nspawn: skip symlink to a combined cgroup hierarchy if it already exists

[elogind.git] / src / shared / util.c

diff --git a/src/shared/util.c b/src/shared/util.c
index 693bb1d9a4b338d68bb2f911a778cf0bbc7b67af..9b67dd8296fde6fab7ae3b862bf7ce63fc21e015 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -2766,6 +2766,28 @@ int symlink_atomic(const char *from, const char *to) {
         return 0;
 }
 
+int symlink_idempotent(const char *from, const char *to) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        assert(from);
+        assert(to);
+
+        if (symlink(from, to) < 0) {
+                if (errno != EEXIST)
+                        return -errno;
+
+                r = readlink_malloc(to, &p);
+                if (r < 0)
+                        return r;
+
+                if (!streq(p, from))
+                        return -EINVAL;
+        }
+
+        return 0;
+}
+
 int mknod_atomic(const char *path, mode_t mode, dev_t dev) {
         _cleanup_free_ char *t = NULL;
         int r;
@@ -3918,7 +3940,7 @@ bool path_is_safe(const char *p) {
         if (streq(p, "..") || startswith(p, "../") || endswith(p, "/..") || strstr(p, "/../"))
                 return false;
 
-        if (strlen(p) > PATH_MAX)
+        if (strlen(p)+1 > PATH_MAX)
                 return false;
 
         /* The following two checks are not really dangerous, but hey, they still are confusing */
@@ -4839,7 +4861,7 @@ int open_tmpfile(const char *path, int flags) {
 
 #ifdef O_TMPFILE
         /* Try O_TMPFILE first, if it is supported */
-        fd = open(path, flags|O_TMPFILE, S_IRUSR|S_IWUSR);
+        fd = open(path, flags|O_TMPFILE|O_EXCL, S_IRUSR|S_IWUSR);
         if (fd >= 0)
                 return fd;
 #endif
@@ -5683,6 +5705,9 @@ int free_and_strdup(char **p, const char *s) {
         /* Replaces a string pointer with an strdup()ed new string,
          * possibly freeing the old one. */
 
+        if (streq_ptr(*p, s))
+                return 0;
+
         if (s) {
                 t = strdup(s);
                 if (!t)
@@ -5693,7 +5718,7 @@ int free_and_strdup(char **p, const char *s) {
         free(*p);
         *p = t;
 
-        return 0;
+        return 1;
 }
 
 int sethostname_idempotent(const char *s) {
@@ -6001,128 +6026,6 @@ int read_attr_path(const char *p, unsigned *ret) {
         return read_attr_fd(fd, ret);
 }
 
-int make_lock_file(const char *p, int operation, LockFile *ret) {
-        _cleanup_close_ int fd = -1;
-        _cleanup_free_ char *t = NULL;
-        int r;
-
-        /*
-         * We use UNPOSIX locks if they are available. They have nice
-         * semantics, and are mostly compatible with NFS. However,
-         * they are only available on new kernels. When we detect we
-         * are running on an older kernel, then we fall back to good
-         * old BSD locks. They also have nice semantics, but are
-         * slightly problematic on NFS, where they are upgraded to
-         * POSIX locks, even though locally they are orthogonal to
-         * POSIX locks.
-         */
-
-        t = strdup(p);
-        if (!t)
-                return -ENOMEM;
-
-        for (;;) {
-                struct flock fl = {
-                        .l_type = (operation & ~LOCK_NB) == LOCK_EX ? F_WRLCK : F_RDLCK,
-                        .l_whence = SEEK_SET,
-                };
-                struct stat st;
-
-                fd = open(p, O_CREAT|O_RDWR|O_NOFOLLOW|O_CLOEXEC|O_NOCTTY, 0600);
-                if (fd < 0)
-                        return -errno;
-
-                r = fcntl(fd, (operation & LOCK_NB) ? F_OFD_SETLK : F_OFD_SETLKW, &fl);
-                if (r < 0) {
-
-                        /* If the kernel is too old, use good old BSD locks */
-                        if (errno == EINVAL)
-                                r = flock(fd, operation);
-
-                        if (r < 0)
-                                return errno == EAGAIN ? -EBUSY : -errno;
-                }
-
-                /* If we acquired the lock, let's check if the file
-                 * still exists in the file system. If not, then the
-                 * previous exclusive owner removed it and then closed
-                 * it. In such a case our acquired lock is worthless,
-                 * hence try again. */
-
-                r = fstat(fd, &st);
-                if (r < 0)
-                        return -errno;
-                if (st.st_nlink > 0)
-                        break;
-
-                fd = safe_close(fd);
-        }
-
-        ret->path = t;
-        ret->fd = fd;
-        ret->operation = operation;
-
-        fd = -1;
-        t = NULL;
-
-        return r;
-}
-
-int make_lock_file_for(const char *p, int operation, LockFile *ret) {
-        const char *fn;
-        char *t;
-
-        assert(p);
-        assert(ret);
-
-        fn = basename(p);
-        if (!filename_is_valid(fn))
-                return -EINVAL;
-
-        t = newa(char, strlen(p) + 2 + 4 + 1);
-        stpcpy(stpcpy(stpcpy(mempcpy(t, p, fn - p), ".#"), fn), ".lck");
-
-        return make_lock_file(t, operation, ret);
-}
-
-void release_lock_file(LockFile *f) {
-        int r;
-
-        if (!f)
-                return;
-
-        if (f->path) {
-
-                /* If we are the exclusive owner we can safely delete
-                 * the lock file itself. If we are not the exclusive
-                 * owner, we can try becoming it. */
-
-                if (f->fd >= 0 &&
-                    (f->operation & ~LOCK_NB) == LOCK_SH) {
-                        static const struct flock fl = {
-                                .l_type = F_WRLCK,
-                                .l_whence = SEEK_SET,
-                        };
-
-                        r = fcntl(f->fd, F_OFD_SETLK, &fl);
-                        if (r < 0 && errno == EINVAL)
-                                r = flock(f->fd, LOCK_EX|LOCK_NB);
-
-                        if (r >= 0)
-                                f->operation = LOCK_EX|LOCK_NB;
-                }
-
-                if ((f->operation & ~LOCK_NB) == LOCK_EX)
-                        unlink_noerrno(f->path);
-
-                free(f->path);
-                f->path = NULL;
-        }
-
-        f->fd = safe_close(f->fd);
-        f->operation = 0;
-}
-
 static size_t nul_length(const uint8_t *p, size_t sz) {
         size_t n = 0;