pstack

pstack

#!/bin/sh

function __pstack() {
    if test ! -r /proc/$1; then
	echo "Process $1 not found." 1>&2
	exit 1
    fi

    # GDB doesn't allow "thread apply all bt" when the process isn't
    # threaded; need to peek at the process to determine if that or the
    # simpler "bt" should be used.

    backtrace="bt"
    if test -d /proc/$1/task ; then
	# Newer kernel; has a task/ directory.
	if test `/bin/ls /proc/$1/task | /usr/bin/wc -l` -gt 1 2>/dev/null ; then
            backtrace="thread apply all bt"
	fi
    elif test -f /proc/$1/maps ; then
	# Older kernel; go by it loading libpthread.
	if /bin/grep -e libpthread /proc/$1/maps > /dev/null 2>&1 ; then
            backtrace="thread apply all bt"
	fi
    fi

    GDB=${GDB:-/usr/bin/gdb}

    if $GDB -nx --quiet --batch --readnever > /dev/null 2>&1; then
	readnever=--readnever
    else
	readnever=
    fi

    # Run GDB, strip out unwanted noise.
    $GDB --quiet $readnever -nx /proc/$1/exe $1 <<EOF 2>&1 |
$backtrace
EOF
    /bin/sed -n \
	     -e 's/^(gdb) //' \
	     -e '/^#/p' \
	     -e '/^Thread/p'
}

if test $# -ne 1; then
    echo "Usage: `basename $0 .sh` <main-process-id>" 1>&2
    exit 1
fi

for pid in $(ls -1 /proc/$1/task/)
do
    __pstack $pid
done