linux/arch/um/kernel/umid.c

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/*
* Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <dirent.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/param.h>
#include "user.h"
#include "umid.h"
#include "init.h"
#include "os.h"
#include "user_util.h"
#include "choose-mode.h"
#define UMID_LEN 64
#define UML_DIR "~/.uml/"
/* Changed by set_umid and make_umid, which are 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;
/* Changed by set_umid */
static int umid_is_random = 1;
static int umid_inited = 0;
static int make_umid(int (*printer)(const char *fmt, ...));
static int __init set_umid(char *name, int is_random,
int (*printer)(const char *fmt, ...))
{
if(umid_inited){
(*printer)("Unique machine name can't be set twice\n");
return(-1);
}
if(strlen(name) > UMID_LEN - 1)
(*printer)("Unique machine name is being truncated to %d "
"characters\n", UMID_LEN);
strlcpy(umid, name, sizeof(umid));
umid_is_random = is_random;
umid_inited = 1;
return 0;
}
static int __init set_umid_arg(char *name, int *add)
{
*add = 0;
return(set_umid(name, 0, printf));
}
__uml_setup("umid=", set_umid_arg,
"umid=<name>\n"
" This is used to assign a unique identity to this UML machine and\n"
" is used for naming the pid file and management console socket.\n\n"
);
int __init umid_file_name(char *name, char *buf, int len)
{
int n;
if(!umid_inited && make_umid(printk)) return(-1);
n = strlen(uml_dir) + strlen(umid) + strlen(name) + 1;
if(n > len){
printk("umid_file_name : buffer too short\n");
return(-1);
}
sprintf(buf, "%s%s/%s", uml_dir, umid, name);
return(0);
}
extern int tracing_pid;
static int __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 0;
fd = os_open_file(file, of_create(of_excl(of_rdwr(OPENFLAGS()))),
0644);
if(fd < 0){
printf("Open of machine pid file \"%s\" failed: %s\n",
file, strerror(-fd));
return 0;
}
sprintf(pid, "%d\n", os_getpid());
n = os_write_file(fd, pid, strlen(pid));
if(n != strlen(pid))
printf("Write of pid file failed - err = %d\n", -n);
os_close_file(fd);
return 0;
}
static int actually_do_remove(char *dir)
{
DIR *directory;
struct dirent *ent;
int len;
char file[256];
directory = opendir(dir);
if(directory == NULL){
printk("actually_do_remove : couldn't open directory '%s', "
"errno = %d\n", dir, errno);
return(1);
}
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)){
printk("Not deleting '%s' from '%s' - name too long\n",
ent->d_name, dir);
continue;
}
sprintf(file, "%s/%s", dir, ent->d_name);
if(unlink(file) < 0){
printk("actually_do_remove : couldn't remove '%s' "
"from '%s', errno = %d\n", ent->d_name, dir,
errno);
return(1);
}
}
if(rmdir(dir) < 0){
printk("actually_do_remove : couldn't rmdir '%s', "
"errno = %d\n", dir, errno);
return(1);
}
return(0);
}
void remove_umid_dir(void)
{
char dir[strlen(uml_dir) + UMID_LEN + 1];
if(!umid_inited) return;
sprintf(dir, "%s%s", uml_dir, umid);
actually_do_remove(dir);
}
char *get_umid(int only_if_set)
{
if(only_if_set && umid_is_random) return(NULL);
return(umid);
}
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;
sprintf(file, "%s/pid", dir);
dead = 0;
fd = os_open_file(file, of_read(OPENFLAGS()), 0);
if(fd < 0){
if(fd != -ENOENT){
printk("not_dead_yet : couldn't open pid file '%s', "
"err = %d\n", file, -fd);
return(1);
}
dead = 1;
}
if(fd > 0){
n = os_read_file(fd, pid, sizeof(pid));
if(n < 0){
printk("not_dead_yet : couldn't read pid file '%s', "
"err = %d\n", file, -n);
return(1);
}
p = strtoul(pid, &end, 0);
if(end == pid){
printk("not_dead_yet : couldn't parse pid file '%s', "
"errno = %d\n", file, errno);
dead = 1;
}
if(((kill(p, 0) < 0) && (errno == ESRCH)) ||
(p == CHOOSE_MODE(tracing_pid, os_getpid())))
dead = 1;
}
if(!dead) return(1);
return(actually_do_remove(dir));
}
static int __init set_uml_dir(char *name, int *add)
{
if((strlen(name) > 0) && (name[strlen(name) - 1] != '/')){
uml_dir = malloc(strlen(name) + 2);
if(uml_dir == NULL){
printf("Failed to malloc uml_dir - error = %d\n",
errno);
uml_dir = name;
/* Return 0 here because do_initcalls doesn't look at
* the return value.
*/
return(0);
}
sprintf(uml_dir, "%s/", name);
}
else uml_dir = name;
return(0);
}
static int __init make_uml_dir(void)
{
char dir[MAXPATHLEN + 1] = { '\0' };
int len;
if(*uml_dir == '~'){
char *home = getenv("HOME");
if(home == NULL){
printf("make_uml_dir : no value in environment for "
"$HOME\n");
exit(1);
}
strlcpy(dir, home, sizeof(dir));
uml_dir++;
}
len = strlen(dir);
strncat(dir, uml_dir, sizeof(dir) - len);
len = strlen(dir);
if((len > 0) && (len < sizeof(dir) - 1) && (dir[len - 1] != '/')){
dir[len] = '/';
dir[len + 1] = '\0';
}
uml_dir = malloc(strlen(dir) + 1);
if(uml_dir == NULL){
printf("make_uml_dir : malloc failed, errno = %d\n", errno);
exit(1);
}
strcpy(uml_dir, dir);
if((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)){
printf("Failed to mkdir %s: %s\n", uml_dir, strerror(errno));
return(-1);
}
return 0;
}
static int __init make_umid(int (*printer)(const char *fmt, ...))
{
int fd, err;
char tmp[strlen(uml_dir) + UMID_LEN + 1];
strlcpy(tmp, uml_dir, sizeof(tmp));
if(!umid_inited){
strcat(tmp, "XXXXXX");
fd = mkstemp(tmp);
if(fd < 0){
(*printer)("make_umid - mkstemp(%s) failed: %s\n",
tmp,strerror(errno));
return(1);
}
os_close_file(fd);
/* 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.
*/
unlink(tmp);
set_umid(&tmp[strlen(uml_dir)], 1, printer);
}
sprintf(tmp, "%s%s", uml_dir, umid);
err = mkdir(tmp, 0777);
if(err < 0){
if(errno == EEXIST){
if(not_dead_yet(tmp)){
(*printer)("umid '%s' is in use\n", umid);
return(-1);
}
err = mkdir(tmp, 0777);
}
}
if(err < 0){
(*printer)("Failed to create %s - errno = %d\n", umid, errno);
return(-1);
}
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 int __init make_umid_setup(void)
{
/* one function with the ordering we need ... */
make_uml_dir();
make_umid(printf);
return create_pid_file();
}
__uml_postsetup(make_umid_setup);
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/