gnulib: upgrade to today's version
* tools/snippet/_Noreturn.h, tools/snippet/c++defs.h, tools/snippet/arg-nonnull.h, tools/snippet/warn-on-use.h: Rename to... * lib/_Noreturn.h, lib/c++defs.h, lib/arg-nonnull.h, lib/warn-on-use.h: ... these. * lib/filename.h, lib/getopt-cdefs.in.h, lib/getopt-core.h, lib/getopt-ext.h, lib/getopt-pfx-core.h, lib/getopt-pfx-ext.h, lib/localtime-buffer.c, lib/localtime-buffer.h, lib/malloca.c, lib/malloca.h, lib/malloca.valgrind, lib/stat-w32.c, lib/stat-w32.h, m4/eealloc.m4, m4/localtime-buffer.m4, m4/malloca.m4: New files. * lib/argp-help.c, lib/argp-parse.c, lib/error.c, lib/float.in.h, lib/getopt1.c, lib/getopt.c, lib/getopt.in.h, lib/getopt_int.h, lib/gettext.h, lib/gettimeofday.c, lib/intprops.h, lib/isatty.c, lib/limits.in.h, lib/localcharset.c, lib/Makefile.am, lib/mbrtowc.c, lib/mbsinit.c, lib/msvc-nothrow.c, lib/quotearg.c, lib/stat.c, lib/stdalign.in.h, lib/stdint.in.h, lib/string.in.h, lib/sys_stat.in.h, lib/sys_types.in.h, lib/tempname.c, lib/time.in.h, lib/unistd.in.h, lib/vasnprintf.c, lib/wchar.in.h, lib/wctype.in.h, lib/xalloc.h, lib/xalloc-oversized.h, m4/fcntl-o.m4, m4/float_h.m4, m4/getopt.m4, m4/gettimeofday.m4, m4/gnulib-common.m4, m4/gnulib-comp.m4, m4/include_next.m4, m4/largefile.m4, m4/lstat.m4, m4/mbrtowc.m4, m4/memchr.m4, m4/mkstemp.m4, m4/printf.m4, m4/sleep.m4, m4/stat.m4, m4/stdalign.m4, m4/stdint.m4, m4/strerror.m4, m4/string_h.m4, m4/sys_stat_h.m4, m4/sys_time_h.m4, m4/sys_types_h.m4, m4/time_h.m4, m4/unistd_h.m4, m4/wchar_h.m4, m4/wctype_h.m4, m4/wint_t.m4: Update.
This commit is contained in:
Alexandre Duret-Lutz
parent
aa8cf6ac92
commit
80d50c5665
81 changed files with 3458 additions and 1954 deletions
159
lib/malloca.c
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159
lib/malloca.c
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/* Safe automatic memory allocation.
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Copyright (C) 2003, 2006-2007, 2009-2017 Free Software Foundation, Inc.
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Written by Bruno Haible <bruno@clisp.org>, 2003.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>. */
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#define _GL_USE_STDLIB_ALLOC 1
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#include <config.h>
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/* Specification. */
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#include "malloca.h"
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#include <stdint.h>
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#include "verify.h"
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/* Silence a warning from clang's MemorySanitizer. */
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#if defined __has_feature
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# if __has_feature(memory_sanitizer)
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# define NO_SANITIZE_MEMORY __attribute__((no_sanitize("memory")))
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# endif
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#endif
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#ifndef NO_SANITIZE_MEMORY
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# define NO_SANITIZE_MEMORY
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#endif
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/* The speed critical point in this file is freea() applied to an alloca()
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result: it must be fast, to match the speed of alloca(). The speed of
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mmalloca() and freea() in the other case are not critical, because they
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are only invoked for big memory sizes. */
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#if HAVE_ALLOCA
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/* Store the mmalloca() results in a hash table. This is needed to reliably
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distinguish a mmalloca() result and an alloca() result.
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Although it is possible that the same pointer is returned by alloca() and
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by mmalloca() at different times in the same application, it does not lead
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to a bug in freea(), because:
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- Before a pointer returned by alloca() can point into malloc()ed memory,
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the function must return, and once this has happened the programmer must
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not call freea() on it anyway.
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- Before a pointer returned by mmalloca() can point into the stack, it
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must be freed. The only function that can free it is freea(), and
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when freea() frees it, it also removes it from the hash table. */
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#define MAGIC_NUMBER 0x1415fb4a
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#define MAGIC_SIZE sizeof (int)
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/* This is how the header info would look like without any alignment
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considerations. */
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struct preliminary_header { void *next; int magic; };
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/* But the header's size must be a multiple of sa_alignment_max. */
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#define HEADER_SIZE \
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(((sizeof (struct preliminary_header) + sa_alignment_max - 1) / sa_alignment_max) * sa_alignment_max)
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union header {
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void *next;
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struct {
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char room[HEADER_SIZE - MAGIC_SIZE];
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int word;
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} magic;
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};
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verify (HEADER_SIZE == sizeof (union header));
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/* We make the hash table quite big, so that during lookups the probability
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of empty hash buckets is quite high. There is no need to make the hash
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table resizable, because when the hash table gets filled so much that the
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lookup becomes slow, it means that the application has memory leaks. */
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#define HASH_TABLE_SIZE 257
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static void * mmalloca_results[HASH_TABLE_SIZE];
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#endif
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void *
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mmalloca (size_t n)
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{
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#if HAVE_ALLOCA
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/* Allocate one more word, that serves as an indicator for malloc()ed
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memory, so that freea() of an alloca() result is fast. */
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size_t nplus = n + HEADER_SIZE;
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if (nplus >= n)
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{
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void *p = malloc (nplus);
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if (p != NULL)
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{
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size_t slot;
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union header *h = p;
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p = h + 1;
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/* Put a magic number into the indicator word. */
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h->magic.word = MAGIC_NUMBER;
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/* Enter p into the hash table. */
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slot = (uintptr_t) p % HASH_TABLE_SIZE;
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h->next = mmalloca_results[slot];
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mmalloca_results[slot] = p;
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return p;
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}
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}
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/* Out of memory. */
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return NULL;
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#else
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# if !MALLOC_0_IS_NONNULL
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if (n == 0)
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n = 1;
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# endif
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return malloc (n);
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#endif
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}
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#if HAVE_ALLOCA
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void NO_SANITIZE_MEMORY
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freea (void *p)
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{
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/* mmalloca() may have returned NULL. */
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if (p != NULL)
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{
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/* Attempt to quickly distinguish the mmalloca() result - which has
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a magic indicator word - and the alloca() result - which has an
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uninitialized indicator word. It is for this test that sa_increment
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additional bytes are allocated in the alloca() case. */
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if (((int *) p)[-1] == MAGIC_NUMBER)
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{
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/* Looks like a mmalloca() result. To see whether it really is one,
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perform a lookup in the hash table. */
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size_t slot = (uintptr_t) p % HASH_TABLE_SIZE;
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void **chain = &mmalloca_results[slot];
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for (; *chain != NULL;)
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{
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union header *h = p;
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if (*chain == p)
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{
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/* Found it. Remove it from the hash table and free it. */
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union header *p_begin = h - 1;
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*chain = p_begin->next;
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free (p_begin);
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return;
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}
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h = *chain;
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chain = &h[-1].next;
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}
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}
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/* At this point, we know it was not a mmalloca() result. */
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}
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}
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#endif
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