10 #include <sys/param.h>
16 #define UML_DIR "~/.uml/"
20 /* Changed by set_umid, which is run early in boot */
21 static 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));
71 * Unlinks the files contained in @dir and then removes @dir.
72 * Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
73 * ignore ENOENT errors for anything (they happen, strangely enough - possibly due
74 * to races between multiple dying UML threads).
76 static int remove_files_and_dir(char *dir)
84 directory = opendir(dir);
85 if (directory == NULL) {
92 while ((ent = readdir(directory)) != NULL) {
93 if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
95 len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
96 if (len > sizeof(file)) {
101 sprintf(file, "%s/%s", dir, ent->d_name);
102 if (unlink(file) < 0 && errno != ENOENT) {
108 if (rmdir(dir) < 0 && errno != ENOENT) {
119 /* This says that there isn't already a user of the specified directory even if
120 * there are errors during the checking. This is because if these errors
121 * happen, the directory is unusable by the pre-existing UML, so we might as
122 * well take it over. This could happen either by
123 * the existing UML somehow corrupting its umid directory
124 * something other than UML sticking stuff in the directory
125 * this boot racing with a shutdown of the other UML
126 * In any of these cases, the directory isn't useful for anything else.
128 * Boolean return: 1 if in use, 0 otherwise.
130 static inline int is_umdir_used(char *dir)
132 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
133 char pid[sizeof("nnnnn\0")], *end;
134 int dead, fd, p, n, err;
136 n = snprintf(file, sizeof(file), "%s/pid", dir);
137 if(n >= sizeof(file)){
138 printk("is_umdir_used - pid filename too long\n");
144 fd = open(file, O_RDONLY);
148 printk("is_umdir_used : couldn't open pid file '%s', "
149 "err = %d\n", file, -fd);
155 n = read(fd, pid, sizeof(pid));
157 printk("is_umdir_used : couldn't read pid file '%s', "
158 "err = %d\n", file, errno);
161 printk("is_umdir_used : couldn't read pid file '%s', "
162 "0-byte read\n", file);
166 p = strtoul(pid, &end, 0);
168 printk("is_umdir_used : couldn't parse pid file '%s', "
169 "errno = %d\n", file, errno);
173 if((kill(p, 0) == 0) || (errno != ESRCH)){
174 printk("umid \"%s\" is already in use by pid %d\n", umid, p);
185 * Try to remove the directory @dir unless it's in use.
186 * Precondition: @dir exists.
187 * Returns 0 for success, < 0 for failure in removal or if the directory is in
190 static int umdir_take_if_dead(char *dir)
193 if (is_umdir_used(dir))
196 ret = remove_files_and_dir(dir);
198 printk("is_umdir_used - remove_files_and_dir failed with "
204 static void __init create_pid_file(void)
206 char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
207 char pid[sizeof("nnnnn\0")];
210 if(umid_file_name("pid", file, sizeof(file)))
213 fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0644);
215 printk("Open of machine pid file \"%s\" failed: %s\n",
216 file, strerror(errno));
220 snprintf(pid, sizeof(pid), "%d\n", getpid());
221 n = write(fd, pid, strlen(pid));
223 printk("Write of pid file failed - err = %d\n", errno);
228 int __init set_umid(char *name)
230 if(strlen(name) > UMID_LEN - 1)
233 strlcpy(umid, name, sizeof(umid));
238 /* Changed in make_umid, which is called during early boot */
239 static int umid_setup = 0;
241 int __init make_umid(void)
252 strlcpy(tmp, uml_dir, sizeof(tmp));
253 strlcat(tmp, "XXXXXX", sizeof(tmp));
256 printk("make_umid - mkstemp(%s) failed: %s\n",
257 tmp, strerror(errno));
264 set_umid(&tmp[strlen(uml_dir)]);
266 /* There's a nice tiny little race between this unlink and
267 * the mkdir below. It'd be nice if there were a mkstemp
276 snprintf(tmp, sizeof(tmp), "%s%s", uml_dir, umid);
277 err = mkdir(tmp, 0777);
283 if (umdir_take_if_dead(tmp) < 0)
286 err = mkdir(tmp, 0777);
290 printk("Failed to create '%s' - err = %d\n", umid, -errno);
303 static int __init make_umid_init(void)
308 /* If initializing with the given umid failed, then try again with
311 printk("Failed to initialize umid \"%s\", trying with a random umid\n",
319 __initcall(make_umid_init);
321 int __init umid_file_name(char *name, char *buf, int len)
329 n = snprintf(buf, len, "%s%s/%s", uml_dir, umid, name);
331 printk("umid_file_name : buffer too short\n");
343 static int __init set_uml_dir(char *name, int *add)
346 printf("uml_dir can't be an empty string\n");
350 if(name[strlen(name) - 1] == '/'){
355 uml_dir = malloc(strlen(name) + 2);
357 printf("Failed to malloc uml_dir - error = %d\n", errno);
359 /* Return 0 here because do_initcalls doesn't look at
364 sprintf(uml_dir, "%s/", name);
369 __uml_setup("uml_dir=", set_uml_dir,
370 "uml_dir=<directory>\n"
371 " The location to place the pid and umid files.\n\n"
374 static void remove_umid_dir(void)
376 char dir[strlen(uml_dir) + UMID_LEN + 1], err;
378 sprintf(dir, "%s%s", uml_dir, umid);
379 err = remove_files_and_dir(dir);
381 printf("remove_umid_dir - remove_files_and_dir failed with "
385 __uml_exitcall(remove_umid_dir);