summaryrefslogtreecommitdiffstats
blob: 86219936d4934f4f362a7e695d397ef52b9102d7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <poll.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include <cutils/klog.h>
#include <log/log.h>
#include <logwrap/logwrap.h>

#define ARRAY_SIZE(x)   (sizeof(x) / sizeof(*(x)))
#define MIN(a,b) (((a)<(b))?(a):(b))

static pthread_mutex_t fd_mutex = PTHREAD_MUTEX_INITIALIZER;

#define ERROR(fmt, args...)                                                   \
do {                                                                          \
    fprintf(stderr, fmt, ## args);                                            \
    ALOG(LOG_ERROR, "logwrapper", fmt, ## args);                              \
} while(0)

#define FATAL_CHILD(fmt, args...)                                             \
do {                                                                          \
    ERROR(fmt, ## args);                                                      \
    _exit(-1);                                                                \
} while(0)

#define MAX_KLOG_TAG 16

/* This is a simple buffer that holds up to the first beginning_buf->buf_size
 * bytes of output from a command.
 */
#define BEGINNING_BUF_SIZE 0x1000
struct beginning_buf {
    char *buf;
    size_t alloc_len;
    /* buf_size is the usable space, which is one less than the allocated size */
    size_t buf_size;
    size_t used_len;
};

/* This is a circular buf that holds up to the last ending_buf->buf_size bytes
 * of output from a command after the first beginning_buf->buf_size bytes
 * (which are held in beginning_buf above).
 */
#define ENDING_BUF_SIZE 0x1000
struct ending_buf {
    char *buf;
    ssize_t alloc_len;
    /* buf_size is the usable space, which is one less than the allocated size */
    ssize_t buf_size;
    ssize_t used_len;
    /* read and write offsets into the circular buffer */
    int read;
    int write;
};

 /* A structure to hold all the abbreviated buf data */
struct abbr_buf {
    struct beginning_buf b_buf;
    struct ending_buf e_buf;
    int beginning_buf_full;
};

/* Collect all the various bits of info needed for logging in one place. */
struct log_info {
    int log_target;
    char klog_fmt[MAX_KLOG_TAG * 2];
    char *btag;
    bool abbreviated;
    FILE *fp;
    struct abbr_buf a_buf;
};

/* Forware declaration */
static void add_line_to_abbr_buf(struct abbr_buf *a_buf, char *linebuf, int linelen);

/* Return 0 on success, and 1 when full */
static int add_line_to_linear_buf(struct beginning_buf *b_buf,
                                   char *line, ssize_t line_len)
{
    int full = 0;

    if ((line_len + b_buf->used_len) > b_buf->buf_size) {
        full = 1;
    } else {
        /* Add to the end of the buf */
        memcpy(b_buf->buf + b_buf->used_len, line, line_len);
        b_buf->used_len += line_len;
    }

    return full;
}

static void add_line_to_circular_buf(struct ending_buf *e_buf,
                                     char *line, ssize_t line_len)
{
    ssize_t free_len;
    ssize_t needed_space;
    int cnt;

    if (e_buf->buf == NULL) {
        return;
    }

   if (line_len > e_buf->buf_size) {
       return;
   }

    free_len = e_buf->buf_size - e_buf->used_len;

    if (line_len > free_len) {
        /* remove oldest entries at read, and move read to make
         * room for the new string */
        needed_space = line_len - free_len;
        e_buf->read = (e_buf->read + needed_space) % e_buf->buf_size;
        e_buf->used_len -= needed_space;
    }

    /* Copy the line into the circular buffer, dealing with possible
     * wraparound.
     */
    cnt = MIN(line_len, e_buf->buf_size - e_buf->write);
    memcpy(e_buf->buf + e_buf->write, line, cnt);
    if (cnt < line_len) {
        memcpy(e_buf->buf, line + cnt, line_len - cnt);
    }
    e_buf->used_len += line_len;
    e_buf->write = (e_buf->write + line_len) % e_buf->buf_size;
}

/* Log directly to the specified log */
static void do_log_line(struct log_info *log_info, char *line) {
    if (log_info->log_target & LOG_KLOG) {
        klog_write(6, log_info->klog_fmt, line);
    }
    if (log_info->log_target & LOG_ALOG) {
        ALOG(LOG_INFO, log_info->btag, "%s", line);
    }
    if (log_info->log_target & LOG_FILE) {
        fprintf(log_info->fp, "%s\n", line);
    }
}

