From 95157aa7d44750e248665744518f453ec65e2636 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Tue, 4 May 2021 12:16:18 +0000
Subject:  Also allow shared locks in s6lockd-helper

---
 src/daemontools-extras/deps-exe/s6-setlock |  1 +
 src/daemontools-extras/s6-setlock.c        | 27 ++---------------------
 src/include-local/s6lockd.h                |  8 +++++++
 src/libs6/deps-exe/s6lockd-helper          |  1 +
 src/libs6/deps-lib/s6lockd                 |  1 +
 src/libs6/s6lockd-helper.c                 | 14 ++++--------
 src/libs6/s6lockd_openandlock.c            | 35 ++++++++++++++++++++++++++++++
 7 files changed, 52 insertions(+), 35 deletions(-)
 create mode 100644 src/include-local/s6lockd.h
 create mode 100644 src/libs6/deps-lib/s6lockd
 create mode 100644 src/libs6/s6lockd_openandlock.c

(limited to 'src')

diff --git a/src/daemontools-extras/deps-exe/s6-setlock b/src/daemontools-extras/deps-exe/s6-setlock
index 756dcc2..9bb3918 100644
--- a/src/daemontools-extras/deps-exe/s6-setlock
+++ b/src/daemontools-extras/deps-exe/s6-setlock
@@ -1,3 +1,4 @@
+libs6lockd.a.xyzzy
 -lskarnet
 ${SYSCLOCK_LIB}
 ${SPAWN_LIB}
diff --git a/src/daemontools-extras/s6-setlock.c b/src/daemontools-extras/s6-setlock.c
index 6ba2ec8..6497600 100644
--- a/src/daemontools-extras/s6-setlock.c
+++ b/src/daemontools-extras/s6-setlock.c
@@ -14,6 +14,7 @@
 #include <skalibs/exec.h>
 
 #include <s6/config.h>
+#include "s6lockd.h"
 
 #define USAGE "s6-setlock [ -r | -w ] [ -n | -N | -t timeout ] lockfile prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
@@ -40,31 +41,7 @@ int main (int argc, char const *const *argv)
   argc -= subgetopt_here.ind ; argv += subgetopt_here.ind ;
   if (argc < 2) dieusage() ;
 
-  if (nb < 2)
-  {
-    int r, fd ;
-    if (ex)
-    {
-      fd = open_create(argv[0]) ;
-      if (fd < 0) strerr_diefu3sys(111, "open ", argv[0], " for writing") ;
-    }
-    else
-    {
-      fd = open_read(argv[0]) ;
-      if (fd < 0)
-      {
-        if (errno != ENOENT) strerr_diefu3sys(111, "open ", argv[0], " for reading") ;
-        fd = open_create(argv[0]) ;
-        if (fd < 0) strerr_diefu2sys(111, "create ", argv[0]) ;
-        close(fd) ;
-        fd = open_read(argv[0]) ;
-        if (fd < 0) strerr_diefu3sys(111, "open ", argv[0], " for reading") ;
-      }
-    }
-    r = fd_lock(fd, ex, nb) ;
-    if (!r) errno = EBUSY ;
-    if (r < 1) strerr_diefu2sys(1, "lock ", argv[0]) ;
-  }
+  if (nb < 2) s6lockd_openandlock(argv[0], ex, nb) ;
   else
   {
     char const *cargv[4] = { "s6lockd-helper", ex ? "w" : "r", argv[0], 0 } ;
diff --git a/src/include-local/s6lockd.h b/src/include-local/s6lockd.h
new file mode 100644
index 0000000..61a23b8
--- /dev/null
+++ b/src/include-local/s6lockd.h
@@ -0,0 +1,8 @@
+/* ISC license. */
+
+#ifndef S6LOCKD_H
+#define S6LOCKD_H
+
+extern int s6lockd_openandlock (char const *, int, int) ;
+
+#endif
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 ;
+}
-- 
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