1 /*
2 * Copyright (C) 2007-2016 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 /*
18 * pmsg write handler
19 */
20
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <stdbool.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <sys/types.h>
27 #include <time.h>
28
29 #include <log/log_properties.h>
30 #include <private/android_filesystem_config.h>
31 #include <private/android_logger.h>
32
33 #include "config_write.h"
34 #include "log_portability.h"
35 #include "logger.h"
36
37 static int pmsgOpen();
38 static void pmsgClose();
39 static int pmsgAvailable(log_id_t logId);
40 static int pmsgWrite(log_id_t logId, struct timespec* ts, struct iovec* vec,
41 size_t nr);
42
43 LIBLOG_HIDDEN struct android_log_transport_write pmsgLoggerWrite = {
44 .node = { &pmsgLoggerWrite.node, &pmsgLoggerWrite.node },
45 .context.fd = -1,
46 .name = "pmsg",
47 .available = pmsgAvailable,
48 .open = pmsgOpen,
49 .close = pmsgClose,
50 .write = pmsgWrite,
51 };
52
pmsgOpen()53 static int pmsgOpen() {
54 int fd = atomic_load(&pmsgLoggerWrite.context.fd);
55 if (fd < 0) {
56 int i;
57
58 fd = TEMP_FAILURE_RETRY(open("/dev/pmsg0", O_WRONLY | O_CLOEXEC));
59 i = atomic_exchange(&pmsgLoggerWrite.context.fd, fd);
60 if ((i >= 0) && (i != fd)) {
61 close(i);
62 }
63 }
64
65 return fd;
66 }
67
pmsgClose()68 static void pmsgClose() {
69 int fd = atomic_exchange(&pmsgLoggerWrite.context.fd, -1);
70 if (fd >= 0) {
71 close(fd);
72 }
73 }
74
pmsgAvailable(log_id_t logId)75 static int pmsgAvailable(log_id_t logId) {
76 if (logId > LOG_ID_SECURITY) {
77 return -EINVAL;
78 }
79 if ((logId != LOG_ID_SECURITY) && (logId != LOG_ID_EVENTS) &&
80 !__android_log_is_debuggable()) {
81 return -EINVAL;
82 }
83 if (atomic_load(&pmsgLoggerWrite.context.fd) < 0) {
84 if (access("/dev/pmsg0", W_OK) == 0) {
85 return 0;
86 }
87 return -EBADF;
88 }
89 return 1;
90 }
91
92 /*
93 * Extract a 4-byte value from a byte stream.
94 */
get4LE(const uint8_t * src)95 static inline uint32_t get4LE(const uint8_t* src) {
96 return src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
97 }
98
pmsgWrite(log_id_t logId,struct timespec * ts,struct iovec * vec,size_t nr)99 static int pmsgWrite(log_id_t logId, struct timespec* ts, struct iovec* vec,
100 size_t nr) {
101 static const unsigned headerLength = 2;
102 struct iovec newVec[nr + headerLength];
103 android_log_header_t header;
104 android_pmsg_log_header_t pmsgHeader;
105 size_t i, payloadSize;
106 ssize_t ret;
107
108 if ((logId == LOG_ID_EVENTS) && !__android_log_is_debuggable()) {
109 if (vec[0].iov_len < 4) {
110 return -EINVAL;
111 }
112
113 if (SNET_EVENT_LOG_TAG != get4LE(vec[0].iov_base)) {
114 return -EPERM;
115 }
116 }
117
118 if (atomic_load(&pmsgLoggerWrite.context.fd) < 0) {
119 return -EBADF;
120 }
121
122 /*
123 * struct {
124 * // what we provide to pstore
125 * android_pmsg_log_header_t pmsgHeader;
126 * // what we provide to file
127 * android_log_header_t header;
128 * // caller provides
129 * union {
130 * struct {
131 * char prio;
132 * char payload[];
133 * } string;
134 * struct {
135 * uint32_t tag
136 * char payload[];
137 * } binary;
138 * };
139 * };
140 */
141
142 pmsgHeader.magic = LOGGER_MAGIC;
143 pmsgHeader.len = sizeof(pmsgHeader) + sizeof(header);
144 pmsgHeader.uid = __android_log_uid();
145 pmsgHeader.pid = getpid();
146
147 header.id = logId;
148 header.tid = gettid();
149 header.realtime.tv_sec = ts->tv_sec;
150 header.realtime.tv_nsec = ts->tv_nsec;
151
152 newVec[0].iov_base = (unsigned char*)&pmsgHeader;
153 newVec[0].iov_len = sizeof(pmsgHeader);
154 newVec[1].iov_base = (unsigned char*)&header;
155 newVec[1].iov_len = sizeof(header);
156
157 for (payloadSize = 0, i = headerLength; i < nr + headerLength; i++) {
158 newVec[i].iov_base = vec[i - headerLength].iov_base;
159 payloadSize += newVec[i].iov_len = vec[i - headerLength].iov_len;
160
161 if (payloadSize > LOGGER_ENTRY_MAX_PAYLOAD) {
162 newVec[i].iov_len -= payloadSize - LOGGER_ENTRY_MAX_PAYLOAD;
163 if (newVec[i].iov_len) {
164 ++i;
165 }
166 payloadSize = LOGGER_ENTRY_MAX_PAYLOAD;
167 break;
168 }
169 }
170 pmsgHeader.len += payloadSize;
171
172 ret = TEMP_FAILURE_RETRY(
173 writev(atomic_load(&pmsgLoggerWrite.context.fd), newVec, i));
174 if (ret < 0) {
175 ret = errno ? -errno : -ENOTCONN;
176 }
177
178 if (ret > (ssize_t)(sizeof(header) + sizeof(pmsgHeader))) {
179 ret -= sizeof(header) - sizeof(pmsgHeader);
180 }
181
182 return ret;
183 }
184
185 /*
186 * Virtual pmsg filesystem
187 *
188 * Payload will comprise the string "<basedir>:<basefile>\0<content>" to a
189 * maximum of LOGGER_ENTRY_MAX_PAYLOAD, but scaled to the last newline in the
190 * file.