/* Log to either the abbreviated buf, or directly to the specified log
 * via do_log_line() above.
 */
static void log_line(struct log_info *log_info, char *line, int len) {
    if (log_info->abbreviated) {
        add_line_to_abbr_buf(&log_info->a_buf, line, len);
    } else {
        do_log_line(log_info, line);
    }
}

/*
 * The kernel will take a maximum of 1024 bytes in any single write to
 * the kernel logging device file, so find and print each line one at
 * a time.  The allocated size for buf should be at least 1 byte larger
 * than buf_size (the usable size of the buffer) to make sure there is
 * room to temporarily stuff a null byte to terminate a line for logging.
 */
static void print_buf_lines(struct log_info *log_info, char *buf, int buf_size)
{
    char *line_start;
    char c;
    int i;

    line_start = buf;
    for (i = 0; i < buf_size; i++) {
        if (*(buf + i) == '\n') {
            /* Found a line ending, print the line and compute new line_start */
            /* Save the next char and replace with \0 */
            c = *(buf + i + 1);
            *(buf + i + 1) = '\0';
            do_log_line(log_info, line_start);
            /* Restore the saved char */
            *(buf + i + 1) = c;
            line_start = buf + i + 1;
        } else if (*(buf + i) == '\0') {
            /* The end of the buffer, print the last bit */
            do_log_line(log_info, line_start);
            break;
        }
    }
    /* If the buffer was completely full, and didn't end with a newline, just
     * ignore the partial last line.
     */
}

static void init_abbr_buf(struct abbr_buf *a_buf) {
    char *new_buf;

    memset(a_buf, 0, sizeof(struct abbr_buf));
    new_buf = malloc(BEGINNING_BUF_SIZE);
    if (new_buf) {
        a_buf->b_buf.buf = new_buf;
        a_buf->b_buf.alloc_len = BEGINNING_BUF_SIZE;
        a_buf->b_buf.buf_size = BEGINNING_BUF_SIZE - 1;
    }
    new_buf = malloc(ENDING_BUF_SIZE);
    if (new_buf) {
        a_buf->e_buf.buf = new_buf;
        a_buf->e_buf.alloc_len = ENDING_BUF_SIZE;
        a_buf->e_buf.buf_size = ENDING_BUF_SIZE - 1;
    }
}

static void free_abbr_buf(struct abbr_buf *a_buf) {
    free(a_buf->b_buf.buf);
    free(a_buf->e_buf.buf);
}

static void add_line_to_abbr_buf(struct abbr_buf *a_buf, char *linebuf, int linelen) {
    if (!a_buf->beginning_buf_full) {
        a_buf->beginning_buf_full =
            add_line_to_linear_buf(&a_buf->b_buf, linebuf, linelen);
    }
    if (a_buf->beginning_buf_full) {
        add_line_to_circular_buf(&a_buf->e_buf, linebuf, linelen);
    }
}

static void print_abbr_buf(struct log_info *log_info) {
    struct abbr_buf *a_buf = &log_info->a_buf;

    /* Add the abbreviated output to the kernel log */
    if (a_buf->b_buf.alloc_len) {
        print_buf_lines(log_info, a_buf->b_buf.buf, a_buf->b_buf.used_len);
    }

    /* Print an ellipsis to indicate that the buffer has wrapped or
     * is full, and some data was not logged.
     */
    if (a_buf->e_buf.used_len == a_buf->e_buf.buf_size) {
        do_log_line(log_info, "...\n");
    }

    if (a_buf->e_buf.used_len == 0) {
        return;
    }

    /* Simplest way to print the circular buffer is allocate a second buf
     * of the same size, and memcpy it so it's a simple linear buffer,
     * and then cal print_buf_lines on it */
    if (a_buf->e_buf.read < a_buf->e_buf.write) {
        /* no wrap around, just print it */
        print_buf_lines(log_info, a_buf->e_buf.buf + a_buf->e_buf.read,
                        a_buf->e_buf.used_len);
    } else {
        /* The circular buffer will always have at least 1 byte unused,
         * so by allocating alloc_len here we will have at least
         * 1 byte of space available as required by print_buf_lines().
         */
        char * nbuf = malloc(a_buf->e_buf.alloc_len);
        if (!nbuf) {
            return;
        }
        int first_chunk_len = a_buf->e_buf.buf_size - a_buf->e_buf.read;
        memcpy(nbuf, a_buf->e_buf.buf + a_buf->e_buf.read, first_chunk_len);
        /* copy second chunk */
        memcpy(nbuf + first_chunk_len, a_buf->e_buf.buf, a_buf->e_buf.write);
        print_buf_lines(log_info, nbuf, first_chunk_len + a_buf->e_buf.write);
        free(nbuf);
    }
}

