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Implement dotlocking for W32.

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This commit is contained in:
Werner Koch 2008-06-13 16:18:59 +00:00
parent 04e965c7fc
commit 5bc7732a73
4 changed files with 267 additions and 127 deletions
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2
g10/build-packet.c
View File

@ -589,7 +589,7 @@ do_compressed( IOBUF out, int ctb, PKT_compressed *cd )
{
int rc = 0;
/* We must use the old convention and don't use blockmode for tyhe
/* We must use the old convention and don't use blockmode for the
sake of PGP 2 compatibility. However if the new_ctb flag was
set, CTB is already formatted as new style and write_header2
does create a partial length encoding using new the new

5
jnlib/ChangeLog
View File

@ -1,3 +1,8 @@
2008-06-13 Werner Koch <wk@g10code.com>
* dotlock.c: Reformat code and implement locking for W32.
(create_dotlock): Use snprintf.
2008-06-11 Werner Koch <wk@g10code.com>
* utf8conv.c: Remove useless variable ACTIVE_CHARSET. Suggested

386
jnlib/dotlock.c
View File

@ -1,6 +1,6 @@
/* dotlock.c - dotfile locking
* Copyright (C) 1998, 2000, 2001, 2003, 2004,
* 2005, 2006 Free Software Foundation, Inc.
* 2005, 2006, 2008 Free Software Foundation, Inc.
*
* This file is part of JNLIB.
*
@ -25,8 +25,11 @@
#include <ctype.h>
#include <errno.h>
#include <unistd.h>
#ifndef HAVE_DOSISH_SYSTEM
#include <sys/utsname.h>
#ifdef HAVE_DOSISH_SYSTEM
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#else
# include <sys/utsname.h>
#endif
#include <sys/types.h>
#include <sys/time.h>
@ -54,69 +57,97 @@
#endif
/* The object describing a lock. */
struct dotlock_handle
{
struct dotlock_handle *next;
char *tname; /* Name of lockfile template. */
char *lockname; /* Name of the actual lockfile. */
int locked; /* Lock status. */
int disable; /* If true, locking is disabled. */
#ifdef HAVE_DOSISH_SYSTEM
HANDLE lockhd; /* The W32 handle of the lock file. */
#else
char *tname; /* Name of the lockfile template. */
size_t nodename_off; /* Offset in TNAME of the nodename part. */
size_t nodename_len; /* Length of the nodename part. */
char *lockname; /* Name of the real lockfile. */
int locked; /* Lock status. */
int disable; /* When true, locking is disabled. */
size_t nodename_len; /* Length of the nodename part. */
#endif /* HAVE_DOSISH_SYSTEM */
};
/* A list of of all lock handles. */
static volatile DOTLOCK all_lockfiles;
/* If this has the value true all locking is disabled. */
static int never_lock;
static int read_lockfile (DOTLOCK h, int *same_node);
/* Local protototypes. */
#ifndef HAVE_DOSISH_SYSTEM
static int read_lockfile (DOTLOCK h, int *same_node);
#endif /*!HAVE_DOSISH_SYSTEM*/
/* Entirely disable all locking. This function should be called
before any locking is done. It may be called right at startup of
the process as it only sets a global value. */
void
disable_dotlock(void)
{
never_lock = 1;
}
/****************
* Create a lockfile with the given name and return an object of
* type DOTLOCK which may be used later to actually do the lock.
* A cleanup routine gets installed to cleanup left over locks
* or other files used together with the lock mechanism.
* Although the function is called dotlock, this does not necessarily
* mean that real lockfiles are used - the function may decide to
* use fcntl locking. Calling the function with NULL only install
* the atexit handler and maybe used to assure that the cleanup
* is called after all other atexit handlers.
*
* Notes: This function creates a lock file in the same directory
* as file_to_lock with the name "file_to_lock.lock"
* A temporary file ".#lk.<hostname>.pid[.threadid] is used.
* This function does nothing for Windoze.
/* Create a lockfile for a file name FILE_TO_LOCK and returns an
object of type DOTLOCK which may be used later to actually acquire
the lock. A cleanup routine gets installed to cleanup left over
locks or other files used internally by the lock mechanism.
Calling this function with NULL does only install the atexit
handler and may thus be used to assure that the cleanup is called
after all other atexit handlers.
This function creates a lock file in the same directory as
FILE_TO_LOCK using that name and a suffix of ".lock". Note that on
POSIX systems a temporary file ".#lk.<hostname>.pid[.threadid] is
used.
