1 /*
2 * Copyright © 2012 Collabora, Ltd.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the
13 * next paragraph) shall be included in all copies or substantial
14 * portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
20 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
21 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE.
24 */
25
26 /*
27 * Based on weston shared/os-compatibility.c
28 */
29
30 #include "anon_file.h"
31 #include "detect_os.h"
32
33 #ifndef _WIN32
34
35 #include <unistd.h>
36 #include <fcntl.h>
37 #include <errno.h>
38 #include <stdlib.h>
39
40 #if defined(HAVE_MEMFD_CREATE) || defined(__FreeBSD__) || defined(__OpenBSD__)
41 #include <sys/mman.h>
42 #elif DETECT_OS_ANDROID
43 #include <sys/syscall.h>
44 #include <linux/memfd.h>
45 #else
46 #include <stdio.h>
47 #endif
48
49 #if !(defined(__FreeBSD__) || defined(HAVE_MEMFD_CREATE) || defined(HAVE_MKOSTEMP) || defined(ANDROID))
50 static int
set_cloexec_or_close(int fd)51 set_cloexec_or_close(int fd)
52 {
53 long flags;
54
55 if (fd == -1)
56 return -1;
57
58 flags = fcntl(fd, F_GETFD);
59 if (flags == -1)
60 goto err;
61
62 if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1)
63 goto err;
64
65 return fd;
66
67 err:
68 close(fd);
69 return -1;
70 }
71 #endif
72
73 #if !(defined(__FreeBSD__) || defined(HAVE_MEMFD_CREATE) || defined(ANDROID))
74 static int
create_tmpfile_cloexec(char * tmpname)75 create_tmpfile_cloexec(char *tmpname)
76 {
77 int fd;
78
79 #ifdef HAVE_MKOSTEMP
80 fd = mkostemp(tmpname, O_CLOEXEC);
81 #else
82 fd = mkstemp(tmpname);
83 #endif
84
85 if (fd < 0) {
86 return fd;
87 }
88
89 #ifndef HAVE_MKOSTEMP
90 fd = set_cloexec_or_close(fd);
91 #endif
92
93 unlink(tmpname);
94 return fd;
95 }
96 #endif
97
98 /*
99 * Create a new, unique, anonymous file of the given size, and
100 * return the file descriptor for it. The file descriptor is set
101 * CLOEXEC. The file is immediately suitable for mmap()'ing
102 * the given size at offset zero.
103 *
104 * An optional name for debugging can be provided as the second argument.
105 *
106 * The file should not have a permanent backing store like a disk,
107 * but may have if XDG_RUNTIME_DIR is not properly implemented in OS.
108 *
109 * If memfd or SHM_ANON is supported, the filesystem is not touched at all.
110 * Otherwise, the file name is deleted from the file system.
111 *
112 * The file is suitable for buffer sharing between processes by
113 * transmitting the file descriptor over Unix sockets using the
114 * SCM_RIGHTS methods.
115 */
116 int
os_create_anonymous_file(int64_t size,const char * debug_name)117 os_create_anonymous_file(int64_t size, const char *debug_name)
118 {
119 int fd, ret;
120 #if defined(HAVE_MEMFD_CREATE)
121 if (!debug_name)
122 debug_name = "mesa-shared";
123 fd = memfd_create(debug_name, MFD_CLOEXEC | MFD_ALLOW_SEALING);
124 #elif DETECT_OS_ANDROID
125 if (!debug_name)
126 debug_name = "mesa-shared";
127 fd = syscall(SYS_memfd_create, debug_name, MFD_CLOEXEC | MFD_ALLOW_SEALING);
128 #elif defined(__FreeBSD__)
129 fd = shm_open(SHM_ANON, O_CREAT | O_RDWR | O_CLOEXEC, 0600);
130 #elif defined(__OpenBSD__)
131 char template[] = "/tmp/mesa-XXXXXXXXXX";
132 fd = shm_mkstemp(template);
133 if (fd != -1)
134 shm_unlink(template);
135 #else
136 const char *path;
137 char *name;
138
139 path = getenv("XDG_RUNTIME_DIR");
140 if (!path) {
141 errno = ENOENT;
142 return -1;
143 }
144
145 if (debug_name)
146 asprintf(&name, "%s/mesa-shared-%s-XXXXXX", path, debug_name);
147 else
148 asprintf(&name, "%s/mesa-shared-XXXXXX", path);
149 if (!name)
150 return -1;
151
152 fd = create_tmpfile_cloexec(name);
153
154 free(name);
155 #endif
156
157 if (fd < 0)
158 return -1;
159
160 ret = ftruncate(fd, (off_t)size);
161 if (ret < 0) {
162 close(fd);
163 return -1;
164 }
165
166 return fd;
167 }
168 #else
169
170 #include <windows.h>
171 #include <io.h>
172
173 int
os_create_anonymous_file(int64_t size,const char * debug_name)174 os_create_anonymous_file(int64_t size, const char *debug_name)
175 {
176 (void)debug_name;
177 HANDLE h = CreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
178 PAGE_READWRITE, (size >> 32), size & 0xFFFFFFFF, NULL);
179 return _open_osfhandle((intptr_t)h, 0);
180 }
181 #endif
182