#define UMID_LEN 64
/* Changed by set_umid, which is run early in boot */
-char umid[UMID_LEN] = { 0 };
+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;
return err;
}
-static int actually_do_remove(char *dir)
+/*
+ * Unlinks the files contained in @dir and then removes @dir.
+ * Doesn't handle directory trees, so it's not like rm -rf, but almost such. We
+ * ignore ENOENT errors for anything (they happen, strangely enough - possibly due
+ * to races between multiple dying UML threads).
+ */
+static int remove_files_and_dir(char *dir)
{
DIR *directory;
struct dirent *ent;
int len;
char file[256];
+ int ret;
directory = opendir(dir);
- if(directory == NULL)
- return -errno;
+ if (directory == NULL) {
+ if (errno != ENOENT)
+ return -errno;
+ else
+ return 0;
+ }
- while((ent = readdir(directory)) != NULL){
- if(!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
+ 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))
- return -E2BIG;
+ if (len > sizeof(file)) {
+ ret = -E2BIG;
+ goto out;
+ }
sprintf(file, "%s/%s", dir, ent->d_name);
- if(unlink(file) < 0)
- return -errno;
+ if (unlink(file) < 0 && errno != ENOENT) {
+ ret = -errno;
+ goto out;
+ }
}
- if(rmdir(dir) < 0)
- return -errno;
- return 0;
+ if (rmdir(dir) < 0 && errno != ENOENT) {
+ ret = -errno;
+ goto out;
+ }
+
+ ret = 0;
+out:
+ closedir(directory);
+ return ret;
}
/* This says that there isn't already a user of the specified directory even if
* something other than UML sticking stuff in the directory
* this boot racing with a shutdown of the other UML
* In any of these cases, the directory isn't useful for anything else.
+ *
+ * Boolean return: 1 if in use, 0 otherwise.
*/
-
-static int not_dead_yet(char *dir)
+static inline int is_umdir_used(char *dir)
{
char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
char pid[sizeof("nnnnn\0")], *end;
n = snprintf(file, sizeof(file), "%s/pid", dir);
if(n >= sizeof(file)){
- printk("not_dead_yet - pid filename too long\n");
+ printk("is_umdir_used - pid filename too long\n");
err = -E2BIG;
goto out;
}
if(fd < 0) {
fd = -errno;
if(fd != -ENOENT){
- printk("not_dead_yet : couldn't open pid file '%s', "
+ printk("is_umdir_used : couldn't open pid file '%s', "
"err = %d\n", file, -fd);
}
goto out;
err = 0;
n = read(fd, pid, sizeof(pid));
if(n < 0){
- printk("not_dead_yet : couldn't read pid file '%s', "
+ printk("is_umdir_used : couldn't read pid file '%s', "
"err = %d\n", file, errno);
goto out_close;
} else if(n == 0){
- printk("not_dead_yet : couldn't read pid file '%s', "
+ printk("is_umdir_used : couldn't read pid file '%s', "
"0-byte read\n", file);
goto out_close;
}
p = strtoul(pid, &end, 0);
if(end == pid){
- printk("not_dead_yet : couldn't parse pid file '%s', "
+ printk("is_umdir_used : couldn't parse pid file '%s', "
"errno = %d\n", file, errno);
goto out_close;
}
return 1;
}
- err = actually_do_remove(dir);
- if(err)
- printk("not_dead_yet - actually_do_remove failed with "
- "err = %d\n", err);
-
- return err;
-
out_close:
close(fd);
out:
return 0;
}
+/*
+ * Try to remove the directory @dir unless it's in use.
+ * Precondition: @dir exists.
+ * Returns 0 for success, < 0 for failure in removal or if the directory is in
+ * use.
+ */
+static int umdir_take_if_dead(char *dir)
+{
+ int ret;
+ if (is_umdir_used(dir))
+ return -EEXIST;
+
+ ret = remove_files_and_dir(dir);
+ if (ret) {
+ printk("is_umdir_used - remove_files_and_dir failed with "
+ "err = %d\n", ret);
+ }
+ return ret;
+}
+
static void __init create_pid_file(void)
{
char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
return 0;
}
+/* Changed in make_umid, which is called during early boot */
static int umid_setup = 0;
int __init make_umid(void)
if(err != -EEXIST)
goto err;
- /* 1 -> this umid is already in use
- * < 0 -> we couldn't remove the umid directory
- * In either case, we can't use this umid, so return -EEXIST.
- */
- if(not_dead_yet(tmp) != 0)
+ if (umdir_take_if_dead(tmp) < 0)
goto err;
err = mkdir(tmp, 0777);
char dir[strlen(uml_dir) + UMID_LEN + 1], err;
sprintf(dir, "%s%s", uml_dir, umid);
- err = actually_do_remove(dir);
+ err = remove_files_and_dir(dir);
if(err)
- printf("remove_umid_dir - actually_do_remove failed with "
+ printf("remove_umid_dir - remove_files_and_dir failed with "
"err = %d\n", err);
}
git.openpandora.org / pandora-kernel.git / blobdiff