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/* Validate a thread handle.
Copyright (C) 1999-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include "thread_dbP.h"
#include <stdbool.h>
static td_err_e
check_thread_list (const td_thrhandle_t *th, psaddr_t head, bool *uninit)
{
td_err_e err;
psaddr_t next, ofs;
err = DB_GET_FIELD (next, th->th_ta_p, head, list_t, next, 0);
if (err == TD_OK)
{
if (next == 0)
{
*uninit = true;
return TD_NOTHR;
}
err = DB_GET_FIELD_ADDRESS (ofs, th->th_ta_p, 0, pthread, list, 0);
}
while (err == TD_OK)
{
if (next == head)
return TD_NOTHR;
if (next - (ofs - (psaddr_t) 0) == th->th_unique)
return TD_OK;
err = DB_GET_FIELD (next, th->th_ta_p, next, list_t, next, 0);
}
return err;
}
td_err_e
td_thr_validate (const td_thrhandle_t *th)
{
td_err_e err;
psaddr_t list;
LOG ("td_thr_validate");
/* First check the list with threads using user allocated stacks. */
bool uninit = false;
err = DB_GET_SYMBOL (list, th->th_ta_p, __stack_user);
if (err == TD_OK)
err = check_thread_list (th, list, &uninit);
/* If our thread is not on this list search the list with stack
using implementation allocated stacks. */
if (err == TD_NOTHR)
{
err = DB_GET_SYMBOL (list, th->th_ta_p, stack_used);
if (err == TD_OK)
err = check_thread_list (th, list, &uninit);
if (err == TD_NOTHR && uninit && th->th_unique == 0)
/* __pthread_initialize_minimal has not run yet.
There is only the special case thread handle. */
err = TD_OK;
}
if (err == TD_OK)
{
/* Verify that this is not a stale element in a fork child. */
pid_t match_pid = ps_getpid (th->th_ta_p->ph);
psaddr_t pid;
err = DB_GET_FIELD (pid, th->th_ta_p, th->th_unique, pthread, pid, 0);
if (err == TD_OK && (pid_t) (uintptr_t) pid < 0)
{
/* This was a thread that was about to fork, or it is the new sole
thread in a fork child. In the latter case, its tid was stored
via CLONE_CHILD_SETTID and so is already the proper child PID. */
if (-(pid_t) (uintptr_t) pid == match_pid)
/* It is about to do a fork, but is really still the parent PID. */
pid = (psaddr_t) (uintptr_t) match_pid;
else
/* It must be a fork child, whose new PID is in the tid field. */
err = DB_GET_FIELD (pid, th->th_ta_p, th->th_unique,
pthread, tid, 0);
}
if (err == TD_OK && (pid_t) (uintptr_t) pid != match_pid)
err = TD_NOTHR;
}
return err;
}
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