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#include <endian.h>
18#include <errno.h>
19#include <fcntl.h>
20#include <inttypes.h>
21#include <poll.h>
22#include <stdarg.h>
23#include <stdatomic.h>
24#include <stdio.h>
25#include <stdlib.h>
26#include <string.h>
27#include <sys/stat.h>
28#include <sys/types.h>
29#include <sys/socket.h>
30#include <sys/un.h>
31#include <time.h>
32#include <unistd.h>
33
34#include <cutils/sockets.h>
35#include <log/logd.h>
36#include <log/logger.h>
37#include <log/log_read.h>
38#include <private/android_filesystem_config.h>
39#include <private/android_logger.h>
40
41#include "config_read.h"
42#include "log_portability.h"
43#include "logger.h"
44
45/* branchless on many architectures. */
46#define min(x,y) ((y) ^ (((x) ^ (y)) & -((x) < (y))))
47
48static int logdAvailable(log_id_t LogId);
49static int logdVersion(struct android_log_logger *logger,
50                       struct android_log_transport_context *transp);
51static int logdRead(struct android_log_logger_list *logger_list,
52                    struct android_log_transport_context *transp,
53                    struct log_msg *log_msg);
54static int logdPoll(struct android_log_logger_list *logger_list,
55                    struct android_log_transport_context *transp);
56static void logdClose(struct android_log_logger_list *logger_list,
57                      struct android_log_transport_context *transp);
58static int logdClear(struct android_log_logger *logger,
59                     struct android_log_transport_context *transp);
60static ssize_t logdSetSize(struct android_log_logger *logger,
61                           struct android_log_transport_context *transp,
62                           size_t size);
63static ssize_t logdGetSize(struct android_log_logger *logger,
64                           struct android_log_transport_context *transp);
65static ssize_t logdGetReadableSize(struct android_log_logger *logger,
66                                   struct android_log_transport_context *transp);
67static ssize_t logdGetPrune(struct android_log_logger_list *logger,
68                            struct android_log_transport_context *transp,
69                            char *buf, size_t len);
70static ssize_t logdSetPrune(struct android_log_logger_list *logger,
71                            struct android_log_transport_context *transp,
72                            char *buf, size_t len);
73static ssize_t logdGetStats(struct android_log_logger_list *logger,
74                            struct android_log_transport_context *transp,
75                            char *buf, size_t len);
76
77LIBLOG_HIDDEN struct android_log_transport_read logdLoggerRead = {
78    .node = { &logdLoggerRead.node, &logdLoggerRead.node },
79    .name = "logd",
80    .available = logdAvailable,
81    .version = logdVersion,
82    .read = logdRead,
83    .poll = logdPoll,
84    .close = logdClose,
85    .clear = logdClear,
86    .getSize = logdGetSize,
87    .setSize = logdSetSize,
88    .getReadableSize = logdGetReadableSize,
89    .getPrune = logdGetPrune,
90    .setPrune = logdSetPrune,
91    .getStats = logdGetStats,
92};
93
94static int logdAvailable(log_id_t logId)
95{
96    if (logId > LOG_ID_KERNEL) {
97        return -EINVAL;
98    }
99    if (logId == LOG_ID_SECURITY) {
100        uid_t uid = __android_log_uid();
101        if (uid != AID_SYSTEM) {
102            return -EPERM;
103        }
104    }
105    if (access("/dev/socket/logdw", W_OK) == 0) {
106        return 0;
107    }
108    return -EBADF;
109}
110
111/* Private copy of ../libcutils/socket_local_client.c prevent library loops */
112
113#if defined(_WIN32)
114
115LIBLOG_WEAK int socket_local_client(const char *name, int namespaceId, int type)
116{
117    errno = ENOSYS;
118    return -ENOSYS;
119}
120
121#else /* !_WIN32 */
122
123#include <sys/socket.h>
124#include <sys/un.h>
125#include <sys/select.h>
126#include <sys/types.h>
127
128/* Private copy of ../libcutils/socket_local.h prevent library loops */
129#define FILESYSTEM_SOCKET_PREFIX "/tmp/"
130#define ANDROID_RESERVED_SOCKET_PREFIX "/dev/socket/"
131/* End of ../libcutils/socket_local.h */
132
133#define LISTEN_BACKLOG 4
134
135/* Documented in header file. */
136LIBLOG_WEAK int socket_make_sockaddr_un(const char *name, int namespaceId,
137                                        struct sockaddr_un *p_addr,
138                                        socklen_t *alen)
139{
140    memset (p_addr, 0, sizeof (*p_addr));
141    size_t namelen;
142
143    switch (namespaceId) {
144    case ANDROID_SOCKET_NAMESPACE_ABSTRACT:
145#if defined(__linux__)
146        namelen  = strlen(name);
147
148        /* Test with length +1 for the *initial* '\0'. */
149        if ((namelen + 1) > sizeof(p_addr->sun_path)) {
150            goto error;
151        }
152
153        /*
154         * Note: The path in this case is *not* supposed to be
155         * '\0'-terminated. ("man 7 unix" for the gory details.)
