[PATCH] compatibility symlinks for udev

[thirdparty/systemd.git] / namedev.c

diff --git a/namedev.c b/namedev.c
index 52417e3793b655fcca041ff1ead58e7a0ba8d4ce..466016c297972c46afef90aa964df47adb357a63 100644 (file)
--- a/namedev.c
+++ b/namedev.c
@@ -42,6 +42,7 @@
 #include "logging.h"
 #include "namedev.h"
 #include "klibc_fixups.h"
+#include "udevdb.h"
 
 static struct sysfs_attribute *find_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device, char *attr);
 
@@ -179,6 +180,37 @@ static int get_format_len(char **str)
        return -1;
 }
 
+/** Finds the lowest positive N such that <name>N isn't present in 
+ *  $(udevroot) either as a file or a symlink.
+ *
+ *  @param  name                Name to check for
+ *  @return                     0 if <name> didn't exist and N otherwise.
+ */
+static unsigned int find_free_number (struct udevice *udev, char *name)
+{
+       char temp[NAME_SIZE];
+       char path[NAME_SIZE];
+       struct udevice dev;
+       int result;
+
+       /* have to sweep the database for each lookup */
+       result = 0;
+       strncpy(temp, name, sizeof (temp));
+       while (1) {
+               if (udevdb_get_dev_byname(temp, path, &dev) != 0)
+                       goto found;
+               /* symlink might be stale if $(udevroot) isn't cleaned; check
+                * on major/minor to see if it's the same device
+                */
+               if (dev.major == udev->major && dev.minor == udev->minor)
+                       goto found;
+               snprintf (temp, sizeof(temp), "%s%d", name, ++result);
+       }
+
+found:
+       return result;
+}
+
 static void apply_format(struct udevice *udev, char *string, size_t maxsize,
                         struct sysfs_class_device *class_dev,
                         struct sysfs_device *sysfs_device)
@@ -195,6 +227,7 @@ static void apply_format(struct udevice *udev, char *string, size_t maxsize,
        char *rest;
        int slen;
        struct sysfs_attribute *tmpattr;
+       unsigned int next_free_number;
 
        pos = string;
        while (1) {
@@ -284,6 +317,13 @@ static void apply_format(struct udevice *udev, char *string, size_t maxsize,
                        strfieldcatmax(string, "%", maxsize);
                        pos++;
                        break;
+               case 'e':
+                       next_free_number = find_free_number(udev, string);
+                       if (next_free_number > 0) {
+                               snprintf(temp2, sizeof(temp2), "%d", next_free_number);
+                               strfieldcatmax(string, temp2, maxsize);
+                       }
+                       break;
                default:
                        dbg("unknown substitution type '%%%c'", c);
                        break;