logger.h revision cf983bcbae801e4660521b9747d9a7516e7df1c1 
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 */
32union android_log_context {
33  void *private;
34  atomic_int sock;
35  atomic_int fd;
36  struct listnode *node;
37  atomic_uintptr_t atomic_pointer;
38};
39
40struct 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,
51               struct iovec *vec, size_t nr);
52};
53
54struct android_log_logger_list;
55struct android_log_transport_context;
56struct android_log_logger;
57
58struct 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,
84                     size_t size);
85  ssize_t (*getSize)(struct android_log_logger *logger,
86                     struct android_log_transport_context *transp);
87  ssize_t (*getReadableSize)(struct android_log_logger *logger,
88                             struct android_log_transport_context *transp);
89
90  ssize_t (*getPrune)(struct android_log_logger_list *logger_list,
91                      struct android_log_transport_context *transp,
92                      char *buf, size_t len);
93  ssize_t (*setPrune)(struct android_log_logger_list *logger_list,
94                      struct android_log_transport_context *transp,
95                      char *buf, size_t len);
96  ssize_t (*getStats)(struct android_log_logger_list *logger_list,
97                      struct android_log_transport_context *transp,
98                      char *buf, size_t len);
99};
100
101struct android_log_logger_list {
102  struct listnode node;
103  struct listnode logger;
104  struct listnode transport;
105  int mode;
106  unsigned int tail;
107  log_time start;
108  pid_t pid;
109};
110
111struct android_log_logger {
112  struct listnode node;
113  struct android_log_logger_list *parent;
114
115  log_id_t logId;
116};
117
118struct android_log_transport_context {
119  struct listnode node;
120  union android_log_context context; /* zero init per-transport context */
121  struct android_log_logger_list *parent;
122
123  struct android_log_transport_read *transport;
124  unsigned logMask;      /* mask of requested log buffers */
125  int ret;               /* return value associated with following data */
126  struct log_msg logMsg; /* peek at upcoming data, valid if logMsg.len != 0 */
127};
128
129/* assumes caller has structures read-locked, single threaded, or fenced */
130#define transport_context_for_each(transp, logger_list)              \
131  for ((transp) = node_to_item((logger_list)->transport.next,        \
132                             struct android_log_transport_context,   \
133                             node);                                  \
134       ((transp) != node_to_item(&(logger_list)->transport,          \
135                               struct android_log_transport_context, \
136                               node)) &&                             \
137           ((transp)->parent == (logger_list));                      \
138       (transp) = node_to_item((transp)->node.next,                  \
139                             struct android_log_transport_context, node))
140
141#define logger_for_each(logp, logger_list)                          \
142    for ((logp) = node_to_item((logger_list)->logger.next,          \
143                             struct android_log_logger, node);      \
144         ((logp) != node_to_item(&(logger_list)->logger,            \
145                               struct android_log_logger, node)) && \
146             ((logp)->parent == (logger_list));                     \
147         (logp) = node_to_item((logp)->node.next,                   \
148                             struct android_log_logger, node))
149
150/*
151 *    Global list of log readers.
152 *
153 * Usage case: search out transport contexts for all readers
154 */
155
156LIBLOG_HIDDEN struct listnode __android_log_readers;
157
158#if defined(_WIN32)
159#define logger_list_rdlock()
160#define logger_list_wrlock()
161#define logger_list_unlock()
162#else
163LIBLOG_HIDDEN pthread_rwlock_t __android_log_readers_lock;
164
165#define logger_list_rdlock() pthread_rwlock_rdlock(&__android_log_readers_lock)
166#define logger_list_wrlock() pthread_rwlock_wrlock(&__android_log_readers_lock)
167#define logger_list_unlock() pthread_rwlock_unlock(&__android_log_readers_lock)
168#endif
169
170/* Must be called with logger_list_rdlock() or logger_list_wrlock() held */
171#define logger_list_for_each(logger_list)                              \
172    for ((logger_list) = node_to_item(&__android_log_readers,          \
173                                      struct android_log_logger_list,  \
174                                      node);                           \
175         (logger_list) != node_to_item(&__android_log_readers,         \
176                                       struct android_log_logger_list, \
177                                       node) &&                        \
178         (logger_list) != node_to_item((logger_list)->node.next,       \
179                                       struct android_log_logger_list, \
180                                       node);                          \
181         (logger_list) = node_to_item((logger_list)->node.next,        \
182                                      struct android_log_logger_list,  \
183                                      node))
184
185/* OS specific dribs and drabs */
186
187#if defined(_WIN32)
188#include <private/android_filesystem_config.h>
189typedef uint32_t uid_t;
190static inline uid_t __android_log_uid() { return AID_SYSTEM; }
191#else
192static inline uid_t __android_log_uid() { return getuid(); }
193#endif
194
195LIBLOG_HIDDEN void __android_log_lock();
196LIBLOG_HIDDEN int __android_log_trylock();
197LIBLOG_HIDDEN void __android_log_unlock();
198
199__END_DECLS
200
201#endif /* _LIBLOG_LOGGER_H__ */
202