/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ /* * This file defines a wrapper around libudev so we can avoid * linking directly to it and use dlopen instead. */ #ifndef HAL_LINUX_UDEV_H_ #define HAL_LINUX_UDEV_H_ #include <dlfcn.h> #include "mozilla/ArrayUtils.h" namespace mozilla { struct udev; struct udev_device; struct udev_enumerate; struct udev_list_entry; struct udev_monitor; class udev_lib { public: udev_lib() : lib(nullptr), udev(nullptr) { // Be careful about ABI compat! 0 -> 1 didn't change any // symbols this code relies on, per: // https://lists.fedoraproject.org/pipermail/devel/2012-June/168227.html const char* lib_names[] = {"libudev.so.0", "libudev.so.1"}; // Check whether a library is already loaded so we don't load two // conflicting libs. for (unsigned i = 0; i < ArrayLength(lib_names); i++) { lib = dlopen(lib_names[i], RTLD_NOLOAD | RTLD_LAZY | RTLD_GLOBAL); if (lib) { break; } } // If nothing loads the first time through, it means no version of libudev // was already loaded. if (!lib) { for (unsigned i = 0; i < ArrayLength(lib_names); i++) { lib = dlopen(lib_names[i], RTLD_LAZY | RTLD_GLOBAL); if (lib) { break; } } } if (lib && LoadSymbols()) { udev = udev_new(); } } ~udev_lib() { if (udev) { udev_unref(udev); } if (lib) { dlclose(lib); } } explicit operator bool() { return udev; } private: bool LoadSymbols() { #define DLSYM(s) \ do { \ s = (typeof(s))dlsym(lib, #s); \ if (!s) return false; \ } while (0) DLSYM(udev_new); DLSYM(udev_unref); DLSYM(udev_device_unref); DLSYM(udev_device_new_from_syspath); DLSYM(udev_device_get_devnode); DLSYM(udev_device_get_parent_with_subsystem_devtype); DLSYM(udev_device_get_property_value); DLSYM(udev_device_get_action); DLSYM(udev_device_get_sysattr_value); DLSYM(udev_enumerate_new); DLSYM(udev_enumerate_unref); DLSYM(udev_enumerate_add_match_subsystem); DLSYM(udev_enumerate_scan_devices); DLSYM(udev_enumerate_get_list_entry); DLSYM(udev_list_entry_get_next); DLSYM(udev_list_entry_get_name); DLSYM(udev_monitor_new_from_netlink); DLSYM(udev_monitor_filter_add_match_subsystem_devtype); DLSYM(udev_monitor_enable_receiving); DLSYM(udev_monitor_get_fd); DLSYM(udev_monitor_receive_device); DLSYM(udev_monitor_unref); #undef DLSYM return true; } void* lib; public: struct udev* udev; // Function pointers returned from dlsym. struct udev* (*udev_new)(void); void (*udev_unref)(struct udev*); void (*udev_device_unref)(struct udev_device*); struct udev_device* (*udev_device_new_from_syspath)(struct udev*, const char*); const char* (*udev_device_get_devnode)(struct udev_device*); struct udev_device* (*udev_device_get_parent_with_subsystem_devtype) (struct udev_device*, const char*, const char*); const char* (*udev_device_get_property_value)(struct udev_device*, const char*); const char* (*udev_device_get_action)(struct udev_device*); const char* (*udev_device_get_sysattr_value)(struct udev_device*, const char*); struct udev_enumerate* (*udev_enumerate_new)(struct udev*); void (*udev_enumerate_unref)(struct udev_enumerate*); int (*udev_enumerate_add_match_subsystem)(struct udev_enumerate*, const char*); int (*udev_enumerate_scan_devices)(struct udev_enumerate*); struct udev_list_entry* (*udev_enumerate_get_list_entry) (struct udev_enumerate*); struct udev_list_entry* (*udev_list_entry_get_next)(struct udev_list_entry *); const char* (*udev_list_entry_get_name)(struct udev_list_entry*); struct udev_monitor* (*udev_monitor_new_from_netlink)(struct udev*, const char*); int (*udev_monitor_filter_add_match_subsystem_devtype) (struct udev_monitor*, const char*, const char*); int (*udev_monitor_enable_receiving)(struct udev_monitor*); int (*udev_monitor_get_fd)(struct udev_monitor*); struct udev_device* (*udev_monitor_receive_device)(struct udev_monitor*); void (*udev_monitor_unref)(struct udev_monitor*); }; } // namespace mozilla #endif // HAL_LINUX_UDEV_H_