Moved 1.9 branch to trunk

1 files changed, 557 insertions, 0 deletions

diff --git a/jnlib/dotlock.c b/jnlib/dotlock.c
new file mode 100644
index 000000000..f5de8fa54
--- /dev/null
+++ b/jnlib/dotlock.c
@@ -0,0 +1,557 @@
+/* dotlock.c - dotfile locking
+ * Copyright (C) 1998, 2000, 2001, 2003, 2004, 
+ *               2005, 2006 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * USA.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <errno.h>
+#include <unistd.h>
+#ifndef  HAVE_DOSISH_SYSTEM
+#include <sys/utsname.h>
+#endif
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <signal.h>
+
+#include "libjnlib-config.h"
+#include "dotlock.h"
+
+#if !defined(DIRSEP_C) && !defined(EXTSEP_C) \
+    && !defined(DIRSEP_S) && !defined(EXTSEP_S)
+#ifdef HAVE_DOSISH_SYSTEM
+#define DIRSEP_C '\\'
+#define EXTSEP_C '.'
+#define DIRSEP_S "\\"
+#define EXTSEP_S "."
+#else
+#define DIRSEP_C '/'
+#define EXTSEP_C '.'
+#define DIRSEP_S "/"
+#define EXTSEP_S "."
+#endif
+#endif
+
+
+struct dotlock_handle 
+{
+  struct dotlock_handle *next;
+  char *tname;    /* Name of 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.  */
+};
+
+
+static volatile DOTLOCK all_lockfiles;
+static int never_lock;
+
+static int read_lockfile (DOTLOCK h, int *same_node);
+
+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.
+ */
+DOTLOCK
+create_dotlock( const char *file_to_lock )
+{
+  static int initialized;
+  DOTLOCK h;
+  int  fd = -1;
+  char pidstr[16];
+  const char *nodename;
+  const char *dirpart;
+  int dirpartlen;
+#ifndef  HAVE_DOSISH_SYSTEM
+  struct utsname utsbuf;
+#endif
+
+  if ( !initialized )
+    {
+      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->disable = 1;
+#ifdef _REENTRANT
+      /* fixme: aquire mutex on all_lockfiles */
+#endif
+      h->next = all_lockfiles;
+      all_lockfiles = h;
+      return h;
+    }
+
+#ifndef HAVE_DOSISH_SYSTEM
+  sprintf (pidstr, "%10d\n", (int)getpid() );
+  /* fixme: add the hostname to the second line (FQDN or IP addr?) */
+
+  /* Create a temporary file. */
+  if ( uname ( &utsbuf ) )
+    nodename = "unknown";
+  else
+    nodename = utsbuf.nodename;
+  
+#ifdef __riscos__
+  {
+    char *iter = (char *) nodename;
+    for (; iter[0]; iter++)
+      if (iter[0] == '.')
+        iter[0] = '/';
+  }
+#endif /* __riscos__ */
+
+  if ( !(dirpart = strrchr ( file_to_lock, DIRSEP_C )) )
+    {
+      dirpart = EXTSEP_S;
+      dirpartlen = 1;
+    }
+  else
+    {
+      dirpartlen = dirpart - file_to_lock;
+      dirpart = file_to_lock;
+    }
+
+#ifdef _REENTRANT
+    /* fixme: aquire mutex on all_lockfiles */
+#endif
+  h->next = all_lockfiles;
+  all_lockfiles = h;
+
+  h->tname = jnlib_xmalloc ( dirpartlen + 6+30+ strlen(nodename) + 11 );
+  h->nodename_len = strlen (nodename);
+#ifndef __riscos__
+  sprintf (h->tname, "%.*s/.#lk%p.", dirpartlen, dirpart, h );
+  h->nodename_off = strlen (h->tname);
+  sprintf (h->tname+h->nodename_off, "%s.%d", nodename, (int)getpid ());
+#else /* __riscos__ */
+  sprintf (h->tname, "%.*s.lk%p/", dirpartlen, dirpart, h );
+  h->nodename_off = strlen (h->tname);
+  sprintf (h->tname+h->nodename_off, "%s/%d", nodename, (int)getpid () );
+#endif /* __riscos__ */
+
+  do 
+    {
+      errno = 0;
+      fd = open (h->tname, O_WRONLY|O_CREAT|O_EXCL,
+                 S_IRUSR|S_IRGRP|S_IROTH|S_IWUSR );
+    } 
+  while (fd == -1 && errno == EINTR);
+
+  if ( fd == -1 ) 
+    {
+      all_lockfiles = h->next;
+      log_error ( "failed to create temporary file `%s': %s\n",
