[thirdparty/mdadm.git] / lib.c

/*
 * mdadm - manage Linux "md" devices aka RAID arrays.
 *
 * Copyright (C) 2011  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@suse.de>
 */

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

/* This fill contains various 'library' style function.  They
 * have no dependency on anything outside this file.
 */

int get_mdp_major(void)
{
static int mdp_major = -1;
	FILE *fl;
	char *w;
	int have_block = 0;
	int have_devices = 0;
	int last_num = -1;

	if (mdp_major != -1)
		return mdp_major;
	fl = fopen("/proc/devices", "r");
	if (!fl)
		return -1;
	while ((w = conf_word(fl, 1))) {
		if (have_block && strcmp(w, "devices:")==0)
			have_devices = 1;
		have_block =  (strcmp(w, "Block")==0);
		if (isdigit(w[0]))
			last_num = atoi(w);
		if (have_devices && strcmp(w, "mdp")==0)
			mdp_major = last_num;
		free(w);
	}
	fclose(fl);
	return mdp_major;
}


void fmt_devname(char *name, int num)
{
	if (num >= 0)
		sprintf(name, "md%d", num);
	else
		sprintf(name, "md_d%d", -1-num);
}

char *devnum2devname(int num)
{
	char name[100];
	fmt_devname(name,num);
	return xstrdup(name);
}

int devname2devnum(char *name)
{
	char *ep;
	int num;
	if (strncmp(name, "md_d", 4)==0)
		num = -1-strtoul(name+4, &ep, 10);
	else
		num = strtoul(name+2, &ep, 10);
	return num;
}

int stat2devnum(struct stat *st)
{
	char path[30];
	char link[200];
	char *cp;
	int n;

	if ((S_IFMT & st->st_mode) == S_IFBLK) {
		if (major(st->st_rdev) == MD_MAJOR)
			return minor(st->st_rdev);
		else if (major(st->st_rdev) == (unsigned)get_mdp_major())
			return -1- (minor(st->st_rdev)>>MdpMinorShift);

		/* must be an extended-minor partition. Look at the
		 * /sys/dev/block/%d:%d link which must look like
		 * ../../block/mdXXX/mdXXXpYY
		 */
		sprintf(path, "/sys/dev/block/%d:%d", major(st->st_rdev),
			minor(st->st_rdev));
		n = readlink(path, link, sizeof(link)-1);
		if (n <= 0)
			return NoMdDev;
		link[n] = 0;
		cp = strrchr(link, '/');
		if (cp) *cp = 0;
		cp = strrchr(link, '/');
		if (cp && strncmp(cp, "/md", 3) == 0)
			return devname2devnum(cp+1);
	}
	return NoMdDev;

}

int fd2devnum(int fd)
{
	struct stat stb;
	if (fstat(fd, &stb) == 0)
		return stat2devnum(&stb);
	return NoMdDev;
}


/*
 * convert a major/minor pair for a block device into a name in /dev, if possible.
 * On the first call, walk /dev collecting name.
 * Put them in a simple linked listfor now.
 */
struct devmap {
    int major, minor;
    char *name;
    struct devmap *next;
} *devlist = NULL;
int devlist_ready = 0;

int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s)
{
	struct stat st;

	if (S_ISLNK(stb->st_mode)) {
		if (stat(name, &st) != 0)
			return 0;
		stb = &st;
	}

	if ((stb->st_mode&S_IFMT)== S_IFBLK) {
		char *n = xstrdup(name);
		struct devmap *dm = xmalloc(sizeof(*dm));
		if (strncmp(n, "/dev/./", 7)==0)
			strcpy(n+4, name+6);
		if (dm) {
			dm->major = major(stb->st_rdev);
			dm->minor = minor(stb->st_rdev);
			dm->name = n;
			dm->next = devlist;
			devlist = dm;
		}
	}
	return 0;
}

#ifndef HAVE_NFTW
#ifdef HAVE_FTW
int add_dev_1(const char *name, const struct stat *stb, int flag)
{
	return add_dev(name, stb, flag, NULL);
}
int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
{
	return ftw(path, add_dev_1, nopenfd);
}
#else
int nftw(const char *path, int (*han)(const char *name, const struct stat *stb, int flag, struct FTW *s), int nopenfd, int flags)
{
	return 0;
}
#endif /* HAVE_FTW */
#endif /* HAVE_NFTW */