The function returns an new handle which needs to be released using
destroy_dotlock but gets also released at the termination of the
process. On error NULL is returned.
*/
DOTLOCK
create_dotlock( const char *file_to_lock )
create_dotlock (const char *file_to_lock)
{
static int initialized;
DOTLOCK h;
#ifndef HAVE_DOSISH_SYSTEM
int fd = -1;
char pidstr[16];
const char *nodename;
const char *dirpart;
int dirpartlen;
#ifndef HAVE_DOSISH_SYSTEM
struct utsname utsbuf;
size_t tnamelen;
#endif
if ( !initialized )
{
atexit( dotlock_remove_lockfiles );
atexit (dotlock_remove_lockfiles);
initialized = 1;
}
if ( !file_to_lock )
return NULL; /* Only initialization was requested. */
h = jnlib_xcalloc ( 1, sizeof *h );
if( never_lock )
h = jnlib_calloc (1, sizeof *h);
if (!h)
return NULL;
if (never_lock)
{
h->disable = 1;
#ifdef _REENTRANT
@ -128,7 +159,12 @@ create_dotlock( const char *file_to_lock )
}
#ifndef HAVE_DOSISH_SYSTEM
sprintf (pidstr, "%10d\n", (int)getpid() );
/*
This is the POSIX version which uses a temporary file and the
link system call to make locking an atomic operation.
*/
snprintf (pidstr, sizeof pidstr, "%10d\n", (int)getpid() );
/* fixme: add the hostname to the second line (FQDN or IP addr?) */
/* Create a temporary file. */
@ -146,7 +182,7 @@ create_dotlock( const char *file_to_lock )
}
#endif /* __riscos__ */
if ( !(dirpart = strrchr ( file_to_lock, DIRSEP_C )) )
if ( !(dirpart = strrchr (file_to_lock, DIRSEP_C)) )
{
dirpart = EXTSEP_S;
dirpartlen = 1;
@ -163,16 +199,26 @@ create_dotlock( const char *file_to_lock )
h->next = all_lockfiles;
all_lockfiles = h;
h->tname = jnlib_xmalloc ( dirpartlen + 6+30+ strlen(nodename) + 11 );
tnamelen = dirpartlen + 6 + 30 + strlen(nodename) + 10;
h->tname = jnlib_malloc (tnamelen + 1);
if (!h->tname)
{
all_lockfiles = h->next;
jnlib_free (h);
return NULL;
}
h->nodename_len = strlen (nodename);
#ifndef __riscos__
sprintf (h->tname, "%.*s/.#lk%p.", dirpartlen, dirpart, h );
snprintf (h->tname, tnamelen, "%.*s/.#lk%p.", dirpartlen, dirpart, h );
h->nodename_off = strlen (h->tname);
sprintf (h->tname+h->nodename_off, "%s.%d", nodename, (int)getpid ());
snprintf (h->tname+h->nodename_off, tnamelen - h->nodename_off,
"%s.%d", nodename, (int)getpid ());
#else /* __riscos__ */
sprintf (h->tname, "%.*s.lk%p/", dirpartlen, dirpart, h );
snprintf (h->tname, tnamelen, "%.*s.lk%p/", dirpartlen, dirpart, h );
h->nodename_off = strlen (h->tname);
sprintf (h->tname+h->nodename_off, "%s/%d", nodename, (int)getpid () );
snprintf (h->tname+h->nodename_off, tnamelen - h->modename_off,
"%s/%d", nodename, (int)getpid () );
#endif /* __riscos__ */
do
@ -186,10 +232,10 @@ create_dotlock( const char *file_to_lock )
if ( fd == -1 )
{
all_lockfiles = h->next;
log_error ( "failed to create temporary file `%s': %s\n",
log_error (_("failed to create temporary file `%s': %s\n"),
h->tname, strerror(errno));
jnlib_free(h->tname);
jnlib_free(h);
jnlib_free (h->tname);
jnlib_free (h);
return NULL;
}
if ( write (fd, pidstr, 11 ) != 11 )
@ -204,61 +250,120 @@ create_dotlock( const char *file_to_lock )
# ifdef _REENTRANT
/* release mutex */
# endif
#endif /* !HAVE_DOSISH_SYSTEM */
h->lockname = jnlib_xmalloc ( strlen (file_to_lock) + 6 );
strcpy (stpcpy(h->lockname, file_to_lock), EXTSEP_S "lock");
h->lockname = jnlib_malloc ( strlen (file_to_lock) + 6 );
if (!h->lockname)
{
all_lockfiles = h->next;
