[linux.git] / arch / um / os-Linux / umid.c

/*
 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include "init.h"
#include "kern_constants.h"
#include "os.h"
#include "user.h"

#define UML_DIR "~/.uml/"

#define UMID_LEN 64

/* Changed by set_umid, which is run early in boot */
static char umid[UMID_LEN] = { 0 };

/* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
static char *uml_dir = UML_DIR;

static int __init make_uml_dir(void)
{
	char dir[512] = { '\0' };
	int len, err;

	if (*uml_dir == '~') {
		char *home = getenv("HOME");

		err = -ENOENT;
		if (home == NULL) {
			printk(UM_KERN_ERR "make_uml_dir : no value in "
			       "environment for $HOME\n");
			goto err;
		}
		strlcpy(dir, home, sizeof(dir));
		uml_dir++;
	}
	strlcat(dir, uml_dir, sizeof(dir));
	len = strlen(dir);
	if (len > 0 && dir[len - 1] != '/')
		strlcat(dir, "/", sizeof(dir));

	err = -ENOMEM;
	uml_dir = malloc(strlen(dir) + 1);
	if (uml_dir == NULL) {
		printf("make_uml_dir : malloc failed, errno = %d\n", errno);
		goto err;
	}
	strcpy(uml_dir, dir);

	if ((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)) {
	        printf("Failed to mkdir '%s': %s\n", uml_dir, strerror(errno));
		err = -errno;
		goto err_free;
	}
	return 0;

err_free:
	free(uml_dir);
err:
	uml_dir = NULL;
	return err;
}

/*
 * Unlinks the files contained in @dir and then removes @dir.
 * Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
 * ignore ENOENT errors for anything (they happen, strangely enough - possibly
 * due to races between multiple dying UML threads).
 */
static int remove_files_and_dir(char *dir)
{
	DIR *directory;
	struct dirent *ent;
	int len;
	char file[256];
	int ret;

	directory = opendir(dir);
	if (directory == NULL) {
		if (errno != ENOENT)
			return -errno;
		else
			return 0;
	}

	while ((ent = readdir(directory)) != NULL) {
		if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
			continue;
		len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
		if (len > sizeof(file)) {
			ret = -E2BIG;
			goto out;
		}

		sprintf(file, "%s/%s", dir, ent->d_name);
		if (unlink(file) < 0 && errno != ENOENT) {
			ret = -errno;
			goto out;
		}
	}

	if (rmdir(dir) < 0 && errno != ENOENT) {
		ret = -errno;
		goto out;
	}

	ret = 0;
out:
	closedir(directory);
	return ret;
}

/*
 * This says that there isn't already a user of the specified directory even if
 * there are errors during the checking.  This is because if these errors
 * happen, the directory is unusable by the pre-existing UML, so we might as
 * well take it over.  This could happen either by
 * 	the existing UML somehow corrupting its umid directory
 * 	something other than UML sticking stuff in the directory
 *	this boot racing with a shutdown of the other UML
 * In any of these cases, the directory isn't useful for anything else.
 *
 * Boolean return: 1 if in use, 0 otherwise.
 */
static inline int is_umdir_used(char *dir)
{
	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
	char pid[sizeof("nnnnn\0")], *end;
	int dead, fd, p, n, err;

	n = snprintf(file, sizeof(file), "%s/pid", dir);
	if (n >= sizeof(file)) {
		printk(UM_KERN_ERR "is_umdir_used - pid filename too long\n");
		err = -E2BIG;
		goto out;
	}

	dead = 0;
	fd = open(file, O_RDONLY);
	if (fd < 0) {
		fd = -errno;
		if (fd != -ENOENT) {
			printk(UM_KERN_ERR "is_umdir_used : couldn't open pid "
			       "file '%s', err = %d\n", file, -fd);
		}
		goto out;
	}

	err = 0;
	n = read(fd, pid, sizeof(pid));
	if (n < 0) {
		printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
		       "'%s', err = %d\n", file, errno);
		goto out_close;
	} else if (n == 0) {
		printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
		       "'%s', 0-byte read\n", file);
		goto out_close;
	}

	p = strtoul(pid, &end, 0);
	if (end == pid) {
		printk(UM_KERN_ERR "is_umdir_used : couldn't parse pid file "
		       "'%s', errno = %d\n", file, errno);
		goto out_close;
	}