/*
 * Find a block device with the right major/minor number.
 * If we find multiple names, choose the shortest.
 * If we find a name in /dev/md/, we prefer that.
 * This applies only to names for MD devices.
 * If 'prefer' is set (normally to e.g. /by-path/)
 * then we prefer a name which contains that string.
 */
char *map_dev_preferred(int major, int minor, int create,
			char *prefer)
{
	struct devmap *p;
	char *regular = NULL, *preferred=NULL;
	int did_check = 0;

	if (major == 0 && minor == 0)
			return NULL;

 retry:
	if (!devlist_ready) {
		char *dev = "/dev";
		struct stat stb;
		while(devlist) {
			struct devmap *d = devlist;
			devlist = d->next;
			free(d->name);
			free(d);
		}
		if (lstat(dev, &stb)==0 &&
		    S_ISLNK(stb.st_mode))
			dev = "/dev/.";
		nftw(dev, add_dev, 10, FTW_PHYS);
		devlist_ready=1;
		did_check = 1;
	}

	for (p=devlist; p; p=p->next)
		if (p->major == major &&
		    p->minor == minor) {
			if (strncmp(p->name, "/dev/md/",8) == 0
			    || (prefer && strstr(p->name, prefer))) {
				if (preferred == NULL ||
				    strlen(p->name) < strlen(preferred))
					preferred = p->name;
			} else {
				if (regular == NULL ||
				    strlen(p->name) < strlen(regular))
					regular = p->name;
			}
		}
	if (!regular && !preferred && !did_check) {
		devlist_ready = 0;
		goto retry;
	}
	if (create && !regular && !preferred) {
		static char buf[30];
		snprintf(buf, sizeof(buf), "%d:%d", major, minor);
		regular = buf;
	}

	return preferred ? preferred : regular;
}


/* conf_word gets one word from the conf file.
 * if "allow_key", then accept words at the start of a line,
 * otherwise stop when such a word is found.
 * We assume that the file pointer is at the end of a word, so the
 * next character is a space, or a newline.  If not, it is the start of a line.
 */

char *conf_word(FILE *file, int allow_key)
{
	int wsize = 100;
	int len = 0;
	int c;
	int quote;
	int wordfound = 0;
	char *word = xmalloc(wsize);

	while (wordfound==0) {
		/* at the end of a word.. */
		c = getc(file);
		if (c == '#')
			while (c != EOF && c != '\n')
				c = getc(file);
		if (c == EOF) break;
		if (c == '\n') continue;

		if (c != ' ' && c != '\t' && ! allow_key) {
			ungetc(c, file);
			break;
		}
		/* looks like it is safe to get a word here, if there is one */
		quote = 0;
		/* first, skip any spaces */
		while (c == ' ' || c == '\t')
			c = getc(file);
		if (c != EOF && c != '\n' && c != '#') {
			/* we really have a character of a word, so start saving it */
			while (c != EOF && c != '\n' && (quote || (c!=' ' && c != '\t'))) {
				wordfound = 1;
				if (quote && c == quote) quote = 0;
				else if (quote == 0 && (c == '\'' || c == '"'))
					quote = c;
				else {
					if (len == wsize-1) {
						wsize += 100;
						word = xrealloc(word, wsize);
					}
					word[len++] = c;
				}
				c = getc(file);
				/* Hack for broken kernels (2.6.14-.24) that put
				 *        "active(auto-read-only)"
				 * in /proc/mdstat instead of
				 *        "active (auto-read-only)"
				 */
				if (c == '(' && len >= 6
				    && strncmp(word+len-6, "active", 6) == 0)
					c = ' ';
			}
		}
		if (c != EOF) ungetc(c, file);
	}
	word[len] = 0;

	/* Further HACK for broken kernels.. 2.6.14-2.6.24 */
	if (strcmp(word, "auto-read-only)") == 0)
		strcpy(word, "(auto-read-only)");

