logwrapper.c revision ccecf1425412beb2bc3bb38d470293fdc244d6f1 
1/*
2 * Copyright (C) 2008 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 <errno.h>
18#include <stdio.h>
19#include <stdlib.h>
20#include <sys/wait.h>
21#include <unistd.h>
22
23#include <logwrap/logwrap.h>
24#include <cutils/klog.h>
25
26#include "cutils/log.h"
27
28void fatal(const char *msg) {
29    fprintf(stderr, "%s", msg);
30    ALOG(LOG_ERROR, "logwrapper", "%s", msg);
31    exit(-1);
32}
33
34void usage() {
35    fatal(
36        "Usage: logwrapper [-a] [-d] [-k] BINARY [ARGS ...]\n"
37        "\n"
38        "Forks and executes BINARY ARGS, redirecting stdout and stderr to\n"
39        "the Android logging system. Tag is set to BINARY, priority is\n"
40        "always LOG_INFO.\n"
41        "\n"
42        "-a: Causes logwrapper to do abbreviated logging.\n"
43        "    This logs up to the first 4K and last 4K of the command\n"
44        "    being run, and logs the output when the command exits\n"
45        "-d: Causes logwrapper to SIGSEGV when BINARY terminates\n"
46        "    fault address is set to the status of wait()\n"
47        "-k: Causes logwrapper to log to the kernel log instead of\n"
48        "    the Android system log\n");
49}
50
51int main(int argc, char* argv[]) {
52    int seg_fault_on_exit = 0;
53    int log_target = LOG_ALOG;
54    bool abbreviated = false;
55    int ch;
56    int status = 0xAAAA;
57    int rc;
58
59    while ((ch = getopt(argc, argv, "adk")) != -1) {
60        switch (ch) {
61            case 'a':
62                abbreviated = true;
63                break;
64            case 'd':
65                seg_fault_on_exit = 1;
66                break;
67            case 'k':
68                log_target = LOG_KLOG;
69                klog_set_level(6);
70                break;
71            case '?':
72            default:
73              usage();
74        }
75    }
76    argc -= optind;
77    argv += optind;
78
79    if (argc < 1) {
80        usage();
81    }
82
83    rc = android_fork_execvp_ext(argc, &argv[0], &status, true,
84                                 log_target, abbreviated, NULL);
85    if (!rc) {
86        if (WIFEXITED(status))
87            rc = WEXITSTATUS(status);
88        else
89            rc = -ECHILD;
90    }
91
92    if (seg_fault_on_exit) {
93        uintptr_t fault_address = (uintptr_t) status;
94        *(int *) fault_address = 0;  // causes SIGSEGV with fault_address = status
95    }
96
97    return rc;
98}
99