156         */
157
158        p_addr->sun_path[0] = 0;
159        memcpy(p_addr->sun_path + 1, name, namelen);
160#else
161        /* this OS doesn't have the Linux abstract namespace */
162
163        namelen = strlen(name) + strlen(FILESYSTEM_SOCKET_PREFIX);
164        /* unix_path_max appears to be missing on linux */
165        if (namelen > sizeof(*p_addr)
166                - offsetof(struct sockaddr_un, sun_path) - 1) {
167            goto error;
168        }
169
170        strcpy(p_addr->sun_path, FILESYSTEM_SOCKET_PREFIX);
171        strcat(p_addr->sun_path, name);
172#endif
173        break;
174
175    case ANDROID_SOCKET_NAMESPACE_RESERVED:
176        namelen = strlen(name) + strlen(ANDROID_RESERVED_SOCKET_PREFIX);
177        /* unix_path_max appears to be missing on linux */
178        if (namelen > sizeof(*p_addr)
179                - offsetof(struct sockaddr_un, sun_path) - 1) {
180            goto error;
181        }
182
183        strcpy(p_addr->sun_path, ANDROID_RESERVED_SOCKET_PREFIX);
184        strcat(p_addr->sun_path, name);
185        break;
186
187    case ANDROID_SOCKET_NAMESPACE_FILESYSTEM:
188        namelen = strlen(name);
189        /* unix_path_max appears to be missing on linux */
190        if (namelen > sizeof(*p_addr)
191                - offsetof(struct sockaddr_un, sun_path) - 1) {
192            goto error;
193        }
194
195        strcpy(p_addr->sun_path, name);
196        break;
197
198    default:
199        /* invalid namespace id */
200        return -1;
201    }
202
203    p_addr->sun_family = AF_LOCAL;
204    *alen = namelen + offsetof(struct sockaddr_un, sun_path) + 1;
205    return 0;
206error:
207    return -1;
208}
209
210/**
211 * connect to peer named "name" on fd
212 * returns same fd or -1 on error.
213 * fd is not closed on error. that's your job.
