[PATCH 1/4] Remove the restriction of File I/O functions to regular files only

[Julio Guerra <guerr@julio.in>]

The major goal is being able to write advanced embedded testing functions, like:
- reading/writing to a dedicated fifo between the embedded program and the host,
  instead of using the GDB console only.
- mocking features based on host's.

Tested with https://github.com/farjump/raspberry-pi/blob/ea31c48d7c7eed27d39fb1bec2d3a1d308cb8ae7/src/semihosting/semihosting.c

Also answers to an old RFC I did on the ML: https://sourceware.org/ml/gdb/2016-07/msg00003.html

2018-04-28  Julio Guerra  <julio@farjump.io>

	* gdb/remote-fileio.c: allow using File I/O functions with special
	files.

Signed-off-by: Julio Guerra <julio@farjump.io>
---
 gdb/ChangeLog       |  5 +++++
 gdb/remote-fileio.c | 24 ------------------------
 2 files changed, 5 insertions(+), 24 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 55e640581a..a9ddac5f98 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2018-04-28  Julio Guerra  <julio@farjump.io>
+
+	* gdb/remote-fileio.c: allow using File I/O functions with special
+	files.
+
 2018-04-27  Alexandre Oliva  <aoliva@redhat.com>
 
 	* compile/compile-c-types.c (convert_int, convert_float):
diff --git a/gdb/remote-fileio.c b/gdb/remote-fileio.c
index 4c648a9c83..fa3cb15033 100644
--- a/gdb/remote-fileio.c
+++ b/gdb/remote-fileio.c
@@ -407,24 +407,6 @@ remote_fileio_func_open (char *buf)
       return;
     }
 
-  /* Check if pathname exists and is not a regular file or directory.  If so,
-     return an appropriate error code.  Same for trying to open directories
-     for writing.  */
-  if (!stat (pathname, &st))
-    {
-      if (!S_ISREG (st.st_mode) && !S_ISDIR (st.st_mode))
-	{
-	  remote_fileio_reply (-1, FILEIO_ENODEV);
-	  return;
-	}
-      if (S_ISDIR (st.st_mode)
-	  && ((flags & O_WRONLY) == O_WRONLY || (flags & O_RDWR) == O_RDWR))
-	{
-	  remote_fileio_reply (-1, FILEIO_EISDIR);
-	  return;
-	}
-    }
-
   fd = gdb_open_cloexec (pathname, flags, mode);
   if (fd < 0)
     {
@@ -885,12 +867,6 @@ remote_fileio_func_stat (char *buf)
       remote_fileio_return_errno (-1);
       return;
     }
-  /* Only operate on regular files and directories.  */
-  if (!ret && !S_ISREG (st.st_mode) && !S_ISDIR (st.st_mode))
-    {
-      remote_fileio_reply (-1, FILEIO_EACCES);
-      return;
-    }
   if (statptr)
     {
       host_to_fileio_stat (&st, &fst);
-- 
2.17.0