2 * Copyright © 2018 Broadcom
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
27 * Implements wrappers of libc functions to fake having a DRM device that
28 * isn't actually present in the kernel.
31 /* Prevent glibc from defining open64 when we want to alias it. */
32 #undef _FILE_OFFSET_BITS
33 #define _LARGEFILE64_SOURCE
40 #include <sys/ioctl.h>
43 #include <sys/sysmacros.h>
48 #include <c11/threads.h>
49 #include <drm-uapi/drm.h>
52 #include "util/u_debug.h"
55 #define REAL_FUNCTION_POINTER(x) typeof(x) *real_##x
57 static mtx_t shim_lock
= _MTX_INITIALIZER_NP
;
58 struct set
*opendir_set
;
61 /* If /dev/dri doesn't exist, we'll need an arbitrary pointer that wouldn't be
62 * returned by any other opendir() call so we can return just our fake node.
64 DIR *fake_dev_dri
= (void *)&opendir_set
;
66 /* XXX: implement REAL_FUNCTION_POINTER(close); */
67 REAL_FUNCTION_POINTER(closedir
);
68 REAL_FUNCTION_POINTER(dup
);
69 REAL_FUNCTION_POINTER(fcntl
);
70 REAL_FUNCTION_POINTER(fopen
);
71 REAL_FUNCTION_POINTER(ioctl
);
72 REAL_FUNCTION_POINTER(mmap
);
73 REAL_FUNCTION_POINTER(open
);
74 REAL_FUNCTION_POINTER(opendir
);
75 REAL_FUNCTION_POINTER(readdir
);
76 REAL_FUNCTION_POINTER(readdir64
);
77 REAL_FUNCTION_POINTER(readlink
);
78 REAL_FUNCTION_POINTER(realpath
);
79 REAL_FUNCTION_POINTER(__xstat
);
80 REAL_FUNCTION_POINTER(__xstat64
);
81 REAL_FUNCTION_POINTER(__fxstat
);
82 REAL_FUNCTION_POINTER(__fxstat64
);
84 /* Full path of /dev/dri/renderD* */
85 static char *render_node_path
;
87 static char *render_node_dirent_name
;
88 /* /sys/dev/char/major:minor/device */
89 static char *device_path
;
90 /* /sys/dev/char/major:minor/device/subsystem */
91 static char *subsystem_path
;
92 int render_node_minor
= -1;
94 struct file_override
{
98 static struct file_override file_overrides
[10];
99 static int file_overrides_count
;
100 extern bool drm_shim_driver_prefers_first_render_node
;
102 /* Pick the minor and filename for our shimmed render node. This can be
103 * either a new one that didn't exist on the system, or if the driver wants,
104 * it can replace the first render node.
107 get_dri_render_node_minor(void)
109 for (int i
= 0; i
< 10; i
++) {
111 asprintf(&render_node_dirent_name
, "renderD%d", minor
);
112 asprintf(&render_node_path
, "/dev/dri/%s",
113 render_node_dirent_name
);
115 if (drm_shim_driver_prefers_first_render_node
||
116 stat(render_node_path
, &st
) == -1) {
118 render_node_minor
= minor
;
123 fprintf(stderr
, "Couldn't find a spare render node slot\n");
126 static void *get_function_pointer(const char *name
)
128 void *func
= dlsym(RTLD_NEXT
, name
);
130 fprintf(stderr
, "Failed to resolve %s\n", name
);
136 #define GET_FUNCTION_POINTER(x) real_##x = get_function_pointer(#x)
139 drm_shim_override_file(const char *contents
, const char *path_format
, ...)
141 assert(file_overrides_count
< ARRAY_SIZE(file_overrides
));
145 va_start(ap
, path_format
);
146 vasprintf(&path
, path_format
, ap
);
149 struct file_override
*override
= &file_overrides
[file_overrides_count
++];
150 override
->path
= path
;
151 override
->contents
= strdup(contents
);
157 _mesa_set_destroy(opendir_set
, NULL
);
158 free(render_node_path
);
159 free(render_node_dirent_name
);
160 free(subsystem_path
);
163 /* Initialization, which will be called from the first general library call
164 * that might need to be wrapped with the shim.