unlink (h->tname);
jnlib_free (h->tname);
jnlib_free (h);
return NULL;
}
strcpy (stpcpy (h->lockname, file_to_lock), EXTSEP_S "lock");
return h;
write_failed:
all_lockfiles = h->next;
# ifdef _REENTRANT
/* fixme: release mutex */
# endif
log_error ( "error writing to `%s': %s\n", h->tname, strerror(errno) );
close(fd);
unlink(h->tname);
jnlib_free(h->tname);
jnlib_free(h);
log_error ( _("error writing to `%s': %s\n"), h->tname, strerror(errno) );
close (fd);
unlink (h->tname);
jnlib_free (h->tname);
jnlib_free (h);
return NULL;
#else /* HAVE_DOSISH_SYSTEM */
/* The Windows version does not need a temporary file but uses the
plain lock file along with record locking. We create this file
here so that we later do only need to do the file locking. For
error reporting it is useful to keep the name of the file in the
handle. */
h->next = all_lockfiles;
all_lockfiles = h;
h->lockname = jnlib_malloc ( strlen (file_to_lock) + 6 );
if (!h->lockname)
{
all_lockfiles = h->next;
jnlib_free (h);
return NULL;
}
strcpy (stpcpy(h->lockname, file_to_lock), EXTSEP_S "lock");
/* If would be nice if we would use the FILE_FLAG_DELETE_ON_CLOSE
along with FILE_SHARE_DELETE but that does not work due to a race
condition: Despite the OPEN_ALWAYS flag CreateFile may return an
error and we can't reliable create/open the lock file unless we
would wait here until it works - however there are other valid
reasons why a lock file can't be created and thus the process
would not stop as expected but spin til until Windows crashes.
Our solution is to keep the lock file open; that does not
harm. */
h->lockhd = CreateFile (h->lockname,
GENERIC_READ|GENERIC_WRITE,
FILE_SHARE_READ|FILE_SHARE_WRITE,
NULL, OPEN_ALWAYS, 0, NULL);
if (h->lockhd == INVALID_HANDLE_VALUE)
{
log_error (_("can't create `%s': %s\n"), h->lockname, w32_strerror (-1));
all_lockfiles = h->next;
jnlib_free (h->lockname);
jnlib_free (h);
return NULL;
}
return h;
#endif /* HAVE_DOSISH_SYSTEM */
}
/* Destroy the local handle H and release the lock. */
void
destroy_dotlock ( DOTLOCK h )
{
#ifndef HAVE_DOSISH_SYSTEM
if ( h )
DOTLOCK hprev, htmp;
if ( !h )
return;
/* First remove the handle from our global list of all locks. */
for (hprev=NULL, htmp=all_lockfiles; htmp; hprev=htmp, htmp=htmp->next)
if (htmp == h)
{
if (hprev)
hprev->next = htmp->next;
else
all_lockfiles = htmp->next;
h->next = NULL;
break;
}
/* Then destroy the lock. */
if (!h->disable)
{
DOTLOCK hprev, htmp;
/* First remove the handle from our global list of all locks. */
for (hprev=NULL, htmp=all_lockfiles; htmp; hprev=htmp, htmp=htmp->next)
if (htmp == h)
{
if (hprev)
hprev->next = htmp->next;
else
all_lockfiles = htmp->next;
h->next = NULL;
break;
}
/* Second destroy the lock. */
if (!h->disable)
#ifdef HAVE_DOSISH_SYSTEM
if (h->locked)
{
if (h->locked && h->lockname)
unlink (h->lockname);
if (h->tname)
unlink (h->tname);
jnlib_free (h->tname);
jnlib_free (h->lockname);
UnlockFile (h->lockhd, 0, 0, 1, 0);
}
jnlib_free(h);
CloseHandle (h->lockhd);
#else /* !HAVE_DOSISH_SYSTEM */
if (h->locked && h->lockname)
unlink (h->lockname);
if (h->tname)
unlink (h->tname);
jnlib_free (h->tname);
#endif /* HAVE_DOSISH_SYSTEM */
jnlib_free (h->lockname);
}
#endif /*!HAVE_DOSISH_SYSTEM*/
jnlib_free(h);
}
#ifndef HAVE_DOSISH_SYSTEM
static int
maybe_deadlock( DOTLOCK h )
{
@ -271,22 +376,22 @@ maybe_deadlock( DOTLOCK h )
