logwrapper.c revision 96e11b5bc473918d61b088f1840e4d1ec48fd3ab 
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 <stdio.h>
18#include <stdlib.h>
19#include <sys/wait.h>
20#include <unistd.h>
21
22#include <logwrap/logwrap.h>
23#include <cutils/klog.h>
24
25#include "cutils/log.h"
26
27void fatal(const char *msg) {
28    fprintf(stderr, "%s", msg);
29    ALOG(LOG_ERROR, "logwrapper", "%s", msg);
30    exit(-1);
31}
32
33void usage() {
34    fatal(
35        "Usage: logwrapper [-a] [-d] [-k] BINARY [ARGS ...]\n"
36        "\n"
37        "Forks and executes BINARY ARGS, redirecting stdout and stderr to\n"
38        "the Android logging system. Tag is set to BINARY, priority is\n"
39        "always LOG_INFO.\n"
40        "\n"
41        "-a: Causes logwrapper to do abbreviated logging.\n"
42        "    This logs up to the first 4K and last 4K of the command\n"
43        "    being run, and logs the output when the command exits\n"
44        "-d: Causes logwrapper to SIGSEGV when BINARY terminates\n"
45        "    fault address is set to the status of wait()\n"
46        "-k: Causes logwrapper to log to the kernel log instead of\n"
47        "    the Android system log\n");
48}
49
50int main(int argc, char* argv[]) {
51    int seg_fault_on_exit = 0;
52    int log_target = LOG_ALOG;
53    bool abbreviated = false;
54    int ch;
55    int status = 0xAAAA;
56    int rc;
57
58    while ((ch = getopt(argc, argv, "adk")) != -1) {
59        switch (ch) {
60            case 'a':
61                abbreviated = true;
62                break;
63            case 'd':
64                seg_fault_on_exit = 1;
65                break;
66            case 'k':
67                log_target = LOG_KLOG;
68                klog_set_level(6);
69                break;
70            case '?':
71            default:
72              usage();
73        }
74    }
75    argc -= optind;
76    argv += optind;
77
78    if (argc < 1) {
79        usage();
80    }
81
82    rc = android_fork_execvp_ext(argc, &argv[0], &status, true,
83                                 log_target, abbreviated);
84    if (!rc) {
85        if (WIFEXITED(status))
86            rc = WEXITSTATUS(status);
87        else
88            rc = -ECHILD;
89    }
90
91    if (seg_fault_on_exit) {
92        *(int *)status = 0;  // causes SIGSEGV with fault_address = status
93    }
94
95    return rc;
96}
97