mkXXXX: unify [KBYTES] parameter handling (added it to mkswap)

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

8 files changed, 66 insertions, 49 deletions

diff --git a/include/libbb.h b/include/libbb.h
index a86d64400..09852d036 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -412,6 +412,11 @@ int rename_or_warn(const char *oldpath, const char *newpath) FAST_FUNC;
 off_t xlseek(int fd, off_t offset, int whence) FAST_FUNC;
 off_t fdlength(int fd) FAST_FUNC;
 
+uoff_t FAST_FUNC get_volume_size_in_bytes(int fd,
+                const char *override,
+                unsigned override_units,
+                int extend);
+
 void xpipe(int filedes[2]) FAST_FUNC;
 /* In this form code with pipes is much more readable */
 struct fd_pair { int rd; int wr; };
diff --git a/include/usage.h b/include/usage.h
index 44cc83422..683d53fbd 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2844,7 +2844,7 @@
        "$ mknod -m 644 /tmp/pipe p\n"
 
 #define mkswap_trivial_usage \
-       "[OPTIONS] BLOCKDEV" /* [SIZE_IN_KB] */
+       "[OPTIONS] BLOCKDEV [KBYTES]"
 #define mkswap_full_usage "\n\n" \
        "Prepare BLOCKDEV to be used as swap partition\n" \
      "\nOptions:" \
diff --git a/libbb/Kbuild b/libbb/Kbuild
index 7e793109e..c205ceb4c 100644
--- a/libbb/Kbuild
+++ b/libbb/Kbuild
@@ -42,6 +42,7 @@ lib-y += get_last_path_component.o
 lib-y += get_line_from_file.o
 lib-y += getopt32.o
 lib-y += getpty.o
+lib-y += get_volsize.o
 lib-y += herror_msg.o
 lib-y += herror_msg_and_die.o
 lib-y += human_readable.o
diff --git a/libbb/get_volsize.c b/libbb/get_volsize.c
new file mode 100644
index 000000000..5b0270968
--- /dev/null
+++ b/libbb/get_volsize.c
@@ -0,0 +1,48 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 2010 Denys Vlasenko
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+#include "libbb.h"
+
+uoff_t FAST_FUNC get_volume_size_in_bytes(int fd,
+		const char *override,
+		unsigned override_units,
+		int extend)
+{
+	uoff_t result;
+
+	if (override) {
+		result = XATOOFF(override);
+		if (result >= (uoff_t)(MAXINT(off_t)) / override_units)
+			bb_error_msg_and_die("image size is too big");
+		result *= override_units;
+		/* seek past end fails on block devices but works on files */
+		if (lseek(fd, result - 1, SEEK_SET) != (off_t)-1) {
+			if (extend)
+				xwrite(fd, "", 1); /* file grows if needed */
+		}
+		//else {
+		//	bb_error_msg("warning, block device is smaller");
+		//}
+	} else {
+		/* more portable than BLKGETSIZE[64] */
+		result = xlseek(fd, 0, SEEK_END);
+	}
+
+	xlseek(fd, 0, SEEK_SET);
+
+	/* Prevent things like this:
+	 * $ dd if=/dev/zero of=foo count=1 bs=1024
+	 * $ mkswap foo
+	 * Setting up swapspace version 1, size = 18446744073709548544 bytes
+	 *
+	 * Picked 16k arbitrarily: */
+	if (result < 16*1024)
+		bb_error_msg_and_die("image is too small");
+
+	return result;
+}
diff --git a/util-linux/mkfs_ext2.c b/util-linux/mkfs_ext2.c
index 19c3c673e..44fb40250 100644
--- a/util-linux/mkfs_ext2.c
+++ b/util-linux/mkfs_ext2.c
@@ -230,19 +230,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
 		bb_error_msg_and_die("can't format mounted filesystem");
 
 	// open the device, get size in kbytes
-	if (argv[1]) {
-		kilobytes = xatoull(argv[1]);
-		// seek past end fails on block devices but works on files
-		if (lseek(fd, kilobytes * 1024 - 1, SEEK_SET) != (off_t)-1) {
-			if (!(option_mask32 & OPT_n))
-				xwrite(fd, "", 1); // file grows if needed
-		}
-		//else {
-		//	bb_error_msg("warning, block device is smaller");
-		//}
-	} else {
-		kilobytes = (uoff_t)xlseek(fd, 0, SEEK_END) / 1024;
-	}
+	kilobytes = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ !(option_mask32 & OPT_n)) / 1024;
 
 	bytes_per_inode = 16384;
 	if (kilobytes < 512*1024)
diff --git a/util-linux/mkfs_reiser.c b/util-linux/mkfs_reiser.c
index 7f37eb845..eb2c94d02 100644
--- a/util-linux/mkfs_reiser.c
+++ b/util-linux/mkfs_reiser.c
@@ -175,23 +175,12 @@ int mkfs_reiser_main(int argc UNUSED_PARAM, char **argv)
 
