Re: udevinfo reverse lookup for symlinks

[Kay Sievers <kay.sievers@vrfy.org>]

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On Sun, Feb 29, 2004 at 08:42:47PM +0100, Olaf Hering wrote:
>  On Mon, Feb 09, Kay Sievers wrote:
> 
> > On Mon, Feb 09, 2004 at 05:33:32PM +0100, Olaf Hering wrote:
> > > 
> > > How do I reverse lookup symlinks?
> > > It seem that is not implemented.
> > > 
> > > nectarine:~ # udevinfo -n cdrom -q path
> > > device not found in database
> > 
> > It's not implemented. I didn't see the need for this,
> > cause it's easy to follow the link to the real node
> > and query this instead. But feel free to send a patch :)

Nice, looks good.
Thanks.


>  		memcpy(find_dev, dev, sizeof(*find_dev));
> -		strfieldcpy(find_path, path);
> +		strncpy(find_path, path, NAME_SIZE);
>  		find_found = 1;

strncpy() does not terminate the string!
I changed it to strnfieldcpy(), you are right the strfieldcpy() can't work.
I've added a 'all' query option to print all attributes and changed the
man page to reflect the new capability. Please have a look.

thanks again,
Kay

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===== udevdb.c 1.23 vs edited =====
--- 1.23/udevdb.c	Wed Feb 25 01:04:14 2004
+++ edited/udevdb.c	Sun Feb 29 21:02:04 2004
@@ -27,6 +27,7 @@
 #define _KLIBC_HAS_ARCH_SIG_ATOMIC_T
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <fcntl.h>
 #include <string.h>
 #include <sys/stat.h>
@@ -178,13 +179,29 @@
 
 static int find_device_by_name(char *path, struct udevice *dev)
 {
+	int l, i, j;
 	if (strncmp(dev->name, find_name, sizeof(dev->name)) == 0) {
 		memcpy(find_dev, dev, sizeof(*find_dev));
-		strfieldcpy(find_path, path);
+		strnfieldcpy(find_path, path, NAME_SIZE);
 		find_found = 1;
 		/* stop search */
 		return 1;
 	}
+	/* look for matching symlink*/
+	l = strlen(dev->symlink);
+	if (!l)
+		return 0;
+	i = j = 0;
+	do {
+		j = strcspn(&dev->symlink[i], " ");
+		if (j && strncmp(&dev->symlink[i], find_name, j -i) == 0) {
+			memcpy(find_dev, dev, sizeof(*find_dev));
+			strncpy(find_path, path, NAME_SIZE);
+			find_found = 1;
+			return 1;
+		}
+		i = i + j + 1;
+	} while (i < l);
 	return 0;
 }
 
===== udevinfo.8 1.5 vs edited =====
--- 1.5/udevinfo.8	Tue Feb 17 04:09:57 2004
+++ edited/udevinfo.8	Sun Feb 29 21:13:17 2004
@@ -28,13 +28,13 @@
 .RB Needs " -p " or " -n " specified.
 .br
 Valid types are:
-.BR name ", " symlink ", " mode " ," owner " , " group " or " path.
+.BR name ", " symlink ", " mode " ," owner " , " group " , " path " or " all.
 .TP
 .BI -p " sysfs_path"
 Specify the sysfs path of the device to query.
 .TP
 .BI -n " name"
-Specify the name of the node for the device to query.
+Specify the name of the node or the symlink for the device to query.
 .TP
 .B -a
 Print all
===== udevinfo.c 1.14 vs edited =====
--- 1.14/udevinfo.c	Wed Feb 25 01:04:14 2004
+++ edited/udevinfo.c	Sun Feb 29 21:10:19 2004
@@ -122,7 +122,8 @@
 	SYMLINK,
 	MODE,
 	OWNER,
-	GROUP
+	GROUP,
+	ALL
 };
 
 static int print_device_chain(const char *path)
@@ -258,6 +259,11 @@
 				break;
 			}
 
+			if (strcmp(optarg, "all") == 0) {
+				query = ALL;
+				break;
+			}
+
 			printf("unknown query type\n");
 			exit(1);
 
@@ -366,6 +372,10 @@
 			strfieldcpy(result, path);
 			break;
 
+		case ALL:
+			print_record(path, &dev);
+			goto exit;
+
 		default:
 			goto exit;
 		}
@@ -406,8 +416,10 @@
 	       "             'owner'   of node\n"
 	       "             'group'   of node\n"
 	       "             'path'    sysfs device path\n"
+	       "             'all'     all values\n"
+	       "\n"
 	       "  -p PATH  sysfs device path used for query or chain\n"
-	       "  -n NAME  node name used for query\n"
+	       "  -n NAME  node/symlink name used for query\n"
 	       "\n"
 	       "  -r       print udev root\n"
 	       "  -a       print all SYSFS_attributes along the device chain\n"