libdasd: Add common DASD ioctl's to the lib

This will avoid code duplication in dasd-related programs.

GitHub-ID: #19

Signed-off-by: Rafael Fonseca <r4f4rfs@gmail.com>
Acked-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>

libdasd/Makefile

@@ -4,7 +4,7 @@ lib = libdasd.a
 
 all: $(lib)
 
-objects = dasd_sys.o
+objects = dasd_sys.o dasd_ioctl.o
 
 $(lib): $(objects) Makefile
 

libdasd/dasd_ioctl.c

@@ -0,0 +1,263 @@
+/*
+ * dasd_ioctl - Library for dasd-related ioctls
+ *
+ * DASD related helper functions for accessing device information via ioctls
+ *
+ * Copyright IBM Corp. 2013, 2017
+ * Copyright Red Hat Inc. 2017
+ *
+ * s390-tools is free software; you can redistribute it and/or modify
+ * it under the terms of the MIT license. See LICENSE for details.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "lib/dasd_base.h"
+
+#define COULD_NOT_OPEN_WARN(device) \
+	warn("Could not open device '%s'", device)
+
+#define COULD_NOT_CLOSE_WARN \
+	warn("Unable to close device")
+
+#define RUN_IOCTL(fd, req, argp)				\
+	do {							\
+		if (ioctl(fd, req, argp) != 0) {		\
+			int err = errno;			\
+			if (err != EBADF)			\
+				dasd_close_device(fd);		\
+			return err;				\
+		}						\
+	} while (0)
+
+static int dasd_open_device(const char *device, int flags)
+{
+	int fd;
+
+	fd = open(device, flags);
+	if (fd == -1)
+		COULD_NOT_OPEN_WARN(device);
+
+	return fd;
+}
+
+static void dasd_close_device(int fd)
+{
+	if (close(fd) != 0)
+		COULD_NOT_CLOSE_WARN;
+}
+
+/*
+ * Get DASD block size information for device
+ *
+ * @param[in] device node	device node's name
+ * @param[out] blksize		the block size
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ *
+ */
+int dasd_get_blocksize(const char *device, unsigned int *blksize)
+{
+	int fd;
+
+	fd = dasd_open_device(device, O_RDONLY);
+	RUN_IOCTL(fd, BLKSSZGET, blksize);
+	dasd_close_device(fd);
+
+	return 0;
+}
+
+/*
+ * Get DASD block size information (in bytes) for device
+ *
+ * @param[in] device node	device node's name
+ * @param[out] blksize		block size in bytes
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ */
+int dasd_get_blocksize_in_bytes(const char *device, unsigned long long *blksize)
+{
+	int fd;
+
+	fd = dasd_open_device(device, O_RDONLY);
+	RUN_IOCTL(fd, BLKGETSIZE64, blksize);
+	dasd_close_device(fd);
+
+	return 0;
+}
+
+/*
+ * Get DASD disk information for device
+ *
+ * @param[in] device node	device node's name
+ * @param[out] info		pointer to dasd information
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ */
+int dasd_get_info(const char *device, dasd_information2_t *info)
+{
+	int fd;
+
+	fd = dasd_open_device(device, O_RDONLY);
+	RUN_IOCTL(fd, BIODASDINFO2, info);
+	dasd_close_device(fd);
+
+	return 0;
+}
+
+/*
+ * Get DASD disk geometry information for device
+ *
+ * @param[in] device node	device node's name
+ * @param[out] geo		pointer to device geometry information
+ *
+ * @retval errno	in case of failure
+ * @retval 0		in case of success
+ */
+int dasd_get_geo(const char *device, struct hd_geometry *geo)
+{
+	int fd;
+
+	fd = dasd_open_device(device, O_RDONLY);
+	RUN_IOCTL(fd, HDIO_GETGEO, geo);
+	dasd_close_device(fd);
+
+	return 0;
+}
+
+/*
+ * Get DASD read/write status information for device
+ *
+ * @param[in] device node	device node's name
+ * @param[out] ro		read-only status (1 for ro, 0 for rw)
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ */
+int dasd_is_ro(const char *device, bool *ro)
+{
+	int fd, val;
+
+	fd = dasd_open_device(device, O_RDWR);
+	RUN_IOCTL(fd, BLKROGET, &val);
+	*ro = (val != 0) ? true : false;
+
+	return 0;
+}
+
+/*
+ * Disable DASD disk.
+ *
+ * @param[in] device node	device node's name
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ *
+ * Note: Before BIODASDFMT can be called, a DASD has to be disabled (or rather
+ * put into a BASIC state) via BIODASDDISABLE. However, if you disable the DASD,
+ * close the file descriptor, and then try to reopen it, it won't work as the
+ * device isn't fully usable anymore. For BIODASDFMT to work, the file
+ * descriptor opened for BIODASDISABLE has to be kept open until BIODASDFMT has
+ * finished.
+ */
+int dasd_disk_disable(const char *device, int *fd)
+{
+	*fd = dasd_open_device(device, O_RDWR);
+	RUN_IOCTL(*fd, BIODASDDISABLE, NULL);
+
+	return 0;
+}
+
+/*
+ * Enable DASD disk
+ *
+ * @param[in] device node	device node's name
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ */
+int dasd_disk_enable(int fd)
+{
+	RUN_IOCTL(fd, BIODASDENABLE, NULL);
+	dasd_close_device(fd);
+
+	return 0;
+}
+
+/*
+ * Format DASD disk
+ *
+ * @param[in] fd		device node's file descriptor
+ * @param[in] p			format options
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ */
+int dasd_format_disk(int fd, format_data_t *p)
+{
+	RUN_IOCTL(fd, BIODASDFMT, p);
+
+	return 0;
+}
+
+/*
+ * Check DASD format
+ *
+ * @param[in] device node	device node's name
+ * @param[in] p			format params
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ */
+int dasd_check_format(const char *device, format_check_t *p)
+{
+	int fd;
+
+	fd = dasd_open_device(device, O_RDONLY);
+	RUN_IOCTL(fd, BIODASDCHECKFMT, p);
+	dasd_close_device(fd);
+
+	return 0;
+}
+
+/*
+ * Reread partition table
+ *
+ * @param[in] device node	device node's name
+ * @param[in] ntries		maximum number of tries
+ *
+ * @retval 0		in case of success
+ * @retval errno	in case of failure
+ */
+int dasd_reread_partition_table(const char *device, int ntries)
+{
+	int i, fd, err = 0;
+
+	fd = dasd_open_device(device, O_RDONLY);
+
+	/*
+	 * If the BLKRRPART ioctl fails, it is most likely due to the device
+	 * just being in use by udev. So it is worthwhile to retry the ioctl
+	 * after a second as it is likely to succeed.
+	 */
+	for (i = 0; i < ntries; i++) {
+		if (ioctl(fd, BLKRRPART, NULL) != 0) {
+			err = errno;
+			sleep(1);
+		} else {
+			err = 0;
+			break;
+		}
+	}
+	dasd_close_device(fd);
+
+	return err;
+}