+2016-08-26 Florian Weimer <fweimer@redhat.com>
+
+ [BZ #20432]
+ Avoid strong references to malloc-internal symbols when linking
+ statically, to support statically interposed mallocs.
+ * include/libc-symbols.h (call_function_static_weak): New macro.
+ * malloc/Makefile (extra-tests-objs): Add tst-interpose-aux-nothread.o,
+ tst-interpose-aux-thread.o.
+ (test-extras): Add tst-interpose-aux-nothread,
+ tst-interpose-aux-thread.
+ * malloc/tst-interpose-aux-nothread.c: New file.
+ * malloc/tst-interpose-aux-thread.c: Likewise.
+ * malloc/tst-interpose-aux.c: Likewise.
+ * malloc/tst-interpose-aux.h: Likewise.
+ * sysdeps/mach/hurd/fork.c (__fork): Only call
+ __malloc_fork_lock_parent, __malloc_fork_unlock_parent,
+ __malloc_fork_unlock_child if defined.
+ * sysdeps/nptl/fork.c (__libc_fork): Likewise.
+
2016-08-02 Florian Weimer <fweimer@redhat.com>
[BZ #19469]
# define weak_extern(symbol) _weak_extern (weak symbol)
# define _weak_extern(expr) _Pragma (#expr)
+/* In shared builds, the expression call_function_static_weak
+ (FUNCTION-SYMBOL, ARGUMENTS) invokes FUNCTION-SYMBOL (an
+ identifier) unconditionally, with the (potentially empty) argument
+ list ARGUMENTS. In static builds, if FUNCTION-SYMBOL has a
+ definition, the function is invoked as before; if FUNCTION-SYMBOL
+ is NULL, no call is performed. */
+# ifdef SHARED
+# define call_function_static_weak(func, ...) func (__VA_ARGS__)
+# else /* !SHARED */
+# define call_function_static_weak(func, ...) \
+ ({ \
+ extern __typeof__ (func) func weak_function; \
+ (func != NULL ? func (__VA_ARGS__) : (void)0); \
+ })
+# endif
#else /* __ASSEMBLER__ */
tst-malloc-backtrace tst-malloc-thread-exit \
tst-malloc-thread-fail tst-malloc-fork-deadlock \
tst-mallocfork2
+
test-srcs = tst-mtrace
routines = malloc morecore mcheck mtrace obstack \
extra-libs = libmemusage
extra-libs-others = $(extra-libs)
+# Helper objects for some tests.
+extra-tests-objs += \
+ tst-interpose-aux-nothread.o \
+ tst-interpose-aux-thread.o \
+
+test-extras = \
+ tst-interpose-aux-nothread \
+ tst-interpose-aux-thread \
+
libmemusage-routines = memusage
libmemusage-inhibit-o = $(filter-out .os,$(object-suffixes))
--- /dev/null
+/* Interposed malloc, version without threading support.
+ Copyright (C) 2016 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; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#define INTERPOSE_THREADS 0
+#include "tst-interpose-aux.c"
--- /dev/null
+/* Interposed malloc, version with threading support.
+ Copyright (C) 2016 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; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#define INTERPOSE_THREADS 1
+#include "tst-interpose-aux.c"
--- /dev/null
+/* Minimal malloc implementation for interposition tests.
+ Copyright (C) 2016 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; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#include "tst-interpose-aux.h"
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#if INTERPOSE_THREADS
+#include <pthread.h>
+#endif
+
+/* Print the error message and terminate the process with status 1. */
+__attribute__ ((noreturn))
+__attribute__ ((format (printf, 1, 2)))
+static void *
+fail (const char *format, ...)
