arch/um/os-Linux/umid.c - kernel/msm-4.19 - Gitiles

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

 #define UML_DIR "~/.uml/"

 #define UMID_LEN 64

 /* Changed by set_umid, which is run early in boot */
 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("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;
 }

 static int actually_do_remove(char *dir)
 {
 	DIR *directory;
 	struct dirent *ent;
 	int len;
 	char file[256];

 	directory = opendir(dir);
 	if(directory == NULL)
 		return -errno;

 	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))
 			return -E2BIG;

 		sprintf(file, "%s/%s", dir, ent->d_name);
 		if(unlink(file) < 0)
 			return -errno;
 	}
 	if(rmdir(dir) < 0)
 		return -errno;

 	return 0;
 }

 /* 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.
  */

 static int not_dead_yet(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("not_dead_yet - pid filename too long\n");
 		err = -E2BIG;
 		goto out;
 	}

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

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

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

 	err = actually_do_remove(dir);
 	if(err)
 		printk("not_dead_yet - actually_do_remove failed with "
 		       "err = %d\n", err);

 	return err;

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

 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("Open of machine pid file \"%s\" failed: %s\n",
 		       file, strerror(-fd));
 		return;
 	}

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

 	close(fd);
 }

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

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

 	return 0;
 }

 static int umid_setup = 0;

 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("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;

 		/* 1   -> this umid is already in use
 		 * < 0 -> we couldn't remove the umid directory
 		 * In either case, we can't use this umid, so return -EEXIST.
 		 */
 		if(not_dead_yet(tmp) != 0)
 			goto err;

 		err = mkdir(tmp, 0777);
 	}
 	if(err){
 		err = -errno;
 		printk("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("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("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 = actually_do_remove(dir);
 	if(err)
 		printf("remove_umid_dir - actually_do_remove failed with "
 		       "err = %d\n", err);
 }

 __uml_exitcall(remove_umid_dir);
	#include <stdio.h>
	#include <unistd.h>
	#include <stdlib.h>
	#include <string.h>
	#include <errno.h>
	#include <signal.h>
	#include <dirent.h>
	#include <sys/fcntl.h>
	#include <sys/stat.h>
	#include <sys/param.h>
	#include "init.h"
	#include "os.h"
	#include "user.h"
	#include "mode.h"

	#define UML_DIR "~/.uml/"

	#define UMID_LEN 64

	/* Changed by set_umid, which is run early in boot */
	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("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;
	}

	static int actually_do_remove(char *dir)
	{
	DIR *directory;
	struct dirent *ent;
	int len;
	char file[256];

	directory = opendir(dir);
	if(directory == NULL)
	return -errno;

	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))
	return -E2BIG;

	sprintf(file, "%s/%s", dir, ent->d_name);
	if(unlink(file) < 0)
	return -errno;
	}
	if(rmdir(dir) < 0)
	return -errno;

	return 0;
	}

	/* 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.
	*/

	static int not_dead_yet(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("not_dead_yet - pid filename too long\n");
	err = -E2BIG;
	goto out;
	}

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

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

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

	err = actually_do_remove(dir);
	if(err)
	printk("not_dead_yet - actually_do_remove failed with "
	"err = %d\n", err);

	return err;

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

	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("Open of machine pid file \"%s\" failed: %s\n",
	file, strerror(-fd));
	return;
	}

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

	close(fd);
	}

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

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

	return 0;
	}

	static int umid_setup = 0;

	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("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;

	/* 1 -> this umid is already in use
	* < 0 -> we couldn't remove the umid directory
	* In either case, we can't use this umid, so return -EEXIST.
	*/
	if(not_dead_yet(tmp) != 0)
	goto err;

	err = mkdir(tmp, 0777);
	}
	if(err){
	err = -errno;
	printk("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("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("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 = actually_do_remove(dir);
	if(err)
	printf("remove_umid_dir - actually_do_remove failed with "
	"err = %d\n", err);
	}

	__uml_exitcall(remove_umid_dir);