From 7c6b4d6a9970e997278398745373ec2670b794e0 Mon Sep 17 00:00:00 2001
From: Mattias Ellert <mattias.ellert@fysast.uu.se>
Date: Sun, 18 Nov 2007 10:59:18 +0000
Subject: [PATCH] Fix handling of valid "negative" PIDs

---
 ChangeLog                | 11 ++++++++++-
 backend/agfafocus.c      |  6 +++---
 backend/artec_eplus48u.c |  4 ++--
 backend/avision.c        |  8 ++++----
 backend/coolscan.c       |  8 ++++----
 backend/hp3500.c         |  6 +++---
 backend/microtek2.c      |  2 +-
 backend/mustek.c         |  6 +++---
 backend/pie.c            |  4 ++--
 backend/pixma.c          |  8 ++++----
 backend/plustek.c        |  4 ++--
 backend/plustek_pp.c     |  4 ++--
 backend/snapscan.c       |  9 ++++++---
 backend/sp15c.c          |  9 ++++++---
 backend/tamarack.c       |  6 +++---
 backend/test.c           |  6 +++---
 backend/u12.c            |  4 ++--
 backend/umax.c           |  6 +++---
 18 files changed, 63 insertions(+), 48 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 41d1872bd..54f270490 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,13 @@
-2007-11-28  Alessandro Zummo <a.zummo@towertech.it>
+2007-11-18  Mattias Ellert <mattias.ellert@tsl.uu.se>
+
+	* backend/agfafocus.c, backend/artec_eplus48u.c, backend/avision.c,
+	  backend/coolscan.c, backend/hp3500.c, backend/microtek2.c,
+	  backend/mustek.c, backend/pie.c, backend/pixma.c, backend/plustek.c,
+	  backend/plustek_pp.c, backend/snapscan.c, backend/sp15c.c,
+	  backend/tamarack.c, backend/test.c, backend/u12.c, backend/umax.c:
+	  Fix handling of valid "negative" PIDs.
+
+2007-11-18  Alessandro Zummo <a.zummo@towertech.it>
 
 	* backend/epson2.c: removed quick-format option. it's
 	the job of a frontend to provide such a commodity.
diff --git a/backend/agfafocus.c b/backend/agfafocus.c
index b2d27d0f9..98ead6b6a 100644
--- a/backend/agfafocus.c
+++ b/backend/agfafocus.c
@@ -947,14 +947,14 @@ do_cancel (AgfaFocus_Scanner * s)
 
   do_eof (s);
 
-  if (s->reader_pid > 0)
+  if (s->reader_pid != -1)
     {
       int exit_status;
 
       /* ensure child knows it's time to stop: */
       sanei_thread_kill (s->reader_pid);
       sanei_thread_waitpid (s->reader_pid, &exit_status);
-      s->reader_pid = 0;
+      s->reader_pid = -1;
     }
 
   if (s->fd >= 0)
@@ -2052,7 +2052,7 @@ sane_cancel (SANE_Handle handle)
 {
   AgfaFocus_Scanner *s = handle;
 
-  if (s->reader_pid > 0)
+  if (s->reader_pid != -1)
     sanei_thread_kill (s->reader_pid);
   s->scanning = SANE_FALSE;
 }
diff --git a/backend/artec_eplus48u.c b/backend/artec_eplus48u.c
index c245d756f..32db306c1 100644
--- a/backend/artec_eplus48u.c
+++ b/backend/artec_eplus48u.c
@@ -3483,7 +3483,7 @@ do_cancel (Artec48U_Scanner * s, SANE_Bool closepipe)
 
   s->scanning = SANE_FALSE;
 
-  if (s->reader_pid > 0)
+  if (s->reader_pid != -1)
     {
       /*parent */
       XDBG ((1, "killing reader_process\n"));
@@ -3507,7 +3507,7 @@ do_cancel (Artec48U_Scanner * s, SANE_Bool closepipe)
 	{
 	  XDBG ((1, "sanei_thread_waitpid() failed !\n"));
 	}
-      s->reader_pid = 0;
+      s->reader_pid = -1;
       XDBG ((1, "reader_process killed\n"));
     }
   if (SANE_TRUE == closepipe)
diff --git a/backend/avision.c b/backend/avision.c
index e198bc556..14cbf3744 100644
--- a/backend/avision.c
+++ b/backend/avision.c
@@ -5731,7 +5731,7 @@ do_eof (Avision_Scanner *s)
   /* join our processes - without a wait() you will produce defunct
      childs */
   sanei_thread_waitpid (s->reader_pid, &exit_status);
-  s->reader_pid = 0;
+  s->reader_pid = -1;
 
