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-rw-r--r--config_test/child_test.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/config_test/child_test.c b/config_test/child_test.c
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1// Base code taken from http://www-h.eng.cam.ac.uk/help/tpl/unix/fork.html
2// Fix for redhat suggested by Ptere Pramberger, peter@pramberger.at
3#include <unistd.h>
4#include <sys/wait.h>
5#include <stdio.h>
6#include <sys/types.h>
7#include <signal.h>
8void popen_sigchld_handler (int);
9int childtermd;
10
11int main(){
12 char str[1024];
13 int pipefd[2];
14 pid_t pid;
15 int status, died;
16
17 if (signal (SIGCHLD, popen_sigchld_handler) == SIG_ERR) {
18 printf ("Cannot catch SIGCHLD\n");
19 _exit(-1);
20 }
21
22 pipe (pipefd);
23 switch(pid=fork()){
24 case -1:
25 printf("can't fork\n");
26 _exit(-1);
27
28 case 0 : // this is the code the child runs
29 close(1); // close stdout
30 // pipefd[1] is for writing to the pipe. We want the output
31 // that used to go to the standard output (file descriptor 1)
32 // to be written to the pipe. The following command does this,
33 // creating a new file descripter 1 (the lowest available)
34 // that writes where pipefd[1] goes.
35 dup (pipefd[1]); // points pipefd at file descriptor
36 // the child isn't going to read from the pipe, so
37 // pipefd[0] can be closed
38 close (pipefd[0]);
39
40 //These are the commands to run, with success commented. dig and nslookup only problems
41 //execl ("/bin/date","date",0); // 100%
42 //execl ("/bin/cat", "cat", "/etc/hosts", 0); // 100%
43 //execl ("/usr/bin/dig", "dig", "redhat.com", 0); // 69%
44 //execl("/bin/sleep", "sleep", "1", 0); // 100%
45 execl ("/usr/bin/nslookup","nslookup","redhat.com",0); // 90% (after 100 tests), 40% (after 10 tests)
46 //execl ("/bin/ping","ping","-c","1","localhost",0); // 100%
47 //execl ("/bin/ping","ping","-c","1","192.168.10.32",0); // 100%
48 _exit(0);
49
50 default: // this is the code the parent runs
51
52 close(0); // close stdin
53 // Set file descriptor 0 (stdin) to read from the pipe
54 dup (pipefd[0]);
55 // the parent isn't going to write to the pipe
56 close (pipefd[1]);
57 // Now read from the pipe
58 fgets(str, 1023, stdin);
59 //printf("1st line output is %s\n", str);
60
61 //while (!childtermd); // Uncomment this line to fix
62
63 died= wait(&status);
64 //printf("died=%d status=%d\n", died, status);
65 if (died > 0) _exit(0);
66 else _exit(1);
67 }
68}
69
70void
71popen_sigchld_handler (int signo)
72{
73 if (signo == SIGCHLD) {
74 //printf("Caught sigchld\n");
75 childtermd = 1;
76 }
77}