10 #include <sys/param.h>
16 #define UML_DIR "~/.uml/"
20 /* Changed by set_umid, which is run early in boot */
21 char umid[UMID_LEN] = { 0 };
23 /* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
24 static char *uml_dir = UML_DIR;
26 static int __init make_uml_dir(void)
28 char dir[512] = { '\0' };
32 char *home = getenv("HOME");
36 printk("make_uml_dir : no value in environment for "
40 strlcpy(dir, home, sizeof(dir));
43 strlcat(dir, uml_dir, sizeof(dir));
45 if (len > 0 && dir[len - 1] != '/')
46 strlcat(dir, "/", sizeof(dir));
49 uml_dir = malloc(strlen(dir) + 1);
50 if (uml_dir == NULL) {
51 printf("make_uml_dir : malloc failed, errno = %d\n", errno);
56 if((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)){
57 printf("Failed to mkdir '%s': %s\n", uml_dir, strerror(errno));
70 static int actually_do_remove(char *dir)
77 directory = opendir(dir);
81 while((ent = readdir(directory)) != NULL){
82 if(!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
84 len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
85 if(len > sizeof(file))
88 sprintf(file, "%s/%s", dir, ent->d_name);
98 /* This says that there isn't already a user of the specified directory even if
99 * there are errors during the checking. This is because if these errors
100 * happen, the directory is unusable by the pre-existing UML, so we might as
101 * well take it over. This could happen either by
102 * the existing UML somehow corrupting its umid directory
103 * something other than UML sticking stuff in the directory
104 * this boot racing with a shutdown of the other UML
105 * In any of these cases, the directory isn't useful for anything else.
107 * Boolean return: 1 if in use, 0 otherwise.
109 static inline int is_umdir_used(char *dir)
111 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
112 char pid[sizeof("nnnnn\0")], *end;
113 int dead, fd, p, n, err;
115 n = snprintf(file, sizeof(file), "%s/pid", dir);
116 if(n >= sizeof(file)){
117 printk("is_umdir_used - pid filename too long\n");
123 fd = open(file, O_RDONLY);
127 printk("is_umdir_used : couldn't open pid file '%s', "
128 "err = %d\n", file, -fd);
134 n = read(fd, pid, sizeof(pid));
136 printk("is_umdir_used : couldn't read pid file '%s', "
137 "err = %d\n", file, errno);
140 printk("is_umdir_used : couldn't read pid file '%s', "
141 "0-byte read\n", file);
145 p = strtoul(pid, &end, 0);
147 printk("is_umdir_used : couldn't parse pid file '%s', "
148 "errno = %d\n", file, errno);
152 if((kill(p, 0) == 0) || (errno != ESRCH)){
153 printk("umid \"%s\" is already in use by pid %d\n", umid, p);
164 * Try to remove the directory @dir unless it's in use.
165 * Precondition: @dir exists.
166 * Returns 0 for success, < 0 for failure in removal or if the directory is in
169 static int umdir_take_if_dead(char *dir)
172 if (is_umdir_used(dir))
175 ret = actually_do_remove(dir);
177 printk("is_umdir_used - actually_do_remove failed with "
183 static void __init create_pid_file(void)
185 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
186 char pid[sizeof("nnnnn\0")];
189 if(umid_file_name("pid", file, sizeof(file)))
192 fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0644);
194 printk("Open of machine pid file \"%s\" failed: %s\n",
195 file, strerror(errno));
199 snprintf(pid, sizeof(pid), "%d\n", getpid());
200 n = write(fd, pid, strlen(pid));
202 printk("Write of pid file failed - err = %d\n", errno);
207 int __init set_umid(char *name)
209 if(strlen(name) > UMID_LEN - 1)
212 strlcpy(umid, name, sizeof(umid));
217 static int umid_setup = 0;
219 int __init make_umid(void)
230 strlcpy(tmp, uml_dir, sizeof(tmp));
231 strlcat(tmp, "XXXXXX", sizeof(tmp));
234 printk("make_umid - mkstemp(%s) failed: %s\n",
235 tmp, strerror(errno));
242 set_umid(&tmp[strlen(uml_dir)]);
244 /* There's a nice tiny little race between this unlink and
245 * the mkdir below. It'd be nice if there were a mkstemp
254 snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
255 err = mkdir(tmp, 0777);
261 if (umdir_take_if_dead(tmp) < 0)
264 err = mkdir(tmp, 0777);
268 printk("Failed to create '%s' - err = %d\n", umid, -errno);
281 static int __init make_umid_init(void)
286 /* If initializing with the given umid failed, then try again with
289 printk("Failed to initialize umid \"%s\", trying with a random umid\n",
297 __initcall(make_umid_init);
299 int __init umid_file_name(char *name, char *buf, int len)
307 n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
309 printk("umid_file_name : buffer too short\n");
321 static int __init set_uml_dir(char *name, int *add)
324 printf("uml_dir can't be an empty string\n");
328 if(name[strlen(name) - 1] == '/'){
333 uml_dir = malloc(strlen(name) + 2);
335 printf("Failed to malloc uml_dir - error = %d\n", errno);
337 /* Return 0 here because do_initcalls doesn't look at
342 sprintf(uml_dir, "%s/", name);
347 __uml_setup("uml_dir=", set_uml_dir,
348 "uml_dir=<directory>\n"
349 " The location to place the pid and umid files.\n\n"
352 static void remove_umid_dir(void)
354 char dir[strlen(uml_dir) + UMID_LEN + 1], err;
356 sprintf(dir, "%s%s", uml_dir, umid);
357 err = actually_do_remove(dir);
359 printf("remove_umid_dir - actually_do_remove failed with "
363 __uml_exitcall(remove_umid_dir);