   DBG (3, "do_eof: returning %d\n", exit_status);
   return (SANE_Status)exit_status;
@@ -5746,13 +5746,13 @@ do_cancel (Avision_Scanner* s)
   s->duplex_rear_valid = SANE_FALSE;
   s->page = 0;
   
-  if (s->reader_pid > 0) {
+  if (s->reader_pid != -1) {
     int exit_status;
     
     /* ensure child knows it's time to stop: */
     sanei_thread_kill (s->reader_pid);
     sanei_thread_waitpid (s->reader_pid, &exit_status);
-    s->reader_pid = 0;
+    s->reader_pid = -1;
   }
 
   return SANE_STATUS_CANCELLED;
@@ -7889,7 +7889,7 @@ sane_start (SANE_Handle handle)
   s->read_fds = fds[0];
   s->write_fds = fds[1];
 
-  s->reader_pid = 0; /* the thread will be started uppon the first read */
+  s->reader_pid = -1; /* the thread will be started upon the first read */
 
   /* create reader routine as new process or thread */
   DBG (3, "sane_start: starting thread\n");
diff --git a/backend/coolscan.c b/backend/coolscan.c
index 68dce3c19..104ada69f 100644
--- a/backend/coolscan.c
+++ b/backend/coolscan.c
@@ -2027,7 +2027,7 @@ do_cancel (Coolscan_t * scanner)
 
   do_eof (scanner);		/* close pipe and reposition scanner */
 
-  if (scanner->reader_pid > 0)
+  if (scanner->reader_pid != -1)
     {
       int exit_status;
 
@@ -2037,7 +2037,7 @@ do_cancel (Coolscan_t * scanner)
       sanei_thread_kill (scanner->reader_pid);
       while (sanei_thread_waitpid(scanner->reader_pid, &exit_status) !=
                                                         scanner->reader_pid );
-      scanner->reader_pid = 0;
+      scanner->reader_pid = -1;
     }
 
   if (scanner->sfd >= 0)
@@ -4150,11 +4150,11 @@ sane_cancel (SANE_Handle handle)
 {
   Coolscan_t *s = handle;
 
-  if (s->reader_pid > 0)
+  if (s->reader_pid != -1)
     {
       sanei_thread_kill   ( s->reader_pid );
       sanei_thread_waitpid( s->reader_pid, NULL );
-      s->reader_pid = 0;
+      s->reader_pid = -1;
     }
   swap_res (s);
   s->scanning = SANE_FALSE;
diff --git a/backend/hp3500.c b/backend/hp3500.c
index 4a0d8336e..3ae834134 100644
--- a/backend/hp3500.c
+++ b/backend/hp3500.c
@@ -925,7 +925,7 @@ attachScanner (const char *devicename)
   dev->devicename = strdup (devicename);
   dev->sfd = -1;
   dev->last_scan = 0;
-  dev->reader_pid = 0;
+  dev->reader_pid = -1;
   dev->pipe_r = dev->pipe_w = -1;
 
   dev->sane.name = dev->devicename;
@@ -1056,7 +1056,7 @@ do_reset (struct hp3500_data *scanner)
 static void
 do_cancel (struct hp3500_data *scanner)
 {
-  if (scanner->reader_pid > 0)
+  if (scanner->reader_pid != -1)
     {
 
       if (sanei_thread_kill (scanner->reader_pid) == 0)
@@ -1065,7 +1065,7 @@ do_cancel (struct hp3500_data *scanner)
 
 	  sanei_thread_waitpid (scanner->reader_pid, &exit_status);
 	}
-      scanner->reader_pid = 0;
+      scanner->reader_pid = -1;
     }
   if (scanner->pipe_r >= 0)
     {
diff --git a/backend/microtek2.c b/backend/microtek2.c
index 67dd39de3..7ecb4a031 100644
--- a/backend/microtek2.c
+++ b/backend/microtek2.c
@@ -908,7 +908,7 @@ cancel_scan(Microtek2_Scanner *ms)
        of material on a feeder, then pid may be already -1 and
        kill(-1, SIGTERM), i.e. killing all our processes, is not
        likely what we really want - --mj, 2001/Nov/19 */
-    if (ms->pid > 1)
+    if (ms->pid != -1)
       {
        sanei_thread_kill(ms->pid);
        sanei_thread_waitpid(ms->pid, NULL);
diff --git a/backend/mustek.c b/backend/mustek.c
index 960675d3b..f13d8aa85 100644
--- a/backend/mustek.c
+++ b/backend/mustek.c
@@ -2946,7 +2946,7 @@ do_stop (Mustek_Scanner * s)
   s->scanning = SANE_FALSE;
   s->pass = 0;
 