	if ((kill(p, 0) == 0) || (errno != ESRCH)) {
		printk(UM_KERN_ERR "umid \"%s\" is already in use by pid %d\n",
		       umid, p);
		return 1;
	}

out_close:
	close(fd);
out:
	return 0;
}

/*
 * Try to remove the directory @dir unless it's in use.
 * Precondition: @dir exists.
 * Returns 0 for success, < 0 for failure in removal or if the directory is in
 * use.
 */
static int umdir_take_if_dead(char *dir)
{
	int ret;
	if (is_umdir_used(dir))
		return -EEXIST;

	ret = remove_files_and_dir(dir);
	if (ret) {
		printk(UM_KERN_ERR "is_umdir_used - remove_files_and_dir "
		       "failed with err = %d\n", ret);
	}
	return ret;
}

static void __init create_pid_file(void)
{
	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
	char pid[sizeof("nnnnn\0")];
	int fd, n;

	if (umid_file_name("pid", file, sizeof(file)))
		return;

	fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0644);
	if (fd < 0) {
		printk(UM_KERN_ERR "Open of machine pid file \"%s\" failed: "
		       "%s\n", file, strerror(errno));
		return;
	}

	snprintf(pid, sizeof(pid), "%d\n", getpid());
	n = write(fd, pid, strlen(pid));
	if (n != strlen(pid))
		printk(UM_KERN_ERR "Write of pid file failed - err = %d\n",
		       errno);

	close(fd);
}

int __init set_umid(char *name)
{
	if (strlen(name) > UMID_LEN - 1)
		return -E2BIG;

	strlcpy(umid, name, sizeof(umid));

	return 0;
}

/* Changed in make_umid, which is called during early boot */
static int umid_setup = 0;

static int __init make_umid(void)
{
	int fd, err;
	char tmp[256];

	if (umid_setup)
		return 0;

	make_uml_dir();

	if (*umid == '\0') {
		strlcpy(tmp, uml_dir, sizeof(tmp));
		strlcat(tmp, "XXXXXX", sizeof(tmp));
		fd = mkstemp(tmp);
		if (fd < 0) {
			printk(UM_KERN_ERR "make_umid - mkstemp(%s) failed: "
			       "%s\n", tmp, strerror(errno));
			err = -errno;
			goto err;
		}

		close(fd);

		set_umid(&tmp[strlen(uml_dir)]);

		/*
		 * There's a nice tiny little race between this unlink and
		 * the mkdir below.  It'd be nice if there were a mkstemp
		 * for directories.
		 */
		if (unlink(tmp)) {
			err = -errno;
			goto err;
		}
	}

	snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
	err = mkdir(tmp, 0777);
	if (err < 0) {
		err = -errno;
		if (err != -EEXIST)
			goto err;

		if (umdir_take_if_dead(tmp) < 0)
			goto err;

		err = mkdir(tmp, 0777);
	}
	if (err) {
		err = -errno;
		printk(UM_KERN_ERR "Failed to create '%s' - err = %d\n", umid,
		       errno);
		goto err;
	}

	umid_setup = 1;

	create_pid_file();

	err = 0;
 err:
	return err;
}

static int __init make_umid_init(void)
{
	if (!make_umid())
		return 0;

	/*
	 * If initializing with the given umid failed, then try again with
	 * a random one.
	 */
	printk(UM_KERN_ERR "Failed to initialize umid \"%s\", trying with a "
	       "random umid\n", umid);
	*umid = '\0';
	make_umid();

	return 0;
}

__initcall(make_umid_init);

int __init umid_file_name(char *name, char *buf, int len)
{
	int n, err;

	err = make_umid();
	if (err)
		return err;

	n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
	if (n >= len) {
		printk(UM_KERN_ERR "umid_file_name : buffer too short\n");
		return -E2BIG;
	}

	return 0;
}

char *get_umid(void)
{
	return umid;
}

static int __init set_uml_dir(char *name, int *add)
{
	if (*name == '\0') {
		printf("uml_dir can't be an empty string\n");
		return 0;
	}

	if (name[strlen(name) - 1] == '/') {
		uml_dir = name;
		return 0;
	}

	uml_dir = malloc(strlen(name) + 2);
	if (uml_dir == NULL) {
		printf("Failed to malloc uml_dir - error = %d\n", errno);

