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Corinna Vinschen e528cfe919 Cygwin: split malloc_init
Cygwin 3.3 only: Replace SRWLOCK usage for malloc synchronization with
the first incarnation of the patch splitting malloc_init into two parts.
The SRWLOCK usage requires TryAcquireSRWLockExclusive, which isn't
available on Vista / Server 2008, unfortunately.

Per https://cygwin.com/pipermail/cygwin-developers/2021-October/012429.html,
we may encounter a crash when starting multiple threads during process
startup (here: fhandler_fifo::fixup_after_{fork,exec}) which in turn
allocate memory via malloc.

The problem is concurrent usage of malloc before the malloc muto has
been initialized.

To fix this issue, split malloc_init into malloc_init_0, called from
dll_crt0_0, and malloc_init_1, called from dll_crt_0_1.  malloc_init_0
just initializes the muto, malloc_init_1 checks for user space provided
malloc.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2021-10-28 22:35:17 +02:00

50 lines
1.2 KiB
C

/* cygmalloc.h: cygwin DLL malloc stuff
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#ifdef __cplusplus
extern "C" {
#endif
#include "regparm.h"
void __reg1 dlfree (void *p);
void __reg1 *dlmalloc (size_t size);
void __reg2 *dlrealloc (void *p, size_t size);
void __reg2 *dlcalloc (size_t nmemb, size_t size);
void __reg2 *dlmemalign (size_t alignment, size_t bytes);
void __reg1 *dlvalloc (size_t bytes);
size_t __reg1 dlmalloc_usable_size (void *p);
int __reg1 dlmalloc_trim (size_t);
int __reg2 dlmallopt (int p, int v);
void dlmalloc_stats ();
#ifdef __x86_64__
#define MALLOC_ALIGNMENT ((size_t)16U)
#endif
#if defined (DLMALLOC_VERSION) /* Building malloc.cc */
extern "C" void __set_ENOMEM ();
void *mmap64 (void *, size_t, int, int, int, off_t);
# define mmap mmap64
# define MALLOC_FAILURE_ACTION __set_ENOMEM ()
# define USE_DL_PREFIX 1
#elif defined (__INSIDE_CYGWIN__)
# define __malloc_lock() mallock.acquire ()
# define __malloc_unlock() mallock.release ()
extern muto mallock;
inline void malloc_init_0 () { mallock.init ("mallock"); }
extern void malloc_init_1 ();
#endif
#ifdef __cplusplus
}
#endif