newlib/winsup/cygwin/shared_info.h
Michael Haubenwallner 5a41aa6f4d forkables: Keep hardlinks disabled via shared mem.
To avoid the need for each process to check the filesystem to detect
that hardlink creation is impossible or disabled, cache this fact in
shared memory.  Removing cygfork directory while in use does disable
hardlinks creation.  To (re-)enable hardlinks creation, the cygfork
directory has to exist before the first cygwin process does fork.

	* forkable.cc (dll_list::forkable_ntnamesize): Short cut
	forkables needs to impossible when disabled via shared memory.
	(dll_list::update_forkables_needs): When detecting hardlink
	creation as impossible (not on NTFS) while still (we are the
	first one checking) enabled via shared memory, disable the
	shared memory value.
	(dll_list::request_forkables): Disable the shared memory value
	when hardlinks creation became disabled, that is when the
	cygfork directory was removed.
	* include/cygwin/version.h: Bump CYGWIN_VERSION_SHARED_DATA 6.
	* shared_info.h (struct shared_info): Add member
	prefer_forkable_hardlinks.  Update CURR_SHARED_MAGIC.
	* shared.cc (shared_info::initialize): Initialize
	prefer_forkable_hardlinks to 1 (Yes).
2019-02-07 15:58:02 +01:00

98 lines
2.4 KiB
C++

/* shared_info.h: shared info for cygwin
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. */
#include "tty.h"
#include "security.h"
#include "mtinfo.h"
#include "limits.h"
#include "mount.h"
#include "loadavg.h"
#define CURR_USER_MAGIC 0xab1fcce8U
class user_info
{
void initialize ();
public:
LONG version;
DWORD cb;
bool warned_msdos;
bool warned_notty;
bool warned_nonativesyms;
mount_info mountinfo;
friend void dll_crt0_1 (void *);
static void create (bool);
};
/******** Shared Info ********/
/* Data accessible to all tasks */
#define CURR_SHARED_MAGIC 0x3a6025edU
#define USER_VERSION 1
/* NOTE: Do not make gratuitous changes to the names or organization of the
below class. The layout is checksummed to determine compatibility between
different cygwin versions. */
class shared_info
{
LONG version;
DWORD cb;
public:
tty_list tty;
LONG last_used_bindresvport;
DWORD obcaseinsensitive;
mtinfo mt;
loadavginfo loadavg;
LONG pid_src;
char prefer_forkable_hardlinks; /* single byte access always is atomic */
void initialize ();
void init_obcaseinsensitive ();
unsigned heap_chunk_size ();
static void create ();
};
extern shared_info *cygwin_shared;
extern user_info *user_shared;
#define mount_table (&(user_shared->mountinfo))
extern HANDLE cygwin_user_h;
enum shared_locations
{
SH_CYGWIN_SHARED,
SH_USER_SHARED,
SH_MYSELF,
SH_SHARED_CONSOLE,
SH_TOTAL_SIZE,
SH_JUSTCREATE,
SH_JUSTOPEN
};
void memory_init ();
void __stdcall shared_destroy ();
#define shared_align_past(p) \
((char *) (system_info.dwAllocationGranularity * \
(((DWORD) ((p) + 1) + system_info.dwAllocationGranularity - 1) / \
system_info.dwAllocationGranularity)))
HANDLE get_shared_parent_dir ();
HANDLE get_session_parent_dir ();
char *__stdcall shared_name (char *, const char *, int);
WCHAR *__stdcall shared_name (WCHAR *, const WCHAR *, int);
void *__stdcall open_shared (const WCHAR *, int, HANDLE&, DWORD,
shared_locations, PSECURITY_ATTRIBUTES = &sec_all,
DWORD = FILE_MAP_READ | FILE_MAP_WRITE);
void *__stdcall open_shared (const WCHAR *, int, HANDLE&, DWORD,
shared_locations *, PSECURITY_ATTRIBUTES = &sec_all,
DWORD = FILE_MAP_READ | FILE_MAP_WRITE);
extern void user_shared_create (bool reinit);