		/*
		 * Return 0 here because do_initcalls doesn't look at
		 * the return value.
		 */
		return 0;
	}
	sprintf(uml_dir, "%s/", name);

	return 0;
}

__uml_setup("uml_dir=", set_uml_dir,
"uml_dir=<directory>\n"
"    The location to place the pid and umid files.\n\n"
);

static void remove_umid_dir(void)
{
	char dir[strlen(uml_dir) + UMID_LEN + 1], err;

	sprintf(dir, "%s%s", uml_dir, umid);
	err = remove_files_and_dir(dir);
	if (err)
		printf("remove_umid_dir - remove_files_and_dir failed with "
		       "err = %d\n", err);
}

__uml_exitcall(remove_umid_dir);
Commit	Line	Data
ba180fd4 JD	1	/*
	2	* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
	3	* Licensed under the GPL
	4	*/
	5
2264c475	6	#include <stdio.h>
2264c475	7	#include <stdlib.h>
ba180fd4	8	#include <dirent.h>
2264c475	9	#include <errno.h>
ba180fd4	10	#include <fcntl.h>
2264c475	11	#include <signal.h>
ba180fd4 JD	12	#include <string.h>
ba180fd4 JD	13	#include <unistd.h>
2264c475	14	#include <sys/stat.h>
2264c475	15	#include "init.h"
ba180fd4	16	#include "kern_constants.h"
2264c475 JD	17	#include "os.h"
2264c475 JD	18	#include "user.h"
2264c475 JD	19
	20	#define UML_DIR "~/.uml/"
	21
	22	#define UMID_LEN 64
	23
	24	/* Changed by set_umid, which is run early in boot */
de5fe76e	25	static char umid[UMID_LEN] = { 0 };
2264c475 JD	26
	27	/* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
	28	static char *uml_dir = UML_DIR;
	29
	30	static int __init make_uml_dir(void)
	31	{
	32	char dir[512] = { '\0' };
7eebe8a9	33	int len, err;
2264c475	34
ba180fd4	35	if (*uml_dir == '~') {
2264c475 JD	36	char *home = getenv("HOME");
2264c475 JD	37
7eebe8a9	38	err = -ENOENT;
ba180fd4 JD	39	if (home == NULL) {
	40	printk(UM_KERN_ERR "make_uml_dir : no value in "
	41	"environment for $HOME\n");
7eebe8a9	42	goto err;
2264c475 JD	43	}
	44	strlcpy(dir, home, sizeof(dir));
	45	uml_dir++;
	46	}
	47	strlcat(dir, uml_dir, sizeof(dir));
	48	len = strlen(dir);
	49	if (len > 0 && dir[len - 1] != '/')
	50	strlcat(dir, "/", sizeof(dir));
	51
7eebe8a9	52	err = -ENOMEM;
2264c475 JD	53	uml_dir = malloc(strlen(dir) + 1);
	54	if (uml_dir == NULL) {
	55	printf("make_uml_dir : malloc failed, errno = %d\n", errno);
7eebe8a9	56	goto err;
2264c475 JD	57	}
	58	strcpy(uml_dir, dir);
	59
ba180fd4	60	if ((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)) {
2264c475	61	printf("Failed to mkdir '%s': %s\n", uml_dir, strerror(errno));
7eebe8a9 JD	62	err = -errno;
7eebe8a9 JD	63	goto err_free;
2264c475 JD	64	}
2264c475 JD	65	return 0;
7eebe8a9 JD	66
	67	err_free:
	68	free(uml_dir);
	69	err:
	70	uml_dir = NULL;
	71	return err;
2264c475 JD	72	}
2264c475 JD	73
eb28931e PBG	74	/*
	75	* Unlinks the files contained in @dir and then removes @dir.
	76	* Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
ba180fd4 JD	77	* ignore ENOENT errors for anything (they happen, strangely enough - possibly
ba180fd4 JD	78	* due to races between multiple dying UML threads).
eb28931e PBG	79	*/
eb28931e PBG	80	static int remove_files_and_dir(char *dir)
2264c475 JD	81	{
	82	DIR *directory;
	83	struct dirent *ent;
