[PATCH] Adding '%s' format specifier to NAME and SYMLINK

On Thu, Feb 12, 2004 at 05:34:57PM -0800, Greg KH wrote:
> On Tue, Feb 10, 2004 at 09:14:20AM +0100, Hannes Reinecke wrote:
> > Hi all,
> >
> > this patch makes the format for NAME and SYMLINK a bit more flexible:
> > I've added a new format specifier '%s{<SYSFS_var>}', which allows for
> > the value of any sysfs entry found for this device to be inserted.
> > Example (for our S/390 fcp adapter):
> >
> > BUS="ccw", SYSFS_devtype="1732/03", NAME="%k" \
> > SYMLINK="zfcp-%s{hba_id}-%s{wwpn}:%s{fcp_lun}"
> >
> > I know this could also be done with an external program, but having this
> > incorporated into udev makes life easier, especially if run from
> > initramfs. Plus it makes the rules easier to follow, as the result is
> > directly visible and need not to be looked up in some external program.
> >
> > Comments etc. welcome.
>
> Oops, sorry I missed this for the 017 release.  I'll look at it tomorrow
> and get back to you.  At first glance it looks like a good thing.
>
> Oh, you forgot to update the documentation, that's important to do if
> you want this change to make it in :)

I took a part of the code and made a version that uses already implemented
attribute finding logic.

The parsing of the format length '%3x' and the '%x{attribute}' is a fuction now,
maybe there are more possible users in the future.

I've also added the test to udev-test.pl.

diff --git a/namedev.c b/namedev.c
index f138fe976955fe99bb3c24318acb132369619c1b..cd38f25cb0979541ad42e119734b2fdb61abaa35 100644 (file)
--- a/namedev.c
+++ b/namedev.c
@@ -41,6 +41,8 @@
 #include "libsysfs/libsysfs.h"
 #include "klibc_fixups.h"
 
+static struct sysfs_attribute *find_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device, char *attr);
+
 LIST_HEAD(config_device_list);
 LIST_HEAD(perm_device_list);
 
@@ -168,7 +170,46 @@ static char *get_default_group(void)
        return default_group_str;
 }
 
-static void apply_format(struct udevice *udev, unsigned char *string)
+/* extract possible {attr} and move str behind it */
+static char *get_format_attribute(char **str)
+{
+       char *pos;
+       char *attr = NULL;
+
+       if (*str[0] == '{') {
+               pos = strchr(*str, '}');
+               if (pos == NULL) {
+                       dbg("missing closing brace for format");
+                       return NULL;
+               }
+               pos[0] = '\0';
+               attr = *str+1;
+               *str = pos+1;
+               dbg("attribute='%s', str='%s'", attr, *str);
+       }
+       return attr;
+}
+
+/* extract possible format length and move str behind it*/
+static int get_format_len(char **str)
+{
+       int num;
+       char *tail;
+
+       if (isdigit(*str[0])) {
+               num = (int) strtoul(*str, &tail, 10);
+               if (tail != NULL) {
+                       *str = tail;
+                       dbg("format length=%i", num);
+                       return num;
+               } else {
+                       dbg("format parsing error '%s'", *str);
+               }
+       }
+       return -1;
+}
+
+static void apply_format(struct udevice *udev, unsigned char *string, struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device)
 {
        char temp[NAME_SIZE];
        char temp1[NAME_SIZE];
@@ -176,87 +217,100 @@ static void apply_format(struct udevice *udev, unsigned char *string)
        char *pos;
        char *pos2;
        char *pos3;
+       char *attr;
        int num;
+       char c;
+       struct sysfs_attribute *tmpattr;
 
        pos = string;
+
        while (1) {
-               num = 0;
                pos = strchr(pos, '%');
-
-               if (pos) {
+               if (pos != NULL) {
                        pos[0] = '\0';
                        tail = pos+1;
-                       if (isdigit(tail[0])) {
-                               num = (int) strtoul(&pos[1], &tail, 10);
-                               if (tail == NULL) {
-                                       dbg("format parsing error '%s'", pos+1);
-                                       break;
-                               }
-                       }
+                       num = get_format_len(&tail);
+                       c = tail[0];
                        strfieldcpy(temp, tail+1);
+                       tail = temp;
+               } else {
+                       break;
+               }
+               dbg("format=%c, string='%s', tail='%s'",c , string, tail);
 