static int parent(const char *tag, int parent_read, pid_t pid,
        int *chld_sts, int log_target, bool abbreviated, char *file_path) {
    int status = 0;
    char buffer[4096];
    struct pollfd poll_fds[] = {
        [0] = {
            .fd = parent_read,
            .events = POLLIN,
        },
    };
    int rc = 0;
    int fd;

    struct log_info log_info;

    int a = 0;  // start index of unprocessed data
    int b = 0;  // end index of unprocessed data
    int sz;
    bool found_child = false;
    char tmpbuf[256];

    log_info.btag = basename(tag);
    if (!log_info.btag) {
        log_info.btag = (char*) tag;
    }

    if (abbreviated && (log_target == LOG_NONE)) {
        abbreviated = 0;
    }
    if (abbreviated) {
        init_abbr_buf(&log_info.a_buf);
    }

    if (log_target & LOG_KLOG) {
        snprintf(log_info.klog_fmt, sizeof(log_info.klog_fmt),
                 "<6>%.*s: %%s\n", MAX_KLOG_TAG, log_info.btag);
    }

    if ((log_target & LOG_FILE) && !file_path) {
        /* No file_path specified, clear the LOG_FILE bit */
        log_target &= ~LOG_FILE;
    }

    if (log_target & LOG_FILE) {
        fd = open(file_path, O_WRONLY | O_CREAT, 0664);
        if (fd < 0) {
            ERROR("Cannot log to file %s\n", file_path);
            log_target &= ~LOG_FILE;
        } else {
            lseek(fd, 0, SEEK_END);
            log_info.fp = fdopen(fd, "a");
        }
    }

    log_info.log_target = log_target;
    log_info.abbreviated = abbreviated;

    while (!found_child) {
        if (TEMP_FAILURE_RETRY(poll(poll_fds, ARRAY_SIZE(poll_fds), -1)) < 0) {
            ERROR("poll failed\n");
            rc = -1;
            goto err_poll;
        }

        if (poll_fds[0].revents & POLLIN) {
            sz = TEMP_FAILURE_RETRY(
                read(parent_read, &buffer[b], sizeof(buffer) - 1 - b));

            sz += b;
            // Log one line at a time
            for (b = 0; b < sz; b++) {
                if (buffer[b] == '\r') {
                    if (abbreviated) {
                        /* The abbreviated logging code uses newline as
                         * the line separator.  Lucikly, the pty layer
                         * helpfully cooks the output of the command
                         * being run and inserts a CR before NL.  So
                         * I just change it to NL here when doing
                         * abbreviated logging.
                         */
                        buffer[b] = '\n';
                    } else {
                        buffer[b] = '\0';
                    }
                } else if (buffer[b] == '\n') {
                    buffer[b] = '\0';
                    log_line(&log_info, &buffer[a], b - a);
                    a = b + 1;
                }
            }

            if (a == 0 && b == sizeof(buffer) - 1) {
                // buffer is full, flush
                buffer[b] = '\0';
                log_line(&log_info, &buffer[a], b - a);
                b = 0;
            } else if (a != b) {
                // Keep left-overs
                b -= a;
                memmove(buffer, &buffer[a], b);
                a = 0;
            } else {
                a = 0;
                b = 0;
            }
        }

        if (poll_fds[0].revents & POLLHUP) {
            int ret;

            ret = TEMP_FAILURE_RETRY(waitpid(pid, &status, 0));
            if (ret < 0) {
                rc = errno;
                ALOG(LOG_ERROR, "logwrap", "waitpid failed with %s\n", strerror(errno));
                goto err_waitpid;
            }
            if (ret > 0) {
                found_child = true;
            }
        }
    }

    if (chld_sts != NULL) {
        *chld_sts = status;
    } else {
      if (WIFEXITED(status))
        rc = WEXITSTATUS(status);
      else
        rc = -ECHILD;
    }

    // Flush remaining data
    if (a != b) {
      buffer[b] = '\0';
      log_line(&log_info, &buffer[a], b - a);
    }

