Re: Path to executable of current process?
In <[EMAIL PROTECTED]>, Michael B Allen <[EMAIL PROTECTED]> wrote: >Actually what I'm *really* trying to do is port some code that invokes >GDB to do a backtrace and I need to give GDB the path to the >executable of the current process (e.g. on linux this is >/proc//exe) and the pid of the process to trace (easy - getpid). >The first argument is trickey since FreeBSD frequently does not have a >/proc filesystem. So it seems kvm_getargv should have this path no? # mount_procfs proc /proc # /bin/ls -l /proc//file Note that if the executable on disk gets replaced, this won't work. -- Steve Watt KD6GGD PP-ASEL-IA ICBM: 121W 56' 57.5" / 37N 20' 15.3" Internet: steve @ Watt.COM Whois: SW32-ARIN Free time? There's no such thing. It just comes in varying prices... ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: Path to executable of current process?
On 2007-Jul-19 22:00:23 -0400, Michael B Allen <[EMAIL PROTECTED]> wrote: >Well I figured out how to get kvm_getargv working. Unfortunately it >seems only root can call kvm_open so the faulting process can't >backtrace unless it so happens to be running as root (which it's not). > >Is there any way to get argv[0] for the current process without being root? I suggest you have a look at the source to ps - it does not run with elevated privileges. Note that argv[0] is not necessarily a full pathname - it is whatever the program was invoked with. Even if it _is_ a full pathname, there is no guarantee that it points to the same object - the executable may be in a chroot environment or that pathname may have been replaced. The only guaranteed way to access the executable associated with a running process is via procfs. As you point out earlier, this is not mounted by default on FreeBSD because none of the base system utilities need it (apart from 'ps -e') - you will need to arrange for it to be mounted. On 2007-Jul-19 23:23:45 -0400, Michael B Allen <[EMAIL PROTECTED]> wrote: >After more digging I see sysctl seems to be the way to do this but can I >get the full path to the executable form kinfo_proc? > >How does ps do this? It uses kvm_getargv(3). If you want to do it directly via sysctl(2), I suggest you examine /usr/src/lib/libkvm/kvm_proc.c. > mib[2] = KERN_PROC_PID; This should be KERN_PROC_ARGS > len = sizeof(struct kinfo_proc); > if (sysctl(mib, 4, &ki_proc, &len, NULL, 0) == -1) And the buffer argument should be char[], not struct kinfo_proc. -- Peter Jeremy pgp5pk4M5uA63.pgp Description: PGP signature
Re: Path to executable of current process?
Is there any way to get argv[0] for [a particular] process without being root?
After more digging I see sysctl seems to be the way to do this but can I get
the full path to the executable form kinfo_proc?
How does ps do this?
static const char *
getcmdline(pid_t pid)
{
static struct kinfo_proc ki_proc;
int mib[4], len;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_PID;
mib[3] = pid;
len = sizeof(struct kinfo_proc);
if (sysctl(mib, 4, &ki_proc, &len, NULL, 0) == -1)
return NULL;
return ki_proc.ki_???
}
Mike
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Re: Path to executable of current process?
On 7/19/07, Michael B Allen <[EMAIL PROTECTED]> wrote: Hello, I'm looking for an example that uses kvm_getargv but from just googling around I can't seem to find an example. Can someone give me a pointer? Actually what I'm *really* trying to do is port some code that invokes GDB to do a backtrace and I need to give GDB the path to the executable of the current process (e.g. on linux this is /proc//exe) and the pid of the process to trace (easy - getpid). The first argument is trickey since FreeBSD frequently does not have a /proc filesystem. So it seems kvm_getargv should have this path no? Well I figured out how to get kvm_getargv working. Unfortunately it seems only root can call kvm_open so the faulting process can't backtrace unless it so happens to be running as root (which it's not). Is there any way to get argv[0] for the current process without being root? Mike ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Path to executable of current process?
Hello, I'm looking for an example that uses kvm_getargv but from just googling around I can't seem to find an example. Can someone give me a pointer? Actually what I'm *really* trying to do is port some code that invokes GDB to do a backtrace and I need to give GDB the path to the executable of the current process (e.g. on linux this is /proc//exe) and the pid of the process to trace (easy - getpid). The first argument is trickey since FreeBSD frequently does not have a /proc filesystem. So it seems kvm_getargv should have this path no? Mike ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