+                  h->tname, strerror(errno));
+      jnlib_free(h->tname);
+      jnlib_free(h);
+      return NULL;
+    }
+  if ( write (fd, pidstr, 11 ) != 11 )
+    goto write_failed;
+  if ( write (fd, nodename, strlen (nodename) ) != strlen (nodename) )
+    goto write_failed;
+  if ( write (fd, "\n", 1 ) != 1 )
+    goto write_failed;
+  if ( close (fd) )
+    goto write_failed;
+
+# 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");
+  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);
+  return NULL;
+}
+
+
+void
+destroy_dotlock ( DOTLOCK h )
+{
+#ifndef HAVE_DOSISH_SYSTEM
+  if ( h )
+    {
+      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)
+        {
+          if (h->locked && h->lockname)
+            unlink (h->lockname);
+          if (h->tname)
+              unlink (h->tname);
+          jnlib_free (h->tname);
+          jnlib_free (h->lockname);
+        }
+      jnlib_free(h);
+    }
+#endif /*!HAVE_DOSISH_SYSTEM*/
+}
+
+
+
+static int
+maybe_deadlock( DOTLOCK h )
+{
+  DOTLOCK r;
+
+  for ( r=all_lockfiles; r; r = r->next )
+    {
+      if ( r != h && r->locked )
+        return 1;
+    }
+  return 0;
+}
+
+/****************
+ * 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 )
+{
+#ifdef HAVE_DOSISH_SYSTEM
+  return 0;
+#else
+  int  pid;
+  const char *maybe_dead="";
+  int backoff=0;
+  int same_node;
+
+  if ( h->disable )
+    return 0; /* Locks are completely disabled.  Return success. */
+
+  if ( h->locked ) 
+    {
+#ifndef __riscos__
+      log_debug("oops, `%s' is already locked\n", h->lockname );
+#endif /* !__riscos__ */
+      return 0;
+    }
+
+  for(;;)
+    {
+#ifndef __riscos__
+      if ( !link(h->tname, h->lockname) )
+        {
+          /* fixme: better use stat to check the link count */
+          h->locked = 1;
+          return 0; /* okay */
+	}
+      if ( errno != EEXIST )
+        {
+          log_error( "lock not made: link() failed: %s\n", strerror(errno) );
+          return -1;
+	}
+#else /* __riscos__ */
+      if ( !renamefile(h->tname, h->lockname) ) 
+        {
+          h->locked = 1;
+          return 0; /* okay */
+        }
+      if ( errno != EEXIST ) 
+        {
+          log_error( "lock not made: rename() failed: %s\n", strerror(errno) );
+          return -1;
+        }
+#endif /* __riscos__ */
+
+      if ( (pid = read_lockfile (h, &same_node)) == -1 ) 
+        {
+          if ( errno != ENOENT )
+            {
+              log_info ("cannot read lockfile\n");
+              return -1;
+	    }
+          log_info( "lockfile disappeared\n");
+          continue;
+	}
+      else if ( pid == getpid() && same_node )
+        {
+          log_info( "Oops: lock already held by us\n");
+          h->locked = 1;
+          return 0; /* okay */
+	}
+      else if ( same_node && kill (pid, 0) && errno == ESRCH )
+        {
+#ifndef __riscos__
+          log_info ("removing stale lockfile (created by %d)", pid );
+          unlink (h->lockname);
+          continue;
+#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";
+          unlink(h->lockname);
+#endif /* __riscos__ */
+	}
+
+      if ( timeout == -1 ) 
+        {
+          /* 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?) ":"");
+
+
+          /* We can't use sleep, cause signals may be blocked. */
+          tv.tv_sec = 1 + backoff;
+          tv.tv_usec = 0;
+          select(0, NULL, NULL, NULL, &tv);
+          if ( backoff < 10 )