    /* All the output has been processed, time to dump the abbreviated output */
    if (abbreviated) {
        print_abbr_buf(&log_info);
    }

    if (WIFEXITED(status)) {
      if (WEXITSTATUS(status)) {
        snprintf(tmpbuf, sizeof(tmpbuf),
                 "%s terminated by exit(%d)\n", log_info.btag, WEXITSTATUS(status));
        do_log_line(&log_info, tmpbuf);
      }
    } else {
      if (WIFSIGNALED(status)) {
        snprintf(tmpbuf, sizeof(tmpbuf),
                       "%s terminated by signal %d\n", log_info.btag, WTERMSIG(status));
        do_log_line(&log_info, tmpbuf);
      } else if (WIFSTOPPED(status)) {
        snprintf(tmpbuf, sizeof(tmpbuf),
                       "%s stopped by signal %d\n", log_info.btag, WSTOPSIG(status));
        do_log_line(&log_info, tmpbuf);
      }
    }

err_waitpid:
err_poll:
    if (log_target & LOG_FILE) {
        fclose(log_info.fp); /* Also closes underlying fd */
    }
    if (abbreviated) {
        free_abbr_buf(&log_info.a_buf);
    }
    return rc;
}

static void child(int argc, char* argv[]) {
    // create null terminated argv_child array
    char* argv_child[argc + 1];
    memcpy(argv_child, argv, argc * sizeof(char *));
    argv_child[argc] = NULL;

    if (execvp(argv_child[0], argv_child)) {
        FATAL_CHILD("executing %s failed: %s\n", argv_child[0],
                strerror(errno));
    }
}

int android_fork_execvp_ext(int argc, char* argv[], int *status, bool ignore_int_quit,
        int log_target, bool abbreviated, char *file_path,
        void *unused_opts, int unused_opts_len) {
    pid_t pid;
    int parent_ptty;
    int child_ptty;
    struct sigaction intact;
    struct sigaction quitact;
    sigset_t blockset;
    sigset_t oldset;
    int rc = 0;

    LOG_ALWAYS_FATAL_IF(unused_opts != NULL);
    LOG_ALWAYS_FATAL_IF(unused_opts_len != 0);

    rc = pthread_mutex_lock(&fd_mutex);
    if (rc) {
        ERROR("failed to lock signal_fd mutex\n");
        goto err_lock;
    }

    /* Use ptty instead of socketpair so that STDOUT is not buffered */
    parent_ptty = TEMP_FAILURE_RETRY(open("/dev/ptmx", O_RDWR));
    if (parent_ptty < 0) {
        ERROR("Cannot create parent ptty\n");
        rc = -1;
        goto err_open;
    }

    char child_devname[64];
    if (grantpt(parent_ptty) || unlockpt(parent_ptty) ||
            ptsname_r(parent_ptty, child_devname, sizeof(child_devname)) != 0) {
        ERROR("Problem with /dev/ptmx\n");
        rc = -1;
        goto err_ptty;
    }

    child_ptty = TEMP_FAILURE_RETRY(open(child_devname, O_RDWR));
    if (child_ptty < 0) {
        ERROR("Cannot open child_ptty\n");
        rc = -1;
        goto err_child_ptty;
    }

    sigemptyset(&blockset);
    sigaddset(&blockset, SIGINT);
    sigaddset(&blockset, SIGQUIT);
    pthread_sigmask(SIG_BLOCK, &blockset, &oldset);

    pid = fork();
    if (pid < 0) {
        close(child_ptty);
        ERROR("Failed to fork\n");
        rc = -1;
        goto err_fork;
    } else if (pid == 0) {
        pthread_mutex_unlock(&fd_mutex);
        pthread_sigmask(SIG_SETMASK, &oldset, NULL);
        close(parent_ptty);

        dup2(child_ptty, 1);
        dup2(child_ptty, 2);
        close(child_ptty);

        child(argc, argv);
    } else {
        close(child_ptty);
        if (ignore_int_quit) {
            struct sigaction ignact;

            memset(&ignact, 0, sizeof(ignact));
            ignact.sa_handler = SIG_IGN;
            sigaction(SIGINT, &ignact, &intact);
            sigaction(SIGQUIT, &ignact, &quitact);
        }

        rc = parent(argv[0], parent_ptty, pid, status, log_target,
                    abbreviated, file_path);
    }

    if (ignore_int_quit) {
        sigaction(SIGINT, &intact, NULL);
        sigaction(SIGQUIT, &quitact, NULL);
    }
err_fork:
    pthread_sigmask(SIG_SETMASK, &oldset, NULL);
err_child_ptty:
err_ptty:
    close(parent_ptty);
err_open:
    pthread_mutex_unlock(&fd_mutex);
err_lock:
    return rc;
}