From: Karel Zak <kzak@redhat.com>
Date: Wed, 5 Dec 2012 16:08:54 +0000 (+0100)
Subject: libfdisk: add firstsector utils
X-Git-Tag: v2.23-rc1~163
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3eb78aa7453f9466e6050e9ee876c672b5e7d7dd;p=thirdparty%2Futil-linux.git

libfdisk: add firstsector utils

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/fdisks/fdisk.h b/fdisks/fdisk.h
index 8afa7e9d19..4736bccb9b 100644
--- a/fdisks/fdisk.h
+++ b/fdisks/fdisk.h
@@ -75,7 +75,6 @@ extern struct fdisk_context *fdisk_new_context_from_filename(const char *fname,
 extern int fdisk_dev_has_topology(struct fdisk_context *cxt);
 extern int fdisk_dev_sectsz_is_default(struct fdisk_context *cxt);
 extern void fdisk_free_context(struct fdisk_context *cxt);
-extern void fdisk_zeroize_firstsector(struct fdisk_context *cxt);
 extern int fdisk_context_force_sector_size(struct fdisk_context *cxt, sector_t s);
 extern int fdisk_context_set_user_geometry(struct fdisk_context *cxt,
 			    unsigned int cylinders, unsigned int heads,
diff --git a/fdisks/utils.c b/fdisks/utils.c
index 275fee139a..24f169efd0 100644
--- a/fdisks/utils.c
+++ b/fdisks/utils.c
@@ -69,26 +69,6 @@ static int __probe_labels(struct fdisk_context *cxt)
 	return 1; /* not found */
 }
 
-static int __init_firstsector_buffer(struct fdisk_context *cxt)
-{
-	DBG(TOPOLOGY, dbgprint("initialize first sector buffer"));
-
-	cxt->firstsector = calloc(1, MAX_SECTOR_SIZE);
-	if (!cxt->firstsector)
-		goto fail;
-
-	/* read MBR */
-	if (512 != read(cxt->dev_fd, cxt->firstsector, 512)) {
-		if (errno == 0)
-			errno = EINVAL;	/* probably too small file/device */
-		goto fail;
-	}
-
-	return 0;
-fail:
-	return -errno;
-}
-
 static unsigned long __get_sector_size(int fd)
 {
 	int sect_sz;
@@ -236,24 +216,6 @@ static int __discover_topology(struct fdisk_context *cxt)
 	return 0;
 }
 
-
-/**
- * fdisk_zeroize_firstsector:
- * @cxt: fdisk context
- *
- * Zeros in-memory first sector buffer
- */
-void fdisk_zeroize_firstsector(struct fdisk_context *cxt)
-{
-	if (!cxt)
-		return;
-
-	if (cxt->firstsector) {
-		DBG(CONTEXT, dbgprint("zeroize in-memory first sector buffer"));
-		memset(cxt->firstsector, 0, MAX_SECTOR_SIZE);
-	}
-}
-
 /**
  * fdisk_dev_sectsz_is_default:
  * @cxt: fdisk context
@@ -475,12 +437,12 @@ struct fdisk_context *fdisk_new_context_from_filename(const char *fname, int rea
 	if (!cxt->dev_path)
 		goto fail;
 
-	if (__init_firstsector_buffer(cxt) < 0)
-		goto fail;
-
 	__discover_topology(cxt);
 	__discover_system_geometry(cxt);
 
+	if (fdisk_read_firstsector(cxt) < 0)
+		goto fail;
+
 	/* detect labels and apply labes specific stuff (e.g geomery)
 	 * to the context */
 	__probe_labels(cxt);
diff --git a/libfdisk/src/Makemodule.am b/libfdisk/src/Makemodule.am
index f14e1541d4..639a3d2f00 100644
--- a/libfdisk/src/Makemodule.am
+++ b/libfdisk/src/Makemodule.am
@@ -11,6 +11,7 @@ libfdisk_la_SOURCES = \
 	libfdisk/src/init.c \
 	libfdisk/src/alignment.c \
 	libfdisk/src/label.c \
+	libfdisk/src/utils.c \
 	libfdisk/src/parttype.c
 
 
diff --git a/libfdisk/src/fdiskP.h b/libfdisk/src/fdiskP.h
index 6d2fef1cf7..4f5585733a 100644
--- a/libfdisk/src/fdiskP.h
+++ b/libfdisk/src/fdiskP.h
@@ -191,4 +191,9 @@ extern sector_t fdisk_align_lba(struct fdisk_context *cxt, sector_t lba, int dir
 extern sector_t fdisk_align_lba_in_range(struct fdisk_context *cxt, sector_t lba,
 					 sector_t start, sector_t stop);
 
+
+/* utils.c */
+extern void fdisk_zeroize_firstsector(struct fdisk_context *cxt);
+extern int fdisk_read_firstsector(struct fdisk_context *cxt);
+
 #endif /* _LIBFDISK_PRIVATE_H */
diff --git a/libfdisk/src/utils.c b/libfdisk/src/utils.c
new file mode 100644
index 0000000000..6668e23e34
--- /dev/null
+++ b/libfdisk/src/utils.c
@@ -0,0 +1,42 @@
+
+#include "fdiskP.h"
+
+/*
+ * Zeros in-memory first sector buffer
+ */
+void fdisk_zeroize_firstsector(struct fdisk_context *cxt)
+{
+	if (!cxt || !cxt->firstsector)
+		return;
+
+	DBG(CONTEXT, dbgprint("zeroize in-memory first sector buffer"));
+	memset(cxt->firstsector, 0, cxt->sector_size);
+}
+
+int fdisk_read_firstsector(struct fdisk_context *cxt)
+{
+	ssize_t r;
+
+	assert(cxt);
+	assert(cxt->sector_size);
+
+	DBG(TOPOLOGY, dbgprint("initialize first sector "
+				"buffer [sector_size=%lu]", cxt->sector_size));
+
+	if (!cxt->firstsector) {
+		cxt->firstsector = calloc(1, cxt->sector_size);
+		if (!cxt->firstsector)
+			return -ENOMEM;
+	} else
+		fdisk_zeroize_firstsector(cxt);
+
+	r = read(cxt->dev_fd, cxt->firstsector, cxt->sector_size);
+
+	if (r != cxt->sector_size) {
+		if (!errno)
+			errno = EINVAL;	/* probably too small file/device */
+		return -errno;
+	}
+
+	return 0;
+}