-  if (s->reader_pid > 0)
+  if (s->reader_pid != -1)
     {
       SANE_Int exit_status;
       struct timeval now;
@@ -2977,7 +2977,7 @@ do_stop (Mustek_Scanner * s)
       sanei_thread_kill (s->reader_pid);
 
       pid = sanei_thread_waitpid (s->reader_pid, &exit_status);
-      if (pid < 0)
+      if (pid == -1)
 	{
 	  DBG (1,
 	       "do_stop: sanei_thread_waitpid failed, already terminated? (%s)\n",
@@ -2992,7 +2992,7 @@ do_stop (Mustek_Scanner * s)
 	    status = exit_status;
 	}
 
-      s->reader_pid = 0;
+      s->reader_pid = -1;
     }
 
   if (s->fd >= 0)
diff --git a/backend/pie.c b/backend/pie.c
index f0d2fb7cf..bbc568d30 100644
--- a/backend/pie.c
+++ b/backend/pie.c
@@ -2897,12 +2897,12 @@ do_cancel (Pie_Scanner * scanner)
 
   scanner->scanning = SANE_FALSE;
 
-  if (scanner->reader_pid > 0)
+  if (scanner->reader_pid != -1)
     {
       DBG (DBG_sane_info, "killing reader_process\n");
       sanei_thread_kill (scanner->reader_pid);
       sanei_thread_waitpid (scanner->reader_pid, 0);
-      scanner->reader_pid = 0;
+      scanner->reader_pid = -1;
       DBG (DBG_sane_info, "reader_process killed\n");
     }
 
diff --git a/backend/pixma.c b/backend/pixma.c
index a83433fe6..e6f1e2c82 100644
--- a/backend/pixma.c
+++ b/backend/pixma.c
@@ -810,7 +810,7 @@ terminate_reader_task (pixma_sane_t * ss, int *exit_code)
   int status = 0;
 
   pid = ss->reader_taskid;
-  if (pid <= 0)
+  if (pid == -1)
     return -1;
   if (sanei_thread_is_forked ())
     {
@@ -822,7 +822,7 @@ terminate_reader_task (pixma_sane_t * ss, int *exit_code)
       pixma_cancel (ss->s);
     }
   result = sanei_thread_waitpid (pid, &status);
-  ss->reader_taskid = 0;
+  ss->reader_taskid = -1;
   if (result == pid)
     {
       if (exit_code)
@@ -852,7 +852,7 @@ start_reader_task (pixma_sane_t * ss)
       ss->rpipe = -1;
       ss->wpipe = -1;
     }
-  if (ss->reader_taskid > 0)
+  if (ss->reader_taskid != -1)
     {
       PDBG (pixma_dbg (1, "BUG:reader_taskid(%d) != 0\n", ss->reader_taskid));
       terminate_reader_task (ss, NULL);
@@ -893,7 +893,7 @@ start_reader_task (pixma_sane_t * ss)
   PDBG (pixma_dbg (3, "Reader task id=%d (%s)\n", pid,
 		   (is_forked) ? "forked" : "threaded"));
   ss->reader_taskid = pid;
-  return pid;
+  return 0;
 }
 
 static SANE_Status
diff --git a/backend/plustek.c b/backend/plustek.c
index 2006364af..3eb8088f1 100644
--- a/backend/plustek.c
+++ b/backend/plustek.c
@@ -570,7 +570,7 @@ do_cancel( Plustek_Scanner *scanner, SANE_Bool closepipe )
 	DBG( _DBG_PROC,"do_cancel\n" );
 	scanner->scanning = SANE_FALSE;
 
-	if( scanner->reader_pid > 0 ) {
+	if( scanner->reader_pid != -1 ) {
 
 		DBG( _DBG_PROC, ">>>>>>>> killing reader_process <<<<<<<<\n" );
 
@@ -602,7 +602,7 @@ do_cancel( Plustek_Scanner *scanner, SANE_Bool closepipe )
 #endif
 		}
 
