mdopen.c - pub/scm/utils/mdadm/mdadm - Git at Google

 /*
  * mdadm - manage Linux "md" devices aka RAID arrays.
  *
  * Copyright (C) 2001-2006 Neil Brown <neilb@suse.de>
  *
  *
  *    This program is free software; you can redistribute it and/or modify
  *    it under the terms of the GNU General Public License as published by
  *    the Free Software Foundation; either version 2 of the License, or
  *    (at your option) any later version.
  *
  *    This program is distributed in the hope that it will be useful,
  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *    GNU General Public License for more details.
  *
  *    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
  *
  *    Author: Neil Brown
  *    Email: <neilb@cse.unsw.edu.au>
  *    Paper: Neil Brown
  *           School of Computer Science and Engineering
  *           The University of New South Wales
  *           Sydney, 2052
  *           Australia
  */

 #include "mdadm.h"
 #include "md_p.h"
 #include <ctype.h>


 void make_dev_symlink(char *dev)
 {
 	char *new = strdup(dev);

 	if (!new) return;
 	/* /dev/md/0 -> /dev/md0
 	 * /dev/md/d0 -> /dev/md_d0
 	 */
 	if (isdigit(new[8]))
 		strcpy(new+7, new+8);
 	else
 		new[7] = '_';
 	if (symlink(dev+5, new))
 		perror(new);
 }


 void make_parts(char *dev, int cnt, int symlinks)
 {
 	/* make 'cnt' partition devices for 'dev'
 	 * We use the major/minor from dev and add 1..cnt
 	 * If dev ends with a digit, we add "p%d" else "%d"
 	 * If the name exists, we use it's owner/mode,
 	 * else that of dev
 	 */
 	struct stat stb;
 	int major_num, minor_num;
 	int i;
 	int nlen = strlen(dev) + 20;
 	char *name = malloc(nlen);
 	int dig = isdigit(dev[strlen(dev)-1]);

 	if (cnt==0) cnt=4;
 	if (stat(dev, &stb)!= 0)
 		return;
 	if (!S_ISBLK(stb.st_mode))
 		return;
 	major_num = major(stb.st_rdev);
 	minor_num = minor(stb.st_rdev);
 	for (i=1; i <= cnt ; i++) {
 		struct stat stb2;
 		snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
 		if (stat(name, &stb2)==0) {
 			if (!S_ISBLK(stb2.st_mode))
 				continue;
 			if (stb2.st_rdev == makedev(major_num, minor_num+i))
 				continue;
 			unlink(name);
 		} else {
 			stb2 = stb;
 		}
 		if (mknod(name, S_IFBLK | 0600, makedev(major_num, minor_num+i)))
 			perror("mknod");
 		if (chown(name, stb2.st_uid, stb2.st_gid))
 			perror("chown");
 		if (chmod(name, stb2.st_mode & 07777))
 			perror("chmod");
 		if (symlinks && strncmp(name, "/dev/md/", 8) == 0)
 			make_dev_symlink(name);
 		stat(name, &stb2);
 		add_dev(name, &stb2, 0, NULL);
 	}
 }


 /*
  * Open a given md device, and check that it really is one.
  * If 'autof' is given, then we need to create, or recreate, the md device.
  * If the name already exists, and is not a block device, we fail.
  * If it exists and is not an md device, is not the right type (partitioned or not),
  * or is currently in-use, we remove the device, but remember the owner and mode.
  * If it now doesn't exist, we find a new md array and create the device.
  * Default ownership/mode comes from config file.
  */
 int open_mddev(char *dev, int autof)
 {
 	int mdfd;
 	struct stat stb;
 	int major_num = MD_MAJOR;
 	int minor_num = 0;
 	int must_remove = 0;
 	int num;
 	struct createinfo *ci = conf_get_create_info();
 	int parts;

 	if (autof == 0)
 		autof = ci->autof;

 	parts = autof >> 3;
 	autof &= 7;

