26c10c83f13978cde49f96a30e74d74bfd434e72
[lttng-tools.git] / 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 * This library is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU Lesser General Public License as published by the
6 * Free Software Foundation; version 2.1 of the License.
7 *
8 * This library is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
11 * for more details.
12 *
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this library; if not, write to the Free Software Foundation,
15 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
16 */
17
18 #include <fcntl.h>
19 #include <signal.h>
20 #include <stdbool.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <sys/syscall.h>
25 #include <sys/types.h>
26 #include <unistd.h>
27
28 #include "utils.h"
29
30 /**
31 * The process waits for the creation of a file passed as argument from an
32 * external processes to execute a syscall and exiting. This is useful for tests
33 * in combinaison with LTTng's PID tracker feature where we can trace the kernel
34 * events generated by our test process only.
35 */
36
37 #if defined(__clang__)
38 #define nooptimization __attribute__((noinline)) __attribute__((optnone))
39 #else
40 #define nooptimization __attribute__((noinline)) __attribute__((optimize(0)))
41 #endif
42
43 volatile int val = 0;
44
45 long nooptimization
46 my_gettid(void)
47 {
48 long ret;
49 #ifdef __x86_64
50 asm volatile
51 (
52 "syscall"
53 : "=a" (ret)
54 : "0"(__NR_gettid)
55 : "cc", "rcx", "r11", "memory"
56 );
57 #elif __i386
58 asm volatile
59 (
60 "int $0x80"
61 : "=a" (ret)
62 : "0"(__NR_gettid)
63 : "cc", "edi", "esi", "memory"
64 );
65 #else
66 #error "Userspace callstack test not supported for this architecture."
67 #endif
68 return ret;
69 }
70
71 int nooptimization
72 fct_c(void)
73 {
74 return my_gettid();
75 }
76
77 int nooptimization
78 fct_b(void)
79 {
80 val += fct_c();
81 return val;
82 }
83
84 int nooptimization
85 fct_a(void)
86 {
87 val += fct_b();
88 return val;
89 }
90
91 int main(int argc, char **argv)
92 {
93 int ret = 0;
94 char *start_file;
95
96 if (argc != 2) {
97 fprintf(stderr, "Error: Missing argument\n");
98 fprintf(stderr, "USAGE: %s PATH_WAIT_FILE\n", argv[0]);
99 ret = -1;
100 goto error;
101 }
102
103 start_file = argv[1];
104
105 /*
106 * Wait for the start_file to be created by an external process
107 * (typically the test script) before executing the syscall
108 */
109 ret = wait_on_file(start_file);
110 if (ret != 0) {
111 goto error;
112 }
113
114 /* Start the callchain to the syscall */
115 ret = fct_a();
116
117 /* Return success */
118 if (ret >= 0) {
119 ret = 0;
120 }
121
122 error:
123 return ret;
124 }
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