/* * Copyright © 2018 Broadcom * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ /** * @file * * Implements wrappers of libc functions to fake having a DRM device that * isn't actually present in the kernel. */ /* Prevent glibc from defining open64 when we want to alias it. */ #undef _FILE_OFFSET_BITS #define _LARGEFILE64_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "util/set.h" #include "util/u_debug.h" #include "drm_shim.h" #define REAL_FUNCTION_POINTER(x) typeof(x) *real_##x static mtx_t shim_lock = _MTX_INITIALIZER_NP; struct set *opendir_set; bool drm_shim_debug; /* If /dev/dri doesn't exist, we'll need an arbitrary pointer that wouldn't be * returned by any other opendir() call so we can return just our fake node. */ DIR *fake_dev_dri = (void *)&opendir_set; /* XXX: implement REAL_FUNCTION_POINTER(close); */ REAL_FUNCTION_POINTER(closedir); REAL_FUNCTION_POINTER(dup); REAL_FUNCTION_POINTER(fcntl); REAL_FUNCTION_POINTER(fopen); REAL_FUNCTION_POINTER(ioctl); REAL_FUNCTION_POINTER(mmap); REAL_FUNCTION_POINTER(open); REAL_FUNCTION_POINTER(opendir); REAL_FUNCTION_POINTER(readdir); REAL_FUNCTION_POINTER(readdir64); REAL_FUNCTION_POINTER(readlink); REAL_FUNCTION_POINTER(__xstat); REAL_FUNCTION_POINTER(__xstat64); REAL_FUNCTION_POINTER(__fxstat); REAL_FUNCTION_POINTER(__fxstat64); /* Full path of /dev/dri/renderD* */ static char *render_node_path; /* renderD* */ static char *render_node_dirent_name; /* /sys/dev/char/major:minor/device/subsystem */ static char *subsystem_path; int render_node_minor = -1; struct file_override { const char *path; char *contents; }; static struct file_override file_overrides[10]; static int file_overrides_count; /* Come up with a filename for a render node that doesn't actually exist on * the system. */ static void get_dri_render_node_minor(void) { for (int i = 0; i < 10; i++) { int minor = 128 + i; asprintf(&render_node_dirent_name, "renderD%d", minor); asprintf(&render_node_path, "/dev/dri/%s", render_node_dirent_name); struct stat st; if (stat(render_node_path, &st) == -1) { render_node_minor = minor; return; } } fprintf(stderr, "Couldn't find a spare render node slot\n"); } static void *get_function_pointer(const char *name) { void *func = dlsym(RTLD_NEXT, name); if (!func) { fprintf(stderr, "Failed to resolve %s\n", name); abort(); } return func; } #define GET_FUNCTION_POINTER(x) real_##x = get_function_pointer(#x) void drm_shim_override_file(const char *contents, const char *path_format, ...) { assert(file_overrides_count < ARRAY_SIZE(file_overrides)); char *path; va_list ap; va_start(ap, path_format); vasprintf(&path, path_format, ap); va_end(ap); struct file_override *override = &file_overrides[file_overrides_count++]; override->path = path; override->contents = strdup(contents); } static void destroy_shim(void) { _mesa_set_destroy(opendir_set, NULL); free(render_node_path); free(render_node_dirent_name); free(subsystem_path); } /* Initialization, which will be called from the first general library call * that might need to be wrapped with the shim. */ static void init_shim(void) { static bool inited = false; drm_shim_debug = debug_get_bool_option("DRM_SHIM_DEBUG", false); /* We can't lock this, because we recurse during initialization. */ if (inited) return; /* This comes first (and we're locked), to make sure we don't recurse * during initialization. */ inited = true; opendir_set = _mesa_set_create(NULL, _mesa_hash_string, _mesa_key_string_equal); GET_FUNCTION_POINTER(closedir); GET_FUNCTION_POINTER(dup); GET_FUNCTION_POINTER(fcntl); GET_FUNCTION_POINTER(fopen); GET_FUNCTION_POINTER(ioctl); GET_FUNCTION_POINTER(mmap); GET_FUNCTION_POINTER(open); GET_FUNCTION_POINTER(opendir); GET_FUNCTION_POINTER(readdir); GET_FUNCTION_POINTER(readdir64); GET_FUNCTION_POINTER(readlink); GET_FUNCTION_POINTER(__xstat); GET_FUNCTION_POINTER(__xstat64); GET_FUNCTION_POINTER(__fxstat); GET_FUNCTION_POINTER(__fxstat64); get_dri_render_node_minor(); if (drm_shim_debug) { fprintf(stderr, "Initializing DRM shim on %s\n", render_node_path); } asprintf(&subsystem_path, "/sys/dev/char/%d:%d/device/subsystem", DRM_MAJOR, render_node_minor); drm_shim_device_init(); atexit(destroy_shim); } /* Override libdrm's reading of various sysfs files for device enumeration. */ PUBLIC FILE *fopen(const char *path, const char *mode) { init_shim(); for (int i = 0; i < file_overrides_count; i++) { if (strcmp(file_overrides[i].path, path) == 0) { int fds[2]; pipe(fds); write(fds[1], file_overrides[i].contents, strlen(file_overrides[i].contents)); close(fds[1]); return fdopen(fds[0], "r"); } } return real_fopen(path, mode); } PUBLIC FILE *fopen64(const char *path, const char *mode) __attribute__((alias("fopen"))); /* Intercepts open(render_node_path) to redirect it to the simulator. */ PUBLIC int open(const char *path, int flags, ...) { init_shim(); va_list ap; va_start(ap, flags); mode_t mode = va_arg(ap, mode_t); va_end(ap); if (strcmp(path, render_node_path) != 0) return real_open(path, flags, mode); int fd = real_open("/dev/null", O_RDWR, 0); drm_shim_fd_register(fd, NULL); return fd; } PUBLIC int open64(const char*, int, ...) __attribute__((alias("open"))); /* Fakes stat to return character device stuff for our fake render node. */ PUBLIC int __xstat(int ver, const char *path, struct stat *st) { init_shim(); /* Note: call real stat if we're in the process of probing for a free * render node! */ if (render_node_minor == -1) return real___xstat(ver, path, st); /* Fool libdrm's probe of whether the /sys dir for this char dev is * there. */ char *sys_dev_drm_dir; asprintf(&sys_dev_drm_dir, "/sys/dev/char/%d:%d/device/drm", DRM_MAJOR, render_node_minor); if (strcmp(path, sys_dev_drm_dir) == 0) { free(sys_dev_drm_dir); return 0; } free(sys_dev_drm_dir); if (strcmp(path, render_node_path) != 0) return real___xstat(ver, path, st); memset(st, 0, sizeof(*st)); st->st_rdev = makedev(DRM_MAJOR, render_node_minor); st->st_mode = S_IFCHR; return 0; } /* Fakes stat to return character device stuff for our fake render node. */ PUBLIC int __xstat64(int ver, const char *path, struct stat64 *st) { init_shim(); /* Note: call real stat if we're in the process of probing for a free * render node! */ if (render_node_minor == -1) return real___xstat64(ver, path, st); /* Fool libdrm's probe of whether the /sys dir for this char dev is * there. */ char *sys_dev_drm_dir; asprintf(&sys_dev_drm_dir, "/sys/dev/char/%d:%d/device/drm", DRM_MAJOR, render_node_minor); if (strcmp(path, sys_dev_drm_dir) == 0) { free(sys_dev_drm_dir); return 0; } free(sys_dev_drm_dir); if (strcmp(path, render_node_path) != 0) return real___xstat64(ver, path, st); memset(st, 0, sizeof(*st)); st->st_rdev = makedev(DRM_MAJOR, render_node_minor); st->st_mode = S_IFCHR; return 0; } /* Fakes fstat to return character device stuff for our fake render node. */ PUBLIC int __fxstat(int ver, int fd, struct stat *st) { init_shim(); struct shim_fd *shim_fd = drm_shim_fd_lookup(fd); if (!shim_fd) return real___fxstat(ver, fd, st); memset(st, 0, sizeof(*st)); st->st_rdev = makedev(DRM_MAJOR, render_node_minor); st->st_mode = S_IFCHR; return 0; } PUBLIC int __fxstat64(int ver, int fd, struct stat64 *st) { init_shim(); struct shim_fd *shim_fd = drm_shim_fd_lookup(fd); if (!shim_fd) return real___fxstat64(ver, fd, st); memset(st, 0, sizeof(*st)); st->st_rdev = makedev(DRM_MAJOR, render_node_minor); st->st_mode = S_IFCHR; return 0; } /* Tracks if the opendir was on /dev/dri. */ PUBLIC DIR * opendir(const char *name) { init_shim(); DIR *dir = real_opendir(name); if (strcmp(name, "/dev/dri") == 0) { if (!dir) { /* If /dev/dri didn't exist, we still want to be able to return our * fake /dev/dri/render* even though we probably can't * mkdir("/dev/dri"). Return a fake DIR pointer for that. */ dir = fake_dev_dri; } mtx_lock(&shim_lock); _mesa_set_add(opendir_set, dir); mtx_unlock(&shim_lock); } return dir; } /* If we've reached the end of the real directory list and we're * looking at /dev/dri, add our render node to the list. */ PUBLIC struct dirent * readdir(DIR *dir) { init_shim(); struct dirent *ent = NULL; if (dir != fake_dev_dri) ent = real_readdir(dir); static struct dirent render_node_dirent = { 0 }; if (!ent) { mtx_lock(&shim_lock); if (_mesa_set_search(opendir_set, dir)) { strcpy(render_node_dirent.d_name, render_node_dirent_name); ent = &render_node_dirent; _mesa_set_remove_key(opendir_set, dir); } mtx_unlock(&shim_lock); } return ent; } /* If we've reached the end of the real directory list and we're * looking at /dev/dri, add our render node to the list. */ PUBLIC struct dirent64 * readdir64(DIR *dir) { init_shim(); struct dirent64 *ent = NULL; if (dir != fake_dev_dri) ent = real_readdir64(dir); static struct dirent64 render_node_dirent = { 0 }; if (!ent) { mtx_lock(&shim_lock); if (_mesa_set_search(opendir_set, dir)) { strcpy(render_node_dirent.d_name, render_node_dirent_name); ent = &render_node_dirent; _mesa_set_remove_key(opendir_set, dir); } mtx_unlock(&shim_lock); } return ent; } /* Cleans up tracking of opendir("/dev/dri") */ PUBLIC int closedir(DIR *dir) { init_shim(); mtx_lock(&shim_lock); _mesa_set_remove_key(opendir_set, dir); mtx_unlock(&shim_lock); if (dir != fake_dev_dri) return real_closedir(dir); else return 0; } /* Handles libdrm's readlink to figure out what kind of device we have. */ PUBLIC ssize_t readlink(const char *path, char *buf, size_t size) { init_shim(); if (strcmp(path, subsystem_path) != 0) return real_readlink(path, buf, size); strncpy(buf, "/platform", size); buf[size - 1] = 0; return strlen(buf) + 1; } /* Main entrypoint to DRM drivers: the ioctl syscall. We send all ioctls on * our DRM fd to drm_shim_ioctl(). */ PUBLIC int ioctl(int fd, unsigned long request, ...) { init_shim(); va_list ap; va_start(ap, request); void *arg = va_arg(ap, void *); va_end(ap); struct shim_fd *shim_fd = drm_shim_fd_lookup(fd); if (!shim_fd) return real_ioctl(fd, request, arg); return drm_shim_ioctl(fd, request, arg); } /* Gallium uses this to dup the incoming fd on gbm screen creation */ PUBLIC int fcntl(int fd, int cmd, ...) { init_shim(); struct shim_fd *shim_fd = drm_shim_fd_lookup(fd); va_list ap; va_start(ap, cmd); void *arg = va_arg(ap, void *); va_end(ap); int ret = real_fcntl(fd, cmd, arg); if (shim_fd && (cmd == F_DUPFD || cmd == F_DUPFD_CLOEXEC)) drm_shim_fd_register(ret, shim_fd); return ret; } PUBLIC int fcntl64(int, int, ...) __attribute__((alias("fcntl"))); /* I wrote this when trying to fix gallium screen creation, leaving it around * since it's probably good to have. */ PUBLIC int dup(int fd) { init_shim(); int ret = real_dup(fd); struct shim_fd *shim_fd = drm_shim_fd_lookup(fd); if (shim_fd && ret >= 0) drm_shim_fd_register(ret, shim_fd); return ret; } PUBLIC void * mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset) { init_shim(); struct shim_fd *shim_fd = drm_shim_fd_lookup(fd); if (shim_fd) return drm_shim_mmap(shim_fd, length, prot, flags, fd, offset); return real_mmap(addr, length, prot, flags, fd, offset); } PUBLIC void *mmap64(void*, size_t, int, int, int, off_t) __attribute__((alias("mmap")));