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Re: process attaching gdb to itself
- From: Michael Elizabeth Chastain <mec at shout dot net>
- To: aurelien dot chanudet at enst dot fr, gdb at sources dot redhat dot com
- Date: Sun, 28 Sep 2003 18:25:09 -0400
- Subject: Re: process attaching gdb to itself
Hello,
char cmd [256];
sprintf (cmd, "gdb attach %d", getpid ());
system (cmd);
'system' waits for the program that it calls to finish.
Thus, your program is waiting for gdb to finish before it
does anything.
Try the appended program which uses raw fork/exec.
It works for me on red hat linux 8, native i686-pc-linux-gnu.
If you try to do this in production code then you are likely
to run into a blizzard of race conditions, error cases,
and signal handling problems. If you are doing this as a learning
experience, that's great -- read up on 'man fork' and
'man execlp', and check out a book on Linux systems programming.
Michael C
GDB QA Guy
===
#include <stdio.h>
int main ()
{
int pid = fork ();
if (pid == -1)
{
/* error */
fprintf (stderr, "fork error\n");
exit (2);
}
if (pid != 0)
{
/* parent process */
char spid [256];
sprintf (spid, "%d", pid);
execlp ("gdb", "gdb", "a.out", spid, NULL);
/* execlp returns only if error */
fprintf (stderr, "execlp error\n");
_exit (2);
}
/* child process */
sleep (5);
printf ("hello hacker\n");
return 0;
}