Attempt to fix /dev/mapper/control transparently if it's wrong.

WHATS_NEW_DM

@@ -1,5 +1,6 @@
 Version 1.00.20 -
 =============================
+  Attempt to fix /dev/mapper/control transparently if it's wrong.
   Configuration-time option for setting uid/gid/mode for /dev/mapper nodes.
   Update kernel patches for 2.4.27/2.4.28-pre-4 (includes minor fixes).
   Add --noheadings columns option for colon-separated dmsetup output.

libdm/Makefile.in

@@ -1,6 +1,6 @@
 #
 # Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
-# Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+# Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
 #
 # This file is part of the device-mapper userspace tools.
 #
@@ -17,7 +17,7 @@ top_srcdir = @top_srcdir@
 VPATH = @srcdir@
 interface = @interface@
 
-SOURCES = libdm-common.c $(interface)/libdm-iface.c
+SOURCES = libdm-common.c libdm-file.c $(interface)/libdm-iface.c
 
 INCLUDES = -I$(interface)
 

libdm/ioctl/libdm-iface.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
  *
  * This file is part of the device-mapper userspace tools.
  *
@@ -13,22 +13,17 @@
  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#include "lib.h"
 #include "libdm-targets.h"
 #include "libdm-common.h"
-#include "log.h"
+#include "libdm-file.h"
 
 #ifdef DM_COMPAT
 #  include "libdm-compat.h"
 #endif
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
 #include <fcntl.h>
 #include <dirent.h>
-#include <errno.h>
-#include <sys/stat.h>
 #include <sys/ioctl.h>
 #include <limits.h>
 
@@ -53,6 +48,13 @@
 #error The version of dm-ioctl.h included is incompatible.
 #endif
 
+/* FIXME This should be exported in device-mapper.h */
+#define DM_NAME "device-mapper"
+
+#define PROC_MISC "/proc/misc"
+#define PROC_DEVICES "/proc/devices"
+#define MISC_NAME "misc"
+
 /* dm major version no for running kernel */
 static int _dm_version = DM_VERSION_MAJOR;
 static int _log_suppress = 0;
@@ -114,22 +116,144 @@ static void *_align(void *ptr, unsigned int a)
 	return (void *) (((unsigned long) ptr + agn) & ~agn);
 }
 
+static int _get_proc_number(const char *file, const char *name,
+			    uint32_t *number)
+{
+	FILE *fl;
+	char nm[256];
+	int c;
+
+	if (!(fl = fopen(file, "r"))) {
+		log_error("%s: fopen failed: %s", file, strerror(errno));
+		return 0;
+	}
+
+	while (!feof(fl)) {
+		if (fscanf(fl, "%d %255s\n", number, &nm[0]) == 2) {
+			if (!strcmp(name, nm)) {
+				fclose(fl);
+				return 1;
+			}
+		}
+		do {
+			c = fgetc(fl);
+		} while (c != EOF && c != '\n');
+	}
+	fclose(fl);
+
+	log_error("%s: No entry for %s found", file, name);
+	return 0;
+}
+
+static int _control_device_number(uint32_t *major, uint32_t *minor)
+{
+	if (!_get_proc_number(PROC_DEVICES, MISC_NAME, major) ||
+	    !_get_proc_number(PROC_MISC, DM_NAME, minor)) {
+		*major = 0;
+		return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Returns 1 if exists; 0 if it doesn't; -1 if it's wrong
+ */
+static int _control_exists(const char *control, uint32_t major, uint32_t minor)
+{
+	struct stat buf;
+
+	if (stat(control, &buf) < 0) {
+		if (errno != ENOENT)
+			log_error("%s: stat failed: %s", control,
+				  strerror(errno));
+		return 0;
+	}
+
+	if (!S_ISCHR(buf.st_mode)) {
+		log_verbose("%s: Wrong inode type", control);
+		if (!unlink(control))
+			return 0;
+		log_error("%s: unlink failed: %s", control,
+			  strerror(errno));
+		return -1;
+	}
+
+	if (major && buf.st_rdev != MKDEV(major, minor)) {
+		log_verbose("%s: Wrong device number: (%u, %u) instead of "
+			    "(%u, %u)", control,
+			    MAJOR(buf.st_mode), MINOR(buf.st_mode),
+			    major, minor);
+		if (!unlink(control))
+			return 0;
+		log_error("%s: unlink failed: %s", control,
+			  strerror(errno));
+		return -1;
+	}
+
+	return 1;
+}
+
+static int _create_control(const char *control, uint32_t major, uint32_t minor)
+{
+	int ret;
+	mode_t old_umask;
+
+	if (!major)
+		return 0;
+
+	old_umask = umask(0022);
+	ret = create_dir(dm_dir());
+	umask(old_umask);
+
+	if (!ret)
+		return 0;
+
+	log_verbose("Creating device %s (%u, %u)", control, major, minor);
+
+	if (mknod(control, S_IFCHR | S_IRUSR | S_IWUSR,
+		  MKDEV(major, minor)) < 0)  {
+		log_error("%s: mknod failed: %s", control, strerror(errno));
+		return 0;
+	}
+
+#ifdef HAVE_SELINUX
+        if (!set_selinux_context(control)) {
+                stack;
+                return 0;
+        }
+#endif
+
+	return 1;
+}
+
 static int _open_control(void)
 {
 	char control[PATH_MAX];
+	uint32_t major = 0, minor;
 
 	if (_control_fd != -1)
 		return 1;
 
 	snprintf(control, sizeof(control), "%s/control", dm_dir());
 
