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030312cf 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 | ||
030312cf FD |
18 | #include <fcntl.h> |
19 | #include <stdio.h> | |
20 | #include <sys/syscall.h> | |
21 | #include <unistd.h> | |
22 | ||
23 | #include "utils.h" | |
24 | ||
25 | #define MAX_LEN 16 | |
26 | /* | |
27 | * The process waits for the creation of a file passed as argument from an | |
28 | * external processes to execute a syscall and exiting. This is useful for tests | |
29 | * in combinaison with LTTng's PID tracker feature where we can trace the kernel | |
30 | * events generated by our test process only. | |
31 | */ | |
32 | int main(int argc, char **argv) | |
33 | { | |
c8e51d15 | 34 | int fd, ret; |
030312cf FD |
35 | char buf[MAX_LEN]; |
36 | char *start_file; | |
37 | ||
38 | if (argc != 2) { | |
39 | fprintf(stderr, "Error: Missing argument\n"); | |
40 | fprintf(stderr, "USAGE: %s PATH_WAIT_FILE\n", argv[0]); | |
41 | ret = -1; | |
42 | goto error; | |
43 | } | |
44 | ||
45 | start_file = argv[1]; | |
46 | ||
47 | /* | |
48 | * Wait for the start_file to be created by an external process | |
49 | * (typically the test script) before executing the syscalls. | |
50 | */ | |
51 | ret = wait_on_file(start_file); | |
52 | if (ret != 0) { | |
53 | goto error; | |
54 | } | |
55 | ||
56 | /* | |
57 | * Start generating syscalls. We use syscall(2) to prevent libc to change | |
58 | * the underlying syscall. e.g. calling openat(2) instead of open(2). | |
59 | */ | |
8192bd8f | 60 | fd = syscall(SYS_openat, AT_FDCWD, "/proc/cpuinfo", O_RDONLY); |
030312cf FD |
61 | if (fd < 0) { |
62 | perror("open"); | |
63 | ret = -1; | |
64 | goto error; | |
65 | } | |
66 | ||
67 | ret = syscall(SYS_read, fd, buf, MAX_LEN); | |
68 | if (ret < 0) { | |
69 | perror("read"); | |
70 | ret = -1; | |
71 | goto error; | |
72 | } | |
73 | ||
74 | ret = syscall(SYS_close, fd); | |
75 | if (ret == -1) { | |
76 | perror("close"); | |
77 | ret = -1; | |
78 | goto error; | |
79 | } | |
80 | ||
81 | error: | |
82 | return ret; | |
83 | } |