1 files changed, 137 insertions, 0 deletions
diff --git a/init/do_mounts_devfs.c b/init/do_mounts_devfs.c
new file mode 100644
index 000000000000..cc526474690a
--- /dev/null
+++ b/init/do_mounts_devfs.c
@@ -0,0 +1,137 @@
+
+#include <linux/kernel.h>
+#include <linux/dirent.h>
+#include <linux/string.h>
+
+#include "do_mounts.h"
+
+void __init mount_devfs(void)
+{
+	sys_mount("devfs", "/dev", "devfs", 0, NULL);
+}
+
+void __init umount_devfs(char *path)
+{
+	sys_umount(path, 0);
+}
+
+/*
+ * If the dir will fit in *buf, return its length.  If it won't fit, return
+ * zero.  Return -ve on error.
+ */
+static int __init do_read_dir(int fd, void *buf, int len)
+{
+	long bytes, n;
+	char *p = buf;
+	sys_lseek(fd, 0, 0);
+
+	for (bytes = 0; bytes < len; bytes += n) {
+		n = sys_getdents64(fd, (struct linux_dirent64 *)(p + bytes),
+					len - bytes);
+		if (n < 0)
+			return n;
+		if (n == 0)
+			return bytes;
+	}
+	return 0;
+}
+
+/*
+ * Try to read all of a directory.  Returns the contents at *p, which
+ * is kmalloced memory.  Returns the number of bytes read at *len.  Returns
+ * NULL on error.
+ */
+static void * __init read_dir(char *path, int *len)
+{
+	int size;
+	int fd = sys_open(path, 0, 0);
+
+	*len = 0;
+	if (fd < 0)
+		return NULL;
+
+	for (size = 1 << 9; size <= (PAGE_SIZE << MAX_ORDER); size <<= 1) {
+		void *p = kmalloc(size, GFP_KERNEL);
+		int n;
+		if (!p)
+			break;
+		n = do_read_dir(fd, p, size);
+		if (n > 0) {
+			sys_close(fd);
+			*len = n;
+			return p;
+		}
+		kfree(p);
+		if (n == -EINVAL)
+			continue;	/* Try a larger buffer */
+		if (n < 0)
+			break;
+	}
+	sys_close(fd);
+	return NULL;
+}
+
+/*
+ * recursively scan <path>, looking for a device node of type <dev>
+ */
+static int __init find_in_devfs(char *path, unsigned dev)
+{
+	char *end = path + strlen(path);
+	int rest = path + 64 - end;
+	int size;
+	char *p = read_dir(path, &size);
+	char *s;
+
+	if (!p)
+		return -1;
+	for (s = p; s < p + size; s += ((struct linux_dirent64 *)s)->d_reclen) {
+		struct linux_dirent64 *d = (struct linux_dirent64 *)s;
+		if (strlen(d->d_name) + 2 > rest)
+			continue;
+		switch (d->d_type) {
+			case DT_BLK:
+				sprintf(end, "/%s", d->d_name);
+				if (bstat(path) != dev)
+					break;
+				kfree(p);
+				return 0;
+			case DT_DIR:
+				if (strcmp(d->d_name, ".") == 0)
+					break;
+				if (strcmp(d->d_name, "..") == 0)
+					break;
+				sprintf(end, "/%s", d->d_name);
+				if (find_in_devfs(path, dev) < 0)
+					break;
+				kfree(p);
+				return 0;
+		}
+	}
+	kfree(p);
+	return -1;
+}
+
+/*
+ * create a device node called <name> which points to
+ * <devfs_name> if possible, otherwise find a device node
+ * which matches <dev> and make <name> a symlink pointing to it.
+ */
+int __init create_dev(char *name, dev_t dev, char *devfs_name)
+{
+	char path[64];
+
+	sys_unlink(name);
+	if (devfs_name && devfs_name[0]) {
+		if (strncmp(devfs_name, "/dev/", 5) == 0)
+			devfs_name += 5;
+		sprintf(path, "/dev/%s", devfs_name);
+		if (sys_access(path, 0) == 0)
+			return sys_symlink(devfs_name, name);
+	}
+	if (!dev)
+		return -1;
+	strcpy(path, "/dev");
+	if (find_in_devfs(path, new_encode_dev(dev)) < 0)
+		return -1;
+	return sys_symlink(path + 5, name);
+}