/*    printf("word is <%s>\n", word); */
	if (!wordfound) {
		free(word);
		word = NULL;
	}
	return word;
}
Commit	Line	Data
78c0a3b1 N	1	/*
	2	* mdadm - manage Linux "md" devices aka RAID arrays.
	3	*
	4	* Copyright (C) 2011 Neil Brown <neilb@suse.de>
	5	*
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*
	21	* Author: Neil Brown
	22	* Email: <neilb@suse.de>
	23	*/
	24
	25	#include "mdadm.h"
	26	#include <ctype.h>
	27
	28	/* This fill contains various 'library' style function. They
	29	* have no dependency on anything outside this file.
	30	*/
	31
	32	int get_mdp_major(void)
	33	{
	34	static int mdp_major = -1;
	35	FILE *fl;
	36	char *w;
	37	int have_block = 0;
	38	int have_devices = 0;
	39	int last_num = -1;
	40
	41	if (mdp_major != -1)
	42	return mdp_major;
	43	fl = fopen("/proc/devices", "r");
	44	if (!fl)
	45	return -1;
	46	while ((w = conf_word(fl, 1))) {
	47	if (have_block && strcmp(w, "devices:")==0)
	48	have_devices = 1;
	49	have_block = (strcmp(w, "Block")==0);
	50	if (isdigit(w[0]))
	51	last_num = atoi(w);
	52	if (have_devices && strcmp(w, "mdp")==0)
	53	mdp_major = last_num;
	54	free(w);
	55	}
	56	fclose(fl);
	57	return mdp_major;
	58	}
	59
	60
	61	void fmt_devname(char *name, int num)
	62	{
	63	if (num >= 0)
	64	sprintf(name, "md%d", num);
65	else
66	sprintf(name, "md_d%d", -1-num);
67	}
68
69	char *devnum2devname(int num)
70	{
71	char name[100];
72	fmt_devname(name,num);
503975b9	73	return xstrdup(name);
78c0a3b1 N	74	}
	75
	76	int devname2devnum(char *name)
	77	{
	78	char *ep;
	79	int num;
	80	if (strncmp(name, "md_d", 4)==0)
	81	num = -1-strtoul(name+4, &ep, 10);
	82	else
	83	num = strtoul(name+2, &ep, 10);
	84	return num;
	85	}
	86
	87	int stat2devnum(struct stat *st)
	88	{
	89	char path[30];
	90	char link[200];
	91	char *cp;
	92	int n;
	93
	94	if ((S_IFMT & st->st_mode) == S_IFBLK) {
	95	if (major(st->st_rdev) == MD_MAJOR)
	96	return minor(st->st_rdev);
	97	else if (major(st->st_rdev) == (unsigned)get_mdp_major())
	98	return -1- (minor(st->st_rdev)>>MdpMinorShift);
	99
	100	/* must be an extended-minor partition. Look at the
	101	* /sys/dev/block/%d:%d link which must look like
	102	* ../../block/mdXXX/mdXXXpYY
	103	*/
	104	sprintf(path, "/sys/dev/block/%d:%d", major(st->st_rdev),
	105	minor(st->st_rdev));
	106	n = readlink(path, link, sizeof(link)-1);
	107	if (n <= 0)
	108	return NoMdDev;
	109	link[n] = 0;
	110	cp = strrchr(link, '/');
	111	if (cp) *cp = 0;
	112	cp = strrchr(link, '/');
	113	if (cp && strncmp(cp, "/md", 3) == 0)
	114	return devname2devnum(cp+1);
	115	}
	116	return NoMdDev;
	117
	118	}
	119
	120	int fd2devnum(int fd)
	121	{
	122	struct stat stb;
	123	if (fstat(fd, &stb) == 0)
	124	return stat2devnum(&stb);
	125	return NoMdDev;
	126	}
	127
	128
	129
	130	/*
	131	* convert a major/minor pair for a block device into a name in /dev, if possible.
	132	* On the first call, walk /dev collecting name.
	133	* Put them in a simple linked listfor now.
	134	*/
	135	struct devmap {
	136	int major, minor;
	137	char *name;
138	struct devmap *next;
139	} *devlist = NULL;
140	int devlist_ready = 0;
141
142	int add_dev(const char name, const struct stat stb, int flag, struct FTW *s)
143	{
144	struct stat st;
145
146	if (S_ISLNK(stb->st_mode)) {
147	if (stat(name, &st) != 0)
148	return 0;
149	stb = &st;
150	}
151
152	if ((stb->st_mode&S_IFMT)== S_IFBLK) {
503975b9 N	153	char *n = xstrdup(name);
503975b9 N	154	struct devmap dm = xmalloc(sizeof(dm));
78c0a3b1 N	155	if (strncmp(n, "/dev/./", 7)==0)
	156	strcpy(n+4, name+6);
	157	if (dm) {
	158	dm->major = major(stb->st_rdev);
	159	dm->minor = minor(stb->st_rdev);
	160	dm->name = n;
	161	dm->next = devlist;
	162	devlist = dm;
	163	}
	164	}
	165	return 0;
	166	}
	167
	168	#ifndef HAVE_NFTW
	169	#ifdef HAVE_FTW
	170	int add_dev_1(const char name, const struct stat stb, int flag)
	171	{
	172	return add_dev(name, stb, flag, NULL);
	173	}
	174	int nftw(const char path, int (han)(const char name, const struct stat stb, int flag, struct FTW *s), int nopenfd, int flags)
	175	{
	176	return ftw(path, add_dev_1, nopenfd);
	177	}
	178	#else
