[newlib-cygwin] Cygwin: pinfo: add method to send a serialized path_conv and HANDLE

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=c76468182b18272f3e40295e85186fda3d225c66

commit c76468182b18272f3e40295e85186fda3d225c66
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Sat Jan 5 21:57:03 2019 +0100

    Cygwin: pinfo: add method to send a serialized path_conv and HANDLE
    
    To allow reopening a file open in another process by HANDLE, introduce
    a matching file_pathconv method, taking a file descriptor as parameter.
    The result is a serialized path_conv and a HANDLE value.  The HANDLE is
    valid in the foreign process and MUST be duplicated into the target
    process before usage.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/pinfo.cc | 36 +++++++++++++++++++++++++++++++++++-
 winsup/cygwin/pinfo.h  |  4 +++-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/pinfo.cc b/winsup/cygwin/pinfo.cc
index 6b6986c..00b3ed6 100644
--- a/winsup/cygwin/pinfo.cc
+++ b/winsup/cygwin/pinfo.cc
@@ -637,7 +637,7 @@ commune_process (void *arg)
       }
     case PICOM_PIPE_FHANDLER:
       {
-	sigproc_printf ("processing PICOM_FDS");
+	sigproc_printf ("processing PICOM_PIPE_FHANDLER");
 	int64_t unique_id = si._si_commune._si_pipe_unique_id;
 	unsigned int n = 0;
 	cygheap_fdenum cfd;
@@ -656,6 +656,26 @@ commune_process (void *arg)
 	  sigproc_printf ("WritePipeOverlapped sizeof hdl failed, %E");
 	break;
       }
+    case PICOM_FILE_PATHCONV:
+      {
+	sigproc_printf ("processing PICOM_FILE_PATHCONV");
+	int fd = si._si_commune._si_fd;
+	unsigned int n = 0;
+	cygheap_fdget cfd (fd);
+	if (cfd >= 0)
+	  {
+	    fhandler_base *fh = cfd;
+	    void *ser_buf = fh->pc.serialize (fh->get_handle (), n);
+	    if (!WritePipeOverlapped (tothem, &n, sizeof n, &nr, 1000L))
+	      sigproc_printf ("WritePipeOverlapped sizeof hdl failed, %E");
+	    else if (!WritePipeOverlapped (tothem, ser_buf, n, &nr, 1000L))
+	      sigproc_printf ("WritePipeOverlapped hdl failed, %E");
+	    cfree (ser_buf);
+	  }
+	else if (!WritePipeOverlapped (tothem, &n, sizeof n, &nr, 1000L))
+	  sigproc_printf ("WritePipeOverlapped sizeof hdl failed, %E");
+	break;
+      }
     case PICOM_FD:
       {
 	sigproc_printf ("processing PICOM_FD");
@@ -741,6 +761,7 @@ _pinfo::commune_request (__uint32_t code, ...)
       break;
 
     case PICOM_FD:
+    case PICOM_FILE_PATHCONV:
       si._si_commune._si_fd = va_arg (args, int);
       break;
 
@@ -773,6 +794,7 @@ _pinfo::commune_request (__uint32_t code, ...)
     case PICOM_FDS:
     case PICOM_FD:
     case PICOM_PIPE_FHANDLER:
+    case PICOM_FILE_PATHCONV:
       if (!ReadPipeOverlapped (fromthem, &n, sizeof n, &nr, 1000L)
 	  || nr != sizeof n)
 	{
@@ -829,6 +851,18 @@ _pinfo::pipe_fhandler (int64_t unique_id, size_t &n)
   return (fhandler_pipe *) cr.s;
 }
 
+void *
+_pinfo::file_pathconv (int fd, size_t &n)
+{
+  if (!pid)
+    return NULL;
+  if (pid == myself->pid)
+    return NULL;
+  commune_result cr = commune_request (PICOM_FILE_PATHCONV, fd);
+  n = cr.n;
+  return (void *) cr.s;
+}
+
 char *
 _pinfo::fd (int fd, size_t &n)
 {
diff --git a/winsup/cygwin/pinfo.h b/winsup/cygwin/pinfo.h
index aedb3d4..8eb3c43 100644
--- a/winsup/cygwin/pinfo.h
+++ b/winsup/cygwin/pinfo.h
@@ -27,7 +27,8 @@ enum picom
   PICOM_FDS = 4,
   PICOM_FD = 5,
   PICOM_PIPE_FHANDLER = 6,
-  PICOM_ENVIRON = 7
+  PICOM_FILE_PATHCONV = 7,
+  PICOM_ENVIRON = 8
 };
 
 #define EXITCODE_SET		0x8000000
@@ -102,6 +103,7 @@ public:
   commune_result commune_request (__uint32_t, ...);
   bool alive ();
   fhandler_pipe *pipe_fhandler (int64_t, size_t &);
+  void *file_pathconv (int, size_t &);
   char *fd (int fd, size_t &);
   char *fds (size_t &);
   char *root (size_t &);