/* Copyright (C) 1991-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. 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 <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sysdep.h> #include <libc-lock.h> #include "exit.h" #include "set-hooks.h" DEFINE_HOOK (__libc_atexit, (void)) /* Initialize the flag that indicates exit function processing is complete. See concurrency notes in stdlib/exit.h where __exit_funcs_lock is declared. */ bool __exit_funcs_done = false; /* Call all functions registered with `atexit' and `on_exit', in the reverse of the order in which they were registered perform stdio cleanup, and terminate program execution with STATUS. */ void attribute_hidden __run_exit_handlers (int status, struct exit_function_list **listp, bool run_list_atexit, bool run_dtors) { /* First, call the TLS destructors. */ #ifndef SHARED if (&__call_tls_dtors != NULL) #endif if (run_dtors) __call_tls_dtors (); /* We do it this way to handle recursive calls to exit () made by the functions registered with `atexit' and `on_exit'. We call everyone on the list and use the status value in the last exit (). */ while (true) { struct exit_function_list *cur; __libc_lock_lock (__exit_funcs_lock); restart: cur = *listp; if (cur == NULL) { /* Exit processing complete. We will not allow any more atexit/on_exit registrations. */ __exit_funcs_done = true; __libc_lock_unlock (__exit_funcs_lock); break; } while (cur->idx > 0) { struct exit_function *const f = &cur->fns[--cur->idx]; const uint64_t new_exitfn_called = __new_exitfn_called; /* Unlock the list while we call a foreign function. */ __libc_lock_unlock (__exit_funcs_lock); switch (f->flavor) { void (*atfct) (void); void (*onfct) (int status, void *arg); void (*cxafct) (void *arg, int status); case ef_free: case ef_us: break; case ef_on: onfct = f->func.on.fn; #ifdef PTR_DEMANGLE PTR_DEMANGLE (onfct); #endif onfct (status, f->func.on.arg); break; case ef_at: atfct = f->func.at; #ifdef PTR_DEMANGLE PTR_DEMANGLE (atfct); #endif atfct (); break; case ef_cxa: /* To avoid dlclose/exit race calling cxafct twice (BZ 22180), we must mark this function as ef_free. */ f->flavor = ef_free; cxafct = f->func.cxa.fn; #ifdef PTR_DEMANGLE PTR_DEMANGLE (cxafct); #endif cxafct (f->func.cxa.arg, status); break; } /* Re-lock again before looking at global state. */ __libc_lock_lock (__exit_funcs_lock); if (__glibc_unlikely (new_exitfn_called != __new_exitfn_called)) /* The last exit function, or another thread, has registered more exit functions. Start the loop over. */ goto restart; } *listp = cur->next; if (*listp != NULL) /* Don't free the last element in the chain, this is the statically allocate element. */ free (cur); __libc_lock_unlock (__exit_funcs_lock); } if (run_list_atexit) RUN_HOOK (__libc_atexit, ()); _exit (status); } void exit (int status) { __run_exit_handlers (status, &__exit_funcs, true, true); } libc_hidden_def (exit)