-		scanner->reader_pid = 0;
+		scanner->reader_pid = -1;
 		DBG( _DBG_PROC,"reader_process killed\n");
 #ifndef HAVE_SETITIMER
 		usb_StartLampTimer( scanner->hw );
diff --git a/backend/plustek_pp.c b/backend/plustek_pp.c
index 6d28a9b4b..3dafe3386 100644
--- a/backend/plustek_pp.c
+++ b/backend/plustek_pp.c
@@ -468,7 +468,7 @@ static SANE_Status do_cancel( Plustek_Scanner *scanner, SANE_Bool closepipe  )
 
 	scanner->scanning = SANE_FALSE;
 
-	if( scanner->reader_pid > 0 ) {
+	if( scanner->reader_pid != -1 ) {
 
 		DBG( _DBG_PROC, ">>>>>>>> killing reader_process <<<<<<<<\n" );
 
@@ -503,7 +503,7 @@ static SANE_Status do_cancel( Plustek_Scanner *scanner, SANE_Bool closepipe  )
 #endif
 		}			
 
-		scanner->reader_pid = 0;
+		scanner->reader_pid = -1;
 		DBG( _DBG_PROC,"reader_process killed\n");
 	}
 
diff --git a/backend/snapscan.c b/backend/snapscan.c
index 365a1a61a..8b291865c 100644
--- a/backend/snapscan.c
+++ b/backend/snapscan.c
@@ -1765,7 +1765,7 @@ SANE_Status sane_read (SANE_Handle h,
 
     if (pss->psrc == NULL  ||  pss->psrc->remaining(pss->psrc) == 0)
     {
-        if (pss->child > 0)
+        if (pss->child != -1)
         {
             sanei_thread_waitpid (pss->child, 0);        /* ensure no zombies */
             pss->child = -1;
@@ -1825,7 +1825,7 @@ void sane_cancel (SANE_Handle h)
         /* signal a cancellation has occurred */
         pss->state = ST_CANCEL_INIT;
         /* signal the reader, if any */
-        if (pss->child > 0)
+        if (pss->child != -1)
         {
             DBG( DL_INFO, ">>>>>>>> killing reader_process <<<<<<<<\n" );
 
@@ -1934,7 +1934,10 @@ SANE_Status sane_get_select_fd (SANE_Handle h, SANE_Int * fd)
 
 /*
  * $Log$
- * Revision 1.69  2007/11/16 08:04:02  ellert-guest
+ * Revision 1.70  2007/11/18 10:59:18  ellert-guest
+ * Fix handling of valid "negative" PIDs
+ *
+ * Revision 1.69  2007-11-16 08:04:02  ellert-guest
  * Correct the test of the return value from sanei_thread_begin
  *
  * Revision 1.68  2006-09-03 10:00:11  oliver-guest
diff --git a/backend/sp15c.c b/backend/sp15c.c
index e1b0f3ecb..c79074b54 100644
--- a/backend/sp15c.c
+++ b/backend/sp15c.c
@@ -45,7 +45,10 @@ static const char RCSid[] = "$Header$";
 
 /*
  * $Log$
- * Revision 1.14  2007/10/26 14:56:38  jblache
+ * Revision 1.15  2007/11/18 10:59:18  ellert-guest
+ * Fix handling of valid "negative" PIDs
+ *
+ * Revision 1.14  2007-10-26 14:56:38  jblache
  * OPT_NUM_OPTS must be of type SANE_TYPE_INT.
  *
  * Revision 1.13  2006/03/29 20:48:50  hmg-guest
@@ -1747,7 +1750,7 @@ do_cancel (struct sp15c *scanner)
 
   do_eof (scanner);             /* close pipe and reposition scanner */
 
-  if (scanner->reader_pid > 0)
+  if (scanner->reader_pid != -1)
     {
       int exit_status;
       DBG (10, "do_cancel: kill reader_process\n");
@@ -1755,7 +1758,7 @@ do_cancel (struct sp15c *scanner)
       sanei_thread_kill (scanner->reader_pid);
       DBG (50, "wait for scanner to stop\n");
       sanei_thread_waitpid (scanner->reader_pid, &exit_status);
-      scanner->reader_pid = 0;
+      scanner->reader_pid = -1;
     }
 
   if (scanner->sfd >= 0)
diff --git a/backend/tamarack.c b/backend/tamarack.c
index df11baee6..49780acc9 100644
--- a/backend/tamarack.c
+++ b/backend/tamarack.c
@@ -465,14 +465,14 @@ do_cancel (Tamarack_Scanner *s)
 
   do_eof (s);
 
