Also allow shared locks in s6lockd-helper

1 files changed, 35 insertions, 0 deletions

diff --git a/src/libs6/s6lockd_openandlock.c b/src/libs6/s6lockd_openandlock.c
new file mode 100644
index 0000000..42c3ca6
--- /dev/null
+++ b/src/libs6/s6lockd_openandlock.c
@@ -0,0 +1,35 @@
+/* ISC license. */
+
+#include <errno.h>
+
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#include "s6lockd.h"
+
+int s6lockd_openandlock (char const *file, int ex, int nb)
+{
+  int fd, r ;
+  if (ex)
+  {
+    fd = open_create(file) ;
+    if (fd < 0) strerr_diefu3sys(111, "open ", file, " for writing") ;
+  }
+  else
+  {
+    fd = open_read(file) ;
+    if (fd < 0)
+    {
+      if (errno != ENOENT) strerr_diefu3sys(111, "open ", file, " for reading") ;
+      fd = open_create(file) ;
+      if (fd < 0) strerr_diefu2sys(111, "create ", file) ;
+      fd_close(fd) ;
+      fd = open_read(file) ;
+      if (fd < 0) strerr_diefu3sys(111, "open ", file, " for reading") ;
+    }
+  }
+  r = fd_lock(fd, ex, nb) ;
+  if (!r) errno = EBUSY ;
+  if (r < 1) strerr_diefu2sys(1, "lock ", file) ;
+  return fd ;
+}