+{
+ /* This assumes that vsnprintf will not call malloc. It does not do
+ so for the format strings we use. */
+ char message[4096];
+ va_list ap;
+ va_start (ap, format);
+ vsnprintf (message, sizeof (message), format, ap);
+ va_end (ap);
+
+ enum { count = 3 };
+ struct iovec iov[count];
+
+ iov[0].iov_base = (char *) "error: ";
+ iov[1].iov_base = (char *) message;
+ iov[2].iov_base = (char *) "\n";
+
+ for (int i = 0; i < count; ++i)
+ iov[i].iov_len = strlen (iov[i].iov_base);
+
+ int unused __attribute__ ((unused));
+ unused = writev (STDOUT_FILENO, iov, count);
+ _exit (1);
+}
+
+#if INTERPOSE_THREADS
+static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
+
+static void
+lock (void)
+{
+#if INTERPOSE_THREADS
+ int ret = pthread_mutex_lock (&mutex);
+ if (ret != 0)
+ {
+ errno = ret;
+ fail ("pthread_mutex_lock: %m");
+ }
+#endif
+}
+
+static void
+unlock (void)
+{
+#if INTERPOSE_THREADS
+ int ret = pthread_mutex_unlock (&mutex);
+ if (ret != 0)
+ {
+ errno = ret;
+ fail ("pthread_mutex_unlock: %m");
+ }
+#endif
+}
+
+struct __attribute__ ((aligned (__alignof__ (max_align_t)))) allocation_header
+{
+ size_t allocation_index;
+ size_t allocation_size;
+};
+
+/* Array of known allocations, to track invalid frees. */
+enum { max_allocations = 65536 };
+static struct allocation_header *allocations[max_allocations];
+static size_t allocation_index;
+static size_t deallocation_count;
+
+/* Sanity check for successful malloc interposition. */
+__attribute__ ((destructor))
+static void
+check_for_allocations (void)
+{
+ if (allocation_index == 0)
+ {
+ /* Make sure that malloc is called at least once from libc. */
+ void *volatile ptr = strdup ("ptr");
+ free (ptr);
+ /* Compiler barrier. The strdup function calls malloc, which
+ updates allocation_index, but strdup is marked __THROW, so
+ the compiler could optimize away the reload. */
+ __asm__ volatile ("" ::: "memory");
+ /* If the allocation count is still zero, it means we did not
+ interpose malloc successfully. */
+ if (allocation_index == 0)
+ fail ("malloc does not seem to have been interposed");
+ }
+}
+
+static struct allocation_header *get_header (const char *op, void *ptr)
+{
+ struct allocation_header *header = ((struct allocation_header *) ptr) - 1;
+ if (header->allocation_index >= allocation_index)
+ fail ("%s: %p: invalid allocation index: %zu (not less than %zu)",
+ op, ptr, header->allocation_index, allocation_index);
+ if (allocations[header->allocation_index] != header)
+ fail ("%s: %p: allocation pointer does not point to header, but %p",
+ op, ptr, allocations[header->allocation_index]);
+ return header;
+}
+
+/* Internal helper functions. Those must be called while the lock is
+ acquired. */
+
+static void *
+malloc_internal (size_t size)
+{
+ if (allocation_index == max_allocations)
+ {
+ errno = ENOMEM;
+ return NULL;
+ }
+ size_t allocation_size = size + sizeof (struct allocation_header);
+ if (allocation_size < size)
+ {
+ errno = ENOMEM;
+ return NULL;
+ }
+
+ size_t index = allocation_index++;
+ void *result = mmap (NULL, allocation_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (result == MAP_FAILED)
+ return NULL;
+ allocations[index] = result;
+ *allocations[index] = (struct allocation_header)
+ {
+ .allocation_index = index,
+ .allocation_size = allocation_size
+ };
+ return allocations[index] + 1;
+}
+
+static void
+free_internal (const char *op, struct allocation_header *header)
+{
+ size_t index = header->allocation_index;
+ int result = mprotect (header, header->allocation_size, PROT_NONE);
+ if (result != 0)
+ fail ("%s: mprotect (%p, %zu): %m", op, header, header->allocation_size);
