10 #include <sys/param.h>
15 #define UML_DIR "~/.uml/"
19 /* Changed by set_umid, which is run early in boot */
20 static char umid[UMID_LEN] = { 0 };
22 /* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
23 static char *uml_dir = UML_DIR;
25 static int __init make_uml_dir(void)
27 char dir[512] = { '\0' };
31 char *home = getenv("HOME");
35 printk("make_uml_dir : no value in environment for "
39 strlcpy(dir, home, sizeof(dir));
42 strlcat(dir, uml_dir, sizeof(dir));
44 if (len > 0 && dir[len - 1] != '/')
45 strlcat(dir, "/", sizeof(dir));
48 uml_dir = malloc(strlen(dir) + 1);
49 if (uml_dir == NULL) {
50 printf("make_uml_dir : malloc failed, errno = %d\n", errno);
55 if((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)){
56 printf("Failed to mkdir '%s': %s\n", uml_dir, strerror(errno));
70 * Unlinks the files contained in @dir and then removes @dir.
71 * Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
72 * ignore ENOENT errors for anything (they happen, strangely enough - possibly due
73 * to races between multiple dying UML threads).
75 static int remove_files_and_dir(char *dir)
83 directory = opendir(dir);
84 if (directory == NULL) {
91 while ((ent = readdir(directory)) != NULL) {
92 if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
94 len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
95 if (len > sizeof(file)) {
100 sprintf(file, "%s/%s", dir, ent->d_name);
101 if (unlink(file) < 0 && errno != ENOENT) {
107 if (rmdir(dir) < 0 && errno != ENOENT) {
118 /* This says that there isn't already a user of the specified directory even if
119 * there are errors during the checking. This is because if these errors
120 * happen, the directory is unusable by the pre-existing UML, so we might as
121 * well take it over. This could happen either by
122 * the existing UML somehow corrupting its umid directory
123 * something other than UML sticking stuff in the directory
124 * this boot racing with a shutdown of the other UML
125 * In any of these cases, the directory isn't useful for anything else.
127 * Boolean return: 1 if in use, 0 otherwise.
129 static inline int is_umdir_used(char *dir)
131 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
132 char pid[sizeof("nnnnn\0")], *end;
133 int dead, fd, p, n, err;
135 n = snprintf(file, sizeof(file), "%s/pid", dir);
136 if(n >= sizeof(file)){
137 printk("is_umdir_used - pid filename too long\n");
143 fd = open(file, O_RDONLY);
147 printk("is_umdir_used : couldn't open pid file '%s', "
148 "err = %d\n", file, -fd);
154 n = read(fd, pid, sizeof(pid));
156 printk("is_umdir_used : couldn't read pid file '%s', "
157 "err = %d\n", file, errno);
160 printk("is_umdir_used : couldn't read pid file '%s', "
161 "0-byte read\n", file);
165 p = strtoul(pid, &end, 0);
167 printk("is_umdir_used : couldn't parse pid file '%s', "
168 "errno = %d\n", file, errno);
172 if((kill(p, 0) == 0) || (errno != ESRCH)){
173 printk("umid \"%s\" is already in use by pid %d\n", umid, p);
184 * Try to remove the directory @dir unless it's in use.
185 * Precondition: @dir exists.
186 * Returns 0 for success, < 0 for failure in removal or if the directory is in
189 static int umdir_take_if_dead(char *dir)
192 if (is_umdir_used(dir))
195 ret = remove_files_and_dir(dir);
197 printk("is_umdir_used - remove_files_and_dir failed with "
203 static void __init create_pid_file(void)
205 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
206 char pid[sizeof("nnnnn\0")];
209 if(umid_file_name("pid", file, sizeof(file)))
212 fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0644);
214 printk("Open of machine pid file \"%s\" failed: %s\n",
215 file, strerror(errno));
219 snprintf(pid, sizeof(pid), "%d\n", getpid());
220 n = write(fd, pid, strlen(pid));
222 printk("Write of pid file failed - err = %d\n", errno);
227 int __init set_umid(char *name)
229 if(strlen(name) > UMID_LEN - 1)
232 strlcpy(umid, name, sizeof(umid));
237 /* Changed in make_umid, which is called during early boot */
238 static int umid_setup = 0;
240 int __init make_umid(void)
251 strlcpy(tmp, uml_dir, sizeof(tmp));
252 strlcat(tmp, "XXXXXX", sizeof(tmp));
255 printk("make_umid - mkstemp(%s) failed: %s\n",
256 tmp, strerror(errno));
263 set_umid(&tmp[strlen(uml_dir)]);
265 /* There's a nice tiny little race between this unlink and
266 * the mkdir below. It'd be nice if there were a mkstemp
275 snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
276 err = mkdir(tmp, 0777);
282 if (umdir_take_if_dead(tmp) < 0)
285 err = mkdir(tmp, 0777);
289 printk("Failed to create '%s' - err = %d\n", umid, -errno);
302 static int __init make_umid_init(void)
307 /* If initializing with the given umid failed, then try again with
310 printk("Failed to initialize umid \"%s\", trying with a random umid\n",
318 __initcall(make_umid_init);
320 int __init umid_file_name(char *name, char *buf, int len)
328 n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
330 printk("umid_file_name : buffer too short\n");
342 static int __init set_uml_dir(char *name, int *add)
345 printf("uml_dir can't be an empty string\n");
349 if(name[strlen(name) - 1] == '/'){
354 uml_dir = malloc(strlen(name) + 2);
356 printf("Failed to malloc uml_dir - error = %d\n", errno);
358 /* Return 0 here because do_initcalls doesn't look at
363 sprintf(uml_dir, "%s/", name);
368 __uml_setup("uml_dir=", set_uml_dir,
369 "uml_dir=<directory>\n"
370 " The location to place the pid and umid files.\n\n"
373 static void remove_umid_dir(void)
375 char dir[strlen(uml_dir) + UMID_LEN + 1], err;
377 sprintf(dir, "%s%s", uml_dir, umid);
378 err = remove_files_and_dir(dir);
380 printf("remove_umid_dir - remove_files_and_dir failed with "
384 __uml_exitcall(remove_umid_dir);