Implemented sharing datasets via SMB using libshare

Add the initial support for the 'smbshare' option using the
existing libshare infrastructure.  Because this implementation
relies on usershares samba version 3.0.23 is required.

Signed-off-by: Brian Behlendorf <[email protected]>
Closes #493

5 files changed, 495 insertions, 4 deletions

diff --git a/lib/libshare/Makefile.am b/lib/libshare/Makefile.am
index 1439b33ac..047105643 100644
--- a/lib/libshare/Makefile.am
+++ b/lib/libshare/Makefile.am
@@ -7,7 +7,9 @@ DEFAULT_INCLUDES += \
 noinst_LTLIBRARIES = libshare.la
 
 libshare_la_SOURCES = \
+	$(top_srcdir)/lib/libshare/libshare_impl.h \
 	$(top_srcdir)/lib/libshare/libshare.c \
 	$(top_srcdir)/lib/libshare/nfs.c \
-	$(top_srcdir)/lib/libshare/libshare_impl.h \
-	$(top_srcdir)/lib/libshare/nfs.h
+	$(top_srcdir)/lib/libshare/nfs.h \
+	$(top_srcdir)/lib/libshare/smb.c \
+	$(top_srcdir)/lib/libshare/smb.h
diff --git a/lib/libshare/libshare.c b/lib/libshare/libshare.c
index c34e83919..6b39ba872 100644
--- a/lib/libshare/libshare.c
+++ b/lib/libshare/libshare.c
@@ -36,6 +36,7 @@
 #include <libshare.h>
 #include "libshare_impl.h"
 #include "nfs.h"
+#include "smb.h"
 
 static sa_share_impl_t find_share(sa_handle_impl_t handle,
     const char *sharepath);
@@ -103,6 +104,7 @@ __attribute__((constructor)) static void
 libshare_init(void)
 {
 	libshare_nfs_init();
+	libshare_smb_init();
 
 	/*
 	 * This bit causes /etc/dfs/sharetab to be updated before libzfs gets a
diff --git a/lib/libshare/nfs.c b/lib/libshare/nfs.c
index 53691ebe5..00ba0f621 100644
--- a/lib/libshare/nfs.c
+++ b/lib/libshare/nfs.c
@@ -516,7 +516,7 @@ nfs_validate_shareopts(const char *shareopts)
  * Checks whether a share is currently active.
  */
 static boolean_t
-is_share_active(sa_share_impl_t impl_share)
+nfs_is_share_active(sa_share_impl_t impl_share)
 {
 	char line[512];
 	char *tab, *cur;
@@ -587,7 +587,8 @@ nfs_update_shareopts(sa_share_impl_t impl_share, const char *resource,
 	boolean_t needs_reshare = B_FALSE;
 	char *old_shareopts;
 
-	FSINFO(impl_share, nfs_fstype)->active = is_share_active(impl_share);
+	FSINFO(impl_share, nfs_fstype)->active =
+	    nfs_is_share_active(impl_share);
 
 	old_shareopts = FSINFO(impl_share, nfs_fstype)->shareopts;
 