+ /* Catch double-free issues. */
+ allocations[index] = NULL;
+ ++deallocation_count;
+}
+
+static void *
+realloc_internal (void *ptr, size_t new_size)
+{
+ struct allocation_header *header = get_header ("realloc", ptr);
+ size_t old_size = header->allocation_size - sizeof (struct allocation_header);
+ if (old_size >= new_size)
+ return ptr;
+
+ void *newptr = malloc_internal (new_size);
+ if (newptr == NULL)
+ return NULL;
+ memcpy (newptr, ptr, old_size);
+ free_internal ("realloc", header);
+ return newptr;
+}
+
+/* Public interfaces. These functions must perform locking. */
+
+size_t
+malloc_allocation_count (void)
+{
+ lock ();
+ size_t count = allocation_index;
+ unlock ();
+ return count;
+}
+
+size_t
+malloc_deallocation_count (void)
+{
+ lock ();
+ size_t count = deallocation_count;
+ unlock ();
+ return count;
+}
+void *
+malloc (size_t size)
+{
+ lock ();
+ void *result = malloc_internal (size);
+ unlock ();
+ return result;
+}
+
+void
+free (void *ptr)
+{
+ if (ptr == NULL)
+ return;
+ lock ();
+ struct allocation_header *header = get_header ("free", ptr);
+ free_internal ("free", header);
+ unlock ();
+}
+
+void *
+calloc (size_t a, size_t b)
+{
+ if (b > 0 && a > SIZE_MAX / b)
+ {
+ errno = ENOMEM;
+ return NULL;
+ }
+ lock ();
+ /* malloc_internal uses mmap, so the memory is zeroed. */
+ void *result = malloc_internal (a * b);
+ unlock ();
+ return result;
+}
+
+void *
+realloc (void *ptr, size_t n)
+{
+ if (n ==0)
+ {
+ free (ptr);
+ return NULL;
+ }
+ else if (ptr == NULL)
+ return malloc (n);
+ else
+ {
+ lock ();
+ void *result = realloc_internal (ptr, n);
+ unlock ();
+ return result;
+ }
+}
--- /dev/null
+/* Statistics interface for the minimal malloc implementation.
+ Copyright (C) 2016 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; see the file COPYING.LIB. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef TST_INTERPOSE_AUX_H
+#define TST_INTERPOSE_AUX_H
+
+#include <stddef.h>
+
+/* Return the number of allocations performed. */
+size_t malloc_allocation_count (void);
+
+/* Return the number of deallocations performed. */
+size_t malloc_deallocation_count (void);
+
+#endif /* TST_INTERPOSE_AUX_H */
handlers may use malloc, and the libio list lock has an
indirect malloc dependency as well (via the getdelim
function). */
- __malloc_fork_lock_parent ();
+ call_function_static_weak (__malloc_fork_lock_parent);
/* Lock things that want to be locked before we fork. */
{
}
/* Release malloc locks. */
- __malloc_fork_unlock_parent ();
+ call_function_static_weak (__malloc_fork_unlock_parent);
/* Run things that want to run in the parent to restore it to
normality. Usually prepare hooks and parent hooks are
__sigemptyset (&_hurdsig_traced);
/* Release malloc locks. */
- __malloc_fork_unlock_child ();
+ call_function_static_weak (__malloc_fork_unlock_child);
/* Run things that want to run in the child task to set up. */
RUN_HOOK (_hurd_fork_child_hook, ());
handlers may use malloc, and the libio list lock has an
indirect malloc dependency as well (via the getdelim
function). */
- __malloc_fork_lock_parent ();
+ call_function_static_weak (__malloc_fork_lock_parent);
}
#ifndef NDEBUG
if (multiple_threads)
{
/* Release malloc locks. */
- __malloc_fork_unlock_child ();
+ call_function_static_weak (__malloc_fork_unlock_child);
/* Reset the file list. These are recursive mutexes. */
fresetlockfiles ();
if (multiple_threads)
{
/* Release malloc locks, parent process variant. */
- __malloc_fork_unlock_parent ();
+ call_function_static_weak (__malloc_fork_unlock_parent);
/* We execute this even if the 'fork' call failed. */
_IO_list_unlock ();
projects / thirdparty / glibc.git / commitdiff
