[newlib-cygwin] Cygwin: pipe: use /proc/PID/fd/... or /proc/self/fd/... name

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=97d2fe2694ce935bc295ad6107ce9c7de55285b8

commit 97d2fe2694ce935bc295ad6107ce9c7de55285b8
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Sat Jan 5 21:42:33 2019 +0100

    Cygwin: pipe: use /proc/PID/fd/... or /proc/self/fd/... name
    
    Don't emit /dev/fd/... filename.  This simplifies pipe path handling
    and avoids another symlink redirection.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/pipe.cc | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/winsup/cygwin/pipe.cc b/winsup/cygwin/pipe.cc
index f1eace6..a75275d 100644
--- a/winsup/cygwin/pipe.cc
+++ b/winsup/cygwin/pipe.cc
@@ -73,8 +73,15 @@ fhandler_pipe::open (int flags, mode_t mode)
   bool inh;
   bool got_one = false;
 
-  sscanf (get_name (), "/proc/%d/fd/pipe:[%lld]",
-		       &pid, (long long *) &uniq_id);
+  if (sscanf (get_name (), "/proc/self/fd/pipe:[%lld]",
+	      (long long *) &uniq_id) == 1)
+    pid = myself->pid;
+  else if (sscanf (get_name (), "/proc/%d/fd/pipe:[%lld]",
+		   &pid, (long long *) &uniq_id) < 2)
+    {
+      set_errno (ENOENT);
+      return 0;
+    }
   if (pid == myself->pid)
     {
       cygheap_fdenum cfd (true);
@@ -439,8 +446,8 @@ pipe_worker (int filedes[2], unsigned int psize, int mode)
     {
       cygheap_fdnew fdin;
       cygheap_fdnew fdout (fdin, false);
-      char buf[sizeof ("/dev/fd/pipe:[9223372036854775807]")];
-      __small_sprintf (buf, "/dev/fd/pipe:[%D]", fhs[0]->get_plain_ino ());
+      char buf[sizeof ("/proc/self/fd/pipe:[9223372036854775807]")];
+      __small_sprintf (buf, "/proc/self/fd/pipe:[%D]", fhs[0]->get_plain_ino ());
       fhs[0]->pc.set_posix (buf);
       __small_sprintf (buf, "pipe:[%D]", fhs[1]->get_plain_ino ());
       fhs[1]->pc.set_posix (buf);