Re: ptrace PT_CONTINUE
Re: ptrace PT_CONTINUE
- Subject: Re: ptrace PT_CONTINUE
- From: Terry Lambert <email@hidden>
- Date: Wed, 8 Jul 2009 22:35:39 -0700
You are expected to exec after the fork, not be tracing your own
code. See the system_cmds project for the sc_usage source.
What are you really trying to do here?
-- Terry
On Jul 8, 2009, at 7:10 PM, Aron-Zvi wrote:
Hey guys,
I'm trying to get started with basic ptrace functionality with the
following:
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
int main(int argc, char **argv)
{
int pid, status, ret;
if((pid = fork()) == 0)
{
ptrace(PT_TRACE_ME,0,0,0);
execl(argv[1],argv[1],0);
printf("exec failed\n");
}
else{
wait(&status);
if(WIFSTOPPED(status))
printf("child has stopped. child pid: %d\n", pid);
errno = 0;
ret = ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
printf("ret: %d\n", ret);
printf("errno: %s\n", strerror(errno));
}
}
>From my basic understanding, what the above should do is fork a
child process which will stop at exec and cause the parent-tracing
process to exit wait(). The parent process should then have the
child process continue execution normally by calling ptrace() with
PT_CONTINUE.
When I run the code, The child process is created, however, ptrace()
with PT_CONTINUE seems to fail as the child process does not
continue normal execution. ptrace's return value is 0 and errno is
"Unknown error: 0".
Running output:
aronzvis-macbook:ptrace_test aronzvi$ ./ptrace ../voidinc
child has stopped. child pid: 37959
ret: 0
errno: Unknown error: 0
I'm running OS X 10.5.7 and building the code with the 10.5 SDK.
Your help is much appreciated,
Aron-Zvi
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