diff --git a/lib/libshare/smb.c b/lib/libshare/smb.c
new file mode 100644
index 000000000..e34d14259
--- /dev/null
+++ b/lib/libshare/smb.c
@@ -0,0 +1,437 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011,2012 Turbo Fredriksson <[email protected]>, based on nfs.c
+ *                         by Gunnar Beutner
+ *
+ * This is an addition to the zfs device driver to add, modify and remove SMB
+ * shares using the 'net share' command that comes with Samba.
+
+ * TESTING
+ * Make sure that samba listens to 'localhost' (127.0.0.1) and that the options
+ * 'usershare max shares' and 'usershare owner only' have been rewied/set
+ * accordingly (see zfs(8) for information).
+ *
+ * Once configuration in samba have been done, test that this
+ * works with the following three commands (in this case, my ZFS
+ * filesystem is called 'share/Test1'):
+ *
+ *	(root)# net -U root -S 127.0.0.1 usershare add Test1 /share/Test1 \
+ *		"Comment: /share/Test1" "Everyone:F"
+ *	(root)# net usershare list | grep -i test
+ *	(root)# net -U root -S 127.0.0.1 usershare delete Test1
+ *
+ * The first command will create a user share that gives everyone full access.
+ * To limit the access below that, use normal UNIX commands (chmod, chown etc).
+ */
+
+#include <time.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <strings.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <libzfs.h>
+#include <libshare.h>
+#include "libshare_impl.h"
+#include "smb.h"
+
+static boolean_t smb_available(void);
+
+static sa_fstype_t *smb_fstype;
+
+/**
+ * Retrieve the list of SMB shares.
+ */
+static int
+smb_retrieve_shares(void)
+{
+	int rc = SA_OK;
+	char file_path[PATH_MAX], line[512], *token, *key, *value;
+	char *dup_value, *path = NULL, *comment = NULL, *name = NULL;
+	char *guest_ok = NULL;
+	DIR *shares_dir;
+	FILE *share_file_fp = NULL;
+	struct dirent *directory;
+	struct stat eStat;
+	smb_share_t *shares, *new_shares = NULL;
+
+	/* opendir(), stat() */
+	shares_dir = opendir(SHARE_DIR);
+	if (shares_dir == NULL)
+		return SA_SYSTEM_ERR;
+
+	/* Go through the directory, looking for shares */
+	while ((directory = readdir(shares_dir))) {
+		if (directory->d_name[0] == '.')
+			continue;
+
+		snprintf(file_path, sizeof (file_path),
+			 "%s/%s", SHARE_DIR, directory->d_name);
+
+		if (stat(file_path, &eStat) == -1) {
+			rc = SA_SYSTEM_ERR;
+			goto out;
+		}
+
+		if (!S_ISREG(eStat.st_mode))
+			continue;
+
+		if ((share_file_fp = fopen(file_path, "r")) == NULL) {
+			rc = SA_SYSTEM_ERR;
+			goto out;
+		}
+
+		name = strdup(directory->d_name);
+		if (name == NULL) {
+			 rc = SA_NO_MEMORY;
+			 goto out;
+		}
+
+		while (fgets(line, sizeof(line), share_file_fp)) {
+			if (line[0] == '#')
+				continue;
+
+			/* Trim trailing new-line character(s). */
+			while (line[strlen(line) - 1] == '\r' ||
+			       line[strlen(line) - 1] == '\n')
+				line[strlen(line) - 1] = '\0';
+
+			/* Split the line in two, separated by '=' */
+			token = strchr(line, '=');
+			if (token == NULL)
+				continue;
+
+			key = line;
+			value = token + 1;
+			*token = '\0';
+
+			dup_value = strdup(value);
+			if (dup_value == NULL) {
+				rc = SA_NO_MEMORY;
+				goto out;
+			}
+
+			if (strcmp(key, "path") == 0)
+				path = dup_value;
+			if (strcmp(key, "comment") == 0)
+				comment = dup_value;
+			if (strcmp(key, "guest_ok") == 0)
+				guest_ok = dup_value;
+
+			if (path == NULL || comment == NULL || guest_ok == NULL)
+				continue; /* Incomplete share definition */
+			else {
+				shares = (smb_share_t *)
+						malloc(sizeof (smb_share_t));
+				if (shares == NULL) {