 	if (autof && autof != 1) {
 		/* autof is set, so we need to check that the name is ok,
 		 * and possibly create one if not
 		 */
 		int std;
 		stb.st_mode = 0;
 		if (stat(dev, &stb)==0 && ! S_ISBLK(stb.st_mode)) {
 			fprintf(stderr, Name ": %s is not a block device.\n",
 				dev);
 			return -1;
 		}
 		/* check major number is correct */
 		num = -1;
 		std = is_standard(dev, &num);
 		if (std>0) major_num = get_mdp_major();
 		switch(autof) {
 		case 2: /* only create is_standard names */
 			if (!std && !stb.st_mode) {
 				fprintf(stderr, Name
 			": %s does not exist and is not a 'standard' name "
 			"so it cannot be created\n", dev);
 				return -1;
 			}
 			break;
 		case 3: /* create md, reject std>0 */
 			if (std > 0) {
 				fprintf(stderr, Name ": that --auto option "
 				"not compatable with device named %s\n", dev);
 				return -1;
 			}
 			break;
 		case 4: /* create mdp, reject std<0 */
 			if (std < 0) {
 				fprintf(stderr, Name ": that --auto option "
 				"not compatable with device named %s\n", dev);
 				return -1;
 			}
 			major_num = get_mdp_major();
 			break;
 		case 5: /* default to md if not standard */
 			break;
 		case 6: /* default to mdp if not standard */
 			if (std == 0) major_num = get_mdp_major();
 			break;
 		}
 		/* major is final. num is -1 if not standard */
 		if (stb.st_mode && major(stb.st_rdev) != major_num)
 			must_remove = 1;
 		if (stb.st_mode && !must_remove) {
 			/* looks ok, see if it is available */
 			mdfd = open(dev, O_RDWR);
 			if (mdfd < 0) {
 				fprintf(stderr, Name ": error opening %s: %s\n",
 					dev, strerror(errno));
 				return -1;
 			} else if (md_get_version(mdfd) <= 0) {
 				fprintf(stderr, Name ": %s does not appear to be an md device\n",
 					dev);
 				close(mdfd);
 				return -1;
 			}
 			if (major_num != MD_MAJOR && parts > 0)
 				make_parts(dev, parts, ci->symlinks);
 			return mdfd;
 		}
 		/* Ok, need to find a minor that is not in use.
 		 * If the device name is in a 'standard' format,
 		 * intuit the minor from that, else
 		 * easiest to read /proc/mdstat, and hunt through for
 		 * an unused number
 		 */
 		if (num < 0) {
 			/* need to pick an unused number */
 			int num = find_free_devnum(major_num != MD_MAJOR);

 			if (major_num == MD_MAJOR)
 				minor_num = num;
 			else
 				minor_num = (-1-num) << MdpMinorShift;
 		} else if (major_num == MD_MAJOR)
 			minor_num = num;
 		else
 			minor_num = num << MdpMinorShift;
 		/* major and minor have been chosen */

 		/* If it was a 'standard' name and it is in-use, then
 		 * the device could already be correct
 		 */
 		if (stb.st_mode && major(stb.st_rdev) == major_num &&
 		    minor(stb.st_rdev) == minor_num)
 			;
 		else {
 			if (major(makedev(major_num,minor_num)) != major_num ||
 			    minor(makedev(major_num,minor_num)) != minor_num) {
 				fprintf(stderr, Name ": Need newer C library to use more than 4 partitionable md devices, sorry\n");
 				return -1;
 			}
 			if (must_remove)
 				unlink(dev);

 			if (strncmp(dev, "/dev/md/", 8) == 0) {
 				if (mkdir("/dev/md",0700)==0) {
 					if (chown("/dev/md", ci->uid, ci->gid))
 						perror("chown /dev/md");
 					if (chmod("/dev/md", ci->mode| ((ci->mode>>2) & 0111)))
 						perror("chmod /dev/md");
 				}
 			}
 			if (mknod(dev, S_IFBLK|0600, makedev(major_num, minor_num))!= 0) {
 				fprintf(stderr, Name ": failed to create %s\n", dev);
 				return -1;
 			}
 			if (must_remove) {
 				if (chown(dev, stb.st_uid, stb.st_gid))
 					perror("chown");
 				if (chmod(dev, stb.st_mode & 07777))
 					perror("chmod");
 			} else {
 				if (chown(dev, ci->uid, ci->gid))
 					perror("chown");
 				if (chmod(dev, ci->mode))
 					perror("chmod");
 			}
 			stat(dev, &stb);
 			add_dev(dev, &stb, 0, NULL);
 			if (ci->symlinks && strncmp(dev, "/dev/md/", 8) == 0)
 				make_dev_symlink(dev);
 			if (major_num != MD_MAJOR)
 				make_parts(dev,parts, ci->symlinks);
 		}
 	}
 	mdfd = open(dev, O_RDWR);
 	if (mdfd < 0)
 		fprintf(stderr, Name ": error opening %s: %s\n",
 			dev, strerror(errno));
 	else if (md_get_version(mdfd) <= 0) {
 		fprintf(stderr, Name ": %s does not appear to be an md device\n",
 			dev);
 		close(mdfd);
 		mdfd = -1;
 	}
 	return mdfd;
 }


