diff options
| -rw-r--r-- | udev.c | 207 | ||||
| -rw-r--r-- | udev.h | 11 |
2 files changed, 208 insertions, 10 deletions
@@ -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; } @@ -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, ...); |