Implement and document some utility functions that can be used to communicate

with GEOM providers.

OK'ed by:	phk

lib/libgeom/Makefile

@@ -6,6 +6,7 @@ SRCS+=	geom_getxml.c
 SRCS+=	geom_stats.c
 SRCS+=	geom_xml2tree.c
 SRCS+=	geom_ctl.c
+SRCS+=	geom_util.c
 INCS=	libgeom.h
 
 CFLAGS += -I${.CURDIR}
@@ -31,6 +32,15 @@ MLINKS+= \
 	libgeom.3 gctl_rw_param.3 \
 	libgeom.3 gctl_issue.3 \
 	libgeom.3 gctl_free.3 \
-	libgeom.3 gctl_dump.3
+	libgeom.3 gctl_dump.3 \
+	libgeom.3 g_close.3 \
+	libgeom.3 g_delete.3 \
+	libgeom.3 g_flush.3 \
+	libgeom.3 g_get_ident.3 \
+	libgeom.3 g_get_name.3 \
+	libgeom.3 g_mediasize.3 \
+	libgeom.3 g_open.3 \
+	libgeom.3 g_open_by_ident.3 \
+	libgeom.3 g_sectorsize.3
 
 .include <bsd.lib.mk>

lib/libgeom/geom_util.c

@@ -0,0 +1,236 @@
+/*-
+ * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/disk.h>
+#include <sys/stat.h>
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <paths.h>
+
+#include <libgeom.h>
+
+/*
+ * Open the given provider and at least check if this is a block device.
+ */
+int
+g_open(const char *name, int write)
+{
+	char path[MAXPATHLEN];
+	int fd;
+
+	if (name[0] == '/')
+		strlcpy(path, name, sizeof(path));
+	else
+		snprintf(path, sizeof(path), "%s%s", _PATH_DEV, name);
+
+	fd = open(path, write ? O_RDWR : O_RDONLY);
+	if (fd == -1)
+		return (-1);
+	/* Let try to get sectorsize, which will prove it is a GEOM provider. */
+	if (g_sectorsize(fd) == -1) {
+		close(fd);
+		errno = EFTYPE;
+		return (-1);
+	}
+	return (fd);
+}
+
+int
+g_close(int fd)
+{
+
+	return (close(fd));
+}
+
+static int
+g_ioctl_arg(int fd, unsigned long cmd, void *arg)
+{
+	int ret;
+
+	if (arg != NULL)
+		ret = ioctl(fd, cmd, arg);
+	else
+		ret = ioctl(fd, cmd);
+	return (ret >= 0 ? 0 : -1);
+}
+
+static int
+g_ioctl(int fd, unsigned long cmd)
+{
+
+	return (g_ioctl_arg(fd, cmd, NULL));
+}
+
+/*
+ * Return media size of the given provider.
+ */
+off_t
+g_mediasize(int fd)
+{
+	off_t mediasize;
+
+	if (g_ioctl_arg(fd, DIOCGMEDIASIZE, &mediasize) == -1)
+		mediasize = -1;
+	return (mediasize);
+}
+
+/*
+ * Return sector size of the given provider.
+ */
+ssize_t
+g_sectorsize(int fd)
+{
+	u_int sectorsize;
+
+	if (g_ioctl_arg(fd, DIOCGSECTORSIZE, &sectorsize) == -1)
+		return (-1);
+	return ((ssize_t)sectorsize);
+}
+
+/*
+ * Call BIO_FLUSH for the given provider.
+ */
+int
+g_flush(int fd)
+{
+
+	return (g_ioctl(fd, DIOCGFLUSH));
+}
+
+/*
+ * Call BIO_DELETE for the given range.
+ */
+int
+g_delete(int fd, off_t offset, off_t length)
+{
+	off_t arg[2];
+
+	arg[0] = offset;
+	arg[1] = length;
+	return (g_ioctl_arg(fd, DIOCGDELETE, arg));
+}
+
+/*
+ * Return ID of the given provider.
+ */
+int
+g_get_ident(int fd, char *ident, size_t size)
+{
+	char lident[DISK_IDENT_SIZE];
+
+	if (g_ioctl_arg(fd, DIOCGIDENT, lident) == -1)
+		return (-1);
+	if (lident[0] == '\0') {
+		errno = ENOENT;
+		return (-1);
+	}
+	if (strlcpy(ident, lident, size) >= size) {
+		errno = ENAMETOOLONG;
+		return (-1);
+	}
+	return (0);
+}
+
+/*
+ * Return name of the provider, which has the given ID.
+ */
+int
+g_get_name(const char *ident, char *name, size_t size)
+{
+	int fd;
+
+	fd = g_open_by_ident(ident, 0, name, size);
+	if (fd == -1)
+		return (-1);
+	g_close(fd);
+	return (0);
+}
+
+/*
+ * Find provider name by the given ID.
+ */
+int
+g_open_by_ident(const char *ident, int write, char *name, size_t size)
+{
+	char lident[DISK_IDENT_SIZE];
+	struct gmesh mesh;
+	struct gclass *mp;
+	struct ggeom *gp;
+	struct gprovider *pp;
+	int error, fd;
+
+	error = geom_gettree(&mesh);
+	if (error != 0) {
+		errno = error;
+		return (-1);
+	}
+
+	error = ENOENT;
+	fd = -1;
+
+	LIST_FOREACH(mp, &mesh.lg_class, lg_class) {
+		LIST_FOREACH(gp, &mp->lg_geom, lg_geom) {
+			LIST_FOREACH(pp, &gp->lg_provider, lg_provider) {
+				fd = g_open(pp->lg_name, write);
+				if (fd == -1)
+					continue;
+				if (g_get_ident(fd, lident,
+				    sizeof(lident)) == -1) {
+					g_close(fd);
+					continue;
+				}
+				if (strcmp(ident, lident) != 0) {
+					g_close(fd);
+					continue;
+				}
+				error = 0;
+				if (name != NULL && strlcpy(name, pp->lg_name,
+				    size) >= size) {
+					error = ENAMETOOLONG;
+					g_close(fd);
+				}
+				goto end;
+			}
+		}
+	}
+end:
+	geom_deletetree(&mesh);
+	if (error != 0) {
+		errno = error;
+		return (-1);
+	}
+	return (fd);
+}