-  if (s->reader_pid > 0)
+  if (s->reader_pid != -1)
     {
       int exit_status;
 
       /* ensure child knows it's time to stop: */
       sanei_thread_kill (s->reader_pid);
       sanei_thread_waitpid (s->reader_pid, &exit_status);
-      s->reader_pid = 0;
+      s->reader_pid = -1;
     }
 
   if (s->fd >= 0)
@@ -1435,7 +1435,7 @@ sane_cancel (SANE_Handle handle)
 {
   Tamarack_Scanner *s = handle;
 
-  if (s->reader_pid > 0)
+  if (s->reader_pid != -1)
     sanei_thread_kill (s->reader_pid);
   s->scanning = SANE_FALSE;
 }
diff --git a/backend/test.c b/backend/test.c
index 2c020a5b3..acd3ee283 100644
--- a/backend/test.c
+++ b/backend/test.c
@@ -1348,7 +1348,7 @@ finish_pass (Test_Device * test_device)
       DBG (2, "finish_pass: pipe closed\n");
       test_device->pipe = -1;
     }
-  if (test_device->reader_pid > 0)
+  if (test_device->reader_pid != -1)
     {
       int status;
       int pid;
@@ -1357,7 +1357,7 @@ finish_pass (Test_Device * test_device)
 	   test_device->reader_pid);
       sanei_thread_kill (test_device->reader_pid);
       pid = sanei_thread_waitpid (test_device->reader_pid, &status);
-      if (pid < 0)
+      if (pid == -1)
 	{
 	  DBG (1,
 	       "finish_pass: sanei_thread_waitpid failed, already terminated? (%s)\n",
@@ -1368,7 +1368,7 @@ finish_pass (Test_Device * test_device)
 	  DBG (2, "finish_pass: reader process terminated with status: %s\n",
 	       sane_strstatus (status));
 	}
-      test_device->reader_pid = 0;
+      test_device->reader_pid = -1;
     }
   /* this happens when running in thread context... */
   if (test_device->reader_fds >= 0)
diff --git a/backend/u12.c b/backend/u12.c
index 7c386da5c..d04799eee 100644
--- a/backend/u12.c
+++ b/backend/u12.c
@@ -391,7 +391,7 @@ static SANE_Status do_cancel( U12_Scanner *scanner, SANE_Bool closepipe )
 
 	scanner->scanning = SANE_FALSE;
 
-	if( scanner->reader_pid > 0 ) {
+	if( scanner->reader_pid != -1 ) {
 
 		DBG( _DBG_PROC, ">>>>>>>> killing reader_process <<<<<<<<\n" );
 
@@ -421,7 +421,7 @@ static SANE_Status do_cancel( U12_Scanner *scanner, SANE_Bool closepipe )
 			sanei_thread_sendsig( scanner->reader_pid, SIGKILL );
 #endif
 		}
-		scanner->reader_pid = 0;
+		scanner->reader_pid = -1;
 		DBG( _DBG_PROC, "reader_process killed\n");
 
 		if( scanner->hw->fd >= 0 ) {
diff --git a/backend/umax.c b/backend/umax.c
index 8c72dde5e..20d968890 100644
--- a/backend/umax.c
+++ b/backend/umax.c
@@ -4668,14 +4668,14 @@ static SANE_Status do_cancel(Umax_Scanner *scanner)
 
   scanner->scanning = SANE_FALSE;
 
-  if (scanner->reader_pid > 0)
+  if (scanner->reader_pid != -1)
   {
     DBG(DBG_sane_info,"killing reader_process\n");
 
     sanei_thread_kill(scanner->reader_pid);
     pid = sanei_thread_waitpid(scanner->reader_pid, &status);
 
-    if (pid < 0)
+    if (pid == -1)
     {
       DBG(DBG_sane_info, "do_cancel: sanei_thread_waitpid failed, already terminated ? (%s)\n", strerror(errno));
     }
@@ -4684,7 +4684,7 @@ static SANE_Status do_cancel(Umax_Scanner *scanner)
       DBG(DBG_sane_info, "do_cancel: reader_process terminated with status: %s\n", sane_strstatus(status));
     }
 
-    scanner->reader_pid = 0;
+    scanner->reader_pid = -1;
 
     if (scanner->device->pixelbuffer != NULL)					      /* pixelbuffer exists? */
     {