	84	int len;
	85	char file[256];
eb28931e	86	int ret;
2264c475 JD	87
2264c475 JD	88	directory = opendir(dir);
eb28931e PBG	89	if (directory == NULL) {
	90	if (errno != ENOENT)
	91	return -errno;
	92	else
	93	return 0;
	94	}
7eebe8a9	95
eb28931e PBG	96	while ((ent = readdir(directory)) != NULL) {
eb28931e PBG	97	if (!strcmp(ent->d_name, ".") \|\| !strcmp(ent->d_name, ".."))
2264c475 JD	98	continue;
2264c475 JD	99	len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
eb28931e PBG	100	if (len > sizeof(file)) {
	101	ret = -E2BIG;
	102	goto out;
	103	}
7eebe8a9	104
2264c475	105	sprintf(file, "%s/%s", dir, ent->d_name);
eb28931e PBG	106	if (unlink(file) < 0 && errno != ENOENT) {
	107	ret = -errno;
	108	goto out;
	109	}
2264c475	110	}
7eebe8a9	111
eb28931e PBG	112	if (rmdir(dir) < 0 && errno != ENOENT) {
	113	ret = -errno;
	114	goto out;
	115	}
	116
	117	ret = 0;
	118	out:
	119	closedir(directory);
	120	return ret;
2264c475 JD	121	}
2264c475 JD	122
ba180fd4 JD	123	/*
ba180fd4 JD	124	* This says that there isn't already a user of the specified directory even if
7eebe8a9 JD	125	* there are errors during the checking. This is because if these errors
	126	* happen, the directory is unusable by the pre-existing UML, so we might as
	127	* well take it over. This could happen either by
	128	* the existing UML somehow corrupting its umid directory
	129	* something other than UML sticking stuff in the directory
	130	* this boot racing with a shutdown of the other UML
	131	* In any of these cases, the directory isn't useful for anything else.
912ad922 PBG	132	*
912ad922 PBG	133	* Boolean return: 1 if in use, 0 otherwise.
7eebe8a9	134	*/
912ad922	135	static inline int is_umdir_used(char *dir)
2264c475 JD	136	{
	137	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
	138	char pid[sizeof("nnnnn\0")], *end;
7eebe8a9 JD	139	int dead, fd, p, n, err;
	140
	141	n = snprintf(file, sizeof(file), "%s/pid", dir);
ba180fd4 JD	142	if (n >= sizeof(file)) {
ba180fd4 JD	143	printk(UM_KERN_ERR "is_umdir_used - pid filename too long\n");
7eebe8a9 JD	144	err = -E2BIG;
	145	goto out;
	146	}
2264c475	147
2264c475	148	dead = 0;
7eebe8a9	149	fd = open(file, O_RDONLY);
ba180fd4	150	if (fd < 0) {
d84a19ce	151	fd = -errno;
ba180fd4 JD	152	if (fd != -ENOENT) {
	153	printk(UM_KERN_ERR "is_umdir_used : couldn't open pid "
	154	"file '%s', err = %d\n", file, -fd);
2264c475	155	}
7eebe8a9	156	goto out;
2264c475	157	}
7eebe8a9 JD	158
	159	err = 0;
	160	n = read(fd, pid, sizeof(pid));
ba180fd4 JD	161	if (n < 0) {
	162	printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
	163	"'%s', err = %d\n", file, errno);
d84a19ce	164	goto out_close;
ba180fd4 JD	165	} else if (n == 0) {
	166	printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
	167	"'%s', 0-byte read\n", file);
7eebe8a9 JD	168	goto out_close;
	169	}
	170
	171	p = strtoul(pid, &end, 0);
ba180fd4 JD	172	if (end == pid) {
	173	printk(UM_KERN_ERR "is_umdir_used : couldn't parse pid file "
	174	"'%s', errno = %d\n", file, errno);
7eebe8a9	175	goto out_close;
2264c475	176	}
7eebe8a9	177
