Upstream atexit

Change-Id: Ia454a2181b5058ed9783dc02b6b1805d0e4d2715

2 files changed, 0 insertions, 303 deletions

diff --git a/libc/stdlib/atexit.c b/libc/stdlib/atexit.c
deleted file mode 100644
index e10238b..0000000
--- a/libc/stdlib/atexit.c
+++ /dev/null
@@ -1,250 +0,0 @@
-/*	$OpenBSD: atexit.c,v 1.14 2007/09/05 20:47:47 chl Exp $ */
-/*
- * Copyright (c) 2002 Daniel Hartmeier
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- *    - Redistributions of source code must retain the above copyright
- *      notice, this list of conditions and the following disclaimer.
- *    - Redistributions in binary form must reproduce the above
- *      copyright notice, this list of conditions and the following
- *      disclaimer in the documentation and/or other materials provided
- *      with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include "atexit.h"
-#include "private/thread_private.h"
-
-struct atexit *__atexit;
-
-/*
- * TODO: Read this before upstreaming:
- *
- * As of Apr 2014 there is a bug regaring function type detection logic in
- * Free/Open/NetBSD implementations of __cxa_finalize().
- *
- * What it is about:
- * First of all there are two kind of atexit handlers:
- *  1) void handler(void) - this is the regular type
- *     available for to user via atexit(.) function call.
- *
- *  2) void internal_handler(void*) - this is the type
- *     __cxa_atexit() function expects. This handler is used
- *     by C++ compiler to register static destructor calls.
- *     Note that calling this function as the handler of type (1)
- *     results in incorrect this pointer in static d-tors.
- *
- * What is wrong with BSD implementations:
- *
- *  They use dso argument to identify the handler type. The problem
- *  with it is dso is also used to identify the handlers associated
- *  with particular dynamic library and allow __cxa_finalize to call correct
- *  set of functions on dlclose(). And it cannot identify both.
- *
- * What is correct way to identify function type?
- *
- *  Consider this:
- *  1. __cxa_finalize and __cxa_atexit are part of libc and do not have access to hidden
- *     &__dso_handle.
- *  2. __cxa_atexit has only 3 arguments: function pointer, function argument, dso.
- *     none of them can be reliably used to pass information about handler type.
- *  3. following http://www.codesourcery.com/cxx-abi/abi.html#dso-dtor (3.3.5.3 - B)
- *     translation of user atexit -> __cxa_atexit(f, NULL, NULL) results in crashes
- *     on exit() after dlclose() of a library with an atexit() call.
- *
- *  One way to resolve this is to always call second form of handler, which will
- *  result in storing unused argument in register/stack depending on architecture
- *  and should not present any problems.
- *
- *  Another way is to make them dso-local in one way or the other.
- */
-
-/*
- * Function pointers are stored in a linked list of pages. The list
- * is initially empty, and pages are allocated on demand. The first
- * function pointer in the first allocated page (the last one in
- * the linked list) was reserved for the cleanup function.
- *
- * Outside the following functions, all pages are mprotect()'ed
- * to prevent unintentional/malicious corruption.
- */
-
-/*
- * Register a function to be performed at exit or when a shared object
- * with the given dso handle is unloaded dynamically.  Also used as
- * the backend for atexit().  For more info on this API, see:
- *
- *	http://www.codesourcery.com/cxx-abi/abi.html#dso-dtor
- */
-int
-__cxa_atexit(void (*func)(void *), void *arg, void *dso)
-{
-	struct atexit *p = __atexit;
-	struct atexit_fn *fnp;
-	size_t pgsize = getpagesize();
-	int ret = -1;
-
-	if (pgsize < sizeof(*p))
-		return (-1);
-	_ATEXIT_LOCK();
-	p = __atexit;
-	if (p != NULL) {
-		if (p->ind + 1 >= p->max)
-			p = NULL;
-		else if (mprotect(p, pgsize, PROT_READ | PROT_WRITE))
-			goto unlock;
-	}
-	if (p == NULL) {
-		p = mmap(NULL, pgsize, PROT_READ | PROT_WRITE,
-		    MAP_ANON | MAP_PRIVATE, -1, 0);
-		if (p == MAP_FAILED)
-			goto unlock;
-		if (__atexit == NULL) {
-			memset(&p->fns[0], 0, sizeof(p->fns[0]));
-			p->ind = 1;
-		} else
-			p->ind = 0;
-		p->max = (pgsize - ((char *)&p->fns[0] - (char *)p)) /
-		    sizeof(p->fns[0]);
-		p->next = __atexit;
-		__atexit = p;
-	}
-	fnp = &p->fns[p->ind++];
