Pass stderr of program run with "target remote |"

        via gdb_stderr.
        * serial.c (serial_open): Set error_fd to -1.
        * serial.h (struct serial): New field error_fd.
        (struct serial_opts): New field avail.
        * ser-pipe.c (pipe_open): Create another pair
        of sockets.  Pass stderr to gdb.
        * ser-mingw.c (pipe_windows_open): Pass
        PEX_STDERR_TO_PIPE to pex_run.  Initialize
        sd->error_fd.
        (pipe_avail): New.
        (_initialize_ser_windows): Hook pipe_avail.
        * ser-base.c (generic_readchar): Check if there's
        anything in stderr channel and route that to gdb_stderr.

1 files changed, 20 insertions, 0 deletions

diff --git a/gdb/ser-pipe.c b/gdb/ser-pipe.c
index 6b1cb52aca7..f4b11b939bf 100644
--- a/gdb/ser-pipe.c
+++ b/gdb/ser-pipe.c
@@ -62,9 +62,12 @@ pipe_open (struct serial *scb, const char *name)
    * published in UNIX Review, Vol. 6, No. 8.
    */
   int pdes[2];
+  int err_pdes[2];
   int pid;
   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
     return -1;
+  if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)
+    return -1;
 
   /* Create the child process to run the command in.  Note that the
      apparent call to vfork() below *might* actually be a call to
@@ -77,9 +80,18 @@ pipe_open (struct serial *scb, const char *name)
     {
       close (pdes[0]);
       close (pdes[1]);
+      close (err_pdes[0]);
+      close (err_pdes[1]);
       return -1;
     }
 
+  if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
+    {
+      close (err_pdes[0]);
+      close (err_pdes[1]);
+      err_pdes[0] = err_pdes[1] = -1;
+    }
+
   /* Child. */
   if (pid == 0)
     {
@@ -91,6 +103,13 @@ pipe_open (struct serial *scb, const char *name)
 	  close (pdes[1]);
 	}
       dup2 (STDOUT_FILENO, STDIN_FILENO);
+
+      if (err_pdes[0] != -1)
+	{
+	  close (err_pdes[0]);
+	  dup2 (err_pdes[1], STDERR_FILENO);
+	  close (err_pdes[1]);
+	}
 #if 0
       /* close any stray FD's - FIXME - how? */
       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
@@ -109,6 +128,7 @@ pipe_open (struct serial *scb, const char *name)
   state = XMALLOC (struct pipe_state);
   state->pid = pid;
   scb->fd = pdes[0];
+  scb->error_fd = err_pdes[0];
   scb->state = state;
 
   /* If we don't do this, GDB simply exits when the remote side dies.  */