libfdisk: don't use blkdev ioctls for regular files

$ fdisk <diskimage>

open("sdc.img", O_RDONLY|O_CLOEXEC)     = 3
ioctl(3, BLKSSZGET, 0x7ffcf51357c4)     = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(3, BLKGETSIZE64, 0x7ffcf51357b0)  = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(3, BLKGETSIZE, 0x7ffcf51356c8)    = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(3, FDGETPRM, 0x7ffcf51356d0)      = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(3, HDIO_GETGEO, 0x7ffcf5135790)   = -1 ENOTTY (Inappropriate ioctl for device)

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

6 files changed, 43 insertions, 9 deletions

diff --git a/libfdisk/docs/libfdisk-sections.txt b/libfdisk/docs/libfdisk-sections.txt
index 72a7dca34..11b25b108 100644
--- a/libfdisk/docs/libfdisk-sections.txt
+++ b/libfdisk/docs/libfdisk-sections.txt
@@ -315,6 +315,7 @@ fdisk_is_details
 fdisk_is_labeltype
 fdisk_is_listonly
 fdisk_is_readonly
+fdisk_is_regfile
 fdisk_new_context
 fdisk_new_nested_context
 FDISK_PLURAL
diff --git a/libfdisk/src/alignment.c b/libfdisk/src/alignment.c
index 58acefb89..b874a48f8 100644
--- a/libfdisk/src/alignment.c
+++ b/libfdisk/src/alignment.c
@@ -183,12 +183,14 @@ int fdisk_lba_is_phy_aligned(struct fdisk_context *cxt, fdisk_sector_t lba)
 	return lba_is_phy_aligned(cxt, lba);
 }
 
-static unsigned long get_sector_size(int fd)
+static unsigned long get_sector_size(struct fdisk_context *cxt)
 {
 	int sect_sz;
 
-	if (!blkdev_get_sector_size(fd, &sect_sz))
+	if (!fdisk_is_regfile(cxt) &&
+	    !blkdev_get_sector_size(cxt->dev_fd, &sect_sz))
 		return (unsigned long) sect_sz;
+
 	return DEFAULT_SECTOR_SIZE;
 }
 
@@ -423,22 +425,31 @@ int fdisk_reset_device_properties(struct fdisk_context *cxt)
 int fdisk_discover_geometry(struct fdisk_context *cxt)
 {
 	fdisk_sector_t nsects;
+	unsigned int h = 0, s = 0;
 
 	assert(cxt);
 	assert(cxt->geom.heads == 0);
 
 	DBG(CXT, ul_debugobj(cxt, "%s: discovering geometry...", cxt->dev_path));
 
-	/* get number of 512-byte sectors, and convert it the real sectors */
-	if (!blkdev_get_sectors(cxt->dev_fd, (unsigned long long *) &nsects))
-		cxt->total_sectors = (nsects / (cxt->sector_size >> 9));
+	if (fdisk_is_regfile(cxt))
+		cxt->total_sectors = cxt->dev_st.st_size / cxt->sector_size;
+	else {
+		/* get number of 512-byte sectors, and convert it the real sectors */
+		if (!blkdev_get_sectors(cxt->dev_fd, (unsigned long long *) &nsects))
+			cxt->total_sectors = (nsects / (cxt->sector_size >> 9));
+
+		/* what the kernel/bios thinks the geometry is */
+		blkdev_get_geometry(cxt->dev_fd, &h, &s);
+	}
 
 	DBG(CXT, ul_debugobj(cxt, "total sectors: %ju (ioctl=%ju)",
 				(uintmax_t) cxt->total_sectors,
 				(uintmax_t) nsects));
 
-	/* what the kernel/bios thinks the geometry is */
-	blkdev_get_geometry(cxt->dev_fd, &cxt->geom.heads, (unsigned int *) &cxt->geom.sectors);
+	cxt->geom.cylinders = 0;
+	cxt->geom.heads = h;
+	cxt->geom.sectors = s;
 
 	/* obtained heads and sectors */
 	recount_geometry(cxt);
@@ -491,7 +502,7 @@ int fdisk_discover_topology(struct fdisk_context *cxt)
 	blkid_free_probe(pr);
 #endif
 
