[PATCH] improve error handling in util/

[Robert Millan <rmh@aybabtu.com>]

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This improves error handling notably in util/.  For example, from:

$ ./grub-probe -t fs /
grub-probe: error: cannot find a GRUB drive for /dev/sda1.

to:

$ ./grub-probe -t fs /
error: cannot open `/dev/sda1' (Permission denied)
grub-probe: error: cannot find a GRUB drive for /dev/sda1.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)

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2008-02-11  Robert Millan  <rmh@aybabtu.com>

	* util/biosdisk.c (grub_util_biosdisk_open, open_device)
	(grub_util_biosdisk_read, grub_util_biosdisk_write)
	(grub_util_biosdisk_get_grub_dev): When issuing grub_error() calls,
	include `strerror (errno)' information in the message string.

	* util/misc.c (grub_util_error): Invoke grub_print_error() before
	printing the caller-provided string.

diff -x configure -x config.h.in -x CVS -x '*~' -x '*.mk' -urp ../grub2/util/biosdisk.c ./util/biosdisk.c
--- ../grub2/util/biosdisk.c	2008-02-11 16:48:18.000000000 +0100
+++ ./util/biosdisk.c	2008-02-11 16:49:36.000000000 +0100
@@ -168,7 +168,7 @@ grub_util_biosdisk_open (const char *nam
 
     fd = open (map[drive], O_RDONLY);
     if (fd == -1)
-      return grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s'", map[drive]);
+      return grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s' (%s)", map[drive], strerror (errno));
 
     if (fstat (fd, &st) < 0 || ! S_ISBLK (st.st_mode))
       {
@@ -199,7 +199,7 @@ grub_util_biosdisk_open (const char *nam
 # warning "No special routine to get the size of a block device is implemented for your OS. This is not possibly fatal."
 #endif
   if (stat (map[drive], &st) < 0)
-    return grub_error (GRUB_ERR_BAD_DEVICE, "cannot stat `%s'", map[drive]);
+    return grub_error (GRUB_ERR_BAD_DEVICE, "cannot stat `%s' (%s)", map[drive], strerror (errno));
 
   disk->total_sectors = st.st_size >> GRUB_DISK_SECTOR_BITS;
   
@@ -307,7 +307,7 @@ open_device (const grub_disk_t disk, gru
     fd = open (dev, flags);
     if (fd < 0)
       {
-	grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s'", dev);
+	grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s' (%s)", dev, strerror (errno));
 	return -1;
       }
 
@@ -321,7 +321,7 @@ open_device (const grub_disk_t disk, gru
   fd = open (map[disk->id], flags);
   if (fd < 0)
     {
-      grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s'", map[disk->id]);
+      grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s' (%s)", map[disk->id], strerror (errno));
       return -1;
     }
 #endif /* ! __linux__ */
@@ -339,7 +339,7 @@ open_device (const grub_disk_t disk, gru
     offset = (loff_t) sector << GRUB_DISK_SECTOR_BITS;
     if (_llseek (fd, offset >> 32, offset & 0xffffffff, &result, SEEK_SET))
       {
-	grub_error (GRUB_ERR_BAD_DEVICE, "cannot seek `%s'", map[disk->id]);
+	grub_error (GRUB_ERR_BAD_DEVICE, "cannot seek `%s' (%s)", map[disk->id], strerror (errno));
 	close (fd);
 	return -1;
       }
@@ -350,7 +350,7 @@ open_device (const grub_disk_t disk, gru
 
     if (lseek (fd, offset, SEEK_SET) != offset)
       {
-	grub_error (GRUB_ERR_BAD_DEVICE, "cannot seek `%s'", map[disk->id]);
+	grub_error (GRUB_ERR_BAD_DEVICE, "cannot seek `%s' (%s)", map[disk->id], strerror (errno));
 	close (fd);
 	return -1;
       }
@@ -431,7 +431,7 @@ grub_util_biosdisk_read (grub_disk_t dis
 	 parts. -jochen  */
       if (nread (fd, buf, GRUB_DISK_SECTOR_SIZE) != GRUB_DISK_SECTOR_SIZE)
 	{
-	  grub_error (GRUB_ERR_READ_ERROR, "cannot read `%s'", map[disk->id]);
+	  grub_error (GRUB_ERR_READ_ERROR, "cannot read `%s' (%s)", map[disk->id], strerror (errno));
 	  close (fd);
 	  return grub_errno;
 	}
@@ -443,7 +443,7 @@ grub_util_biosdisk_read (grub_disk_t dis
   
   if (nread (fd, buf, size << GRUB_DISK_SECTOR_BITS)
       != (ssize_t) (size << GRUB_DISK_SECTOR_BITS))
-    grub_error (GRUB_ERR_READ_ERROR, "cannot read from `%s'", map[disk->id]);
+    grub_error (GRUB_ERR_READ_ERROR, "cannot read from `%s' (%s)", map[disk->id], strerror (errno));
 
   close (fd);
   return grub_errno;
@@ -461,7 +461,7 @@ grub_util_biosdisk_write (grub_disk_t di
   
   if (nwrite (fd, buf, size << GRUB_DISK_SECTOR_BITS)
       != (ssize_t) (size << GRUB_DISK_SECTOR_BITS))
-    grub_error (GRUB_ERR_WRITE_ERROR, "cannot write to `%s'", map[disk->id]);
+    grub_error (GRUB_ERR_WRITE_ERROR, "cannot write to `%s' (%s)", map[disk->id], strerror (errno));
 
   close (fd);
   return grub_errno;
@@ -695,7 +695,7 @@ grub_util_biosdisk_get_grub_dev (const c
 
   if (stat (os_dev, &st) < 0)
     {
-      grub_error (GRUB_ERR_BAD_DEVICE, "cannot stat `%s'", os_dev);
+      grub_error (GRUB_ERR_BAD_DEVICE, "cannot stat `%s' (%s)", os_dev, strerror (errno));
       return 0;
     }
 
@@ -775,7 +775,7 @@ grub_util_biosdisk_get_grub_dev (const c
     fd = open (os_dev, O_RDONLY);
     if (fd == -1)
       {
-	grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s'", os_dev);
+	grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s' (%s)", os_dev, strerror (errno));
 	free (name);
 	return 0;
       }
@@ -783,7 +783,7 @@ grub_util_biosdisk_get_grub_dev (const c
     if (ioctl (fd, HDIO_GETGEO, &hdg))
       {
 	grub_error (GRUB_ERR_BAD_DEVICE,
-		    "cannot get geometry of `%s'", os_dev);
+		    "cannot get geometry of `%s' (%s)", os_dev, strerror (errno));
 	close (fd);
 	free (name);
 	return 0;
diff -x configure -x config.h.in -x CVS -x '*~' -x '*.mk' -urp ../grub2/util/misc.c ./util/misc.c
--- ../grub2/util/misc.c	2007-10-21 14:29:33.000000000 +0200
+++ ./util/misc.c	2008-02-11 16:49:36.000000000 +0100
@@ -61,6 +61,8 @@ void
 grub_util_error (const char *fmt, ...)
 {
   va_list ap;
+
+  grub_print_error ();
   
   fprintf (stderr, "%s: error: ", progname);
   va_start (ap, fmt);