[PATCH] Creating nodes actually works.

diff --git a/udev.c b/udev.c
index 1ac1c985076be16e6d1eab73fdd65d7b58cb7d33..971ac10809bedb81be6584cc64a16da5e6b91719 100644 (file)
--- a/udev.c
+++ b/udev.c
@@ -23,6 +23,11 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
 #include "udev.h"
 #include "udev_version.h"
 
@@ -36,11 +41,9 @@ static char *get_action(void)
 }
 
 
-/* yeah this should be dynamically allocated... */
-static char device[255];
-
 static char *get_device(void)
 {
+       static char device[255];
        char *temp;
 
        temp = getenv("DEVPATH");
@@ -52,32 +55,216 @@ static char *get_device(void)
        return device;
 }
 
+/* 
+ * Right now the major/minor of a device is stored in a file called
+ * "dev" in sysfs.
+ * The number is stored as:
+ *     MMmm
+ *             MM is the major
+ *             mm is the minor
+ *             The value is in hex.
+ * Yes, this will probably change when we go to a bigger major/minor
+ * range, and will have to be changed at that time.
+ */
+static int get_major_minor (char *dev, int *major, int *minor)
+{
+       char filename[255];
+       char line[20];
+       char temp[3];
+       int fd;
+       int retval = 0;
+
+       /* add the dev file to the directory and see if it's present */
+       strncpy(filename, dev, sizeof(filename));
+       strncat(filename, DEV_FILE, sizeof(filename));
+       fd = open(filename, O_RDONLY);
+       if (fd < 0) {
+               dbg("Can't open %s", filename);
+               return -ENODEV;
+       }
+
+       /* get the major/minor */
+       retval = read(fd, line, sizeof(line));
+       if (retval < 0) {
+               dbg("read error on %s", dev);
+               goto exit;
+       }
+
+       temp[0] = line[0];
+       temp[1] = line[1];
+       temp[2] = 0x00;
+       *major = (int)strtol(&temp[0], NULL, 16);
+
+       temp[0] = line[2];
+       temp[1] = line[3];
+       temp[2] = 0x00;
+       *minor = (int)strtol(&temp[0], NULL, 16);
+
+       dbg("found major = %d, minor = %d", *major, *minor);
+
+       retval = 0;
+exit:
+       close(fd);
+       return retval;
+}
+
+/*
+ * Here would go a call to the naming deamon, to get the name we want to have
+ * for this device.  But for now, let's just default to whatever the kernel is
+ * calling the device as that will keep the "old-style" naming policy
+ */
+static char *get_name(char *dev, int major, int minor)
+{
+       static char name[100];
+       char *temp;
+
+       temp = strrchr(dev, '/');
+       if (temp == NULL)
+               return NULL;
+       strncpy(name, &temp[1], sizeof(name));
+
+       dbg("name is %s", name);
+
+       return &name[0];
+}
+
+/*
+ * Again, this will live in the naming deamon
+ */
+static int get_mode(char *name, char *dev, int major, int minor)
+{
+       /* just default everyone to rw for the world! */
+       return 0666;
+}
+
+/*
+ * We also want to add some permissions here, and possibly some symlinks
+ */
+static int create_node(char *name, char type, int major, int minor, int mode)
+{
+       char *argv[7];
+       char mode_string[100];
+       char type_string[3];
+       char major_string[20];
+       char minor_string[20];
+       char filename[255];
+       int retval = 0;
+
+       strncpy(filename, UDEV_ROOT, sizeof(filename));
+       strncat(filename, name, sizeof(filename));
+
+       snprintf(mode_string, sizeof(mode_string), "--mode=%#o", mode);
+       snprintf(type_string, sizeof(type_string), "%c", type);
+       snprintf(major_string, sizeof(major_string), "%d", major);
+       snprintf(minor_string, sizeof(minor_string), "%d", minor);
+       
+       argv[0] = MKNOD;
+       argv[1] = mode_string;
+       argv[2] = filename;
+       argv[3] = type_string;
+       argv[4] = major_string;
+       argv[5] = minor_string;
+       argv[6] = NULL;
+       dbg ("executing %s %s %s %s %s %s",
+               argv[0], argv[1], argv[2], argv[3], argv[4], argv[5]);
+       switch (fork()) {
+               case 0:
+                       /* we are the child, so lets run the program */
+                       execv (MKNOD, argv);
+                       exit(0);
+                       break;
+               case (-1):
+                       dbg ("fork failed.");
+                       retval = -EFAULT;
+                       break;
+               default:
+                       break;
+       }
+       return retval;
+}
+
+static int remove_node(char *name)
+{
+       return 0;
+}
+
+static int do_it(char *action, char *name, char type, int major, int minor, int mode)
+{
+       if (strcmp(action, "add") == 0)
+               return create_node(name, type, major, minor, mode);
+
+       if (strcmp(action, "remove") == 0)
+               return remove_node(name);
+
+       dbg("Unknown action: %s", action);
+       return -EINVAL;
+}
 
 int main(int argc, char *argv[])
 {
        char *subsystem;
        char *action;
-       char *dev;
+       char *device;
+       char *name;
+       char type;
+       int major;
+       int minor;
+       int mode;
+       int retval = -EINVAL;
        
        if (argc != 2) {
                dbg ("unknown number of arguments");
-               return 1;
+               goto exit;
        }
 
+       /* for now, the block layer is the only place where block devices are */
        subsystem = argv[1];
+       if (strcmp(subsystem, "block") == 0)
+               type = 'b';
+       else
+               type = 'c';
 
        action = get_action();
        if (!action) {
                dbg ("no action?");
-               return 1;
+               goto exit;
        }
 
-       dev = get_device();
-       if (!dev) {
+       device = get_device();
+       if (!device) {
                dbg ("no device?");
-               return 1;
+               goto exit;
        }
+       dbg("looking at %s", device);
 
-       return 0;
+       retval = get_major_minor(device, &major, &minor);
+       if (retval) {
+               dbg ("get_major_minor failed");
+               goto exit;
+       }
+
+       name = get_name(device, major, minor);
+       if (name == NULL) {
+               dbg ("get_name failed");
+               retval = -ENODEV;
+               goto exit;
+       }
+
+       mode = get_mode(name, device, major, minor);
+       if (mode < 0) {
+               dbg ("get_mode failed");
+               retval = -EINVAL;
+               goto exit;
+       }
+
+       retval = do_it(action, name, type, major, minor, mode);
+       if (retval) {
+               dbg ("do_it failed");
+               goto exit;
+       }
+
+       retval = 0;
+exit:  
+       return retval;
 }
 

diff --git a/udev.h b/udev.h
index 83004bb791f5520d9130370f7857d475a60f7dbb..458d1d9c370256e520031c2925fa4f6ebb5c2563 100644 (file)
--- a/udev.h
+++ b/udev.h
@@ -36,10 +36,21 @@
 
 
 /* Lots of constants that should be in a config file sometime */
+
+/* Location of sysfs mount */
 #define SYSFS_ROOT     "/sys"
+
+/* Where udev should create its device nodes, trailing / needed */
+#define UDEV_ROOT      "/home/greg/linux/udev/"
+
+/* device file in sysfs that contains major/minor number, leading / needed */
+#define DEV_FILE       "/dev"
+
+/* Binaries that udev calls to do stuff */
 #define MKNOD          "/bin/mknod"
 
 
+
 extern int log_message (int level, const char *format, ...);