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591ee332 FD |
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 | volatile int val = 0; | |
38 | ||
39 | long __attribute__ ((noinline)) | |
40 | my_gettid(void) | |
41 | { | |
42 | long ret; | |
43 | #ifdef __x86_64 | |
44 | asm volatile | |
45 | ( | |
46 | "syscall" | |
47 | : "=a" (ret) | |
48 | : "0"(__NR_gettid) | |
49 | : "cc", "rcx", "r11", "memory" | |
50 | ); | |
51 | #elif __i386 | |
52 | asm volatile | |
53 | ( | |
54 | "int $0x80" | |
55 | : "=a" (ret) | |
56 | : "0"(__NR_gettid) | |
57 | : "cc", "edi", "esi", "memory" | |
58 | ); | |
59 | #else | |
60 | #error "Userspace callstack test not supported for this architecture." | |
61 | #endif | |
62 | return ret; | |
63 | } | |
64 | ||
65 | int __attribute__ ((noinline)) | |
66 | fct_c(void) | |
67 | { | |
68 | return my_gettid(); | |
69 | } | |
70 | ||
71 | int __attribute__ ((noinline)) | |
72 | fct_b(void) | |
73 | { | |
74 | val += fct_c(); | |
75 | return val; | |
76 | } | |
77 | ||
78 | int __attribute__ ((noinline)) | |
79 | fct_a(void) | |
80 | { | |
81 | val += fct_b(); | |
82 | return val; | |
83 | } | |
84 | ||
85 | int main(int argc, char **argv) | |
86 | { | |
87 | int ret = 0; | |
88 | char *start_file; | |
89 | ||
90 | if (argc != 2) { | |
91 | fprintf(stderr, "Error: Missing argument\n"); | |
92 | fprintf(stderr, "USAGE: %s PATH_WAIT_FILE\n", argv[0]); | |
93 | ret = -1; | |
94 | goto error; | |
95 | } | |
96 | ||
97 | start_file = argv[1]; | |
98 | ||
99 | /* | |
100 | * Wait for the start_file to be created by an external process | |
101 | * (typically the test script) before executing the syscall | |
102 | */ | |
103 | ret = wait_on_file(start_file); | |
104 | if (ret != 0) { | |
105 | goto error; | |
106 | } | |
107 | ||
108 | /* Start the callchain to the syscall */ | |
109 | ret = fct_a(); | |
110 | ||
111 | /* Return success */ | |
112 | if (ret >= 0) { | |
113 | ret = 0; | |
114 | } | |
115 | ||
116 | error: | |
117 | return ret; | |
118 | } |