tests/utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack.c

   1 /*
   2  * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #include "utils.h"
   9
  10 #include <fcntl.h>
  11 #include <signal.h>
  12 #include <stdbool.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/syscall.h>
  17 #include <sys/types.h>
  18 #include <unistd.h>
  19
  20 /**
  21  * The process waits for the creation of a file passed as argument from an
  22  * external processes to execute a syscall and exiting. This is useful for tests
  23  * in combinaison with LTTng's PID tracker feature where we can trace the kernel
  24  * events generated by our test process only.
  25  */
  26
  27 #if defined(__clang__)
  28 #define nooptimization __attribute__((noinline)) __attribute__((optnone))
  29 #else
  30 #define nooptimization __attribute__((noinline)) __attribute__((optimize(0)))
  31 #endif
  32
  33 volatile int val = 0;
  34
  35 long nooptimization my_gettid(void);
  36 long nooptimization my_gettid(void)
  37 {
  38         long ret;
  39 #ifdef __x86_64
  40         asm volatile("syscall" : "=a"(ret) : "0"(__NR_gettid) : "cc", "rcx", "r11", "memory");
  41 #elif defined(__i386)
  42         asm volatile("int $0x80" : "=a"(ret) : "0"(__NR_gettid) : "cc", "edi", "esi", "memory");
  43 #else
  44 #error "Userspace callstack test not supported for this architecture."
  45 #endif
  46         return ret;
  47 }
  48
  49 int nooptimization fct_c(void);
  50 int nooptimization fct_c(void)
  51 {
  52         return my_gettid();
  53 }
  54
  55 int nooptimization fct_b(void);
  56 int nooptimization fct_b(void)
  57 {
  58         val += fct_c();
  59         return val;
  60 }
  61
  62 int nooptimization fct_a(void);
  63 int nooptimization fct_a(void)
  64 {
  65         val += fct_b();
  66         return val;
  67 }
  68
  69 int main(int argc, char **argv)
  70 {
  71         int ret = 0;
  72         char *start_file;
  73
  74         if (argc != 2) {
  75                 fprintf(stderr, "Error: Missing argument\n");
  76                 fprintf(stderr, "USAGE: %s PATH_WAIT_FILE\n", argv[0]);
  77                 ret = -1;
  78                 goto error;
  79         }
  80
  81         start_file = argv[1];
  82
  83         /*
  84          * Wait for the start_file to be created by an external process
  85          * (typically the test script) before executing the syscall
  86          */
  87         ret = wait_on_file(start_file);
  88         if (ret != 0) {
  89                 goto error;
  90         }
  91
  92         /* Start the callchain to the syscall */
  93         ret = fct_a();
  94
  95         /* Return success */
  96         if (ret >= 0) {
  97                 ret = 0;
  98         }
  99
 100 error:
 101         return ret;
 102 }