Date: Sat, 16 Jan 2010 13:02:54 +0200 From: Ali Polatel <alip@exherbo.org> To: freebsd-questions@freebsd.org Subject: A question about ptrace Message-ID: <20100116110254.GA6142@harikalardiyari>
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I'm trying to port a program using ptrace from Linux to FreeBSD.
For this reason I'm trying to understand how ptrace on FreeBSD works.
Below is a sample program I've written which fork()'s and executes
"true" after calling PT_TRACE_ME. Having read the manual page of ptrace
I assume the printf() in parent should print SIGTRAP but it gives:
"Segmentation fault: 11"
Can someone help me figure out the problem?
TIA.
#include <assert.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <unistd.h>
int main(void)
{
int status;
pid_t pid;
char *const myargv[] =3D { "true", NULL };
pid =3D fork();
if (0 > pid)
abort();
else if (!pid) {
ptrace(PT_TRACE_ME, 0, 0, 0);
execvp(myargv[0], myargv);
}
else {
assert(0 < waitpid(pid, &status, 0));
assert(WIFSTOPPED(status));
assert(0 =3D=3D ptrace(PT_TO_SCE, pid, 0, 0));
assert(0 < waitpid(pid, &status, 0));
assert(WIFSTOPPED(status));
printf("%s\n", strsignal(WSTOPSIG(status)));
ptrace(PT_KILL, pid, 0, 0);
return 0;
}
}
--=20
Regards,
Ali Polatel
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