 int open_mddev_devnum(char *devname, int devnum, char *name,
 		      char *chosen_name, int parts)
 {
 	/* Open the md device with number 'devnum', possibly using 'devname',
 	 * possibly constructing a name with 'name', but in any case, copying
 	 * the name into 'chosen_name'
 	 */
 	int major_num, minor_num;
 	struct stat stb;
 	int i;
 	struct createinfo *ci = conf_get_create_info();

 	if (devname)
 		strcpy(chosen_name, devname);
 	else if (name && *name && strchr(name,'/') == NULL) {
 		char *n = strchr(name, ':');
 		if (n) n++; else n = name;
 		if (isdigit(*n) && devnum < 0)
 			sprintf(chosen_name, "/dev/md/d%s", n);
 		else
 			sprintf(chosen_name, "/dev/md/%s", n);
 	} else {
 		if (devnum >= 0)
 			sprintf(chosen_name, "/dev/md%d", devnum);
 		else
 			sprintf(chosen_name, "/dev/md/d%d", -1-devnum);
 	}
 	if (devnum >= 0) {
 		major_num = MD_MAJOR;
 		minor_num = devnum;
 	} else {
 		major_num = get_mdp_major();
 		minor_num = (-1-devnum) << 6;
 	}
 	if (stat(chosen_name, &stb) == 0) {
 		/* It already exists.  Check it is right. */
 		if ( ! S_ISBLK(stb.st_mode) ||
 		     stb.st_rdev != makedev(major_num, minor_num)) {
 			errno = EEXIST;
 			return -1;
 		}
 	} else {
 		/* special case: if --incremental is suggesting a name
 		 * in /dev/md/, we make sure the directory exists.
 		 */
 		if (strncmp(chosen_name, "/dev/md/", 8) == 0) {
 			if (mkdir("/dev/md",0700)==0) {
 				if (chown("/dev/md", ci->uid, ci->gid))
 					perror("chown /dev/md");
 				if (chmod("/dev/md", ci->mode|
 					          ((ci->mode>>2) & 0111)))
 					perror("chmod /dev/md");
 			}
 		}

 		if (mknod(chosen_name, S_IFBLK | 0600,
 			  makedev(major_num, minor_num)) != 0) {
 			return -1;
 		}
 		/* FIXME chown/chmod ?? */
 	}

 	/* Simple locking to avoid --incr being called for the same
 	 * array multiple times in parallel.
 	 */
 	for (i = 0; i < 25 ; i++) {
 		int fd;

 		fd = open(chosen_name, O_RDWR|O_EXCL);
 		if (fd >= 0 || errno != EBUSY) {
 			if (devnum < 0)
 				make_parts(chosen_name, parts, ci->symlinks);
 			return fd;
 		}
 		usleep(200000);
 	}
 	return -1;
 }
	/*
	* mdadm - manage Linux "md" devices aka RAID arrays.
	*
	* Copyright (C) 2001-2006 Neil Brown <neilb@suse.de>
	*
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* 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
	*
	* Author: Neil Brown
	* Email: <neilb@cse.unsw.edu.au>
	* Paper: Neil Brown
	* School of Computer Science and Engineering
	* The University of New South Wales
	* Sydney, 2052
	* Australia
	*/

	#include "mdadm.h"
	#include "md_p.h"
	#include <ctype.h>


	void make_dev_symlink(char *dev)
	{
	char *new = strdup(dev);

	if (!new) return;
	/* /dev/md/0 -> /dev/md0
	* /dev/md/d0 -> /dev/md_d0
	*/
	if (isdigit(new[8]))
	strcpy(new+7, new+8);
	else
	new[7] = '_';
	if (symlink(dev+5, new))
	perror(new);
	}


	void make_parts(char *dev, int cnt, int symlinks)
	{
	/* make 'cnt' partition devices for 'dev'
	* We use the major/minor from dev and add 1..cnt
	* If dev ends with a digit, we add "p%d" else "%d"
	* If the name exists, we use it's owner/mode,
	* else that of dev
	*/
	struct stat stb;
	int major_num, minor_num;
	int i;
	int nlen = strlen(dev) + 20;
	char *name = malloc(nlen);
	int dig = isdigit(dev[strlen(dev)-1]);

