1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 #include <hardware_legacy/power.h> 17 #include <fcntl.h> 18 #include <errno.h> 19 #include <stdlib.h> 20 #include <stdio.h> 21 #include <unistd.h> 22 #include <errno.h> 23 #include <string.h> 24 #include <sys/stat.h> 25 #include <sys/types.h> 26 #include <pthread.h> 27 28 #define LOG_TAG "power" 29 #include <utils/Log.h> 30 31 enum { 32 ACQUIRE_PARTIAL_WAKE_LOCK = 0, 33 RELEASE_WAKE_LOCK, 34 OUR_FD_COUNT 35 }; 36 37 const char * const OLD_PATHS[] = { 38 "/sys/android_power/acquire_partial_wake_lock", 39 "/sys/android_power/release_wake_lock", 40 }; 41 42 const char * const NEW_PATHS[] = { 43 "/sys/power/wake_lock", 44 "/sys/power/wake_unlock", 45 }; 46 47 //XXX static pthread_once_t g_initialized = THREAD_ONCE_INIT; 48 static int g_initialized = 0; 49 static int g_fds[OUR_FD_COUNT]; 50 static int g_error = -1; 51 52 static int 53 open_file_descriptors(const char * const paths[]) 54 { 55 int i; 56 for (i=0; i<OUR_FD_COUNT; i++) { 57 int fd = open(paths[i], O_RDWR | O_CLOEXEC); 58 if (fd < 0) { 59 g_error = -errno; 60 fprintf(stderr, "fatal error opening \"%s\": %s\n", paths[i], 61 strerror(errno)); 62 return -1; 63 } 64 g_fds[i] = fd; 65 } 66 67 g_error = 0; 68 return 0; 69 } 70 71 static inline void 72 initialize_fds(void) 73 { 74 // XXX: should be this: 75 //pthread_once(&g_initialized, open_file_descriptors); 76 // XXX: not this: 77 if (g_initialized == 0) { 78 if(open_file_descriptors(NEW_PATHS) < 0) 79 open_file_descriptors(OLD_PATHS); 80 g_initialized = 1; 81 } 82 } 83 84 int 85 acquire_wake_lock(int lock, const char* id) 86 { 87 initialize_fds(); 88 89 // ALOGI("acquire_wake_lock lock=%d id='%s'\n", lock, id); 90 91 if (g_error) return g_error; 92 93 int fd; 94 size_t len; 95 ssize_t ret; 96 97 if (lock != PARTIAL_WAKE_LOCK) { 98 return -EINVAL; 99 } 100 101 fd = g_fds[ACQUIRE_PARTIAL_WAKE_LOCK]; 102 103 ret = write(fd, id, strlen(id)); 104 if (ret < 0) { 105 return -errno; 106 } 107 108 return ret; 109 } 110 111 int 112 release_wake_lock(const char* id) 113 { 114 initialize_fds(); 115 116 // ALOGI("release_wake_lock id='%s'\n", id); 117 118 if (g_error) return g_error; 119 120 ssize_t len = write(g_fds[RELEASE_WAKE_LOCK], id, strlen(id)); 121 if (len < 0) { 122 return -errno; 123 } 124 return len; 125 } 126