+					rc = SA_NO_MEMORY;
+					goto out;
+				}
+
+				strncpy(shares->name, name,
+					sizeof (shares->name));
+				shares->name [sizeof(shares->name)-1] = '\0';
+
+				strncpy(shares->path, path,
+					sizeof (shares->path));
+				shares->path [sizeof(shares->path)-1] = '\0';
+
+				strncpy(shares->comment, comment,
+					sizeof (shares->comment));
+				shares->comment[sizeof(shares->comment)-1]='\0';
+
+				shares->guest_ok = atoi(guest_ok);
+
+				shares->next = new_shares;
+				new_shares = shares;
+
+				name     = NULL;
+				path     = NULL;
+				comment  = NULL;
+				guest_ok = NULL;
+			}
+		}
+
+out:
+		if (share_file_fp != NULL)
+			fclose(share_file_fp);
+
+		free(name);
+		free(path);
+		free(comment);
+		free(guest_ok);
+	}
+	closedir(shares_dir);
+
+	smb_shares = new_shares;
+
+	return rc;
+}
+
+/**
+ * Used internally by smb_enable_share to enable sharing for a single host.
+ */
+static int
+smb_enable_share_one(const char *sharename, const char *sharepath)
+{
+	char *argv[10], *pos;
+	char name[SMB_NAME_MAX], comment[SMB_COMMENT_MAX];
+	int rc;
+
+	/* Support ZFS share name regexp '[[:alnum:]_-.: ]' */
+	strncpy(name, sharename, sizeof(name));
+	name [sizeof(name)-1] = '\0';
+
+	pos = name;
+	while (*pos != '\0') {
+		switch (*pos) {
+		case '/':
+		case '-':
+		case ':':
+		case ' ':
+			*pos = '_';
+		}
+
+		++pos;
+	}
+
+	/* CMD: net -S NET_CMD_ARG_HOST usershare add Test1 /share/Test1 \
+	 *      "Comment" "Everyone:F" */
+	snprintf(comment, sizeof(comment), "Comment: %s", sharepath);
+
+	argv[0]  = NET_CMD_PATH;
+	argv[1]  = (char*)"-S";
+	argv[2]  = NET_CMD_ARG_HOST;
+	argv[3]  = (char*)"usershare";
+	argv[4]  = (char*)"add";
+	argv[5]  = (char*)name;
+	argv[6]  = (char*)sharepath;
+	argv[7]  = (char*)comment;
+	argv[8] = "Everyone:F";
+	argv[9] = NULL;
+
+	rc = libzfs_run_process(argv[0], argv, 0);
+	if (rc < 0)
+		return SA_SYSTEM_ERR;
+
+	/* Reload the share file */
+	(void) smb_retrieve_shares();
+
+	return SA_OK;
+}
+
+/**
+ * Enables SMB sharing for the specified share.
+ */
+static int
+smb_enable_share(sa_share_impl_t impl_share)
+{
+	char *shareopts;
+
+	if (!smb_available())
+		return SA_SYSTEM_ERR;
+
+	shareopts = FSINFO(impl_share, smb_fstype)->shareopts;
+	if (shareopts == NULL) /* on/off */
+		return SA_SYSTEM_ERR;
+
+	if (strcmp(shareopts, "off") == 0)
+		return SA_OK;
+
+	/* Magic: Enable (i.e., 'create new') share */
+	return smb_enable_share_one(impl_share->dataset, impl_share->sharepath);
+}
+
+/**
+ * Used internally by smb_disable_share to disable sharing for a single host.
+ */
+static int
+smb_disable_share_one(const char *sharename)
+{
+	int rc;
+	char *argv[7];
+
+	/* CMD: net -S NET_CMD_ARG_HOST usershare delete Test1 */
+	argv[0] = NET_CMD_PATH;
+	argv[1] = (char*)"-S";
+	argv[2] = NET_CMD_ARG_HOST;
+	argv[3] = (char*)"usershare";
+	argv[4] = (char*)"delete";
+	argv[5] = strdup(sharename);
+	argv[6] = NULL;
+
+	rc = libzfs_run_process(argv[0], argv, 0);
+	if (rc < 0)
+		return SA_SYSTEM_ERR;
+	else
+		return SA_OK;
+}
+
+/**
+ * Disables SMB sharing for the specified share.
+ */
+static int
+smb_disable_share(sa_share_impl_t impl_share)
+{
+	smb_share_t *shares = smb_shares;
+
+	if (!smb_available()) {
+		/*
+		 * The share can't possibly be active, so nothing
+		 * needs to be done to disable it.
+		 */
+		return SA_OK;
+	}
+
+	while (shares != NULL) {
+		if (strcmp(impl_share->sharepath, shares->path) == 0)
+			return smb_disable_share_one(shares->name);
+
+		shares = shares->next;
+	}
+
+	return SA_OK;
+}
+
+/**
+ * Checks whether the specified SMB share options are syntactically correct.