	if (cnt==0) cnt=4;
	if (stat(dev, &stb)!= 0)
	return;
	if (!S_ISBLK(stb.st_mode))
	return;
	major_num = major(stb.st_rdev);
	minor_num = minor(stb.st_rdev);
	for (i=1; i <= cnt ; i++) {
	struct stat stb2;
	snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
	if (stat(name, &stb2)==0) {
	if (!S_ISBLK(stb2.st_mode))
	continue;
	if (stb2.st_rdev == makedev(major_num, minor_num+i))
	continue;
	unlink(name);
	} else {
	stb2 = stb;
	}
	if (mknod(name, S_IFBLK \| 0600, makedev(major_num, minor_num+i)))
	perror("mknod");
	if (chown(name, stb2.st_uid, stb2.st_gid))
	perror("chown");
	if (chmod(name, stb2.st_mode & 07777))
	perror("chmod");
	if (symlinks && strncmp(name, "/dev/md/", 8) == 0)
	make_dev_symlink(name);
	stat(name, &stb2);
	add_dev(name, &stb2, 0, NULL);
	}
	}


	/*
	* Open a given md device, and check that it really is one.
	* If 'autof' is given, then we need to create, or recreate, the md device.
	* If the name already exists, and is not a block device, we fail.
	* If it exists and is not an md device, is not the right type (partitioned or not),
	* or is currently in-use, we remove the device, but remember the owner and mode.
	* If it now doesn't exist, we find a new md array and create the device.
	* Default ownership/mode comes from config file.
	*/
	int open_mddev(char *dev, int autof)
	{
	int mdfd;
	struct stat stb;
	int major_num = MD_MAJOR;
	int minor_num = 0;
	int must_remove = 0;
	int num;
	struct createinfo *ci = conf_get_create_info();
	int parts;

	if (autof == 0)
	autof = ci->autof;

	parts = autof >> 3;
	autof &= 7;

	if (autof && autof != 1) {
	/* autof is set, so we need to check that the name is ok,
	* and possibly create one if not
	*/
	int std;
	stb.st_mode = 0;
	if (stat(dev, &stb)==0 && ! S_ISBLK(stb.st_mode)) {
	fprintf(stderr, Name ": %s is not a block device.\n",
	dev);
	return -1;
	}
	/* check major number is correct */
	num = -1;
	std = is_standard(dev, &num);
	if (std>0) major_num = get_mdp_major();
	switch(autof) {
	case 2: /* only create is_standard names */
	if (!std && !stb.st_mode) {
	fprintf(stderr, Name
	": %s does not exist and is not a 'standard' name "
	"so it cannot be created\n", dev);
	return -1;
	}
	break;
	case 3: /* create md, reject std>0 */
	if (std > 0) {
	fprintf(stderr, Name ": that --auto option "
	"not compatable with device named %s\n", dev);
	return -1;
	}
	break;
	case 4: /* create mdp, reject std<0 */
	if (std < 0) {
	fprintf(stderr, Name ": that --auto option "
	"not compatable with device named %s\n", dev);
	return -1;
	}
	major_num = get_mdp_major();
	break;
	case 5: /* default to md if not standard */
	break;
	case 6: /* default to mdp if not standard */
	if (std == 0) major_num = get_mdp_major();
	break;
	}
	/* major is final. num is -1 if not standard */
	if (stb.st_mode && major(stb.st_rdev) != major_num)
	must_remove = 1;
	if (stb.st_mode && !must_remove) {
	/* looks ok, see if it is available */
	mdfd = open(dev, O_RDWR);
	if (mdfd < 0) {
	fprintf(stderr, Name ": error opening %s: %s\n",
	dev, strerror(errno));
	return -1;
	} else if (md_get_version(mdfd) <= 0) {
	fprintf(stderr, Name ": %s does not appear to be an md device\n",
	dev);
	close(mdfd);
	return -1;
	}
	if (major_num != MD_MAJOR && parts > 0)
	make_parts(dev, parts, ci->symlinks);
	return mdfd;
	}
	/* Ok, need to find a minor that is not in use.
	* If the device name is in a 'standard' format,
	* intuit the minor from that, else
	* easiest to read /proc/mdstat, and hunt through for
	* an unused number
	*/
	if (num < 0) {
	/* need to pick an unused number */
	int num = find_free_devnum(major_num != MD_MAJOR);

	if (major_num == MD_MAJOR)
	minor_num = num;
	else
	minor_num = (-1-num) << MdpMinorShift;
	} else if (major_num == MD_MAJOR)
	minor_num = num;
	else
	minor_num = num << MdpMinorShift;
	/* major and minor have been chosen */

