4 files changed, 41 insertions, 10 deletions
diff --git a/src/libs6/deps-exe/s6lockd-helper b/src/libs6/deps-exe/s6lockd-helper
index e7187fe..0176a41 100755
--- a/src/libs6/deps-exe/s6lockd-helper
+++ b/src/libs6/deps-exe/s6lockd-helper
@@ -1 +1,2 @@
+libs6lockd.a.xyzzy
 -lskarnet
diff --git a/src/libs6/deps-lib/s6lockd b/src/libs6/deps-lib/s6lockd
new file mode 100644
index 0000000..22cea80
--- /dev/null
+++ b/src/libs6/deps-lib/s6lockd
@@ -0,0 +1 @@
+s6lockd_openandlock.o
diff --git a/src/libs6/s6lockd-helper.c b/src/libs6/s6lockd-helper.c
index 469a417..8dbf255 100644
--- a/src/libs6/s6lockd-helper.c
+++ b/src/libs6/s6lockd-helper.c
@@ -1,25 +1,19 @@
 /* ISC license. */
 
-#include <errno.h>
-
 #include <skalibs/allreadwrite.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/djbunix.h>
 
-#define USAGE "s6lockd-helper lockfile"
+#include "s6lockd.h"
+
+#define USAGE "s6lockd-helper r|w lockfile"
 #define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv)
 {
-  int fd, r ;
   char c ;
   PROG = "s6lockd-helper" ;
   if (argc < 3) dieusage() ;
-  fd = open_create(argv[2]) ;
-  if (fd < 0) strerr_diefu2sys(111, "open ", argv[1]) ;
-  r = fd_lock(fd, argv[1][0] == 'w', 0) ;
-  if (!r) errno = EBUSY ;
-  if (r < 1) strerr_diefu2sys(111, "lock ", argv[2]) ;
+  s6lockd_openandlock(argv[2], argv[1][0] == 'w', 0) ;
   if (fd_write(1, "!", 1) <= 0)
     strerr_diefu1sys(111, "write to stdout") ;
   if (fd_read(0, &c, 1) < 0)
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 ;
+}