 	// check if it is mounted
 	// N.B. what if we format a file? find_mount_point will return false negative since
-	// it is loop block device which mounted!
+	// it is loop block device which is mounted!
 	if (find_mount_point(argv[0], 0))
 		bb_error_msg_and_die("can't format mounted filesystem");
 
 	// open the device, get size in blocks
-	if (argv[1]) {
-		blocks = xatoull(argv[1]);
-		// seek past end fails on block devices but works on files
-		if (lseek(fd, blocks * blocksize - 1, SEEK_SET) != (off_t)-1) {
-			xwrite(fd, "", 1); // file grows if needed
-		}
-		//else {
-		//	bb_error_msg("warning, block device is smaller");
-		//}
-	} else {
-		blocks = (uoff_t)xlseek(fd, 0, SEEK_END) / blocksize;
-	}
+	blocks = get_volume_size_in_bytes(fd, argv[1], blocksize, /*extend:*/ 1) / blocksize;
 
 	// block number sanity check
 	// we have a limit: skipped area, super block, journal and root block
diff --git a/util-linux/mkfs_vfat.c b/util-linux/mkfs_vfat.c
index a9a65aa07..1363612f2 100644
--- a/util-linux/mkfs_vfat.c
+++ b/util-linux/mkfs_vfat.c
@@ -244,7 +244,7 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 	// default volume ID = creation time
 	volume_id = time(NULL);
 
-	dev = xopen(device_name, O_EXCL | O_RDWR);
+	dev = xopen(device_name, O_RDWR);
 	if (fstat(dev, &st) < 0)
 		bb_simple_perror_msg_and_die(device_name);
 
@@ -252,7 +252,6 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 	// Get image size and sector size
 	//
 	bytes_per_sect = SECTOR_SIZE;
-	volume_size_bytes = st.st_size;
 	if (!S_ISBLK(st.st_mode)) {
 		if (!S_ISREG(st.st_mode)) {
 			if (!argv[1])
@@ -262,10 +261,6 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 		opts &= ~OPT_c;
 	} else {
 		int min_bytes_per_sect;
-
-		// more portable than BLKGETSIZE[64]
-		volume_size_bytes = xlseek(dev, 0, SEEK_END);
-		xlseek(dev, 0, SEEK_SET);
 #if 0
 		unsigned device_num;
 		// for true block devices we do check sanity
@@ -290,12 +285,7 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 			bb_error_msg("for this device sector size is %u", min_bytes_per_sect);
 		}
 	}
-	if (argv[1]) {
-		volume_size_bytes = XATOOFF(argv[1]);
-		if (volume_size_bytes >= MAXINT(off_t) / 1024)
-			bb_error_msg_and_die("image size is too big");
-		volume_size_bytes *= 1024;
-	}
+	volume_size_bytes = get_volume_size_in_bytes(dev, argv[1], 1024, /*extend:*/ 1);
 	volume_size_sect = volume_size_bytes / bytes_per_sect;
 
 	//
diff --git a/util-linux/mkswap.c b/util-linux/mkswap.c
index 289692da3..949c71a78 100644
--- a/util-linux/mkswap.c
+++ b/util-linux/mkswap.c
@@ -86,23 +86,19 @@ int mkswap_main(int argc UNUSED_PARAM, char **argv)
 	off_t len;
 	const char *label = "";
 
-	opt_complementary = "=1";
-	/* TODO: -p PAGESZ, -U UUID,
-	 * optional SIZE_IN_KB 2nd param
-	 */
+	opt_complementary = "-1"; /* at least one param */
+	/* TODO: -p PAGESZ, -U UUID */
 	getopt32(argv, "L:", &label);
 	argv += optind;
 
 	fd = xopen(argv[0], O_WRONLY);
 
-	/* Figure out how big the device is and announce our intentions */
-	/* fdlength was reported to be unreliable - use seek */
-	len = xlseek(fd, 0, SEEK_END);
-	if (ENABLE_SELINUX)
-		xlseek(fd, 0, SEEK_SET);
-
+	/* Figure out how big the device is */
+	len = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ 1);
 	pagesize = getpagesize();
 	len -= pagesize;
+
+	/* Announce our intentions */
 	printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
 	mkswap_selinux_setcontext(fd, argv[0]);