-                       switch (tail[0]) {
-                       case 'b':
-                               if (strlen(udev->bus_id) == 0)
-                                       break;
-                               strcat(pos, udev->bus_id);
-                               dbg("substitute bus_id '%s'", udev->bus_id);
+               attr = get_format_attribute(&tail);
+
+               switch (c) {
+               case 'b':
+                       if (strlen(udev->bus_id) == 0)
                                break;
-                       case 'k':
-                               if (strlen(udev->kernel_name) == 0)
-                                       break;
-                               strcat(pos, udev->kernel_name);
-                               dbg("substitute kernel name '%s'", udev->kernel_name);
+                       strcat(pos, udev->bus_id);
+                       dbg("substitute bus_id '%s'", udev->bus_id);
+                       break;
+               case 'k':
+                       if (strlen(udev->kernel_name) == 0)
                                break;
-                       case 'n':
-                               if (strlen(udev->kernel_number) == 0)
-                                       break;
-                               strcat(pos, udev->kernel_number);
-                               dbg("substitute kernel number '%s'", udev->kernel_number);
+                       strcat(pos, udev->kernel_name);
+                       dbg("substitute kernel name '%s'", udev->kernel_name);
+                       break;
+               case 'n':
+                       if (strlen(udev->kernel_number) == 0)
                                break;
-                       case 'm':
-                               sprintf(pos, "%u", udev->minor);
-                               dbg("substitute minor number '%u'", udev->minor);
+                       strcat(pos, udev->kernel_number);
+                       dbg("substitute kernel number '%s'", udev->kernel_number);
                                break;
+               case 'm':
+                       sprintf(pos, "%u", udev->minor);
+                       dbg("substitute minor number '%u'", udev->minor);
+                       break;
                        case 'M':
-                               sprintf(pos, "%u", udev->major);
-                               dbg("substitute major number '%u'", udev->major);
+                       sprintf(pos, "%u", udev->major);
+                       dbg("substitute major number '%u'", udev->major);
+                       break;
+               case 'c':
+                       if (strlen(udev->program_result) == 0)
                                break;
-                       case 'c':
-                               if (strlen(udev->program_result) == 0)
-                                       break;
-                               if (num) {
-                                       /* get part of return string */
-                                       strncpy(temp1, udev->program_result, sizeof(temp1));
-                                       pos2 = temp1;
-                                       while (num) {
-                                               num--;
-                                               pos3 = strsep(&pos2, " ");
-                                               if (pos3 == NULL) {
-                                                       dbg("requested part of result string not found");
-                                                       break;
-                                               }
-                                       }
-                                       if (pos3) {
-                                               strcat(pos, pos3);
-                                               dbg("substitute part of result string '%s'", pos3);
+                       if (num > 0) {
+                               strncpy(temp1, udev->program_result, sizeof(temp1));
+                               pos2 = temp1;
+                               while (num) {
+                                       num--;
+                                       pos3 = strsep(&pos2, " ");
+                                       if (pos3 == NULL) {
+                                               dbg("requested part of result string not found");
+                                               break;
                                        }
-                               } else {
-                                       strcat(pos, udev->program_result);
-                                       dbg("substitute result string '%s'", udev->program_result);
                                }
-                               break;
-                       case '%':
-                               strcat(pos, "%");
-                               pos++;
-                               break;
-                       default:
-                               dbg("unknown substitution type '%%%c'", pos[1]);
-                               break;
+                               if (pos3) {
+                                       strcat(pos, pos3);
+                                       dbg("substitute part of result string '%s'", pos3);
+                               }
+                       } else {
+                               strcat(pos, udev->program_result);
+                               dbg("substitute result string '%s'", udev->program_result);
                        }
-                       strcat(string, temp);
-               } else
                        break;
+               case 's':
+                       if (attr != NULL) {
+                               tmpattr = find_sysfs_attribute(class_dev, sysfs_device, attr);
+                               if (tmpattr == NULL) {
+                                       dbg("sysfa attribute '%s' not found", attr);
+                                       break;
+                               }
+                               strcpy(pos, tmpattr->value);
+                               dbg("substitute sysfs value '%s'", tmpattr->value);
+                       } else {
+                               dbg("missing attribute");
+                       }
+                       break;
+               case '%':
+                       strcat(pos, "%");
+                       break;
+               default:
+                       dbg("unknown substitution type '%%%c'", c);
+                       break;
+               }
+               strcat(pos, tail);
        }
 }
 