169 static bool inited
= false;
170 drm_shim_debug
= debug_get_bool_option("DRM_SHIM_DEBUG", false);
172 /* We can't lock this, because we recurse during initialization. */
176 /* This comes first (and we're locked), to make sure we don't recurse
177 * during initialization.
181 opendir_set
= _mesa_set_create(NULL
,
183 _mesa_key_string_equal
);
185 GET_FUNCTION_POINTER(closedir
);
186 GET_FUNCTION_POINTER(dup
);
187 GET_FUNCTION_POINTER(fcntl
);
188 GET_FUNCTION_POINTER(fopen
);
189 GET_FUNCTION_POINTER(ioctl
);
190 GET_FUNCTION_POINTER(mmap
);
191 GET_FUNCTION_POINTER(open
);
192 GET_FUNCTION_POINTER(opendir
);
193 GET_FUNCTION_POINTER(readdir
);
194 GET_FUNCTION_POINTER(readdir64
);
195 GET_FUNCTION_POINTER(readlink
);
196 GET_FUNCTION_POINTER(realpath
);
197 GET_FUNCTION_POINTER(__xstat
);
198 GET_FUNCTION_POINTER(__xstat64
);
199 GET_FUNCTION_POINTER(__fxstat
);
200 GET_FUNCTION_POINTER(__fxstat64
);
202 get_dri_render_node_minor();
204 if (drm_shim_debug
) {
205 fprintf(stderr
, "Initializing DRM shim on %s\n",
209 asprintf(&device_path
,
210 "/sys/dev/char/%d:%d/device",
211 DRM_MAJOR
, render_node_minor
);
213 asprintf(&subsystem_path
,
214 "/sys/dev/char/%d:%d/device/subsystem",
215 DRM_MAJOR
, render_node_minor
);
217 drm_shim_device_init();
219 atexit(destroy_shim
);
222 /* Override libdrm's reading of various sysfs files for device enumeration. */
223 PUBLIC
FILE *fopen(const char *path
, const char *mode
)
227 for (int i
= 0; i
< file_overrides_count
; i
++) {
228 if (strcmp(file_overrides
[i
].path
, path
) == 0) {
231 write(fds
[1], file_overrides
[i
].contents
,
232 strlen(file_overrides
[i
].contents
));
234 return fdopen(fds
[0], "r");
238 return real_fopen(path
, mode
);
240 PUBLIC
FILE *fopen64(const char *path
, const char *mode
)
241 __attribute__((alias("fopen")));
243 /* Intercepts open(render_node_path) to redirect it to the simulator. */
244 PUBLIC
int open(const char *path
, int flags
, ...)