	/* If it was a 'standard' name and it is in-use, then
	* the device could already be correct
	*/
	if (stb.st_mode && major(stb.st_rdev) == major_num &&
	minor(stb.st_rdev) == minor_num)
	;
	else {
	if (major(makedev(major_num,minor_num)) != major_num \|\|
	minor(makedev(major_num,minor_num)) != minor_num) {
	fprintf(stderr, Name ": Need newer C library to use more than 4 partitionable md devices, sorry\n");
	return -1;
	}
	if (must_remove)
	unlink(dev);

	if (strncmp(dev, "/dev/md/", 8) == 0) {
	if (mkdir("/dev/md",0700)==0) {
	if (chown("/dev/md", ci->uid, ci->gid))
	perror("chown /dev/md");
	if (chmod("/dev/md", ci->mode\| ((ci->mode>>2) & 0111)))
	perror("chmod /dev/md");
	}
	}
	if (mknod(dev, S_IFBLK\|0600, makedev(major_num, minor_num))!= 0) {
	fprintf(stderr, Name ": failed to create %s\n", dev);
	return -1;
	}
	if (must_remove) {
	if (chown(dev, stb.st_uid, stb.st_gid))
	perror("chown");
	if (chmod(dev, stb.st_mode & 07777))
	perror("chmod");
	} else {
	if (chown(dev, ci->uid, ci->gid))
	perror("chown");
	if (chmod(dev, ci->mode))
	perror("chmod");
	}
	stat(dev, &stb);
	add_dev(dev, &stb, 0, NULL);
	if (ci->symlinks && strncmp(dev, "/dev/md/", 8) == 0)
	make_dev_symlink(dev);
	if (major_num != MD_MAJOR)
	make_parts(dev,parts, ci->symlinks);
	}
	}
	mdfd = open(dev, O_RDWR);
	if (mdfd < 0)
	fprintf(stderr, Name ": error opening %s: %s\n",
	dev, strerror(errno));
	else if (md_get_version(mdfd) <= 0) {
	fprintf(stderr, Name ": %s does not appear to be an md device\n",
	dev);
	close(mdfd);
	mdfd = -1;
	}
	return mdfd;
	}


	int open_mddev_devnum(char devname, int devnum, char name,
	char *chosen_name, int parts)
	{
	/* Open the md device with number 'devnum', possibly using 'devname',
	* possibly constructing a name with 'name', but in any case, copying
	* the name into 'chosen_name'
	*/
	int major_num, minor_num;
	struct stat stb;
	int i;
	struct createinfo *ci = conf_get_create_info();

	if (devname)
	strcpy(chosen_name, devname);
	else if (name && *name && strchr(name,'/') == NULL) {
	char *n = strchr(name, ':');
	if (n) n++; else n = name;
	if (isdigit(*n) && devnum < 0)
	sprintf(chosen_name, "/dev/md/d%s", n);
	else
	sprintf(chosen_name, "/dev/md/%s", n);
	} else {
	if (devnum >= 0)
	sprintf(chosen_name, "/dev/md%d", devnum);
	else
	sprintf(chosen_name, "/dev/md/d%d", -1-devnum);
	}
	if (devnum >= 0) {
	major_num = MD_MAJOR;
	minor_num = devnum;
	} else {
	major_num = get_mdp_major();
	minor_num = (-1-devnum) << 6;
	}
	if (stat(chosen_name, &stb) == 0) {
	/* It already exists. Check it is right. */
	if ( ! S_ISBLK(stb.st_mode) \|\|
	stb.st_rdev != makedev(major_num, minor_num)) {
	errno = EEXIST;
	return -1;
	}
	} else {
	/* special case: if --incremental is suggesting a name
	* in /dev/md/, we make sure the directory exists.
	*/
	if (strncmp(chosen_name, "/dev/md/", 8) == 0) {
	if (mkdir("/dev/md",0700)==0) {
	if (chown("/dev/md", ci->uid, ci->gid))
	perror("chown /dev/md");
	if (chmod("/dev/md", ci->mode\|
	((ci->mode>>2) & 0111)))
	perror("chmod /dev/md");
	}
	}

	if (mknod(chosen_name, S_IFBLK \| 0600,
	makedev(major_num, minor_num)) != 0) {
	return -1;
	}
	/* FIXME chown/chmod ?? */
	}

	/* Simple locking to avoid --incr being called for the same
	* array multiple times in parallel.
	*/
	for (i = 0; i < 25 ; i++) {
	int fd;

	fd = open(chosen_name, O_RDWR\|O_EXCL);
	if (fd >= 0 \|\| errno != EBUSY) {
	if (devnum < 0)
	make_parts(chosen_name, parts, ci->symlinks);
	return fd;
	}
	usleep(200000);
	}
	return -1;
	}