arch/um/kernel/umid.c

   1 /*
   2  * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdio.h>
   7 #include <unistd.h>
   8 #include <errno.h>
   9 #include <string.h>
  10 #include <stdlib.h>
  11 #include <dirent.h>
  12 #include <signal.h>
  13 #include <sys/stat.h>
  14 #include <sys/param.h>
  15 #include "user.h"
  16 #include "umid.h"
  17 #include "init.h"
  18 #include "os.h"
  19 #include "user_util.h"
  20 #include "choose-mode.h"
  21
  22 #define UMID_LEN 64
  23 #define UML_DIR "~/.uml/"
  24
  25 /* Changed by set_umid and make_umid, which are run early in boot */
  26 static char umid[UMID_LEN] = { 0 };
  27
  28 /* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
  29 static char *uml_dir = UML_DIR;
  30
  31 /* Changed by set_umid */
  32 static int umid_is_random = 1;
  33 static int umid_inited = 0;
  34 /* Have we created the files? Should we remove them? */
  35 static int umid_owned = 0;
  36
  37 static int make_umid(int (*printer)(const char *fmt, ...));
  38
  39 static int __init set_umid(char *name, int is_random,
  40                            int (*printer)(const char *fmt, ...))
  41 {
  42         if(umid_inited){
  43                 (*printer)("Unique machine name can't be set twice\n");
  44                 return(-1);
  45         }
  46
  47         if(strlen(name) > UMID_LEN - 1)
  48                 (*printer)("Unique machine name is being truncated to %d "
  49                            "characters\n", UMID_LEN);
  50         strlcpy(umid, name, sizeof(umid));
  51
  52         umid_is_random = is_random;
  53         umid_inited = 1;
  54         return 0;
  55 }
  56
  57 static int __init set_umid_arg(char *name, int *add)
  58 {
  59         *add = 0;
  60         return(set_umid(name, 0, printf));
  61 }
  62
  63 __uml_setup("umid=", set_umid_arg,
  64 "umid=<name>\n"
  65 "    This is used to assign a unique identity to this UML machine and\n"
  66 "    is used for naming the pid file and management console socket.\n\n"
  67 );
  68
  69 int __init umid_file_name(char *name, char *buf, int len)
  70 {
  71         int n;
  72
  73         if(!umid_inited && make_umid(printk)) return(-1);
  74
  75         n = strlen(uml_dir) + strlen(umid) + strlen(name) + 1;
  76         if(n > len){
  77                 printk("umid_file_name : buffer too short\n");
  78                 return(-1);
  79         }
  80
  81         sprintf(buf, "%s%s/%s", uml_dir, umid, name);
  82         return(0);
  83 }
  84
  85 extern int tracing_pid;
  86
  87 static void __init create_pid_file(void)
  88 {
  89         char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
  90         char pid[sizeof("nnnnn\0")];
  91         int fd, n;
  92
  93         if(umid_file_name("pid", file, sizeof(file)))
  94                 return;
  95
  96         fd = os_open_file(file, of_create(of_excl(of_rdwr(OPENFLAGS()))),
  97                           0644);
  98         if(fd < 0){
  99                 printf("Open of machine pid file \"%s\" failed: %s\n",
 100                        file, strerror(-fd));
 101                 return;
 102         }
 103
 104         sprintf(pid, "%d\n", os_getpid());
 105         n = os_write_file(fd, pid, strlen(pid));
 106         if(n != strlen(pid))
 107                 printf("Write of pid file failed - err = %d\n", -n);
 108         os_close_file(fd);
 109 }
 110
 111 static int actually_do_remove(char *dir)
 112 {
 113         DIR *directory;
 114         struct dirent *ent;
 115         int len;
 116         char file[256];
 117
 118         directory = opendir(dir);
 119         if(directory == NULL){
 120                 printk("actually_do_remove : couldn't open directory '%s', "
 121                        "errno = %d\n", dir, errno);
 122                 return(1);
 123         }
 124         while((ent = readdir(directory)) != NULL){
 125                 if(!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
 126                         continue;
 127                 len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
 128                 if(len > sizeof(file)){
 129                         printk("Not deleting '%s' from '%s' - name too long\n",
 130                                ent->d_name, dir);
 131                         continue;
 132                 }
 133                 sprintf(file, "%s/%s", dir, ent->d_name);
 134                 if(unlink(file) < 0){
 135                         printk("actually_do_remove : couldn't remove '%s' "
 136                                "from '%s', errno = %d\n", ent->d_name, dir,
 137                                errno);
 138                         return(1);
 139                 }
 140         }
 141         if(rmdir(dir) < 0){
 142                 printk("actually_do_remove : couldn't rmdir '%s', "
 143                        "errno = %d\n", dir, errno);
 144                 return(1);
 145         }
 146         return(0);
 147 }
 148
 149 void remove_umid_dir(void)
 150 {
 151         char dir[strlen(uml_dir) + UMID_LEN + 1];
 152         if (!umid_owned)
 153                 return;
 154
 155         sprintf(dir, "%s%s", uml_dir, umid);
 156         actually_do_remove(dir);
 157 }
 158
 159 char *get_umid(int only_if_set)
 160 {
 161         if(only_if_set && umid_is_random)
 162                 return NULL;
 163         return umid;
 164 }
 165
 166 static int not_dead_yet(char *dir)
 167 {
 168         char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
 169         char pid[sizeof("nnnnn\0")], *end;
 170         int dead, fd, p, n;
 171
 172         sprintf(file, "%s/pid", dir);
 173         dead = 0;
 174         fd = os_open_file(file, of_read(OPENFLAGS()), 0);
 175         if(fd < 0){
 176                 if(fd != -ENOENT){
 177                         printk("not_dead_yet : couldn't open pid file '%s', "
 178                                "err = %d\n", file, -fd);
 179                         return(1);
 180                 }
 181                 dead = 1;
 182         }
 183         if(fd > 0){
 184                 n = os_read_file(fd, pid, sizeof(pid));
 185                 if(n < 0){
 186                         printk("not_dead_yet : couldn't read pid file '%s', "
 187                                "err = %d\n", file, -n);
 188                         return(1);
 189                 }
 190                 p = strtoul(pid, &end, 0);
 191                 if(end == pid){
 192                         printk("not_dead_yet : couldn't parse pid file '%s', "
 193                                "errno = %d\n", file, errno);
 194                         dead = 1;
 195                 }
 196                 if(((kill(p, 0) < 0) && (errno == ESRCH)) ||
 197                    (p == CHOOSE_MODE(tracing_pid, os_getpid())))
 198                         dead = 1;
 199         }
 200         if(!dead)
 201                 return(1);
 202         return(actually_do_remove(dir));
 203 }
 204
 205 static int __init set_uml_dir(char *name, int *add)
 206 {
 207         if((strlen(name) > 0) && (name[strlen(name) - 1] != '/')){
 208                 uml_dir = malloc(strlen(name) + 2);
 209                 if(uml_dir == NULL){
 210                         printf("Failed to malloc uml_dir - error = %d\n",
 211                                errno);
 212                         uml_dir = name;
 213                         /* Return 0 here because do_initcalls doesn't look at
 214                          * the return value.
