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-rw-r--r--e2fslib/getsize.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/e2fslib/getsize.c b/e2fslib/getsize.c
new file mode 100644
index 0000000..e8fadba
--- /dev/null
+++ b/e2fslib/getsize.c
@@ -0,0 +1,157 @@
+/*
+ * getsize.c --- get the size of a partition.
+ *
+ * Copyright (C) 1995, 1995 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#define _LARGEFILE_SOURCE
+#define _LARGEFILE64_SOURCE
+
+#include <stdio.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <fcntl.h>
+#ifdef HAVE_LINUX_FD_H
+#include <sys/ioctl.h>
+#include <linux/fd.h>
+#endif
+#ifdef HAVE_SYS_DISKLABEL_H
+#include <sys/ioctl.h>
+#include <sys/disklabel.h>
+#endif /* HAVE_SYS_DISKLABEL_H */
+
+#if defined(__linux__) && defined(_IO) && !defined(BLKGETSIZE)
+#define BLKGETSIZE _IO(0x12,96) /* return device size */
+#endif
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+static int valid_offset (int fd, ext2_loff_t offset)
+{
+ char ch;
+
+ if (ext2fs_llseek (fd, offset, 0) < 0)
+ return 0;
+ if (read (fd, &ch, 1) < 1)
+ return 0;
+ return 1;
+}
+
+/*
+ * Returns the number of blocks in a partition
+ */
+errcode_t ext2fs_get_device_size(const char *file, int blocksize,
+ blk_t *retblocks)
+{
+ int fd;
+#ifdef BLKGETSIZE
+ unsigned long size;
+#endif
+ ext2_loff_t high, low;
+#ifdef FDGETPRM
+ struct floppy_struct this_floppy;
+#endif
+#ifdef HAVE_SYS_DISKLABEL_H
+ int part;
+ struct disklabel lab;
+ struct partition *pp;
+ char ch;
+#endif /* HAVE_SYS_DISKLABEL_H */
+
+#ifdef HAVE_OPEN64
+ fd = open64(file, O_RDONLY);
+#else
+ fd = open(file, O_RDONLY);
+#endif
+ if (fd < 0)
+ return errno;
+
+#ifdef BLKGETSIZE
+ if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
+ close(fd);
+ *retblocks = size / (blocksize / 512);
+ return 0;
+ }
+#endif
+#ifdef FDGETPRM
+ if (ioctl(fd, FDGETPRM, &this_floppy) >= 0) {
+ close(fd);
+ *retblocks = this_floppy.size / (blocksize / 512);
+ return 0;
+ }
+#endif
+#ifdef HAVE_SYS_DISKLABEL_H
+ part = strlen(file) - 1;
+ if (part >= 0) {
+ ch = file[part];
+ if (isdigit(ch))
+ part = 0;
+ else if (ch >= 'a' && ch <= 'h')
+ part = ch - 'a';
+ else
+ part = -1;
+ }
+ if (part >= 0 && (ioctl(fd, DIOCGDINFO, (char *)&lab) >= 0)) {
+ pp = &lab.d_partitions[part];
+ if (pp->p_size) {
+ close(fd);
+ *retblocks = pp->p_size / (blocksize / 512);
+ return 0;
+ }
+ }
+#endif /* HAVE_SYS_DISKLABEL_H */
+
+ /*
+ * OK, we couldn't figure it out by using a specialized ioctl,
+ * which is generally the best way. So do binary search to
+ * find the size of the partition.
+ */
+ low = 0;
+ for (high = 1024; valid_offset (fd, high); high *= 2)
+ low = high;
+ while (low < high - 1)
+ {
+ const ext2_loff_t mid = (low + high) / 2;
+
+ if (valid_offset (fd, mid))
+ low = mid;
+ else
+ high = mid;
+ }
+ valid_offset (fd, 0);
+ close(fd);
+ *retblocks = (low + 1) / blocksize;
+ return 0;
+}
+
+#ifdef DEBUG
+int main(int argc, char **argv)
+{
+ blk_t blocks;
+ int retval;
+
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s device\n", argv[0]);
+ exit(1);
+ }
+
+ retval = ext2fs_get_device_size(argv[1], 1024, &blocks);
+ if (retval) {
+ com_err(argv[0], retval,
+ "while calling ext2fs_get_device_size");
+ exit(1);
+ }
+ printf("Device %s has %d 1k blocks.\n", argv[1], blocks);
+ exit(0);
+}
+#endif