1 /*
2  * Copyright (C) 2020 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 <signal.h>
19 #include <stdlib.h>
20 
21 #include "profile-extras.h"
22 
23 extern "C" {
24 
25 static sighandler_t chained_signal_handler = SIG_ERR;
26 
27 int __llvm_profile_write_file(void);
28 
llvm_signal_handler(__unused int signum)29 static void llvm_signal_handler(__unused int signum) {
30   __llvm_profile_write_file();
31 
32   if (chained_signal_handler != SIG_ERR &&
33       chained_signal_handler != SIG_IGN &&
34       chained_signal_handler != SIG_DFL) {
35     (chained_signal_handler)(signum);
36   }
37 }
38 
39 // Initialize libprofile-extras:
40 //
41 // - Install a signal handler that triggers __llvm_profile_write_file on
42 // <COVERAGE_FLUSH_SIGNAL>.
43 //
44 // We want this initializer to run during load time.  In addition to marking
45 // this function as a constructor, we link this library with `--whole-archive`
46 // to force this function to be included in the output.
init_profile_extras(void)47 static __attribute__((constructor)) int init_profile_extras(void) {
48   if (chained_signal_handler != SIG_ERR) {
49     return -1;
50   }
51   sighandler_t ret1 = signal(COVERAGE_FLUSH_SIGNAL, llvm_signal_handler);
52   if (ret1 == SIG_ERR) {
53     return -1;
54   }
55   chained_signal_handler = ret1;
56 
57   return 0;
58 }
59 }
60