@@ -422,32 +476,46 @@ static int execute_program(char *path, char *value, int len)
        return retval;
 }
 
-static int compare_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device, struct sysfs_pair *pair)
+static struct sysfs_attribute *find_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device, char *attr)
 {
        struct sysfs_attribute *tmpattr = NULL;
        char *c;
 
-       if ((pair == NULL) || (pair->file[0] == '\0') || (pair->value == '\0'))
-               return -ENODEV;
-
-       dbg("look for device attribute '%s'", pair->file);
+       dbg("look for device attribute '%s'", attr);
        /* try to find the attribute in the class device directory */
-       tmpattr = sysfs_get_classdev_attr(class_dev, pair->file);
+       tmpattr = sysfs_get_classdev_attr(class_dev, attr);
        if (tmpattr)
-               goto label_found;
+               goto attr_found;
 
        /* look in the class device directory if present */
        if (sysfs_device) {
-               tmpattr = sysfs_get_device_attr(sysfs_device, pair->file);
+               tmpattr = sysfs_get_device_attr(sysfs_device, attr);
                if (tmpattr)
-                       goto label_found;
+                       goto attr_found;
        }
-       return -ENODEV;
 
-label_found:
-       c = tmpattr->value + strlen(tmpattr->value)-1;
-       if (*c == '\n')
-               *c = 0x00;
+       return NULL;
+
+attr_found:
+       c = strchr(tmpattr->value, '\n');
+       if (c != NULL)
+               c[0] = '\0';
+
+       dbg("found attribute '%s'", tmpattr->path);
+       return tmpattr;
+}
+
+static int compare_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device, struct sysfs_pair *pair)
+{
+       struct sysfs_attribute *tmpattr;
+
+       if ((pair == NULL) || (pair->file[0] == '\0') || (pair->value == '\0'))
+               return -ENODEV;
+
+       tmpattr = find_sysfs_attribute(class_dev, sysfs_device, pair->file);
+       if (tmpattr == NULL)
+               return -ENODEV;
+
        dbg("compare attribute '%s' value '%s' with '%s'",
                  pair->file, tmpattr->value, pair->value);
        if (strcmp_pattern(pair->value, tmpattr->value) != 0)
@@ -658,7 +726,7 @@ static int match_rule(struct config_device *dev, struct sysfs_class_device *clas
                /* execute external program */
                if (dev->program[0] != '\0') {
                        dbg("check " FIELD_PROGRAM);
-                       apply_format(udev, dev->program);
+                       apply_format(udev, dev->program, class_dev, sysfs_device);
                        if (execute_program(dev->program, udev->program_result, NAME_SIZE) != 0) {
                                dbg(FIELD_PROGRAM " returned nozero");
                                goto try_parent;
@@ -750,8 +818,8 @@ int namedev_name_device(struct sysfs_class_device *class_dev, struct udevice *ud
 
 found:
        /* substitute placeholder */
-       apply_format(udev, udev->name);
-       apply_format(udev, udev->symlink);
+       apply_format(udev, udev->name, class_dev, sysfs_device);
+       apply_format(udev, udev->symlink, class_dev, sysfs_device);
 
 done:
        perm = find_perm(udev->name);

diff --git a/test/udev-test.pl b/test/udev-test.pl
index 62a2bb327b16990521f930a1acbdec09d4b6abf6..cbe110f797eb33a7afe48924f9dee6f30abcab63 100644 (file)
--- a/test/udev-test.pl
+++ b/test/udev-test.pl
@@ -191,6 +191,16 @@ EOF
                expected => "Major:8:minor:3:kernelnumber:3:bus:0:0:0:0" ,
                conf     => <<EOF
 BUS="scsi", PLACE="0:0:0:0", NAME="Major:%M:minor:%m:kernelnumber:%n:bus:%b"
+EOF
+       },
+       {
+               desc     => "sustitution of sysfs value (%s{file})",
+               subsys   => "block",
+               devpath  => "block/sda",
+               expected => "disk-IBM-ESXS-sda" ,
+               conf     => <<EOF
+BUS="scsi", SYSFS_vendor="IBM-ESXS", NAME="disk-%s{vendor}-%k"
+KERNEL="ttyUSB0", NAME="visor"
 EOF
        },
        {