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