[mirror_ubuntu-bionic-kernel.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 <os.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
				"%s: no value in environment for $HOME\n",
				__func__);
			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) {
		printk(UM_KERN_ERR "%s : malloc failed, errno = %d\n",
			__func__, errno);
		goto err;
	}
	strcpy(uml_dir, dir);

	if ((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)) {
		printk(UM_KERN_ERR "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') {
		os_warn("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) {
		os_warn("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)
		os_warn("%s - remove_files_and_dir failed with err = %d\n",
			__func__, 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>
37185b33 AV	15	#include <init.h>
37185b33 AV	16	#include <os.h>
2264c475 JD	17
	18	#define UML_DIR "~/.uml/"
	19
	20	#define UMID_LEN 64
	21
	22	/* Changed by set_umid, which is run early in boot */
de5fe76e	23	static char umid[UMID_LEN] = { 0 };
2264c475 JD	24
	25	/* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
	26	static char *uml_dir = UML_DIR;
	27
	28	static int __init make_uml_dir(void)
	29	{
	30	char dir[512] = { '\0' };
7eebe8a9	31	int len, err;
2264c475	32
ba180fd4	33	if (*uml_dir == '~') {
2264c475 JD	34	char *home = getenv("HOME");
2264c475 JD	35
7eebe8a9	36	err = -ENOENT;
ba180fd4	37	if (home == NULL) {
e03c78ac MH	38	printk(UM_KERN_ERR
	39	"%s: no value in environment for $HOME\n",
	40	__func__);
7eebe8a9	41	goto err;
2264c475 JD	42	}
	43	strlcpy(dir, home, sizeof(dir));
	44	uml_dir++;
	45	}
	46	strlcat(dir, uml_dir, sizeof(dir));
	47	len = strlen(dir);
	48	if (len > 0 && dir[len - 1] != '/')
	49	strlcat(dir, "/", sizeof(dir));
	50
7eebe8a9	51	err = -ENOMEM;
2264c475 JD	52	uml_dir = malloc(strlen(dir) + 1);
2264c475 JD	53	if (uml_dir == NULL) {
e03c78ac MH	54	printk(UM_KERN_ERR "%s : malloc failed, errno = %d\n",
e03c78ac MH	55	__func__, errno);
7eebe8a9	56	goto err;
2264c475 JD	57	}
	58	strcpy(uml_dir, dir);
	59
ba180fd4	60	if ((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)) {
e03c78ac MH	61	printk(UM_KERN_ERR "Failed to mkdir '%s': %s\n",
e03c78ac MH	62	uml_dir, strerror(errno));
7eebe8a9 JD	63	err = -errno;
7eebe8a9 JD	64	goto err_free;
2264c475 JD	65	}
2264c475 JD	66	return 0;
7eebe8a9 JD	67
	68	err_free:
	69	free(uml_dir);
	70	err:
	71	uml_dir = NULL;
	72	return err;
2264c475 JD	73	}
2264c475 JD	74
eb28931e PBG	75	/*
	76	* Unlinks the files contained in @dir and then removes @dir.
	77	* Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
ba180fd4 JD	78	* ignore ENOENT errors for anything (they happen, strangely enough - possibly
ba180fd4 JD	79	* due to races between multiple dying UML threads).
eb28931e PBG	80	*/
eb28931e PBG	81	static int remove_files_and_dir(char *dir)
2264c475 JD	82	{
	83	DIR *directory;
	84	struct dirent *ent;
	85	int len;
	86	char file[256];
eb28931e	87	int ret;
2264c475 JD	88
2264c475 JD	89	directory = opendir(dir);
eb28931e PBG	90	if (directory == NULL) {
	91	if (errno != ENOENT)
	92	return -errno;
	93	else
	94	return 0;
	95	}
7eebe8a9	96
eb28931e PBG	97	while ((ent = readdir(directory)) != NULL) {
eb28931e PBG	98	if (!strcmp(ent->d_name, ".") \|\| !strcmp(ent->d_name, ".."))