-	fnp->cxa_func = func;
-	fnp->fn_arg = arg;
-	fnp->fn_dso = dso;
-	if (mprotect(p, pgsize, PROT_READ))
-		goto unlock;
-	ret = 0;
-unlock:
-	_ATEXIT_UNLOCK();
-	return (ret);
-}
-
-/*
- * Call all handlers registered with __cxa_atexit() for the shared
- * object owning 'dso'.
- * Note: if 'dso' is NULL, then all remaining handlers are called.
- */
-void
-__cxa_finalize(void *dso)
-{
-	struct atexit *p, *q, *original_atexit;
-	struct atexit_fn fn;
-	int n, pgsize = getpagesize(), original_ind;
-	static int call_depth;
-
-	_ATEXIT_LOCK();
-	call_depth++;
-
-	p = original_atexit = __atexit;
-	n = original_ind = p != NULL ? p->ind : 0;
-	while (p != NULL) {
-		if (p->fns[n].cxa_func != NULL /* not called */
-				&& (dso == NULL || dso == p->fns[n].fn_dso)) { /* correct DSO */
-			/*
-			 * Mark handler as having been already called to avoid
-			 * dupes and loops, then call the appropriate function.
-			 */
-			fn = p->fns[n];
-			if (mprotect(p, pgsize, PROT_READ | PROT_WRITE) == 0) {
-				p->fns[n].cxa_func = NULL;
-				mprotect(p, pgsize, PROT_READ);
-			}
-
-			_ATEXIT_UNLOCK();
-			(*fn.cxa_func)(fn.fn_arg);
-			_ATEXIT_LOCK();
-			// check for new atexit handlers
-			if ((__atexit->ind != original_ind) || (__atexit != original_atexit)) {
-				// need to restart now to preserve correct
-				// call order - LIFO
-				p = original_atexit = __atexit;
-				n = original_ind = p->ind;
-				continue;
-			}
-		}
-		if (n == 0) {
-			p = p->next;
-			n = p != NULL ? p->ind : 0;
-		} else {
-			--n;
-		}
-	}
-
-	--call_depth;
-
-	/*
-	 * If called via exit(), unmap the pages since we have now run
-	 * all the handlers.  We defer this until calldepth == 0 so that
-	 * we don't unmap things prematurely if called recursively.
-	 */
-	if (dso == NULL && call_depth == 0) {
-		for (p = __atexit; p != NULL; ) {
-			q = p;
-			p = p->next;
-			munmap(q, pgsize);
-		}
-		__atexit = NULL;
-	}
-	_ATEXIT_UNLOCK();
-}
-
-/*
- * Register the cleanup function
- */
-void
-__atexit_register_cleanup(void (*func)(void))
-{
-        struct atexit *p;
-        size_t pgsize = getpagesize();
-
-        if (pgsize < sizeof(*p))
-                return;
-        _ATEXIT_LOCK();
-        p = __atexit;
-        while (p != NULL && p->next != NULL)
-                p = p->next;
-        if (p == NULL) {
-                p = mmap(NULL, pgsize, PROT_READ | PROT_WRITE,
-                    MAP_ANON | MAP_PRIVATE, -1, 0);
-                if (p == MAP_FAILED)
-                        goto unlock;
-                p->ind = 1;
-                p->max = (pgsize - ((char *)&p->fns[0] - (char *)p)) /
-                    sizeof(p->fns[0]);
-                p->next = NULL;
-                __atexit = p;
-        } else {
-                if (mprotect(p, pgsize, PROT_READ | PROT_WRITE))
-                        goto unlock;
-        }
-        p->fns[0].cxa_func = (void (*)(void*))func;
-        p->fns[0].fn_arg = NULL;
-        p->fns[0].fn_dso = NULL;
-        mprotect(p, pgsize, PROT_READ);
-unlock:
-        _ATEXIT_UNLOCK();
-}
diff --git a/libc/stdlib/atexit.h b/libc/stdlib/atexit.h
deleted file mode 100644
index b530ade..0000000
--- a/libc/stdlib/atexit.h
+++ /dev/null
@@ -1,53 +0,0 @@
-/*	$OpenBSD: atexit.h,v 1.7 2007/09/03 14:40:16 millert Exp $ */
-
-/*
- * Copyright (c) 2002 Daniel Hartmeier
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- *    - Redistributions of source code must retain the above copyright
- *      notice, this list of conditions and the following disclaimer.
- *    - Redistributions in binary form must reproduce the above
- *      copyright notice, this list of conditions and the following
- *      disclaimer in the documentation and/or other materials provided
- *      with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include <sys/cdefs.h>
-
-struct atexit {
-	struct atexit *next;		/* next in list */
-	int ind;			/* next index in this table */
-	int max;			/* max entries >= ATEXIT_SIZE */
-	struct atexit_fn {
-		void (*cxa_func)(void *);
-		void *fn_arg;		/* argument for CXA callback */
-		void *fn_dso;		/* shared module handle */
-	} fns[1];			/* the table itself */
-};
-
-__BEGIN_DECLS
-
-__LIBC_HIDDEN__ extern struct atexit *__atexit;		/* points to head of LIFO stack */
-
-int	__cxa_atexit(void (*)(void *), void *, void *);
-void	__cxa_finalize(void *);
-
-__END_DECLS