191 *
192 * Will hijack the header.realtime.tv_nsec field for a sequence number in usec.
193 */
194
strnrchr(const char * buf,size_t len,char c)195 static inline const char* strnrchr(const char* buf, size_t len, char c) {
196 const char* cp = buf + len;
197 while ((--cp > buf) && (*cp != c))
198 ;
199 if (cp <= buf) {
200 return buf + len;
201 }
202 return cp;
203 }
204
205 /* Write a buffer as filename references (tag = <basedir>:<basename>) */
__android_log_pmsg_file_write(log_id_t logId,char prio,const char * filename,const char * buf,size_t len)206 LIBLOG_ABI_PRIVATE ssize_t __android_log_pmsg_file_write(log_id_t logId,
207 char prio,
208 const char* filename,
209 const char* buf,
210 size_t len) {
211 bool weOpened;
212 size_t length, packet_len;
213 const char* tag;
214 char *cp, *slash;
215 struct timespec ts;
216 struct iovec vec[3];
217
218 /* Make sure the logId value is not a bad idea */
219 if ((logId == LOG_ID_KERNEL) || /* Verbotten */
220 (logId == LOG_ID_EVENTS) || /* Do not support binary content */
221 (logId == LOG_ID_SECURITY) || /* Bad idea to allow */
222 ((unsigned)logId >= 32)) { /* fit within logMask on arch32 */
223 return -EINVAL;
224 }
225
226 clock_gettime(android_log_clockid(), &ts);
227
228 cp = strdup(filename);
229 if (!cp) {
230 return -ENOMEM;
231 }
232
233 tag = cp;
234 slash = strrchr(cp, '/');
235 if (slash) {
236 *slash = ':';
237 slash = strrchr(cp, '/');
238 if (slash) {
239 tag = slash + 1;
240 }
241 }
242
243 length = strlen(tag) + 1;
244 packet_len = LOGGER_ENTRY_MAX_PAYLOAD - sizeof(char) - length;
245
246 vec[0].iov_base = &prio;
247 vec[0].iov_len = sizeof(char);
248 vec[1].iov_base = (unsigned char*)tag;
249 vec[1].iov_len = length;
250
251 weOpened = false;
252 for (ts.tv_nsec = 0, length = len; length;
253 ts.tv_nsec += ANDROID_LOG_PMSG_FILE_SEQUENCE) {
254 ssize_t ret;
255 size_t transfer;
256
257 if ((ts.tv_nsec / ANDROID_LOG_PMSG_FILE_SEQUENCE) >=
258 ANDROID_LOG_PMSG_FILE_MAX_SEQUENCE) {
259 len -= length;
260 break;
261 }
262
263 transfer = length;
264 if (transfer > packet_len) {
265 transfer = strnrchr(buf, packet_len - 1, '\n') - buf;
266 if ((transfer < length) && (buf[transfer] == '\n')) {
267 ++transfer;
268 }
269 }
270
271 vec[2].iov_base = (unsigned char*)buf;
272 vec[2].iov_len = transfer;
273
274 if (atomic_load(&pmsgLoggerWrite.context.fd) < 0) {
275 if (!weOpened) { /* Impossible for weOpened = true here */
276 __android_log_lock();
277 }
278 weOpened = atomic_load(&pmsgLoggerWrite.context.fd) < 0;
279 if (!weOpened) {
280 __android_log_unlock();
281 } else if (pmsgOpen() < 0) {
282 __android_log_unlock();
283 free(cp);
284 return -EBADF;
285 }
286 }
287
288 ret = pmsgWrite(logId, &ts, vec, sizeof(vec) / sizeof(vec[0]));
289
290 if (ret <= 0) {
291 if (weOpened) {
292 pmsgClose();
293 __android_log_unlock();
294 }
295 free(cp);
296 return ret ? ret : (len - length);
297 }
298 length -= transfer;
299 buf += transfer;
300 }
301 if (weOpened) {
302 pmsgClose();
303 __android_log_unlock();
304 }
305 free(cp);
306 return len;
307 }
308