df04ae29b2
is a tty associated with the process. Send SIGHUP on CTRL_LOGOFF_EVENT. * fhandler_tty.cc (fhandler_tty_slave::open): Adjust console open handle counter regardless of whether this is a pty or tty. (fhandler_tty_slave::open): Ditto. (fhandler_tty_slave::dup): Ditto. (fhandler_tty_common::set_close_on_exec): Ditto. (fhandler_tty_master::init_console): Decrement console open handle counter after init since it will now be handled by all tty open. * syscalls.cc (setsid): Rework debugging output slightly.
93 lines
3.8 KiB
C++
93 lines
3.8 KiB
C++
/* ipc.cc: Single unix specification IPC interface for Cygwin
|
|
|
|
Copyright 2001, 2002, 2003 Red Hat, Inc.
|
|
|
|
Originally written by Robert Collins <robert.collins@hotmail.com>
|
|
Updated to 64 bit key_t by Charles Wilson <cygwin@cwilson.fastmail.fm>
|
|
|
|
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 "winsup.h"
|
|
#include <cygwin/ipc.h>
|
|
#include <sys/stat.h>
|
|
|
|
/* Notes: we return a valid key even if id's low order 8 bits are 0. */
|
|
extern "C" key_t
|
|
ftok (const char *path, int id)
|
|
{
|
|
struct __stat64 statbuf;
|
|
key_t tmp;
|
|
if (stat64 (path, &statbuf))
|
|
{
|
|
/* stat set the appropriate errno for us */
|
|
return (key_t) -1;
|
|
}
|
|
|
|
/* Since __CYGWIN_USE_BIG_TYPES__,
|
|
dev_t is 32bits for cygwin
|
|
ino_t is 64bits for cygwin
|
|
and we need 8 bits for the id.
|
|
thus key_t needs 104 bits total -- but we only have 64 (long long)
|
|
We will have to alias; leaving open the possibility that the same
|
|
key will be returned for multiple files. This possibility exists
|
|
also on Linux; the question is, how to minimize this possibility.
|
|
|
|
How to solve? Well, based on C. Vinschen's research, the nFileIndex*
|
|
words vary as follows, on a partition with > 110,000 files
|
|
nFileIndexHigh: 564 values between 0x00010000 -- 0xffff0000
|
|
nFileIndexLow : 103812 values between 0x00000000 -- 0x0003ffff
|
|
R. Collins suggests that these may represent a tree path,
|
|
and that it would require ~2.9M files to force the tree depth
|
|
to increase and reveal more bit usage.
|
|
|
|
Implementation details: dev_t is 32bits, but is formed by
|
|
device(32bits) << 16 | unit(32bits)
|
|
But device is ACTUALLY == status & FH_DEVMASK, where FH_DEVMASK
|
|
is 0x00000fff --> 12 bits
|
|
|
|
As it happens, the maximum number of devices is actually
|
|
FH_NDEV, not FH_DEVMASK, where FH_NDEV is currently 0x0000001d.
|
|
However, FH_NDEV grows as new device types are added. So
|
|
currently the device number needs 5 bits, but later? Let's
|
|
take a cue from Linux, and use the lower 8 bits (instead of the
|
|
lower 12 or 16) for the device (major?) number.
|
|
|
|
Similarly, while 'units' is an int (32bits), it is unclear
|
|
how many of these are significant. For most devices, it seems that
|
|
'units' is equivalent to 'minor'. For FH_TAPE, it's obvious that
|
|
only 8 bits are important. However, for FH_SOCKET...it might be
|
|
as high as 16 significant bits.
|
|
|
|
Let's assume that we only need 8 bits from device (major) and
|
|
only 8 bits from unit (minor). (On linux, only 8 bits of minor
|
|
are used, and none from major).
|
|
---> so, we only need 0x00ff00ff (16 bits) of dev_t
|
|
|
|
---> we MUST have all 8 bits of id.
|
|
|
|
---> So, we only have 64 - 8 - 16 = 40 bits for ino_t. But, we
|
|
need 0xffff0000 for nFileIndexHigh and 0x0003ffff for nFileIndexLow
|
|
minimum, or 16 + 18 = 34 bits. Lucky us - we have 6 more bits
|
|
to distribute.
|
|
|
|
For lack of a better idea, we'll allocate 2 of the extra bits to
|
|
nFileIndexHigh and 4 to nFileIndexLow. */
|
|
|
|
/* get 8 bits from dev_t (major), put into 0xff00000000000000L */
|
|
tmp = (((key_t) statbuf.st_dev) & 0x0000000000ff0000LL) << 40;
|
|
/* get 8 bits from dev_t (minor), put into 0x00ff000000000000L */
|
|
tmp |= (((key_t) statbuf.st_dev) & 0x00000000000000ffLL) << 48;
|
|
/* get upper 16+2 bits from nFileInfoHigh, put into 0x0000ffffc0000000L
|
|
shift down first, then mask, to avoid sign extension on rightshift */
|
|
tmp |= (((key_t) statbuf.st_ino) & 0xffffc00000000000LL) >> 16;
|
|
/* get lower 18+4 bits from nFileInfoLow, put into 0x000000003fffff00L */
|
|
tmp |= (((key_t) statbuf.st_ino) & 0x00000000003fffffLL) << 8;
|
|
/* use all 8 bits of id, and put into 0x00000000000000ffL */
|
|
tmp |= (id & 0x00ff);
|
|
return tmp;
|
|
}
|