+ */
+static int
+smb_validate_shareopts(const char *shareopts)
+{
+	/* TODO: Accept 'name' and sec/acl (?) */
+	if ((strcmp(shareopts, "off") == 0) || (strcmp(shareopts, "on") == 0))
+		return SA_OK;
+
+	return SA_SYNTAX_ERR;
+}
+
+/**
+ * Checks whether a share is currently active.
+ */
+static boolean_t
+smb_is_share_active(sa_share_impl_t impl_share)
+{
+	if (!smb_available())
+		return B_FALSE;
+
+	/* Retrieve the list of (possible) active shares */
+	smb_retrieve_shares();
+
+	while (smb_shares != NULL) {
+		if (strcmp(impl_share->sharepath, smb_shares->path) == 0)
+			return B_TRUE;
+
+		smb_shares = smb_shares->next;
+	}
+
+	return B_FALSE;
+}
+
+/**
+ * Called to update a share's options. A share's options might be out of
+ * date if the share was loaded from disk and the "sharesmb" dataset
+ * property has changed in the meantime. This function also takes care
+ * of re-enabling the share if necessary.
+ */
+static int
+smb_update_shareopts(sa_share_impl_t impl_share, const char *resource,
+    const char *shareopts)
+{
+	char *shareopts_dup;
+	boolean_t needs_reshare = B_FALSE;
+	char *old_shareopts;
+
+	if(!impl_share)
+		return SA_SYSTEM_ERR;
+
+	FSINFO(impl_share, smb_fstype)->active =
+	    smb_is_share_active(impl_share);
+
+	old_shareopts = FSINFO(impl_share, smb_fstype)->shareopts;
+
+	if (FSINFO(impl_share, smb_fstype)->active && old_shareopts != NULL &&
+		strcmp(old_shareopts, shareopts) != 0) {
+		needs_reshare = B_TRUE;
+		smb_disable_share(impl_share);
+	}
+
+	shareopts_dup = strdup(shareopts);
+
+	if (shareopts_dup == NULL)
+		return SA_NO_MEMORY;
+
+	if (old_shareopts != NULL)
+		free(old_shareopts);
+
+	FSINFO(impl_share, smb_fstype)->shareopts = shareopts_dup;
+
+	if (needs_reshare)
+		smb_enable_share(impl_share);
+
+	return SA_OK;
+}
+
+/**
+ * Clears a share's SMB options. Used by libshare to
+ * clean up shares that are about to be free()'d.
+ */
+static void
+smb_clear_shareopts(sa_share_impl_t impl_share)
+{
+	free(FSINFO(impl_share, smb_fstype)->shareopts);
+	FSINFO(impl_share, smb_fstype)->shareopts = NULL;
+}
+
+static const sa_share_ops_t smb_shareops = {
+	.enable_share = smb_enable_share,
+	.disable_share = smb_disable_share,
+
+	.validate_shareopts = smb_validate_shareopts,
+	.update_shareopts = smb_update_shareopts,
+	.clear_shareopts = smb_clear_shareopts,
+};
+
+/*
+ * Provides a convenient wrapper for determining SMB availability
+ */
+static boolean_t
+smb_available(void)
+{
+	/* TODO: Sanity check NET_CMD_PATH and SHARE_DIR */
+	return B_TRUE;
+}
+
+/**
+ * Initializes the SMB functionality of libshare.
+ */
+void
+libshare_smb_init(void)
+{
+	smb_fstype = register_fstype("smb", &smb_shareops);
+}
diff --git a/lib/libshare/smb.h b/lib/libshare/smb.h
new file mode 100644
index 000000000..f5ac83ace
--- /dev/null
+++ b/lib/libshare/smb.h
@@ -0,0 +1,49 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2011 Turbo Fredriksson <[email protected]>.
+ */
+
+/*
+ * The maximum SMB share name seems to be 254 characters, though good
+ * references are hard to find.
+ */
+
+#define SMB_NAME_MAX 255
+#define SMB_COMMENT_MAX 255
+
+#define SHARE_DIR "/var/lib/samba/usershares"
+#define NET_CMD_PATH "/usr/bin/net"
+#define NET_CMD_ARG_HOST "127.0.0.1"
+
+typedef struct smb_share_s {
+	char name[SMB_NAME_MAX];	/* Share name */
+	char path[PATH_MAX];		/* Share path */
+	char comment[SMB_COMMENT_MAX];	/* Share's comment */
+	boolean_t guest_ok;		/* 'y' or 'n' */
+
+	struct smb_share_s *next;
+} smb_share_t;
+
+smb_share_t *smb_shares;
+
+void libshare_smb_init(void);