 215                          */
 216                         return(0);
 217                 }
 218                 sprintf(uml_dir, "%s/", name);
 219         }
 220         else uml_dir = name;
 221         return(0);
 222 }
 223
 224 static int __init make_uml_dir(void)
 225 {
 226         char dir[MAXPATHLEN + 1] = { '\0' };
 227         int len;
 228
 229         if(*uml_dir == '~'){
 230                 char *home = getenv("HOME");
 231
 232                 if(home == NULL){
 233                         printf("make_uml_dir : no value in environment for "
 234                                "$HOME\n");
 235                         exit(1);
 236                 }
 237                 strlcpy(dir, home, sizeof(dir));
 238                 uml_dir++;
 239         }
 240         strlcat(dir, uml_dir, sizeof(dir));
 241         len = strlen(dir);
 242         if (len > 0 && dir[len - 1] != '/')
 243                 strlcat(dir, "/", sizeof(dir));
 244
 245         uml_dir = malloc(strlen(dir) + 1);
 246         if (uml_dir == NULL) {
 247                 printf("make_uml_dir : malloc failed, errno = %d\n", errno);
 248                 exit(1);
 249         }
 250         strcpy(uml_dir, dir);
 251
 252         if((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)){
 253                 printf("Failed to mkdir %s: %s\n", uml_dir, strerror(errno));
 254                 return(-1);
 255         }
 256         return 0;
 257 }
 258
 259 static int __init make_umid(int (*printer)(const char *fmt, ...))
 260 {
 261         int fd, err;
 262         char tmp[strlen(uml_dir) + UMID_LEN + 1];
 263
 264         strlcpy(tmp, uml_dir, sizeof(tmp));
 265
 266         if(!umid_inited){
 267                 strcat(tmp, "XXXXXX");
 268                 fd = mkstemp(tmp);
 269                 if(fd < 0){
 270                         (*printer)("make_umid - mkstemp(%s) failed: %s\n",
 271                                    tmp,strerror(errno));
 272                         return(1);
 273                 }
 274
 275                 os_close_file(fd);
 276                 /* There's a nice tiny little race between this unlink and
 277                  * the mkdir below.  It'd be nice if there were a mkstemp
 278                  * for directories.
 279                  */
 280                 unlink(tmp);
 281                 set_umid(&tmp[strlen(uml_dir)], 1, printer);
 282         }
 283
 284         sprintf(tmp, "%s%s", uml_dir, umid);
 285
 286         err = mkdir(tmp, 0777);
 287         if(err < 0){
 288                 if(errno == EEXIST){
 289                         if(not_dead_yet(tmp)){
 290                                 (*printer)("umid '%s' is in use\n", umid);
 291                                 umid_owned = 0;
 292                                 return(-1);
 293                         }
 294                         err = mkdir(tmp, 0777);
 295                 }
 296         }
 297         if(err < 0){
 298                 (*printer)("Failed to create %s - errno = %d\n", umid, errno);
 299                 return(-1);
 300         }
 301
 302         umid_owned = 1;
 303         return 0;
 304 }
 305
 306 __uml_setup("uml_dir=", set_uml_dir,
 307 "uml_dir=<directory>\n"
 308 "    The location to place the pid and umid files.\n\n"
 309 );
 310
 311 static int __init make_umid_setup(void)
 312 {
 313         /* one function with the ordering we need ... */
 314         make_uml_dir();
 315         make_umid(printf);
 316         create_pid_file();
 317         return 0;
 318 }
 319 __uml_postsetup(make_umid_setup);
 320
 321 /*
 322  * Overrides for Emacs so that we follow Linus's tabbing style.
 323  * Emacs will notice this stuff at the end of the file and automatically
 324  * adjust the settings for this buffer only.  This must remain at the end
 325  * of the file.
 326  * ---------------------------------------------------------------------------
 327  * Local variables:
 328  * c-file-style: "linux"
 329  * End:
 330  */