udevinfo reverse lookup for symlinks

udevinfo reverse lookup for symlinks

[Olaf Hering]

How do I reverse lookup symlinks?
It seem that is not implemented.

nectarine:~ # udevinfo -n cdrom -q path
device not found in database
nectarine:~ # udevinfo -n sr0 -q path
/block/sr0
nectarine:~ # udevinfo -n cdrom -q symlink
device not found in database
nectarine:~ # udevinfo -n cdrom -q name
device not found in database
nectarine:~ # ls -l /dev/cdrom
lrwxrwxrwx    1 root     root            3 2004-02-09 17:27 /dev/cdrom -> sr0


P: /block/sr0
N: sr0
M: 0600
S: cdrom
O: root
G: root


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Re: udevinfo reverse lookup for symlinks

[Kay Sievers]

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 :)

thanks,
Kay


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Re: udevinfo reverse lookup for symlinks

[Olaf Hering]

 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 :)


diff -purN udev-klibc/udevdb.c udev-klibc-debug/udevdb.c
--- udev-klibc/udevdb.c	2004-02-28 02:11:47.000000000 +0100
+++ udev-klibc-debug/udevdb.c	2004-02-29 20:38:39.668973696 +0100
@@ -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_found;
 
 static int find_device_by_name(char *path, struct udevice *dev)
 {
+	char sp[] = " ";
+	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);
+		strncpy(find_path, path, NAME_SIZE);
 		find_found = 1;
 		/* stop search */
 		return 1;
 	}
+	l = strlen(dev->symlink);
+	if (!l)
+		return 0;
+	i = j = 0;
+	do {
+		j = strcspn(&dev->symlink[i], sp);
+		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;
 }
 

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Re: udevinfo reverse lookup for symlinks

[Kay Sievers]

[-- Attachment #1: Type: text/plain, Size: 964 bytes --]

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

[-- Attachment #2: 06-reverse-symlink.patch --]
[-- Type: text/plain, Size: 2749 bytes --]

===== 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"

Re: udevinfo reverse lookup for symlinks

[Olaf Hering]

 On Sun, Feb 29, Kay Sievers wrote:

> strncpy() does not terminate the string!

It would hurt if the tdb is corrupted.

> +			strncpy(find_path, path, NAME_SIZE);

maybe this one needs also strnfieldcpy().


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sUse lINUX ag, n√úRNBERG


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Re: udevinfo reverse lookup for symlinks

[Kay Sievers]

[-- Attachment #1: Type: text/plain, Size: 508 bytes --]

On Sun, Feb 29, 2004 at 09:52:23PM +0100, Olaf Hering wrote:
>  On Sun, Feb 29, Kay Sievers wrote:
> 
> > strncpy() does not terminate the string!
> 
> It would hurt if the tdb is corrupted.
> 
> > +			strncpy(find_path, path, NAME_SIZE);
> 
> maybe this one needs also strnfieldcpy().

Yes, right I already changed it and the following:

It should be:
  if (j && strncmp(&dev->symlink[i], find_name, j) == 0) {

instead of:
  if (j && strncmp(&dev->symlink[i], find_name, j -i) == 0) {

right?

thanks,
Kay

[-- Attachment #2: 06-reverse-symlink.patch --]
[-- Type: text/plain, Size: 2806 bytes --]

===== udevdb.c 1.23 vs edited =====
--- 1.23/udevdb.c	Wed Feb 25 01:04:14 2004
+++ edited/udevdb.c	Sun Feb 29 21:54:33 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);
+		memcpy(find_dev, dev, sizeof(struct udevice));
+		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) == 0) {
+			memcpy(find_dev, dev, sizeof(struct udevice));
+			strnfieldcpy(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"

Re: udevinfo reverse lookup for symlinks

[Olaf Hering]

 On Sun, Feb 29, Kay Sievers wrote:

> On Sun, Feb 29, 2004 at 09:52:23PM +0100, Olaf Hering wrote:
> >  On Sun, Feb 29, Kay Sievers wrote:
> > 
> > > strncpy() does not terminate the string!
> > 
> > It would hurt if the tdb is corrupted.
> > 
> > > +			strncpy(find_path, path, NAME_SIZE);
> > 
> > maybe this one needs also strnfieldcpy().
> 
> Yes, right I already changed it and the following:
> 
> It should be:
>   if (j && strncmp(&dev->symlink[i], find_name, j) = 0) {

yes, j is the lenght to compare. worked for me somehow, even with 2
symlinks.

-- 
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sUse lINUX ag, n√úRNBERG


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