-	cxt->sector_size = get_sector_size(cxt->dev_fd);
+	cxt->sector_size = get_sector_size(cxt);
 	if (!cxt->phy_sector_size) /* could not discover physical size */
 		cxt->phy_sector_size = cxt->sector_size;
 
diff --git a/libfdisk/src/context.c b/libfdisk/src/context.c
index 90f97a565..947f104fa 100644
--- a/libfdisk/src/context.c
+++ b/libfdisk/src/context.c
@@ -488,6 +488,8 @@ static void reset_context(struct fdisk_context *cxt)
 	free(cxt->collision);
 	cxt->collision = NULL;
 
+	memset(&cxt->dev_st, 0, sizeof(cxt->dev_st));
+
 	cxt->dev_fd = -1;
 	cxt->firstsector = NULL;
 	cxt->firstsector_bufsz = 0;
@@ -581,7 +583,7 @@ int fdisk_assign_device(struct fdisk_context *cxt,
 		int rc, org = fdisk_is_listonly(cxt->parent);
 
 		/* assign_device() is sensitive to "listonly" mode, so let's
-		 * follow the current context setting for the parent to avoid 
+		 * follow the current context setting for the parent to avoid
 		 * unwanted extra warnings. */
 		fdisk_enable_listonly(cxt->parent, fdisk_is_listonly(cxt));
 
@@ -601,6 +603,8 @@ int fdisk_assign_device(struct fdisk_context *cxt,
 	if (fd < 0)
 		return -errno;
 
+	fstat(fd, &cxt->dev_st);
+
 	cxt->readonly = readonly;
 	cxt->dev_fd = fd;
 	cxt->dev_path = strdup(fname);
@@ -693,6 +697,18 @@ int fdisk_is_readonly(struct fdisk_context *cxt)
 }
 
 /**
+ * fdisk_is_regfile:
+ * @cxt: context
+ *
+ * Returns: 1 if open file descriptor is regular file rather than a block device.
+ */
+int fdisk_is_regfile(struct fdisk_context *cxt)
+{
+	assert(cxt);
+	return S_ISREG(cxt->dev_st.st_mode);
+}
+
+/**
  * fdisk_unref_context:
  * @cxt: fdisk context
  *
diff --git a/libfdisk/src/fdiskP.h b/libfdisk/src/fdiskP.h
index c624773db..b068638ab 100644
--- a/libfdisk/src/fdiskP.h
+++ b/libfdisk/src/fdiskP.h
@@ -346,11 +346,14 @@ struct fdisk_ask {
 struct fdisk_context {
 	int dev_fd;         /* device descriptor */
 	char *dev_path;     /* device path */
+	struct stat dev_st; /* stat(2) result */
+
 	int refcount;
 
 	unsigned char *firstsector; /* buffer with master boot record */
 	unsigned long firstsector_bufsz;
 
+
 	/* topology */
 	unsigned long io_size;		/* I/O size used by fdisk */
 	unsigned long optimal_io_size;	/* optional I/O returned by device */
@@ -397,6 +400,7 @@ struct fdisk_context {
 	struct fdisk_script	*script;	/* what we want to follow */
 };
 
+
 /* context.c */
 extern int __fdisk_switch_label(struct fdisk_context *cxt,
 				    struct fdisk_label *lb);
diff --git a/libfdisk/src/libfdisk.h.in b/libfdisk/src/libfdisk.h.in
index 59cce190d..141109ec9 100644
--- a/libfdisk/src/libfdisk.h.in
+++ b/libfdisk/src/libfdisk.h.in
@@ -182,6 +182,7 @@ int fdisk_assign_device(struct fdisk_context *cxt,
 			const char *fname, int readonly);
 int fdisk_deassign_device(struct fdisk_context *cxt, int nosync);
 int fdisk_is_readonly(struct fdisk_context *cxt);
+int fdisk_is_regfile(struct fdisk_context *cxt);
 
 int fdisk_enable_details(struct fdisk_context *cxt, int enable);
 int fdisk_is_details(struct fdisk_context *cxt);
diff --git a/libfdisk/src/libfdisk.sym b/libfdisk/src/libfdisk.sym
index d6d4ac557..9b769d8e5 100644
--- a/libfdisk/src/libfdisk.sym
+++ b/libfdisk/src/libfdisk.sym
@@ -278,4 +278,5 @@ FDISK_2.29 {
 
 FDISK_2.30 {
 	fdisk_script_has_force_label;
+	fdisk_is_regfile;
 } FDISK_2.29;