	179	int nftw(const char path, int (han)(const char name, const struct stat stb, int flag, struct FTW *s), int nopenfd, int flags)
	180	{
	181	return 0;
	182	}
	183	#endif /* HAVE_FTW */
	184	#endif /* HAVE_NFTW */
	185
	186	/*
	187	* Find a block device with the right major/minor number.
	188	* If we find multiple names, choose the shortest.
	189	* If we find a name in /dev/md/, we prefer that.
	190	* This applies only to names for MD devices.
c2ecf5f6 N	191	* If 'prefer' is set (normally to e.g. /by-path/)
c2ecf5f6 N	192	* then we prefer a name which contains that string.
78c0a3b1	193	*/
c2ecf5f6 N	194	char *map_dev_preferred(int major, int minor, int create,
c2ecf5f6 N	195	char *prefer)
78c0a3b1 N	196	{
	197	struct devmap *p;
	198	char regular = NULL, preferred=NULL;
	199	int did_check = 0;
	200
	201	if (major == 0 && minor == 0)
	202	return NULL;
	203
	204	retry:
	205	if (!devlist_ready) {
	206	char *dev = "/dev";
	207	struct stat stb;
	208	while(devlist) {
	209	struct devmap *d = devlist;
	210	devlist = d->next;
	211	free(d->name);
	212	free(d);
	213	}
	214	if (lstat(dev, &stb)==0 &&
	215	S_ISLNK(stb.st_mode))
	216	dev = "/dev/.";
	217	nftw(dev, add_dev, 10, FTW_PHYS);
	218	devlist_ready=1;
	219	did_check = 1;
	220	}
	221
	222	for (p=devlist; p; p=p->next)
	223	if (p->major == major &&
	224	p->minor == minor) {
c2ecf5f6 N	225	if (strncmp(p->name, "/dev/md/",8) == 0
c2ecf5f6 N	226	\|\| (prefer && strstr(p->name, prefer))) {
78c0a3b1 N	227	if (preferred == NULL \|\|
	228	strlen(p->name) < strlen(preferred))
	229	preferred = p->name;
	230	} else {
	231	if (regular == NULL \|\|
	232	strlen(p->name) < strlen(regular))
	233	regular = p->name;
	234	}
	235	}
	236	if (!regular && !preferred && !did_check) {
	237	devlist_ready = 0;
	238	goto retry;
	239	}
	240	if (create && !regular && !preferred) {
	241	static char buf[30];
	242	snprintf(buf, sizeof(buf), "%d:%d", major, minor);
	243	regular = buf;
	244	}
	245
	246	return preferred ? preferred : regular;
	247	}
	248
	249
c2ecf5f6	250
78c0a3b1 N	251	/* conf_word gets one word from the conf file.
	252	* if "allow_key", then accept words at the start of a line,
	253	* otherwise stop when such a word is found.
	254	* We assume that the file pointer is at the end of a word, so the
	255	* next character is a space, or a newline. If not, it is the start of a line.
	256	*/
	257
	258	char conf_word(FILE file, int allow_key)
	259	{
	260	int wsize = 100;
	261	int len = 0;
	262	int c;
	263	int quote;
	264	int wordfound = 0;
503975b9	265	char *word = xmalloc(wsize);
78c0a3b1 N	266
	267	while (wordfound==0) {
	268	/* at the end of a word.. */
	269	c = getc(file);
	270	if (c == '#')
	271	while (c != EOF && c != '\n')
	272	c = getc(file);
	273	if (c == EOF) break;
	274	if (c == '\n') continue;
	275
	276	if (c != ' ' && c != '\t' && ! allow_key) {
	277	ungetc(c, file);
	278	break;
	279	}
	280	/* looks like it is safe to get a word here, if there is one */
	281	quote = 0;
	282	/* first, skip any spaces */
	283	while (c == ' ' \|\| c == '\t')
	284	c = getc(file);
	285	if (c != EOF && c != '\n' && c != '#') {
	286	/* we really have a character of a word, so start saving it */
	287	while (c != EOF && c != '\n' && (quote \|\| (c!=' ' && c != '\t'))) {
	288	wordfound = 1;
	289	if (quote && c == quote) quote = 0;
	290	else if (quote == 0 && (c == '\'' \|\| c == '"'))
	291	quote = c;
	292	else {
	293	if (len == wsize-1) {
	294	wsize += 100;
503975b9	295	word = xrealloc(word, wsize);
78c0a3b1 N	296	}
	297	word[len++] = c;
	298	}
	299	c = getc(file);
	300	/* Hack for broken kernels (2.6.14-.24) that put
	301	* "active(auto-read-only)"
	302	* in /proc/mdstat instead of
	303	* "active (auto-read-only)"
	304	*/
	305	if (c == '(' && len >= 6
	306	&& strncmp(word+len-6, "active", 6) == 0)
	307	c = ' ';
	308	}
	309	}
	310	if (c != EOF) ungetc(c, file);
	311	}
	312	word[len] = 0;
	313
	314	/* Further HACK for broken kernels.. 2.6.14-2.6.24 */
	315	if (strcmp(word, "auto-read-only)") == 0)
	316	strcpy(word, "(auto-read-only)");
	317
	318	/* printf("word is <%s>\n", word); */
	319	if (!wordfound) {
	320	free(word);
	321	word = NULL;
	322	}
	323	return word;
	324	}