}
return 0;
}
#endif /*!HAVE_DOSISH_SYSTEM*/
/****************
* Do a lock on H. A TIMEOUT of 0 returns immediately, -1 waits
* forever (hopefully not), other values are reserved (should then be
* timeouts in milliseconds). Returns: 0 on success
*/
/* Do a lock on H. A TIMEOUT of 0 returns immediately, -1 waits
forever (hopefully not), other values are reserved (should then be
timeouts in milliseconds). Returns: 0 on success */
int
make_dotlock( DOTLOCK h, long timeout )
make_dotlock ( DOTLOCK h, long timeout )
{
#ifdef HAVE_DOSISH_SYSTEM
return 0;
#else
int backoff = 0;
#ifndef HAVE_DOSISH_SYSTEM
int pid;
const char *maybe_dead="";
int backoff=0;
int same_node;
#endif /*!HAVE_DOSISH_SYSTEM*/
if ( h->disable )
return 0; /* Locks are completely disabled. Return success. */
@ -294,14 +399,15 @@ make_dotlock( DOTLOCK h, long timeout )
if ( h->locked )
{
#ifndef __riscos__
log_debug("oops, `%s' is already locked\n", h->lockname );
log_debug ("Oops, `%s' is already locked\n", h->lockname);
#endif /* !__riscos__ */
return 0;
}
for(;;)
for (;;)
{
#ifndef __riscos__
#ifndef HAVE_DOSISH_SYSTEM
# ifndef __riscos__
if ( !link(h->tname, h->lockname) )
{
/* fixme: better use stat to check the link count */
@ -310,10 +416,10 @@ make_dotlock( DOTLOCK h, long timeout )
}
if ( errno != EEXIST )
{
log_error( "lock not made: link() failed: %s\n", strerror(errno) );
log_error ( "lock not made: link() failed: %s\n", strerror(errno) );
return -1;
}
#else /* __riscos__ */
# else /* __riscos__ */
if ( !renamefile(h->tname, h->lockname) )
{
h->locked = 1;
@ -324,7 +430,7 @@ make_dotlock( DOTLOCK h, long timeout )
log_error( "lock not made: rename() failed: %s\n", strerror(errno) );
return -1;
}
#endif /* __riscos__ */
# endif /* __riscos__ */
if ( (pid = read_lockfile (h, &same_node)) == -1 )
{
@ -344,16 +450,16 @@ make_dotlock( DOTLOCK h, long timeout )
}
else if ( same_node && kill (pid, 0) && errno == ESRCH )
{
#ifndef __riscos__
log_info ("removing stale lockfile (created by %d)", pid );
# ifndef __riscos__
log_info (_("removing stale lockfile (created by %d)\n"), pid );
unlink (h->lockname);
continue;
#else /* __riscos__ */
# else /* __riscos__ */
/* Under RISCOS we are *pretty* sure that the other task
is dead and therefore we remove the stale lock file. */
maybe_dead = " - probably dead - removing lock";
maybe_dead = _(" - probably dead - removing lock");
unlink(h->lockname);
#endif /* __riscos__ */
# endif /* __riscos__ */
}
if ( timeout == -1 )
@ -361,8 +467,8 @@ make_dotlock( DOTLOCK h, long timeout )
/* Wait until lock has been released. */
struct timeval tv;
log_info ("waiting for lock (held by %d%s) %s...\n",
pid, maybe_dead, maybe_deadlock(h)? "(deadlock?) ":"");
log_info (_("waiting for lock (held by %d%s) %s...\n"),
pid, maybe_dead, maybe_deadlock(h)? _("(deadlock?) "):"");
/* We can't use sleep, cause signals may be blocked. */
@ -374,24 +480,42 @@ make_dotlock( DOTLOCK h, long timeout )
}
else
return -1;
#else /*HAVE_DOSISH_SYSTEM*/
int w32err;
if (LockFile (h->lockhd, 0, 0, 1, 0))
{
h->locked = 1;
return 0; /* okay */
}
w32err = GetLastError ();
if (w32err != ERROR_LOCK_VIOLATION)
{
log_error (_("lock `%s' not made: %s\n"),
h->lockname, w32_strerror (w32err));
return -1;
}
if ( timeout == -1 )
{
/* Wait until lock has been released. */
log_info (_("waiting for lock %s...\n"), h->lockname);
Sleep ((1 + backoff)*1000);