2264c475 JD	99	continue;
2264c475 JD	100	len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
eb28931e PBG	101	if (len > sizeof(file)) {
	102	ret = -E2BIG;
	103	goto out;
	104	}
7eebe8a9	105
2264c475	106	sprintf(file, "%s/%s", dir, ent->d_name);
eb28931e PBG	107	if (unlink(file) < 0 && errno != ENOENT) {
	108	ret = -errno;
	109	goto out;
	110	}
2264c475	111	}
7eebe8a9	112
eb28931e PBG	113	if (rmdir(dir) < 0 && errno != ENOENT) {
	114	ret = -errno;
	115	goto out;
	116	}
	117
	118	ret = 0;
	119	out:
	120	closedir(directory);
	121	return ret;
2264c475 JD	122	}
2264c475 JD	123
ba180fd4 JD	124	/*
ba180fd4 JD	125	* This says that there isn't already a user of the specified directory even if
7eebe8a9 JD	126	* there are errors during the checking. This is because if these errors
	127	* happen, the directory is unusable by the pre-existing UML, so we might as
	128	* well take it over. This could happen either by
	129	* the existing UML somehow corrupting its umid directory
	130	* something other than UML sticking stuff in the directory
	131	* this boot racing with a shutdown of the other UML
	132	* In any of these cases, the directory isn't useful for anything else.
912ad922 PBG	133	*
912ad922 PBG	134	* Boolean return: 1 if in use, 0 otherwise.
7eebe8a9	135	*/
912ad922	136	static inline int is_umdir_used(char *dir)
2264c475 JD	137	{
	138	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
	139	char pid[sizeof("nnnnn\0")], *end;
7eebe8a9 JD	140	int dead, fd, p, n, err;
	141
	142	n = snprintf(file, sizeof(file), "%s/pid", dir);
ba180fd4 JD	143	if (n >= sizeof(file)) {
ba180fd4 JD	144	printk(UM_KERN_ERR "is_umdir_used - pid filename too long\n");
7eebe8a9 JD	145	err = -E2BIG;
	146	goto out;
	147	}
2264c475	148
2264c475	149	dead = 0;
7eebe8a9	150	fd = open(file, O_RDONLY);
ba180fd4	151	if (fd < 0) {
d84a19ce	152	fd = -errno;
ba180fd4 JD	153	if (fd != -ENOENT) {
	154	printk(UM_KERN_ERR "is_umdir_used : couldn't open pid "
	155	"file '%s', err = %d\n", file, -fd);
2264c475	156	}
7eebe8a9	157	goto out;
2264c475	158	}
7eebe8a9 JD	159
	160	err = 0;
	161	n = read(fd, pid, sizeof(pid));
ba180fd4 JD	162	if (n < 0) {
	163	printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
	164	"'%s', err = %d\n", file, errno);
d84a19ce	165	goto out_close;
ba180fd4 JD	166	} else if (n == 0) {
	167	printk(UM_KERN_ERR "is_umdir_used : couldn't read pid file "
	168	"'%s', 0-byte read\n", file);
7eebe8a9 JD	169	goto out_close;
	170	}
	171
	172	p = strtoul(pid, &end, 0);
ba180fd4 JD	173	if (end == pid) {
	174	printk(UM_KERN_ERR "is_umdir_used : couldn't parse pid file "
	175	"'%s', errno = %d\n", file, errno);
7eebe8a9	176	goto out_close;
2264c475	177	}
7eebe8a9	178
ba180fd4 JD	179	if ((kill(p, 0) == 0) \|\| (errno != ESRCH)) {
	180	printk(UM_KERN_ERR "umid \"%s\" is already in use by pid %d\n",
	181	umid, p);
7eebe8a9	182	return 1;
1fbbd684	183	}
7eebe8a9	184
d84a19ce	185	out_close:
7eebe8a9	186	close(fd);
d84a19ce	187	out:
7eebe8a9	188	return 0;
2264c475 JD	189	}
2264c475 JD	190
912ad922 PBG	191	/*
	192	* Try to remove the directory @dir unless it's in use.
	193	* Precondition: @dir exists.
	194	* Returns 0 for success, < 0 for failure in removal or if the directory is in
	195	* use.
