Shrink the code about 50 bytes, allocate less run-time memory, and add a

comment that null terminating the string we sscanf() shouldn't be required
since the kernel adds \n to the end of it and sscanf will stop there.

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 5fea1b8e28cc53ae23d3fefde0f310fc43156821..73938f8deee6b6e8c7018ab5a4676a85eafddce6 100644 (file)
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -38,23 +38,25 @@ static void make_device(char *path)
        int mode = 0660;
        uid_t uid = 0;
        gid_t gid = 0;
+       char *temp = path + strlen(path);
 
-       RESERVE_CONFIG_BUFFER(temp, PATH_MAX);
+       /* Try to read major/minor string.  Note that the kernel puts \n after
+        * the data, so we don't need to worry about null terminating the string
+        * because sscanf() will stop at the first nondigit, which \n is.  We
+        * also depend on path having writeable space after it. */
 
-       /* Try to read major/minor string */
-
-       snprintf(temp, PATH_MAX, "%s/dev", path);
-       fd = open(temp, O_RDONLY);
-       len = read(fd, temp, PATH_MAX-1);
+       strcat(path, "/dev");
+       fd = open(path, O_RDONLY);
+       len = read(fd, temp + 1, 64);
+       *temp++ = 0;
        close(fd);
-       if (len < 1) goto end;
+       if (len < 1) return;
 
        /* Determine device name, type, major and minor */
 
        device_name = strrchr(path, '/') + 1;
-       type = strncmp(path+5, "block/", 6) ? S_IFCHR : S_IFBLK;
-       if (sscanf(temp, "%d:%d", &major, &minor) != 2)
-               goto end;
+       type = path[5]=='c' ? S_IFCHR : S_IFBLK;
+       if (sscanf(temp, "%d:%d", &major, &minor) != 2) return;
 
        /* If we have a config file, look up permissions for this device */
 
@@ -167,18 +169,14 @@ found_device:
                }
        }
 
-       sprintf(temp, "%s/%s", DEV_PATH, device_name);
        umask(0);
-       if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST)
-               bb_perror_msg_and_die("mknod %s failed", temp);
+       if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
+               bb_perror_msg_and_die("mknod %s failed", device_name);
 
        if (major==root_major && minor==root_minor)
-               symlink(temp,DEV_PATH "/root");
+               symlink(device_name, "root");
        
-       if (ENABLE_FEATURE_MDEV_CONF) chown(temp,uid,gid);
-
-end:
-       RELEASE_CONFIG_BUFFER(temp);
+       if (ENABLE_FEATURE_MDEV_CONF) chown(device_name, uid, gid);
 }
 
 /* Recursive search of /sys/block or /sys/class.  path must be a writeable
@@ -220,6 +218,8 @@ int mdev_main(int argc, char *argv[])
        char *env_path;
        RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
 
+       bb_xchdir(DEV_PATH);
+
        /* Scan */
 
        if (argc == 2 && !strcmp(argv[1],"-s")) {
@@ -245,8 +245,7 @@ int mdev_main(int argc, char *argv[])
                        sprintf(temp, "/sys%s", env_path);
                        make_device(temp);
                } else if (!strcmp(action, "remove")) {
-                       sprintf(temp, "%s/%s", DEV_PATH, strrchr(env_path, '/') + 1);
-                       unlink(temp);
+                       unlink(strrchr(env_path, '/') + 1);
                }
        }