ba180fd4 JD	178	if ((kill(p, 0) == 0) \|\| (errno != ESRCH)) {
	179	printk(UM_KERN_ERR "umid \"%s\" is already in use by pid %d\n",
	180	umid, p);
7eebe8a9	181	return 1;
1fbbd684	182	}
7eebe8a9	183
d84a19ce	184	out_close:
7eebe8a9	185	close(fd);
d84a19ce	186	out:
7eebe8a9	187	return 0;
2264c475 JD	188	}
2264c475 JD	189
912ad922 PBG	190	/*
	191	* Try to remove the directory @dir unless it's in use.
	192	* Precondition: @dir exists.
	193	* Returns 0 for success, < 0 for failure in removal or if the directory is in
	194	* use.
	195	*/
	196	static int umdir_take_if_dead(char *dir)
	197	{
	198	int ret;
	199	if (is_umdir_used(dir))
	200	return -EEXIST;
	201
eb28931e	202	ret = remove_files_and_dir(dir);
912ad922	203	if (ret) {
ba180fd4 JD	204	printk(UM_KERN_ERR "is_umdir_used - remove_files_and_dir "
ba180fd4 JD	205	"failed with err = %d\n", ret);
912ad922 PBG	206	}
	207	return ret;
	208	}
	209
2264c475 JD	210	static void __init create_pid_file(void)
	211	{
	212	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
	213	char pid[sizeof("nnnnn\0")];
	214	int fd, n;
	215
ba180fd4	216	if (umid_file_name("pid", file, sizeof(file)))
2264c475 JD	217	return;
2264c475 JD	218
7eebe8a9	219	fd = open(file, O_RDWR \| O_CREAT \| O_EXCL, 0644);
ba180fd4 JD	220	if (fd < 0) {
	221	printk(UM_KERN_ERR "Open of machine pid file \"%s\" failed: "
	222	"%s\n", file, strerror(errno));
2264c475 JD	223	return;
	224	}
	225
7eebe8a9 JD	226	snprintf(pid, sizeof(pid), "%d\n", getpid());
7eebe8a9 JD	227	n = write(fd, pid, strlen(pid));
ba180fd4 JD	228	if (n != strlen(pid))
	229	printk(UM_KERN_ERR "Write of pid file failed - err = %d\n",
	230	errno);
7eebe8a9 JD	231
7eebe8a9 JD	232	close(fd);
2264c475 JD	233	}
2264c475 JD	234
7eebe8a9	235	int __init set_umid(char *name)
2264c475	236	{
ba180fd4	237	if (strlen(name) > UMID_LEN - 1)
7eebe8a9 JD	238	return -E2BIG;
7eebe8a9 JD	239
2264c475 JD	240	strlcpy(umid, name, sizeof(umid));
	241
	242	return 0;
	243	}
	244
de5fe76e	245	/* Changed in make_umid, which is called during early boot */
2264c475 JD	246	static int umid_setup = 0;
2264c475 JD	247
99764fa4	248	static int __init make_umid(void)
2264c475 JD	249	{
	250	int fd, err;
	251	char tmp[256];
	252
ba180fd4	253	if (umid_setup)
7eebe8a9 JD	254	return 0;
7eebe8a9 JD	255
2264c475 JD	256	make_uml_dir();
2264c475 JD	257
ba180fd4	258	if (*umid == '\0') {
2264c475	259	strlcpy(tmp, uml_dir, sizeof(tmp));
7eebe8a9	260	strlcat(tmp, "XXXXXX", sizeof(tmp));
2264c475	261	fd = mkstemp(tmp);
ba180fd4 JD	262	if (fd < 0) {
	263	printk(UM_KERN_ERR "make_umid - mkstemp(%s) failed: "
	264	"%s\n", tmp, strerror(errno));
7eebe8a9 JD	265	err = -errno;
7eebe8a9 JD	266	goto err;
2264c475 JD	267	}
2264c475 JD	268
7eebe8a9 JD	269	close(fd);
	270
	271	set_umid(&tmp[strlen(uml_dir)]);
	272
ba180fd4 JD	273	/*
ba180fd4 JD	274	* There's a nice tiny little race between this unlink and
2264c475 JD	275	* the mkdir below. It'd be nice if there were a mkstemp
	276	* for directories.
	277	*/
ba180fd4	278	if (unlink(tmp)) {
7eebe8a9 JD	279	err = -errno;
	280	goto err;
	281	}
2264c475 JD	282	}
2264c475 JD	283
