From 65e6a29abd7413e21cc45470561e0eee2b24549e Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Mon, 26 Oct 2020 09:33:06 +0000
Subject:  Prepare for 2.9.2.1; add dangling symlink support

---
 src/libs6/s6_supervise_lock_mode.c | 44 +++++++++++++++++++++++++++++++-------
 src/libs6/s6_svc_lock_take.c       |  6 ++++--
 2 files changed, 40 insertions(+), 10 deletions(-)

(limited to 'src/libs6')

diff --git a/src/libs6/s6_supervise_lock_mode.c b/src/libs6/s6_supervise_lock_mode.c
index 039760c..710e3ba 100644
--- a/src/libs6/s6_supervise_lock_mode.c
+++ b/src/libs6/s6_supervise_lock_mode.c
@@ -1,12 +1,22 @@
 /* ISC license. */
 
+#include <limits.h>
+#include <unistd.h>
 #include <sys/stat.h>
 #include <string.h>
 #include <errno.h>
+
 #include <skalibs/strerr2.h>
 #include <skalibs/djbunix.h>
+
 #include <s6/s6-supervise.h>
 
+#ifdef PATH_MAX
+# define S6_PATH_MAX PATH_MAX
+#else
+# define S6_PATH_MAX 4096
+#endif
+
 int s6_supervise_lock_mode (char const *subdir, unsigned int subdirmode, unsigned int controlmode)
 {
   size_t subdirlen = strlen(subdir) ;
@@ -17,8 +27,28 @@ int s6_supervise_lock_mode (char const *subdir, unsigned int subdirmode, unsigne
   memcpy(control + subdirlen, "/control", 9) ;
   memcpy(lock, subdir, subdirlen) ;
   memcpy(lock + subdirlen, "/lock", 6) ;
-  if ((mkdir(subdir, (mode_t)subdirmode) == -1) && (errno != EEXIST))
-    strerr_diefu2sys(111, "mkdir ", subdir) ;
+  if (mkdir(subdir, (mode_t)subdirmode) == -1)
+  {
+    if (errno != EEXIST) strerr_diefu2sys(111, "mkdir ", subdir) ;
+    else
+    {
+      char buf[S6_PATH_MAX] ;
+      ssize_t r = readlink(subdir, buf, S6_PATH_MAX) ;
+      if (r < 0)
+      {
+        errno = EEXIST ;
+        strerr_diefu2sys(111, "mkdir ", subdir) ;
+      }
+      if (r == S6_PATH_MAX)
+      {
+        errno = ENAMETOOLONG ;
+        strerr_diefu2sys(111, "readlink ", subdir) ;
+      }
+      buf[r] = 0 ;
+      if (mkdir(buf, (mode_t)subdirmode) == -1)
+        strerr_diefu2sys(111, "mkdir ", buf) ;
+    }
+  }
   if (mkfifo(control, controlmode) < 0)
   {
     struct stat st ;
@@ -29,24 +59,22 @@ int s6_supervise_lock_mode (char const *subdir, unsigned int subdirmode, unsigne
     if (!S_ISFIFO(st.st_mode))
       strerr_diefu2x(100, control, " is not a FIFO") ;
   }
-  fdlock = open_create(lock) ;
+  fdlock = open_createcoe(lock) ;
   if (fdlock < 0)
     strerr_diefu2sys(111, "open_create ", lock) ;
   if (lock_ex(fdlock) < 0)
     strerr_diefu2sys(111, "lock ", lock) ;
-  fdctlw = open_write(control) ;
+  fdctlw = open_writecoe(control) ;
   if (fdctlw >= 0) strerr_dief1x(100, "directory already locked") ;
   if (errno != ENXIO)
     strerr_diefu2sys(111, "open_write ", control) ;
-  fdctl = open_read(control) ;
+  fdctl = open_readcoe(control) ;
   if (fdctl < 0)
     strerr_diefu2sys(111, "open_read ", control) ;
-  fdctlw = open_write(control) ;
+  fdctlw = open_writecoe(control) ;
   if (fdctlw < 0)
     strerr_diefu2sys(111, "open_write ", control) ;
   fd_close(fdlock) ;
-  if ((coe(fdctlw) < 0) || (coe(fdctl) < 0))
-    strerr_diefu2sys(111, "coe ", control) ;
 
   return fdctl ;
   /* fdctlw is leaking. That's okay, it's coe. */
diff --git a/src/libs6/s6_svc_lock_take.c b/src/libs6/s6_svc_lock_take.c
index 3dec282..a98aeab 100644
--- a/src/libs6/s6_svc_lock_take.c
+++ b/src/libs6/s6_svc_lock_take.c
@@ -6,6 +6,8 @@
 #include <skalibs/djbunix.h>
 #include <s6/s6-supervise.h>
 
+ /* XXX: does not work with dangling S6_SUPERVISE_CTLDIR symlinks */
+
 int s6_svc_lock_take (char const *dir)
 {
   size_t dirlen = strlen(dir) ;
@@ -15,9 +17,9 @@ int s6_svc_lock_take (char const *dir)
   memcpy(lock + dirlen, "/" S6_SUPERVISE_CTLDIR, sizeof(S6_SUPERVISE_CTLDIR) + 1) ;
   if ((mkdir(lock, S_IRWXU) < 0) && (errno != EEXIST)) return -1 ;
   memcpy(lock + dirlen + sizeof(S6_SUPERVISE_CTLDIR), "/lock", 6) ;
-  fdlock = open_create(lock) ;
+  fdlock = open_createcoe(lock) ;
   if (fdlock < 0) return -1 ;
-  if (coe(fdlock) < 0 || lock_ex(fdlock) < 0)
+  if (lock_ex(fdlock) < 0)
   {
     fd_close(fdlock) ;
     return -1 ;
-- 
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