Replace suffix with prefix

1 files changed, 20 insertions, 0 deletions

diff --git a/src/libs6rc/s6rc_livedir_prefix.c b/src/libs6rc/s6rc_livedir_prefix.c
new file mode 100644
index 0000000..18a95fe
--- /dev/null
+++ b/src/libs6rc/s6rc_livedir_prefix.c
@@ -0,0 +1,20 @@
+/* ISC license. */
+
+#include <string.h>
+#include <errno.h>
+#include <skalibs/djbunix.h>
+#include <s6-rc/s6rc-utils.h>
+
+ssize_t s6rc_livedir_prefix (char const *live, char *s, size_t n)
+{
+  size_t llen = strlen(live) ;
+  size_t r ;
+  char sfn[llen + 8] ;
+  memcpy(sfn, live, llen) ;
+  memcpy(sfn + llen, "/prefix", 8) ;
+  r = openreadnclose(sfn, s, n) ;
+  if (r < 0) return r ;
+  if (memchr(s, '/', r) || memchr(s, '\n', r))
+    return (errno = EINVAL, -1) ;
+  return r ;
+}