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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 <cutils/klog.h>
24 #include <log/log.h>
25 #include <logwrap/logwrap.h>
26 
fatal(const char * msg)27 void fatal(const char *msg) {
28     fprintf(stderr, "%s", msg);
29     ALOG(LOG_ERROR, "logwrapper", "%s", msg);
30     exit(-1);
31 }
32 
usage()33 void 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 
main(int argc,char * argv[])50 int 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, NULL, NULL, 0);
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         uintptr_t fault_address = (uintptr_t) status;
93         *(int *) fault_address = 0;  // causes SIGSEGV with fault_address = status
94     }
95 
96     return rc;
97 }
98