#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))
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(errno != EEXIST)
goto err;
if(not_dead_yet(tmp) < 0)
goto err;
err = mkdir(tmp, 0777);
}
if(err < 0){
printk("Failed to create '%s' - err = %d\n", umid, err);
goto err_rmdir;
}
umid_setup = 1;
create_pid_file();
return 0;
err_rmdir:
rmdir(tmp);
err:
return err;
}
static int __init make_umid_init(void)
{
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);
