[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit

Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/app/busybox/src/libbb/loop.c b/ap/app/busybox/src/libbb/loop.c
new file mode 100644
index 0000000..823fba0
--- /dev/null
+++ b/ap/app/busybox/src/libbb/loop.c
@@ -0,0 +1,174 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2005 by Rob Landley <rob@landley.net>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+#include "libbb.h"
+#include <linux/version.h>
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
+
+/* For 2.6, use the cleaned up header to get the 64 bit API. */
+// Commented out per Rob's request
+//# include "fix_u32.h" /* some old toolchains need __u64 for linux/loop.h */
+# include <linux/loop.h>
+typedef struct loop_info64 bb_loop_info;
+# define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
+# define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
+
+#else
+
+/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
+/* Stuff stolen from linux/loop.h for 2.4 and earlier kernels */
+# include <linux/posix_types.h>
+# define LO_NAME_SIZE        64
+# define LO_KEY_SIZE         32
+# define LOOP_SET_FD         0x4C00
+# define LOOP_CLR_FD         0x4C01
+# define BB_LOOP_SET_STATUS  0x4C02
+# define BB_LOOP_GET_STATUS  0x4C03
+typedef struct {
+	int                lo_number;
+	__kernel_dev_t     lo_device;
+	unsigned long      lo_inode;
+	__kernel_dev_t     lo_rdevice;
+	int                lo_offset;
+	int                lo_encrypt_type;
+	int                lo_encrypt_key_size;
+	int                lo_flags;
+	char               lo_file_name[LO_NAME_SIZE];
+	unsigned char      lo_encrypt_key[LO_KEY_SIZE];
+	unsigned long      lo_init[2];
+	char               reserved[4];
+} bb_loop_info;
+#endif
+
+char* FAST_FUNC query_loop(const char *device)
+{
+	int fd;
+	bb_loop_info loopinfo;
+	char *dev = NULL;
+
+	fd = open(device, O_RDONLY);
+	if (fd >= 0) {
+		if (ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo) == 0) {
+			dev = xasprintf("%"OFF_FMT"u %s", (off_t) loopinfo.lo_offset,
+					(char *)loopinfo.lo_file_name);
+		}
+		close(fd);
+	}
+
+	return dev;
+}
+
+int FAST_FUNC del_loop(const char *device)
+{
+	int fd, rc;
+
+	fd = open(device, O_RDONLY);
+	if (fd < 0)
+		return 1;
+	rc = ioctl(fd, LOOP_CLR_FD, 0);
+	close(fd);
+
+	return rc;
+}
+
+/* Returns 0 if mounted RW, 1 if mounted read-only, <0 for error.
+   *device is loop device to use, or if *device==NULL finds a loop device to
+   mount it on and sets *device to a strdup of that loop device name.  This
+   search will re-use an existing loop device already bound to that
+   file/offset if it finds one.
+ */
+int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offset, int ro)
+{
+	char dev[LOOP_NAMESIZE];
+	char *try;
+	bb_loop_info loopinfo;
+	struct stat statbuf;
+	int i, dfd, ffd, mode, rc = -1;
+
+	/* Open the file.  Barf if this doesn't work.  */
+	mode = ro ? O_RDONLY : O_RDWR;
+	ffd = open(file, mode);
+	if (ffd < 0) {
+		if (mode != O_RDONLY) {
+			mode = O_RDONLY;
+			ffd = open(file, mode);
+		}
+		if (ffd < 0)
+			return -errno;
+	}
+
+	/* Find a loop device.  */
+	try = *device ? *device : dev;
+	/* 1048575 is a max possible minor number in Linux circa 2010 */
+	for (i = 0; rc && i < 1048576; i++) {
+		sprintf(dev, LOOP_FORMAT, i);
+
+		IF_FEATURE_MOUNT_LOOP_CREATE(errno = 0;)
+		if (stat(try, &statbuf) != 0 || !S_ISBLK(statbuf.st_mode)) {
+			if (ENABLE_FEATURE_MOUNT_LOOP_CREATE
+			 && errno == ENOENT
+			 && try == dev
+			) {
+				/* Node doesn't exist, try to create it.  */
+				if (mknod(dev, S_IFBLK|0644, makedev(7, i)) == 0)
+					goto try_to_open;
+			}
+			/* Ran out of block devices, return failure.  */
+			rc = -ENOENT;
+			break;
+		}
+ try_to_open:
+		/* Open the sucker and check its loopiness.  */
+		dfd = open(try, mode);
+		if (dfd < 0 && errno == EROFS) {
+			mode = O_RDONLY;
+			dfd = open(try, mode);
+		}
+		if (dfd < 0)
+			goto try_again;
+
+		rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
+
+		/* If device is free, claim it.  */
+		if (rc && errno == ENXIO) {
+			memset(&loopinfo, 0, sizeof(loopinfo));
+			safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
+			loopinfo.lo_offset = offset;
+			/* Associate free loop device with file.  */
+			if (ioctl(dfd, LOOP_SET_FD, ffd) == 0) {
+				if (ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo) == 0)
+					rc = 0;
+				else
+					ioctl(dfd, LOOP_CLR_FD, 0);
+			}
+
+		/* If this block device already set up right, re-use it.
+		 * (Yes this is racy, but associating two loop devices with the same
+		 * file isn't pretty either.  In general, mounting the same file twice
+		 * without using losetup manually is problematic.)
+		 */
+		} else
+		if (strcmp(file, (char *)loopinfo.lo_file_name) != 0
+		 || offset != loopinfo.lo_offset
+		) {
+			rc = -1;
+		}
+		close(dfd);
+ try_again:
+		if (*device) break;
+	}
+	close(ffd);
+	if (rc == 0) {
+		if (!*device)
+			*device = xstrdup(dev);
+		return (mode == O_RDONLY); /* 1:ro, 0:rw */
+	}
+	return rc;
+}