250 mode_t mode
= va_arg(ap
, mode_t
);
253 if (strcmp(path
, render_node_path
) != 0)
254 return real_open(path
, flags
, mode
);
256 int fd
= real_open("/dev/null", O_RDWR
, 0);
258 drm_shim_fd_register(fd
, NULL
);
262 PUBLIC
int open64(const char*, int, ...) __attribute__((alias("open")));
264 /* Fakes stat to return character device stuff for our fake render node. */
265 PUBLIC
int __xstat(int ver
, const char *path
, struct stat
*st
)
269 /* Note: call real stat if we're in the process of probing for a free
272 if (render_node_minor
== -1)
273 return real___xstat(ver
, path
, st
);
275 /* Fool libdrm's probe of whether the /sys dir for this char dev is
278 char *sys_dev_drm_dir
;
279 asprintf(&sys_dev_drm_dir
, "/sys/dev/char/%d:%d/device/drm",
280 DRM_MAJOR
, render_node_minor
);
281 if (strcmp(path
, sys_dev_drm_dir
) == 0) {
282 free(sys_dev_drm_dir
);
285 free(sys_dev_drm_dir
);
287 if (strcmp(path
, render_node_path
) != 0)
288 return real___xstat(ver
, path
, st
);
290 memset(st
, 0, sizeof(*st
));
291 st
->st_rdev
= makedev(DRM_MAJOR
, render_node_minor
);
292 st
->st_mode
= S_IFCHR
;
297 /* Fakes stat to return character device stuff for our fake render node. */
298 PUBLIC
int __xstat64(int ver
, const char *path
, struct stat64
*st
)
302 /* Note: call real stat if we're in the process of probing for a free
305 if (render_node_minor
== -1)
306 return real___xstat64(ver
, path
, st
);
308 /* Fool libdrm's probe of whether the /sys dir for this char dev is
311 char *sys_dev_drm_dir
;
312 asprintf(&sys_dev_drm_dir
, "/sys/dev/char/%d:%d/device/drm",
313 DRM_MAJOR
, render_node_minor
);
314 if (strcmp(path
, sys_dev_drm_dir
) == 0) {
315 free(sys_dev_drm_dir
);
318 free(sys_dev_drm_dir
);
320 if (strcmp(path
, render_node_path
) != 0)
321 return real___xstat64(ver
, path
, st
);
323 memset(st
, 0, sizeof(*st
));
324 st
->st_rdev
= makedev(DRM_MAJOR
, render_node_minor
);
325 st
->st_mode
= S_IFCHR
;
330 /* Fakes fstat to return character device stuff for our fake render node. */
331 PUBLIC
int __fxstat(int ver
, int fd
, struct stat
*st
)
335 struct shim_fd
*shim_fd
= drm_shim_fd_lookup(fd
);
338 return real___fxstat(ver
, fd
, st
);
340 memset(st
, 0, sizeof(*st
));
341 st
->st_rdev
= makedev(DRM_MAJOR
, render_node_minor
);
342 st
->st_mode
= S_IFCHR
;
347 PUBLIC
int __fxstat64(int ver
, int fd
, struct stat64
*st
)
351 struct shim_fd
*shim_fd
= drm_shim_fd_lookup(fd
);
354 return real___fxstat64(ver
, fd
, st
);
356 memset(st
, 0, sizeof(*st
));
357 st
->st_rdev
= makedev(DRM_MAJOR
, render_node_minor
);
358 st
->st_mode
= S_IFCHR
;
363 /* Tracks if the opendir was on /dev/dri. */
365 opendir(const char *name
)
369 DIR *dir
= real_opendir(name
);
370 if (strcmp(name
, "/dev/dri") == 0) {
372 /* If /dev/dri didn't exist, we still want to be able to return our
373 * fake /dev/dri/render* even though we probably can't
374 * mkdir("/dev/dri"). Return a fake DIR pointer for that.
379 mtx_lock(&shim_lock
);
380 _mesa_set_add(opendir_set
, dir
);
381 mtx_unlock(&shim_lock
);
387 /* If we've reached the end of the real directory list and we're
388 * looking at /dev/dri, add our render node to the list.
390 PUBLIC
struct dirent
*
395 struct dirent
*ent
= NULL
;
397 if (dir
!= fake_dev_dri
)
398 ent
= real_readdir(dir
);
399 static struct dirent render_node_dirent
= { 0 };
402 mtx_lock(&shim_lock
);
403 if (_mesa_set_search(opendir_set
, dir
)) {
404 strcpy(render_node_dirent
.d_name
,
405 render_node_dirent_name
);
406 ent
= &render_node_dirent
;
407 _mesa_set_remove_key(opendir_set
, dir
);
409 mtx_unlock(&shim_lock
);
415 /* If we've reached the end of the real directory list and we're
416 * looking at /dev/dri, add our render node to the list.