if ( backoff < 10 )
backoff++ ;
}
else
return -1;
#endif /*HAVE_DOSISH_SYSTEM*/
}
/*NOTREACHED*/
#endif /* !HAVE_DOSISH_SYSTEM */
/*NOTREACHED*/
}
/****************
* release a lock
* Returns: 0 := success
*/
/* Release a lock. Returns 0 on success. */
int
release_dotlock( DOTLOCK h )
{
#ifdef HAVE_DOSISH_SYSTEM
return 0;
#else
int pid, same_node;
/* To avoid atexit race conditions we first check whether there are
any locks left. It might happen that another atexit handler
tries to release the lock while the atexit handler of this module
@ -404,10 +528,20 @@ release_dotlock( DOTLOCK h )
if ( !h->locked )
{
log_debug("oops, `%s' is not locked\n", h->lockname );
log_debug("Oops, `%s' is not locked\n", h->lockname);
return 0;
}
#ifdef HAVE_DOSISH_SYSTEM
if (!UnlockFile (h->lockhd, 0, 0, 1, 0))
{
log_error ("release_dotlock: error removing lockfile `%s': %s\n",
h->lockname, w32_strerror (-1));
return -1;
}
#else
int pid, same_node;
pid = read_lockfile (h, &same_node);
if ( pid == -1 )
{
@ -419,39 +553,38 @@ release_dotlock( DOTLOCK h )
log_error( "release_dotlock: not our lock (pid=%d)\n", pid);
return -1;
}
#ifndef __riscos__
if ( unlink( h->lockname ) )
{
log_error( "release_dotlock: error removing lockfile `%s'",
log_error ("release_dotlock: error removing lockfile `%s'\n",
h->lockname);
return -1;
}
/* Fixme: As an extra check we could check whether the link count is
now really at 1. */
#else /* __riscos__ */
if ( renamefile(h->lockname, h->tname) )
if ( renamefile (h->lockname, h->tname) )
{
log_error( "release_dotlock: error renaming lockfile `%s' to `%s'",
log_error ("release_dotlock: error renaming lockfile `%s' to `%s'\n",
h->lockname, h->tname);
return -1;
}
#endif /* __riscos__ */
/* fixme: check that the link count is now 1 */
#endif /* !HAVE_DOSISH_SYSTEM */
h->locked = 0;
return 0;
#endif /* !HAVE_DOSISH_SYSTEM */
}
/*
Read the lock file and return the pid, returns -1 on error. True
will be stored at SAME_NODE if the lock file has been created on
the same node.
*/
/* Read the lock file and return the pid, returns -1 on error. True
will be stored in the integer at address SAME_NODE if the lock file
has been created on the same node. */
#ifndef HAVE_DOSISH_SYSTEM
static int
read_lockfile (DOTLOCK h, int *same_node )
{
#ifdef HAVE_DOSISH_SYSTEM
return 0;
#else
char buffer_space[10+1+70+1]; /* 70 is just an estimated value; node
name are usually shorter. */
int fd;
@ -505,7 +638,7 @@ read_lockfile (DOTLOCK h, int *same_node )
log_info ("invalid size of lockfile `%s'", h->lockname );
if (buffer != buffer_space)
jnlib_free (buffer);
errno = 0; /* Do not return an inappropriate ERRNO. */
errno = 0; /* Better don't return an inappropriate ERRNO. */
return -1;
}
@ -533,14 +666,16 @@ read_lockfile (DOTLOCK h, int *same_node )
if (buffer != buffer_space)
jnlib_free (buffer);
return pid;
#endif
}
#endif /* !HAVE_DOSISH_SYSTEM */
/* Remove all lockfiles. This is usually called by the atexit handler
installed by this module but may also be called by other
termination handlers. */
void
dotlock_remove_lockfiles()
{
#ifndef HAVE_DOSISH_SYSTEM
DOTLOCK h, h2;
h = all_lockfiles;
@ -552,6 +687,5 @@ dotlock_remove_lockfiles()
destroy_dotlock (h);
h = h2;
}
#endif
}

1
po/POTFILES.in
View File

@ -67,6 +67,7 @@ g10/verify.c
jnlib/argparse.c
jnlib/logging.c
jnlib/utf8conv.c
jnlib/dotlock.c
kbx/kbxutil.c