1 /***
2 This file is part of PulseAudio.
3
4 Copyright 2016 Ahmed S. Darwish <darwish.07@gmail.com>
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/creds.h>
26 #include <pulsecore/macro.h>
27 #include <pulsecore/pdispatch.h>
28 #include <pulsecore/pstream.h>
29 #include <pulsecore/tagstruct.h>
30
31 #include "native-common.h"
32
33 /*
34 * Command handlers shared between client and server
35 */
36
37 /* Check pa_pstream_register_memfd_mempool() for further details */
pa_common_command_register_memfd_shmid(pa_pstream * p,pa_pdispatch * pd,uint32_t version,uint32_t command,pa_tagstruct * t)38 int pa_common_command_register_memfd_shmid(pa_pstream *p, pa_pdispatch *pd, uint32_t version,
39 uint32_t command, pa_tagstruct *t) {
40 #if defined(HAVE_CREDS) && defined(HAVE_MEMFD)
41 pa_cmsg_ancil_data *ancil = NULL;
42 unsigned shm_id;
43 int ret = -1;
44
45 pa_assert(pd);
46 pa_assert(command == PA_COMMAND_REGISTER_MEMFD_SHMID);
47 pa_assert(t);
48
49 ancil = pa_pdispatch_take_ancil_data(pd);
50 if (!ancil)
51 goto finish;
52
53 /* Upon fd leaks and reaching our open fd limit, recvmsg(2)
54 * just strips all passed fds from the ancillary data */
55 if (ancil->nfd == 0) {
56 pa_log("Expected 1 memfd fd to be received over pipe; got 0");
57 pa_log("Did we reach our open file descriptors limit?");
58 goto finish;
59 }
60
61 if (ancil->nfd != 1 || ancil->fds[0] == -1)
62 goto finish;
63
64 if (version < 31 || pa_tagstruct_getu32(t, &shm_id) < 0 || !pa_tagstruct_eof(t))
65 goto finish;
66
67 pa_pstream_attach_memfd_shmid(p, shm_id, ancil->fds[0]);
68
69 ret = 0;
70 finish:
71 if (ancil)
72 pa_cmsg_ancil_data_close_fds(ancil);
73
74 return ret;
75 #else
76 return -1;
77 #endif
78 }
79