* [9fans] acidself
@ 2008-11-26 23:54 erik quanstrom
0 siblings, 0 replies; only message in thread
From: erik quanstrom @ 2008-11-26 23:54 UTC (permalink / raw)
To: 9fans
i hope this is worth a few tens of microseconds of
amusement.
the problem is this. how to get a backtrace when
you may be killed by your parent who is cleaning
up after himself before somone wielding a debugger
has a chance to react? the amusing answer is just run
acid yourself. how? well just catch the note.
sleazy, no? think of it as one more reason to enjoy plan 9.
- erik
----
; cat /rc/bin/stk
#!/bin/rc
for(i)
echo 'stk()' | acid $i
----
#include <u.h>
#include <libc.h>
void
system(char *cmd, char **av)
{
int in, pid;
switch(pid=fork()){
case -1:
return;
case 0:
in = open("/dev/null", OREAD);
close(0);
dup(in, 0);
exec(cmd, av);
_exits(0);
default:
while(waitpid() < 0)
postnote(PNPROC, pid, "die");
break;
}
}
void
acid(void)
{
char *av[3], buf[16];
snprint(buf, sizeof buf, "%d", getpid());
av[0] = "stk";
av[1] = buf;
av[2] = 0;
system("/bin/stk", av);
}
int
an(void*, char*)
{
acid();
return 0;
}
void
main(void)
{
atnotify(an, 1);
abort();
exits("");
}
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