	196	*/
	197	static int umdir_take_if_dead(char *dir)
	198	{
	199	int ret;
	200	if (is_umdir_used(dir))
	201	return -EEXIST;
	202
eb28931e	203	ret = remove_files_and_dir(dir);
912ad922	204	if (ret) {
ba180fd4 JD	205	printk(UM_KERN_ERR "is_umdir_used - remove_files_and_dir "
ba180fd4 JD	206	"failed with err = %d\n", ret);
912ad922 PBG	207	}
	208	return ret;
	209	}
	210
2264c475 JD	211	static void __init create_pid_file(void)
	212	{
	213	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
	214	char pid[sizeof("nnnnn\0")];
	215	int fd, n;
	216
ba180fd4	217	if (umid_file_name("pid", file, sizeof(file)))
2264c475 JD	218	return;
2264c475 JD	219
7eebe8a9	220	fd = open(file, O_RDWR \| O_CREAT \| O_EXCL, 0644);
ba180fd4 JD	221	if (fd < 0) {
	222	printk(UM_KERN_ERR "Open of machine pid file \"%s\" failed: "
	223	"%s\n", file, strerror(errno));
2264c475 JD	224	return;
	225	}
	226
7eebe8a9 JD	227	snprintf(pid, sizeof(pid), "%d\n", getpid());
7eebe8a9 JD	228	n = write(fd, pid, strlen(pid));
ba180fd4 JD	229	if (n != strlen(pid))
	230	printk(UM_KERN_ERR "Write of pid file failed - err = %d\n",
	231	errno);
7eebe8a9 JD	232
7eebe8a9 JD	233	close(fd);
2264c475 JD	234	}
2264c475 JD	235
7eebe8a9	236	int __init set_umid(char *name)
2264c475	237	{
ba180fd4	238	if (strlen(name) > UMID_LEN - 1)
7eebe8a9 JD	239	return -E2BIG;
7eebe8a9 JD	240
2264c475 JD	241	strlcpy(umid, name, sizeof(umid));
	242
	243	return 0;
	244	}
	245
de5fe76e	246	/* Changed in make_umid, which is called during early boot */
2264c475 JD	247	static int umid_setup = 0;
2264c475 JD	248
99764fa4	249	static int __init make_umid(void)
2264c475 JD	250	{
	251	int fd, err;
	252	char tmp[256];
	253
ba180fd4	254	if (umid_setup)
7eebe8a9 JD	255	return 0;
7eebe8a9 JD	256
2264c475 JD	257	make_uml_dir();
2264c475 JD	258
ba180fd4	259	if (*umid == '\0') {
2264c475	260	strlcpy(tmp, uml_dir, sizeof(tmp));
7eebe8a9	261	strlcat(tmp, "XXXXXX", sizeof(tmp));
2264c475	262	fd = mkstemp(tmp);
ba180fd4 JD	263	if (fd < 0) {
	264	printk(UM_KERN_ERR "make_umid - mkstemp(%s) failed: "
	265	"%s\n", tmp, strerror(errno));
7eebe8a9 JD	266	err = -errno;
7eebe8a9 JD	267	goto err;
2264c475 JD	268	}
2264c475 JD	269
7eebe8a9 JD	270	close(fd);
	271
	272	set_umid(&tmp[strlen(uml_dir)]);
	273
ba180fd4 JD	274	/*
ba180fd4 JD	275	* There's a nice tiny little race between this unlink and
2264c475 JD	276	* the mkdir below. It'd be nice if there were a mkstemp
	277	* for directories.
