
103 }
104
pa_pstream_send_tagstruct_with_fds(pa_pstream * p,pa_tagstruct * t,int nfd,const int * fds,bool close_fds)105 void PA_GCC_NORETURN pa_pstream_send_tagstruct_with_fds(pa_pstream *p, pa_tagstruct *t, int nfd, const int *fds,
106 bool close_fds) {
107 pa_assert_not_reached();
108 }
109
110 #endif
111
pa_pstream_send_error(pa_pstream * p,uint32_t tag,uint32_t error)112 void pa_pstream_send_error(pa_pstream *p, uint32_t tag, uint32_t error) {
113 pa_tagstruct *t;
114
115 pa_assert_se(t = pa_tagstruct_new());
116 pa_tagstruct_putu32(t, PA_COMMAND_ERROR);
117 pa_tagstruct_putu32(t, tag);
118 pa_tagstruct_putu32(t, error);
119 pa_pstream_send_tagstruct(p, t);
120 }
121
pa_pstream_send_simple_ack(pa_pstream * p,uint32_t tag)122 void pa_pstream_send_simple_ack(pa_pstream *p, uint32_t tag) {
123 pa_tagstruct *t;
124
125 pa_assert_se(t = pa_tagstruct_new());
126 pa_tagstruct_putu32(t, PA_COMMAND_REPLY);
127 pa_tagstruct_putu32(t, tag);
128 pa_pstream_send_tagstruct(p, t);
129 }
130
131 /* Before sending blocks from a memfd-backed pool over the pipe, we
132 * must call this method first.
133 *
134 * This is needed to transfer memfd blocks without passing their fd
135 * every time, thus minimizing overhead and avoiding fd leaks.
136 *
137 * On registration a packet is sent with the memfd fd as ancil data;
138 * such packet has an ID that uniquely identifies the pool's memfd
139 * region. Upon arrival the other end creates a permanent mapping
140 * between that ID and the passed memfd memory area.
141 *
142 * By doing so, we won't need to reference the pool's memfd fd any
143 * further - just its ID. Both endpoints can then close their fds. */
pa_pstream_register_memfd_mempool(pa_pstream * p,pa_mempool * pool,const char ** fail_reason)144 int pa_pstream_register_memfd_mempool(pa_pstream *p, pa_mempool *pool, const char **fail_reason) {
145 #if defined(HAVE_CREDS) && defined(HAVE_MEMFD)
146 unsigned shm_id;
147 int memfd_fd, ret = -1;
148 pa_tagstruct *t;
149 bool per_client_mempool;
150
151 pa_assert(p);
152 pa_assert(fail_reason);
153
154 *fail_reason = NULL;
155 per_client_mempool = pa_mempool_is_per_client(pool);
156
157 pa_pstream_ref(p);
158
159 if (!pa_mempool_is_shared(pool)) {
160 *fail_reason = "mempool is not shared";
161 goto finish;
162 }
163
164 if (!pa_mempool_is_memfd_backed(pool)) {
165 *fail_reason = "mempool is not memfd-backed";
166 goto finish;
167 }
168
169 if (pa_mempool_get_shm_id(pool, &shm_id)) {
170 *fail_reason = "could not extract pool SHM ID";
171 goto finish;
172 }
173
174 if (!pa_pstream_get_memfd(p)) {
175 *fail_reason = "pipe does not support memfd transport";
176 goto finish;
177 }
178
179 memfd_fd = (per_client_mempool) ? pa_mempool_take_memfd_fd(pool) :
180 pa_mempool_get_memfd_fd(pool);
181
182 /* Note! For per-client mempools we've taken ownership of the memfd
183 * fd, and we're thus the sole code path responsible for closing it.
184 * In case of any failure, it MUST be closed. */
185
186 if (pa_pstream_attach_memfd_shmid(p, shm_id, memfd_fd)) {
187 *fail_reason = "could not attach memfd SHM ID to pipe";
188
189 if (per_client_mempool)
190 pa_assert_se(pa_close(memfd_fd) == 0);
191 goto finish;
192 }
193
194 t = pa_tagstruct_new();
195 pa_tagstruct_putu32(t, PA_COMMAND_REGISTER_MEMFD_SHMID);
196 pa_tagstruct_putu32(t, (uint32_t) -1); /* tag */
197 pa_tagstruct_putu32(t, shm_id);
198 pa_pstream_send_tagstruct_with_fds(p, t, 1, &memfd_fd, per_client_mempool);
199
200 ret = 0;
201 finish:
202 pa_pstream_unref(p);
203 return ret;
204
205 #else
206 pa_assert(fail_reason);
207 *fail_reason = "memfd support not compiled in";
208 return -1;
209 #endif
210 }
211