7eebe8a9	284	snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
2264c475	285	err = mkdir(tmp, 0777);
ba180fd4	286	if (err < 0) {
7eebe8a9	287	err = -errno;
ba180fd4	288	if (err != -EEXIST)
7eebe8a9 JD	289	goto err;
7eebe8a9 JD	290
912ad922	291	if (umdir_take_if_dead(tmp) < 0)
7eebe8a9 JD	292	goto err;
	293
	294	err = mkdir(tmp, 0777);
2264c475	295	}
ba180fd4	296	if (err) {
1fbbd684	297	err = -errno;
ba180fd4 JD	298	printk(UM_KERN_ERR "Failed to create '%s' - err = %d\n", umid,
ba180fd4 JD	299	errno);
1fbbd684	300	goto err;
2264c475 JD	301	}
	302
	303	umid_setup = 1;
	304
	305	create_pid_file();
	306
1fbbd684	307	err = 0;
7eebe8a9 JD	308	err:
7eebe8a9 JD	309	return err;
2264c475 JD	310	}
	311
	312	static int __init make_umid_init(void)
	313	{
ba180fd4	314	if (!make_umid())
1fbbd684 JD	315	return 0;
1fbbd684 JD	316
ba180fd4 JD	317	/*
ba180fd4 JD	318	* If initializing with the given umid failed, then try again with
1fbbd684 JD	319	* a random one.
1fbbd684 JD	320	*/
ba180fd4 JD	321	printk(UM_KERN_ERR "Failed to initialize umid \"%s\", trying with a "
ba180fd4 JD	322	"random umid\n", umid);
1fbbd684	323	*umid = '\0';
7eebe8a9	324	make_umid();
2264c475	325
7eebe8a9	326	return 0;
2264c475 JD	327	}
	328
	329	__initcall(make_umid_init);
	330
	331	int __init umid_file_name(char name, char buf, int len)
	332	{
	333	int n, err;
	334
7eebe8a9	335	err = make_umid();
ba180fd4	336	if (err)
7eebe8a9	337	return err;
2264c475	338
7eebe8a9	339	n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
ba180fd4 JD	340	if (n >= len) {
ba180fd4 JD	341	printk(UM_KERN_ERR "umid_file_name : buffer too short\n");
7eebe8a9	342	return -E2BIG;
2264c475 JD	343	}
2264c475 JD	344
7eebe8a9	345	return 0;
2264c475 JD	346	}
2264c475 JD	347
7eebe8a9	348	char *get_umid(void)
2264c475	349	{
2264c475 JD	350	return umid;
	351	}
	352
	353	static int __init set_uml_dir(char name, int add)
	354	{
ba180fd4	355	if (*name == '\0') {
7eebe8a9 JD	356	printf("uml_dir can't be an empty string\n");
7eebe8a9 JD	357	return 0;
2264c475	358	}
7eebe8a9	359
ba180fd4	360	if (name[strlen(name) - 1] == '/') {
7eebe8a9 JD	361	uml_dir = name;
	362	return 0;
	363	}
	364
	365	uml_dir = malloc(strlen(name) + 2);
ba180fd4	366	if (uml_dir == NULL) {
7eebe8a9 JD	367	printf("Failed to malloc uml_dir - error = %d\n", errno);
7eebe8a9 JD	368
ba180fd4 JD	369	/*
ba180fd4 JD	370	* Return 0 here because do_initcalls doesn't look at
7eebe8a9 JD	371	* the return value.
	372	*/
	373	return 0;
	374	}
	375	sprintf(uml_dir, "%s/", name);
	376
	377	return 0;
2264c475 JD	378	}
	379
	380	__uml_setup("uml_dir=", set_uml_dir,
	381	"uml_dir=<directory>\n"
	382	" The location to place the pid and umid files.\n\n"
	383	);
	384
	385	static void remove_umid_dir(void)
	386	{
7eebe8a9	387	char dir[strlen(uml_dir) + UMID_LEN + 1], err;
2264c475 JD	388
2264c475 JD	389	sprintf(dir, "%s%s", uml_dir, umid);
eb28931e	390	err = remove_files_and_dir(dir);
ba180fd4	391	if (err)
eb28931e	392	printf("remove_umid_dir - remove_files_and_dir failed with "
7eebe8a9	393	"err = %d\n", err);
2264c475 JD	394	}
	395
	396	__uml_exitcall(remove_umid_dir);