214 *
215 * Used by AndroidSocketImpl
216 */
217LIBLOG_WEAK int socket_local_client_connect(int fd, const char *name,
218                                            int namespaceId, int type __unused)
219{
220    struct sockaddr_un addr;
221    socklen_t alen;
222    int err;
223
224    err = socket_make_sockaddr_un(name, namespaceId, &addr, &alen);
225
226    if (err < 0) {
227        goto error;
228    }
229
230    if(connect(fd, (struct sockaddr *) &addr, alen) < 0) {
231        goto error;
232    }
233
234    return fd;
235
236error:
237    return -1;
238}
239
240/**
241 * connect to peer named "name"
242 * returns fd or -1 on error
243 */
244LIBLOG_WEAK int socket_local_client(const char *name, int namespaceId, int type)
245{
246    int s;
247
248    s = socket(AF_LOCAL, type, 0);
249    if(s < 0) return -1;
250
251    if ( 0 > socket_local_client_connect(s, name, namespaceId, type)) {
252        close(s);
253        return -1;
254    }
255
256    return s;
257}
258
259#endif /* !_WIN32 */
260/* End of ../libcutils/socket_local_client.c */
261
262/* worker for sending the command to the logger */
263static ssize_t send_log_msg(struct android_log_logger *logger,
264                            const char *msg, char *buf, size_t buf_size)
265{
266    ssize_t ret;
267    size_t len;
268    char *cp;
269    int errno_save = 0;
270    int sock = socket_local_client("logd", ANDROID_SOCKET_NAMESPACE_RESERVED,
271                                   SOCK_STREAM);
272    if (sock < 0) {
273        return sock;
274    }
275
276    if (msg) {
277        snprintf(buf, buf_size, msg, logger ? logger->logId : (unsigned) -1);
278    }
279
280    len = strlen(buf) + 1;
281    ret = TEMP_FAILURE_RETRY(write(sock, buf, len));
282    if (ret <= 0) {
283        goto done;
284    }
285
286    len = buf_size;
287    cp = buf;
288    while ((ret = TEMP_FAILURE_RETRY(read(sock, cp, len))) > 0) {
289        struct pollfd p;
290
291        if (((size_t)ret == len) || (buf_size < PAGE_SIZE)) {
292            break;
293        }
294
295        len -= ret;
296        cp += ret;
297
298        memset(&p, 0, sizeof(p));
299        p.fd = sock;
300        p.events = POLLIN;
301
302        /* Give other side 20ms to refill pipe */
303        ret = TEMP_FAILURE_RETRY(poll(&p, 1, 20));
304
305        if (ret <= 0) {
306            break;
307        }
308
309        if (!(p.revents & POLLIN)) {
310            ret = 0;
311            break;
312        }
313    }
314
315    if (ret >= 0) {
316        ret += buf_size - len;
317    }
318
319done:
320    if ((ret == -1) && errno) {
321        errno_save = errno;
322    }
323    close(sock);
324    if (errno_save) {
325        errno = errno_save;
326    }
327    return ret;
328}
329
330static int check_log_success(char *buf, ssize_t ret)
331{
332    if (ret < 0) {
333        return ret;
334    }
335
336    if (strncmp(buf, "success", 7)) {
337        errno = EINVAL;
338        return -1;
339    }
340
341    return 0;
342}
343
344static int logdClear(struct android_log_logger *logger,
345                     struct android_log_transport_context *transp __unused)
346{
347    char buf[512];
348
349    return check_log_success(buf,
350        send_log_msg(logger, "clear %d", buf, sizeof(buf)));
351}
352
353/* returns the total size of the log's ring buffer */
354static ssize_t logdGetSize(struct android_log_logger *logger,
355                           struct android_log_transport_context *transp __unused)
356{
357    char buf[512];
358
359    ssize_t ret = send_log_msg(logger, "getLogSize %d", buf, sizeof(buf));
360    if (ret < 0) {
361        return ret;
362    }
363
364    if ((buf[0] < '0') || ('9' < buf[0])) {
365        return -1;
366    }
367
368    return atol(buf);
369}
370
371static ssize_t logdSetSize(
372        struct android_log_logger *logger,
373        struct android_log_transport_context *transp __unused,
374        size_t size)
375{
376    char buf[512];
377
378    snprintf(buf, sizeof(buf), "setLogSize %d %zu", logger->logId, size);
379
380    return check_log_success(buf, send_log_msg(NULL, NULL, buf, sizeof(buf)));
381}
382
383/*
384 * returns the readable size of the log's ring buffer (that is, amount of the
385 * log consumed)
386 */
387static ssize_t logdGetReadableSize(
388       struct android_log_logger *logger,
389       struct android_log_transport_context *transp __unused)
390{
391    char buf[512];
392
