1 // Copyright 2010 Google LLC
2 //
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4 // modification, are permitted provided that the following conditions are
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6 //
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9 //     * Redistributions in binary form must reproduce the above
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15 // this software without specific prior written permission.
16 //
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27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 //
29 // Helper program for the linux_dumper class, which creates a bunch of
30 // threads. The first word of each thread's stack is set to the thread
31 // id.
32 
33 #ifdef HAVE_CONFIG_H
34 #include <config.h>  // Must come first
35 #endif
36 
37 #include <pthread.h>
38 #include <stdint.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <sys/syscall.h>
42 #include <unistd.h>
43 
44 #include "common/scoped_ptr.h"
45 #include "third_party/lss/linux_syscall_support.h"
46 
47 #if defined(__ARM_EABI__)
48 #define TID_PTR_REGISTER "r3"
49 #elif defined(__aarch64__)
50 #define TID_PTR_REGISTER "x3"
51 #elif defined(__i386)
52 #define TID_PTR_REGISTER "ecx"
53 #elif defined(__x86_64)
54 #define TID_PTR_REGISTER "rcx"
55 #elif defined(__mips__)
56 #define TID_PTR_REGISTER "$1"
57 #elif defined(__riscv)
58 #define TID_PTR_REGISTER "x4"
59 #else
60 #error This test has not been ported to this platform.
61 #endif
62 
thread_function(void * data)63 void* thread_function(void* data) {
64   int pipefd = *static_cast<int*>(data);
65   volatile pid_t* thread_id = new pid_t;
66   *thread_id = syscall(__NR_gettid);
67   // Signal parent that a thread has started.
68   uint8_t byte = 1;
69   if (write(pipefd, &byte, sizeof(byte)) != sizeof(byte)) {
70     perror("ERROR: parent notification failed");
71     return NULL;
72   }
73   register volatile pid_t* thread_id_ptr asm(TID_PTR_REGISTER) = thread_id;
74   while (true)
75     asm volatile ("" : : "r" (thread_id_ptr));
76   return NULL;
77 }
78 
main(int argc,char * argv[])79 int main(int argc, char* argv[]) {
80   if (argc < 3) {
81     fprintf(stderr,
82             "usage: linux_dumper_unittest_helper <pipe fd> <# of threads>\n");
83     return 1;
84   }
85   int pipefd = atoi(argv[1]);
86   int num_threads = atoi(argv[2]);
87   if (num_threads < 1) {
88     fprintf(stderr, "ERROR: number of threads is 0");
89     return 1;
90   }
91   google_breakpad::scoped_array<pthread_t> threads(new pthread_t[num_threads]);
92   pthread_attr_t thread_attributes;
93   pthread_attr_init(&thread_attributes);
94   pthread_attr_setdetachstate(&thread_attributes, PTHREAD_CREATE_DETACHED);
95   for (int i = 1; i < num_threads; i++) {
96     pthread_create(&threads[i], &thread_attributes, &thread_function, &pipefd);
97   }
98   thread_function(&pipefd);
99   return 0;
100 }
101