+	if (!_control_device_number(&major, &minor))
+		log_error("Is device-mapper driver missing from kernel?");
+
+	if (!_control_exists(control, major, minor) &&
+	    !_create_control(control, major, minor))
+		goto error;
+
 	if ((_control_fd = open(control, O_RDWR)) < 0) {
 		log_error("%s: open failed: %s", control, strerror(errno));
-		log_error("Is device-mapper driver missing from kernel?");
-		return 0;
+		goto error;
 	}
 
 	return 1;
+
+error:
+	log_error("Failure to communicate with kernel device-mapper driver.");
+	return 0;
 }
 
 void dm_task_destroy(struct dm_task *dmt)

libdm/libdm-common.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
  *
  * This file is part of the device-mapper userspace tools.
  *
@@ -13,20 +13,14 @@
  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#include "lib.h"
 #include "libdm-targets.h"
 #include "libdm-common.h"
 #include "list.h"
-#include "log.h"
 #include "kdev_t.h"
 
-#include <stdio.h>
-#include <stdlib.h>
 #include <stdarg.h>
-#include <string.h>
 #include <sys/param.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <errno.h>
 #include <linux/dm-ioctl.h>
 
 #ifdef HAVE_SELINUX
@@ -100,14 +94,14 @@ struct dm_task *dm_task_create(int type)
 {
 	struct dm_task *dmt = malloc(sizeof(*dmt));
 
-	if (!dm_check_version())
-		return NULL;
-
 	if (!dmt) {
 		log_error("dm_task_create: malloc(%d) failed", sizeof(*dmt));
 		return NULL;
 	}
 
+	if (!dm_check_version())
+		return NULL;
+
 	memset(dmt, 0, sizeof(*dmt));
 
 	dmt->type = type;
@@ -205,7 +199,7 @@ int dm_task_add_target(struct dm_task *dmt, uint64_t start, uint64_t size,
 }
 
 #ifdef HAVE_SELINUX
-static int _set_selinux_context(const char *path)
+int set_selinux_context(const char *path)
 {
 	security_context_t scontext;
 
@@ -270,7 +264,7 @@ static int _add_dev_node(const char *dev_name, uint32_t major, uint32_t minor,
 	}
 
 #ifdef HAVE_SELINUX
-	if (!_set_selinux_context(path))
+	if (!set_selinux_context(path))
 		return 0;
 #endif
 

libdm/libdm-common.h.in

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
  *
  * This file is part of the device-mapper userspace tools.
  *
@@ -28,6 +28,8 @@ int rm_dev_node(const char *dev_name);
 int rename_dev_node(const char *old_name, const char *new_name);
 void update_devs(void);
 
+int set_selinux_context(const char *path);
+
 #define DM_LIB_VERSION @DM_LIB_VERSION@
 
 #endif

libdm/libdm-file.c

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.  
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of the device-mapper userspace tools.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "lib.h"
+#include "libdm-file.h"
+
+#include <sys/file.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <malloc.h>
+
+static int _create_dir_recursive(const char *dir)
+{
+	char *orig, *s;
+	int rc;
+
+	log_verbose("Creating directory \"%s\"", dir);
+	/* Create parent directories */
+	orig = s = strdup(dir);
+	while ((s = strchr(s, '/')) != NULL) {
+		*s = '\0';
+		if (*orig) {
+			rc = mkdir(orig, 0777);
+			if (rc < 0 && errno != EEXIST) {
+				log_error("%s: mkdir failed: %s", orig,
+					  strerror(errno));
+				free(orig);
+				return 0;
+			}
+		}
+		*s++ = '/';
+	}
+	free(orig);
+
+	/* Create final directory */
+	rc = mkdir(dir, 0777);
+	if (rc < 0 && errno != EEXIST) {
+		log_error("%s: mkdir failed: %s", orig,
+			  strerror(errno));
+		return 0;
+	}
+	return 1;
+}
+
+int create_dir(const char *dir)
+{
+	struct stat info;
+
+	if (!*dir)
+		return 1;
+
+	if (stat(dir, &info) < 0)
+		return _create_dir_recursive(dir);
+
+	if (S_ISDIR(info.st_mode))
+		return 1;
+
+	log_error("Directory \"%s\" not found", dir);
+	return 0;
+}
+

libdm/libdm-file.h

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.  
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of the device-mapper userspace tools.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef LIB_DMFILE_H
+#define LIB_DMFILE_H
+
+/*
+ * Create directory (recursively) if necessary.  Return 1
+ * if directory was successfully created (or already exists), else 0.
+ */
+int create_dir(const char *dir);
+
+#endif