+            backoff++ ;
+	}
+      else
+        return -1;
+    }
+    /*NOTREACHED*/
+#endif /* !HAVE_DOSISH_SYSTEM */
+}
+
+
+/****************
+ * release a lock
+ * Returns: 0 := 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
+     already ran and thus H is undefined.  */
+  if (!all_lockfiles)
+    return 0;
+
+  if ( h->disable )
+    return 0;
+
+  if ( !h->locked )
+    {
+      log_debug("oops, `%s' is not locked\n", h->lockname );
+      return 0;
+    }
+
+  pid = read_lockfile (h, &same_node);
+  if ( pid == -1 ) 
+    {
+      log_error( "release_dotlock: lockfile error\n");
+      return -1;
+    }
+  if ( pid != getpid() || !same_node )
+    {
+      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'",
+                 h->lockname);
+      return -1;
+    }
+#else /* __riscos__ */
+  if ( renamefile(h->lockname, h->tname) ) 
+    {
+      log_error( "release_dotlock: error renaming lockfile `%s' to `%s'",
+                 h->lockname, h->tname);
+      return -1;
+    }
+#endif /* __riscos__ */
+  /* fixme: check that the link count is now 1 */
+  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.
+ */
+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, pid;
+  char *buffer, *p;
+  size_t expected_len;
+  int res, nread;
+  
+  *same_node = 0;
+  expected_len = 10 + 1 + h->nodename_len + 1;
+  if ( expected_len >= sizeof buffer_space)
+    buffer = jnlib_xmalloc (expected_len);
+  else
+    buffer = buffer_space;
+
+  if ( (fd = open (h->lockname, O_RDONLY)) == -1 )
+    {
+      int e = errno;
+      log_info ("error opening lockfile `%s': %s\n",
+                h->lockname, strerror(errno) );
+      if (buffer != buffer_space)
+        jnlib_free (buffer);
+      errno = e; /* Need to return ERRNO here. */
+      return -1;
+    }
+
+  p = buffer;
+  nread = 0;
+  do
+    {
+      res = read (fd, p, expected_len - nread);
+      if (res == -1 && errno == EINTR)
+        continue;
+      if (res < 0)
+        {
+          log_info ("error reading lockfile `%s'", h->lockname );
+          close (fd); 
+          if (buffer != buffer_space)
+            jnlib_free (buffer);
+          errno = 0; /* Do not return an inappropriate ERRNO. */
+          return -1;
+        }
+      p += res;
+      nread += res;
+    }
+  while (res && nread != expected_len);
+  close(fd);
+
+  if (nread < 11)
+    {
+      log_info ("invalid size of lockfile `%s'", h->lockname );
+      if (buffer != buffer_space)
+        jnlib_free (buffer);
+      errno = 0; /* Do not return an inappropriate ERRNO. */
+      return -1;
+    }
+
+  if (buffer[10] != '\n'
+      || (buffer[10] = 0, pid = atoi (buffer)) == -1
+#ifndef __riscos__
+      || !pid 
+#else /* __riscos__ */
+      || (!pid && riscos_getpid())
+#endif /* __riscos__ */
+      )
+    {
+      log_error ("invalid pid %d in lockfile `%s'", pid, h->lockname );
+      if (buffer != buffer_space)
+        jnlib_free (buffer);
+      errno = 0;
+      return -1;
+    }
+
+  if (nread == expected_len
+      && !memcmp (h->tname+h->nodename_off, buffer+11, h->nodename_len) 
+      && buffer[11+h->nodename_len] == '\n')
+    *same_node = 1;
+
+  if (buffer != buffer_space)
+    jnlib_free (buffer);
+  return pid;
+#endif
+}
+
+
+void
+dotlock_remove_lockfiles()
+{
+#ifndef HAVE_DOSISH_SYSTEM
+  DOTLOCK h, h2;
+  
+  h = all_lockfiles;
+  all_lockfiles = NULL;
+    
+  while ( h )
+    {
+      h2 = h->next;
+      destroy_dotlock (h);
+      h = h2;
+    }
+#endif
+}
+