	278	*/
ba180fd4	279	if (unlink(tmp)) {
7eebe8a9 JD	280	err = -errno;
	281	goto err;
	282	}
2264c475 JD	283	}
2264c475 JD	284
7eebe8a9	285	snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
2264c475	286	err = mkdir(tmp, 0777);
ba180fd4	287	if (err < 0) {
7eebe8a9	288	err = -errno;
ba180fd4	289	if (err != -EEXIST)
7eebe8a9 JD	290	goto err;
7eebe8a9 JD	291
912ad922	292	if (umdir_take_if_dead(tmp) < 0)
7eebe8a9 JD	293	goto err;
	294
	295	err = mkdir(tmp, 0777);
2264c475	296	}
ba180fd4	297	if (err) {
1fbbd684	298	err = -errno;
ba180fd4 JD	299	printk(UM_KERN_ERR "Failed to create '%s' - err = %d\n", umid,
ba180fd4 JD	300	errno);
1fbbd684	301	goto err;
2264c475 JD	302	}
	303
	304	umid_setup = 1;
	305
	306	create_pid_file();
	307
1fbbd684	308	err = 0;
7eebe8a9 JD	309	err:
7eebe8a9 JD	310	return err;
2264c475 JD	311	}
	312
	313	static int __init make_umid_init(void)
	314	{
ba180fd4	315	if (!make_umid())
1fbbd684 JD	316	return 0;
1fbbd684 JD	317
ba180fd4 JD	318	/*
ba180fd4 JD	319	* If initializing with the given umid failed, then try again with
1fbbd684 JD	320	* a random one.
1fbbd684 JD	321	*/
ba180fd4 JD	322	printk(UM_KERN_ERR "Failed to initialize umid \"%s\", trying with a "
ba180fd4 JD	323	"random umid\n", umid);
1fbbd684	324	*umid = '\0';
7eebe8a9	325	make_umid();
2264c475	326
7eebe8a9	327	return 0;
2264c475 JD	328	}
	329
	330	__initcall(make_umid_init);
	331
	332	int __init umid_file_name(char name, char buf, int len)
	333	{
	334	int n, err;
	335
7eebe8a9	336	err = make_umid();
ba180fd4	337	if (err)
7eebe8a9	338	return err;
2264c475	339
7eebe8a9	340	n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
ba180fd4 JD	341	if (n >= len) {
ba180fd4 JD	342	printk(UM_KERN_ERR "umid_file_name : buffer too short\n");
7eebe8a9	343	return -E2BIG;
2264c475 JD	344	}
2264c475 JD	345
7eebe8a9	346	return 0;
2264c475 JD	347	}
2264c475 JD	348
7eebe8a9	349	char *get_umid(void)
2264c475	350	{
2264c475 JD	351	return umid;
	352	}
	353
	354	static int __init set_uml_dir(char name, int add)
	355	{
ba180fd4	356	if (*name == '\0') {
0936d4f3	357	os_warn("uml_dir can't be an empty string\n");
7eebe8a9	358	return 0;
2264c475	359	}
7eebe8a9	360
ba180fd4	361	if (name[strlen(name) - 1] == '/') {
7eebe8a9 JD	362	uml_dir = name;
	363	return 0;
	364	}
	365
	366	uml_dir = malloc(strlen(name) + 2);
ba180fd4	367	if (uml_dir == NULL) {
0936d4f3	368	os_warn("Failed to malloc uml_dir - error = %d\n", errno);
7eebe8a9	369
ba180fd4 JD	370	/*
ba180fd4 JD	371	* Return 0 here because do_initcalls doesn't look at
7eebe8a9 JD	372	* the return value.
	373	*/
	374	return 0;
	375	}
	376	sprintf(uml_dir, "%s/", name);
	377
	378	return 0;
2264c475 JD	379	}
	380
	381	__uml_setup("uml_dir=", set_uml_dir,
	382	"uml_dir=<directory>\n"
	383	" The location to place the pid and umid files.\n\n"
	384	);
	385
	386	static void remove_umid_dir(void)
	387	{
7eebe8a9	388	char dir[strlen(uml_dir) + UMID_LEN + 1], err;
2264c475 JD	389
2264c475 JD	390	sprintf(dir, "%s%s", uml_dir, umid);
eb28931e	391	err = remove_files_and_dir(dir);
ba180fd4	392	if (err)
0936d4f3 MH	393	os_warn("%s - remove_files_and_dir failed with err = %d\n",
0936d4f3 MH	394	__func__, err);
2264c475 JD	395	}
	396
	397	__uml_exitcall(remove_umid_dir);