393    ssize_t ret = send_log_msg(logger, "getLogSizeUsed %d", buf, sizeof(buf));
394    if (ret < 0) {
395        return ret;
396    }
397
398    if ((buf[0] < '0') || ('9' < buf[0])) {
399        return -1;
400    }
401
402    return atol(buf);
403}
404
405/*
406 * returns the logger version
407 */
408static int logdVersion(
409        struct android_log_logger *logger __unused,
410        struct android_log_transport_context *transp __unused)
411{
412    uid_t uid = __android_log_uid();
413    return ((uid != AID_ROOT) && (uid != AID_LOG) && (uid != AID_SYSTEM)) ? 3 : 4;
414}
415
416/*
417 * returns statistics
418 */
419static ssize_t logdGetStats(struct android_log_logger_list *logger_list,
420                            struct android_log_transport_context *transp __unused,
421                            char *buf, size_t len)
422{
423    struct android_log_logger *logger;
424    char *cp = buf;
425    size_t remaining = len;
426    size_t n;
427
428    n = snprintf(cp, remaining, "getStatistics");
429    n = min(n, remaining);
430    remaining -= n;
431    cp += n;
432
433    logger_for_each(logger, logger_list) {
434        n = snprintf(cp, remaining, " %d", logger->logId);
435        n = min(n, remaining);
436        remaining -= n;
437        cp += n;
438    }
439
440    if (logger_list->pid) {
441        snprintf(cp, remaining, " pid=%u", logger_list->pid);
442    }
443
444    return send_log_msg(NULL, NULL, buf, len);
445}
446
447static ssize_t logdGetPrune(
448        struct android_log_logger_list *logger_list __unused,
449        struct android_log_transport_context *transp __unused,
450        char *buf, size_t len)
451{
452    return send_log_msg(NULL, "getPruneList", buf, len);
453}
454
455static ssize_t logdSetPrune(
456        struct android_log_logger_list *logger_list __unused,
457        struct android_log_transport_context *transp __unused,
458        char *buf, size_t len)
459{
460    const char cmd[] = "setPruneList ";
461    const size_t cmdlen = sizeof(cmd) - 1;
462
463    if (strlen(buf) > (len - cmdlen)) {
464        return -ENOMEM; /* KISS */
465    }
466    memmove(buf + cmdlen, buf, len - cmdlen);
467    buf[len - 1] = '\0';
468    memcpy(buf, cmd, cmdlen);
469
470    return check_log_success(buf, send_log_msg(NULL, NULL, buf, len));
471}
472
473
474static void caught_signal(int signum __unused)
475{
476}
477
478static int logdOpen(struct android_log_logger_list *logger_list,
479                    struct android_log_transport_context *transp)
480{
481    struct android_log_logger *logger;
482    struct sigaction ignore;
483    struct sigaction old_sigaction;
484    unsigned int old_alarm = 0;
485    char buffer[256], *cp, c;
486    int e, ret, remaining;
487
488    int sock = transp->context.sock;
489    if (sock > 0) {
490        return sock;
491    }
492
493    if (!logger_list) {
494        return -EINVAL;
495    }
496
497    sock = socket_local_client("logdr",
498                               ANDROID_SOCKET_NAMESPACE_RESERVED,
499                               SOCK_SEQPACKET);
500    if (sock == 0) {
501        /* Guarantee not file descriptor zero */
502        int newsock = socket_local_client("logdr",
503                                   ANDROID_SOCKET_NAMESPACE_RESERVED,
504                                   SOCK_SEQPACKET);
505        close(sock);
506        sock = newsock;
507    }
508    if (sock <= 0) {
509        if ((sock == -1) && errno) {
510            return -errno;
511        }
512        return sock;
513    }
514
515    strcpy(buffer, (logger_list->mode & ANDROID_LOG_NONBLOCK) ?
516            "dumpAndClose" : "stream");
517    cp = buffer + strlen(buffer);
518
519    strcpy(cp, " lids");
520    cp += 5;
521    c = '=';
522    remaining = sizeof(buffer) - (cp - buffer);
523    logger_for_each(logger, logger_list) {
524        ret = snprintf(cp, remaining, "%c%u", c, logger->logId);
525        ret = min(ret, remaining);
526        remaining -= ret;
527        cp += ret;
528        c = ',';
529    }
530
531    if (logger_list->tail) {
532        ret = snprintf(cp, remaining, " tail=%u", logger_list->tail);
533        ret = min(ret, remaining);
534        remaining -= ret;
535        cp += ret;
536    }
537
538    if (logger_list->start.tv_sec || logger_list->start.tv_nsec) {
539        if (logger_list->mode & ANDROID_LOG_WRAP) {
540            // ToDo: alternate API to allow timeout to be adjusted.