lib/libgeom/libgeom.3

@@ -1,4 +1,5 @@
 .\" Copyright (c) 2003 Poul-Henning Kamp
+.\" Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 .\" All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
@@ -27,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 7, 2004
+.Dd May 6, 2007
 .Dt LIBGEOM 3
 .Os
 .Sh NAME
@@ -44,7 +45,16 @@
 .Nm gctl_rw_param ,
 .Nm gctl_issue ,
 .Nm gctl_free ,
-.Nm gctl_dump
+.Nm gctl_dump ,
+.Nm g_open ,
+.Nm g_close ,
+.Nm g_mediasize ,
+.Nm g_sectorsize ,
+.Nm g_flush ,
+.Nm g_delete ,
+.Nm g_get_ident ,
+.Nm g_get_name ,
+.Nm g_open_by_ident
 .Nd userland API library for kernel GEOM subsystem
 .Sh LIBRARY
 .Lb libgeom
@@ -80,6 +90,25 @@
 .Fn gctl_free "struct gctl_req *req"
 .Ft void
 .Fn gctl_dump "struct gctl_req *req" "FILE *f"
+.Ss "Utility Functions"
+.Ft int
+.Fn g_open "const char *name" "int write"
+.Ft int
+.Fn g_close "int fd"
+.Ft off_t
+.Fn g_mediasize "int fd"
+.Ft ssize_t
+.Fn g_sectorsize "int fd"
+.Ft int
+.Fn g_flush "int fd"
+.Ft int
+.Fn g_delete "int fd" "off_t offset" "off_t length"
+.Ft int
+.Fn g_get_ident "int fd" "char *ident" "size_t size"
+.Ft int
+.Fn g_get_name "const char *ident" "char *name" "size_t size"
+.Ft int
+.Fn g_open_by_ident "const char *ident" "int write" "char *name" "size_t size"
 .Sh DESCRIPTION
 The
 .Nm geom
@@ -232,6 +261,76 @@ which returns
 .Dv NULL
 on success, or an error message corresponding to the
 first error which happened.
+.Ss "Utility Functions"
+The
+.Fn g_*
+functions are used to communicate with GEOM providers.
+.Pp
+The
+.Fn g_open
+function opens the given provider and returns file descriptor number, which can
+be used with other functions.
+The
+.Fa write
+argument indicates if operations that modify the provider (like
+.Fn g_flush
+or
+.Fn g_delete )
+are going to be called.
+.Pp
+The
+.Fn g_close
+function closes the provider.
+.Pp
+The
+.Fn g_mediasize
+function returns size of the given provider.
+.Pp
+The
+.Fn g_sectorsize
+function returns sector size of the given provider.
+.Pp
+The
+.Fn g_flush
+function sends
+.Dv BIO_FLUSH
+request to flush write cache of the provider.
+.Pp
+The
+.Fn g_delete
+function tells the provider that the given data range is no longer used.
+.Pp
+The
+.Fn g_get_ident
+function returns provider's fixed and unique identifier.
+The
+.Fa ident
+argument should be at least
+.Dv DISK_IDENT_SIZE
+big.
+.Pp
+The
+.Fn g_get_name
+function returns name of the provider, which identifier is equal to the
+.Fa ident
+string.
+.Pp
+The
+.Fn g_open_by_ident
+function opens provider using its ident, unlike
+.Fn g_open
+which uses provider's name.
+If the
+.Fa name
+argument is not
+.Dv NULL ,
+the function will store provider's name there.
+.Pp
+All functions return value greater than or equal to
+.Va 0
+on success or
+.Va -1
+on failure.
 .Sh EXAMPLES
 Create a request that is to be sent to the CCD class, and tell
 it to destroy a specific geom:
@@ -256,3 +355,4 @@ library appeared in
 .Sh AUTHORS
 .An Poul-Henning Kamp Aq phk@FreeBSD.org
 .An Lukas Ertl Aq le@FreeBSD.org
+.An Pawel Jakub Dawidek pjd@FreeBSD.org

lib/libgeom/libgeom.h

@@ -144,6 +144,17 @@ const char *gctl_issue(struct gctl_req *req);
 void gctl_ro_param(struct gctl_req *req, const char *name, int len, const void* val);
 void gctl_rw_param(struct gctl_req *req, const char *name, int len, void* val);
 
+/* geom_util.c */
+int g_open(const char *name, int write);
+int g_close(int fd);
+off_t g_mediasize(int fd);
+ssize_t g_sectorsize(int fd);
+int g_flush(int fd);
+int g_delete(int fd, off_t offset, off_t length);
+int g_get_ident(int fd, char *ident, size_t size);
+int g_get_name(const char *ident, char *name, size_t size);
+int g_open_by_ident(const char *ident, int write, char *name, size_t size);
+
 __END_DECLS
 
 #endif /* _LIBGEOM_H_ */