1 | #include <stdbool.h> |
2 | #include <stdio.h> |
3 | #include <unistd.h> |
4 | #include <errno.h> |
5 | #include <sys/types.h> |
6 | #include <sys/stat.h> |
7 | #include <fcntl.h> |
8 | #include <stdlib.h> |
9 | #include <signal.h> |
10 | |
11 | #define _SDT_HAS_SEMAPHORES 1 |
12 | #include "sdt.h" |
13 | |
14 | #define SHARED 1 |
15 | #include "bpf/libbpf_internal.h" |
16 | |
17 | #define SEC(name) __attribute__((section(name), used)) |
18 | |
19 | #define BUF_SIZE 256 |
20 | |
21 | /* defined in urandom_read_aux.c */ |
22 | void urand_read_without_sema(int iter_num, int iter_cnt, int read_sz); |
23 | /* these are coming from urandom_read_lib{1,2}.c */ |
24 | void urandlib_read_with_sema(int iter_num, int iter_cnt, int read_sz); |
25 | void urandlib_read_without_sema(int iter_num, int iter_cnt, int read_sz); |
26 | |
27 | int urandlib_api(void); |
28 | COMPAT_VERSION(urandlib_api_old, urandlib_api, LIBURANDOM_READ_1.0.0) |
29 | int urandlib_api_old(void); |
30 | int urandlib_api_sameoffset(void); |
31 | |
32 | unsigned short urand_read_with_sema_semaphore SEC(".probes" ); |
33 | |
34 | static noinline void urandom_read(int fd, int count) |
35 | { |
36 | char buf[BUF_SIZE]; |
37 | int i; |
38 | |
39 | for (i = 0; i < count; ++i) { |
40 | read(fd, buf, BUF_SIZE); |
41 | |
42 | /* trigger USDTs defined in executable itself */ |
43 | urand_read_without_sema(i, count, BUF_SIZE); |
44 | STAP_PROBE3(urand, read_with_sema, i, count, BUF_SIZE); |
45 | |
46 | /* trigger USDTs defined in shared lib */ |
47 | urandlib_read_without_sema(i, count, BUF_SIZE); |
48 | urandlib_read_with_sema(i, count, BUF_SIZE); |
49 | } |
50 | } |
51 | |
52 | static volatile bool parent_ready; |
53 | |
54 | static void handle_sigpipe(int sig) |
55 | { |
56 | parent_ready = true; |
57 | } |
58 | |
59 | int main(int argc, char *argv[]) |
60 | { |
61 | int fd = open("/dev/urandom" , O_RDONLY); |
62 | int count = 4; |
63 | bool report_pid = false; |
64 | |
65 | if (fd < 0) |
66 | return 1; |
67 | |
68 | if (argc >= 2) |
69 | count = atoi(argv[1]); |
70 | if (argc >= 3) { |
71 | report_pid = true; |
72 | /* install SIGPIPE handler to catch when parent closes their |
73 | * end of the pipe (on the other side of our stdout) |
74 | */ |
75 | signal(SIGPIPE, handle_sigpipe); |
76 | } |
77 | |
78 | /* report PID and wait for parent process to send us "signal" by |
79 | * closing stdout |
80 | */ |
81 | if (report_pid) { |
82 | while (!parent_ready) { |
83 | fprintf(stdout, "%d\n" , getpid()); |
84 | fflush(stdout); |
85 | } |
86 | /* at this point stdout is closed, parent process knows our |
87 | * PID and is ready to trace us |
88 | */ |
89 | } |
90 | |
91 | urandom_read(fd, count); |
92 | |
93 | urandlib_api(); |
94 | urandlib_api_old(); |
95 | urandlib_api_sameoffset(); |
96 | |
97 | close(fd); |
98 | return 0; |
99 | } |
100 | |