541            ret = snprintf(cp, remaining, " timeout=%u",
542                           ANDROID_LOG_WRAP_DEFAULT_TIMEOUT);
543            ret = min(ret, remaining);
544            remaining -= ret;
545            cp += ret;
546        }
547        ret = snprintf(cp, remaining, " start=%" PRIu32 ".%09" PRIu32,
548                       logger_list->start.tv_sec,
549                       logger_list->start.tv_nsec);
550        ret = min(ret, remaining);
551        remaining -= ret;
552        cp += ret;
553    }
554
555    if (logger_list->pid) {
556        ret = snprintf(cp, remaining, " pid=%u", logger_list->pid);
557        ret = min(ret, remaining);
558        cp += ret;
559    }
560
561    if (logger_list->mode & ANDROID_LOG_NONBLOCK) {
562        /* Deal with an unresponsive logd */
563        memset(&ignore, 0, sizeof(ignore));
564        ignore.sa_handler = caught_signal;
565        sigemptyset(&ignore.sa_mask);
566        /* particularily useful if tombstone is reporting for logd */
567        sigaction(SIGALRM, &ignore, &old_sigaction);
568        old_alarm = alarm(30);
569    }
570    ret = write(sock, buffer, cp - buffer);
571    e = errno;
572    if (logger_list->mode & ANDROID_LOG_NONBLOCK) {
573        if (e == EINTR) {
574            e = ETIMEDOUT;
575        }
576        alarm(old_alarm);
577        sigaction(SIGALRM, &old_sigaction, NULL);
578    }
579
580    if (ret <= 0) {
581        close(sock);
582        if ((ret == -1) && e) {
583            return -e;
584        }
585        if (ret == 0) {
586            return -EIO;
587        }
588        return ret;
589    }
590
591    return transp->context.sock = sock;
592}
593
594/* Read from the selected logs */
595static int logdRead(struct android_log_logger_list *logger_list,
596                    struct android_log_transport_context *transp,
597                    struct log_msg *log_msg)
598{
599    int ret, e;
600    struct sigaction ignore;
601    struct sigaction old_sigaction;
602    unsigned int old_alarm = 0;
603
604    ret = logdOpen(logger_list, transp);
605    if (ret < 0) {
606        return ret;
607    }
608
609    memset(log_msg, 0, sizeof(*log_msg));
610
611    if (logger_list->mode & ANDROID_LOG_NONBLOCK) {
612        memset(&ignore, 0, sizeof(ignore));
613        ignore.sa_handler = caught_signal;
614        sigemptyset(&ignore.sa_mask);
615        /* particularily useful if tombstone is reporting for logd */
616        sigaction(SIGALRM, &ignore, &old_sigaction);
617        old_alarm = alarm(30);
618    }
619
620    /* NOTE: SOCK_SEQPACKET guarantees we read exactly one full entry */
621    ret = recv(ret, log_msg, LOGGER_ENTRY_MAX_LEN, 0);
622    e = errno;
623
624    if (logger_list->mode & ANDROID_LOG_NONBLOCK) {
625        if ((ret == 0) || (e == EINTR)) {
626            e = EAGAIN;
627            ret = -1;
628        }
629        alarm(old_alarm);
630        sigaction(SIGALRM, &old_sigaction, NULL);
631    }
632
633    if ((ret == -1) && e) {
634        return -e;
635    }
636    return ret;
637}
638
639static int logdPoll(struct android_log_logger_list *logger_list,
640                    struct android_log_transport_context *transp)
641{
642    struct pollfd p;
643
644    int ret = logdOpen(logger_list, transp);
645    if (ret < 0) {
646        return ret;
647    }
648
649    memset(&p, 0, sizeof(p));
650    p.fd = ret;
651    p.events = POLLIN;
652    ret = poll(&p, 1, 20);
653    if ((ret > 0) && !(p.revents & POLLIN)) {
654        ret = 0;
655    }
656    if ((ret == -1) && errno) {
657        return -errno;
658    }
659    return ret;
660}
661
662/* Close all the logs */
663static void logdClose(struct android_log_logger_list *logger_list __unused,
664                      struct android_log_transport_context *transp)
665{
666    if (transp->context.sock > 0) {
667        close (transp->context.sock);
668        transp->context.sock = -1;
669    }
670}
671