418 PUBLIC
struct dirent64
*
423 struct dirent64
*ent
= NULL
;
424 if (dir
!= fake_dev_dri
)
425 ent
= real_readdir64(dir
);
426 static struct dirent64 render_node_dirent
= { 0 };
429 mtx_lock(&shim_lock
);
430 if (_mesa_set_search(opendir_set
, dir
)) {
431 strcpy(render_node_dirent
.d_name
,
432 render_node_dirent_name
);
433 ent
= &render_node_dirent
;
434 _mesa_set_remove_key(opendir_set
, dir
);
436 mtx_unlock(&shim_lock
);
442 /* Cleans up tracking of opendir("/dev/dri") */
448 mtx_lock(&shim_lock
);
449 _mesa_set_remove_key(opendir_set
, dir
);
450 mtx_unlock(&shim_lock
);
452 if (dir
!= fake_dev_dri
)
453 return real_closedir(dir
);
458 /* Handles libdrm's readlink to figure out what kind of device we have. */
460 readlink(const char *path
, char *buf
, size_t size
)
464 if (strcmp(path
, subsystem_path
) != 0)
465 return real_readlink(path
, buf
, size
);
467 static const struct {
471 { "/pci", DRM_BUS_PCI
},
472 { "/usb", DRM_BUS_USB
},
473 { "/platform", DRM_BUS_PLATFORM
},
474 { "/spi", DRM_BUS_PLATFORM
},
475 { "/host1x", DRM_BUS_HOST1X
},
478 for (uint32_t i
= 0; i
< ARRAY_SIZE(bus_types
); i
++) {
479 if (bus_types
[i
].bus_type
!= shim_device
.bus_type
)
482 strncpy(buf
, bus_types
[i
].name
, size
);
487 return strlen(buf
) + 1;
490 /* Handles libdrm's realpath to figure out what kind of device we have. */
492 realpath(const char *path
, char *resolved_path
)
496 if (strcmp(path
, device_path
) != 0)
497 return real_realpath(path
, resolved_path
);
499 strcpy(resolved_path
, path
);
501 return resolved_path
;
504 /* Main entrypoint to DRM drivers: the ioctl syscall. We send all ioctls on
505 * our DRM fd to drm_shim_ioctl().
508 ioctl(int fd
, unsigned long request
, ...)
513 va_start(ap
, request
);
514 void *arg
= va_arg(ap
, void *);
517 struct shim_fd
*shim_fd
= drm_shim_fd_lookup(fd
);
519 return real_ioctl(fd
, request
, arg
);
521 return drm_shim_ioctl(fd
, request
, arg
);
524 /* Gallium uses this to dup the incoming fd on gbm screen creation */
526 fcntl(int fd
, int cmd
, ...)
530 struct shim_fd
*shim_fd
= drm_shim_fd_lookup(fd
);
534 void *arg
= va_arg(ap
, void *);
537 int ret
= real_fcntl(fd
, cmd
, arg
);
539 if (shim_fd
&& (cmd
== F_DUPFD
|| cmd
== F_DUPFD_CLOEXEC
))
540 drm_shim_fd_register(ret
, shim_fd
);
544 PUBLIC
int fcntl64(int, int, ...)
545 __attribute__((alias("fcntl")));
547 /* I wrote this when trying to fix gallium screen creation, leaving it around
548 * since it's probably good to have.
555 int ret
= real_dup(fd
);
557 struct shim_fd
*shim_fd
= drm_shim_fd_lookup(fd
);
558 if (shim_fd
&& ret
>= 0)
559 drm_shim_fd_register(ret
, shim_fd
);
565 mmap(void *addr
, size_t length
, int prot
, int flags
, int fd
, off_t offset
)
569 struct shim_fd
*shim_fd
= drm_shim_fd_lookup(fd
);
571 return drm_shim_mmap(shim_fd
, length
, prot
, flags
, fd
, offset
);
573 return real_mmap(addr
, length
, prot
, flags
, fd
, offset
);
575 PUBLIC
void *mmap64(void*, size_t, int, int, int, off_t
)
576 __attribute__((alias("mmap")));