1 /*
2 * Copyright (C) 2016 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
17 #ifndef _LIBLOG_LOGGER_H__
18 #define _LIBLOG_LOGGER_H__
19
20 #include <stdatomic.h>
21 #include <stdbool.h>
22
23 #include <cutils/list.h>
24 #include <log/log.h>
25 #include <log/uio.h>
26
27 #include "log_portability.h"
28
29 __BEGIN_DECLS
30
31 /* Union, sock or fd of zero is not allowed unless static initialized */
32 union android_log_context {
33 void* priv;
34 atomic_int sock;
35 atomic_int fd;
36 struct listnode* node;
37 atomic_uintptr_t atomic_pointer;
38 };
39
40 struct android_log_transport_write {
41 struct listnode node;
42 const char* name; /* human name to describe the transport */
43 unsigned logMask; /* mask cache of available() success */
44 union android_log_context context; /* Initialized by static allocation */
45
46 int (*available)(log_id_t logId); /* Does not cause resources to be taken */
47 int (*open)(); /* can be called multiple times, reusing current resources */
48 void (*close)(); /* free up resources */
49 /* write log to transport, returns number of bytes propagated, or -errno */
50 int (*write)(log_id_t logId, struct timespec* ts, struct iovec* vec,
51 size_t nr);
52 };
53
54 struct android_log_logger_list;
55 struct android_log_transport_context;
56 struct android_log_logger;
57
58 struct android_log_transport_read {
59 struct listnode node;
60 const char* name; /* human name to describe the transport */
61
62 /* Does not cause resources to be taken */
63 int (*available)(log_id_t logId);
64 int (*version)(struct android_log_logger* logger,
65 struct android_log_transport_context* transp);
66 /* Release resources taken by the following interfaces */
67 void (*close)(struct android_log_logger_list* logger_list,
68 struct android_log_transport_context* transp);
69 /*
70 * Expect all to instantiate open automagically on any call,
71 * so we do not have an explicit open call.
72 */
73 int (*read)(struct android_log_logger_list* logger_list,
74 struct android_log_transport_context* transp,
75 struct log_msg* log_msg);
76 /* Must only be called if not ANDROID_LOG_NONBLOCK (blocking) */
77 int (*poll)(struct android_log_logger_list* logger_list,
78 struct android_log_transport_context* transp);
79
80 int (*clear)(struct android_log_logger* logger,
81 struct android_log_transport_context* transp);
82 ssize_t (*setSize)(struct android_log_logger* logger,
83 struct android_log_transport_context* transp, size_t size);
84 ssize_t (*getSize)(struct android_log_logger* logger,
85 struct android_log_transport_context* transp);
86 ssize_t (*getReadableSize)(struct android_log_logger* logger,
87 struct android_log_transport_context* transp);
88
89 ssize_t (*getPrune)(struct android_log_logger_list* logger_list,
90 struct android_log_transport_context* transp, char* buf,
91 size_t len);
92 ssize_t (*setPrune)(struct android_log_logger_list* logger_list,
93 struct android_log_transport_context* transp, char* buf,
94 size_t len);
95 ssize_t (*getStats)(struct android_log_logger_list* logger_list,
96 struct android_log_transport_context* transp, char* buf,
97 size_t len);
98 };
99
100 struct android_log_logger_list {
101 struct listnode node;
102 struct listnode logger;
103 struct listnode transport;
104 int mode;
105 unsigned int tail;
106 log_time start;
107 pid_t pid;
108 };
109
110 struct android_log_logger {
111 struct listnode node;
112 struct android_log_logger_list* parent;
113
114 log_id_t logId;
115 };
116
117 struct android_log_transport_context {
118 struct listnode node;
119 union android_log_context context; /* zero init per-transport context */
120 struct android_log_logger_list* parent;
121
122 struct android_log_transport_read* transport;
123 unsigned logMask; /* mask of requested log buffers */
124 int ret; /* return value associated with following data */
125 struct log_msg logMsg; /* peek at upcoming data, valid if logMsg.len != 0 */
126 };
127
128 /* assumes caller has structures read-locked, single threaded, or fenced */
129 #define transport_context_for_each(transp, logger_list) \
130 for ((transp) = node_to_item((logger_list)->transport.next, \
131 struct android_log_transport_context, node); \
132 ((transp) != node_to_item(&(logger_list)->transport, \
133 struct android_log_transport_context, node)) && \
134 ((transp)->parent == (logger_list)); \
135 (transp) = node_to_item((transp)->node.next, \
136 struct android_log_transport_context, node))
137
138 #define logger_for_each(logp, logger_list) \
139 for ((logp) = node_to_item((logger_list)->logger.next, \
140 struct android_log_logger, node); \
141 ((logp) != node_to_item(&(logger_list)->logger, \
142 struct android_log_logger, node)) && \
143 ((logp)->parent == (logger_list)); \
144 (logp) = \
145 node_to_item((logp)->node.next, struct android_log_logger, node))
146
147 /*
148 * Global list of log readers.
149 *
150 * Usage case: search out transport contexts for all readers
151 */
152
153 LIBLOG_HIDDEN struct listnode __android_log_readers;
154
155 #if defined(_WIN32)
156 #define logger_list_rdlock()
157 #define logger_list_wrlock()
158 #define logger_list_unlock()
159 #else
160 LIBLOG_HIDDEN pthread_rwlock_t __android_log_readers_lock;
161
162 #define logger_list_rdlock() pthread_rwlock_rdlock(&__android_log_readers_lock)
163 #define logger_list_wrlock() pthread_rwlock_wrlock(&__android_log_readers_lock)
164 #define logger_list_unlock() pthread_rwlock_unlock(&__android_log_readers_lock)
165 #endif
166
167 /* Must be called with logger_list_rdlock() or logger_list_wrlock() held */
168 #define logger_list_for_each(logger_list) \
169 for ((logger_list) = node_to_item(&__android_log_readers, \
170 struct android_log_logger_list, node); \
171 (logger_list) != node_to_item(&__android_log_readers, \
172 struct android_log_logger_list, node) && \
173 (logger_list) != node_to_item((logger_list)->node.next, \
174 struct android_log_logger_list, node); \
175 (logger_list) = node_to_item((logger_list)->node.next, \
176 struct android_log_logger_list, node))
177
178 /* OS specific dribs and drabs */
179
180 #if defined(_WIN32)
181 #include <private/android_filesystem_config.h>
182 typedef uint32_t uid_t;
__android_log_uid()183 static inline uid_t __android_log_uid() {
184 return AID_SYSTEM;
185 }
186 #else
__android_log_uid()187 static inline uid_t __android_log_uid() {
188 return getuid();
189 }
190 #endif
191
192 LIBLOG_HIDDEN void __android_log_lock();
193 LIBLOG_HIDDEN int __android_log_trylock();
194 LIBLOG_HIDDEN void __android_log_unlock();
195
196 LIBLOG_HIDDEN int __android_log_transport;
197
198 __END_DECLS
199
200 #endif /* _LIBLOG_LOGGER_H__ */
201