From FEDORA_PATCHES Mon Sep 17 00:00:00 2001

From: Keith Seitz <keiths@redhat.com>

Date: Mon, 8 Jun 2020 11:33:47 -0700

Subject: gdb-rhbz1844458-use-fputX_unfiltered.patch

;; Fix fput?_unfiltered functions

;; RH BZ 1844458 (Sergio Durigan Junior and Tom Tromey)

  From: Sergio Durigan Junior <sergiodj@redhat.com>

  Date: Wed, 19 Feb 2020 16:40:48 -0500

  Subject: [PATCH] Make '{putchar,fputc}_unfiltered' use 'fputs_unfiltered'

There is currently a regression when using

'{putchar,fputc}_unfiltered' with 'puts_unfiltered' which was

introduced by one of the commits that reworked the unfiltered print

code.

The regression makes it impossible to use '{putchar,fputc}_unfiltered'

with 'puts_unfiltered', because the former writes directly to the

ui_file stream using 'stream->write', while the latter uses a buffered

mechanism (see 'wrap_buffer') and delays the printing.

If you do a quick & dirty hack on e.g. top.c:show_gdb_datadir:

  @@ -2088,6 +2088,13 @@ static void

   show_gdb_datadir (struct ui_file *file, int from_tty,

                    struct cmd_list_element *c, const char *value)

   {

  +  putchar_unfiltered ('\n');

  +  puts_unfiltered ("TEST");

  +  putchar_unfiltered ('>');

  +  puts_unfiltered ("PUTS");

  +  puts_unfiltered ("PUTS");

  +  putchar_unfiltered ('\n');

rebuild GDB and invoke the "show data-directory" command, you will

see:

  (gdb) show data-directory

  >

  TESTPUTSGDB's data directory is "/usr/local/share/gdb".

Note how the '>' was printed before the output, and "TEST" and "PUTS"

were printed together.

My first attempt to fix this was to always call 'flush_wrap_buffer' at

the end of 'fputs_maybe_filtered', since it seemed to me that the

function should always print what was requested.  But I wasn't sure

this was the right thing to do, so I talked to Tom on IRC and he gave

me another, simpler idea: make '{putchar,fputc}_unfiltered' call into

the already existing 'fputs_unfiltered' function.

This patch implements the idea.  I regtested it on the Buildbot, and

no regressions were detected.

gdb/ChangeLog:

2020-02-20  Sergio Durigan Junior  <sergiodj@redhat.com>

            Tom Tromey  <tom@tromey.com>

        * utils.c (fputs_maybe_filtered): Call 'stream->puts' instead

        of 'fputc_unfiltered'.

        (putchar_unfiltered): Call 'fputc_unfiltered'.

        (fputc_unfiltered): Call 'fputs_unfiltered'.

diff --git a/gdb/utils.c b/gdb/utils.c

--- a/gdb/utils.c

+++ b/gdb/utils.c

@@ -1783,7 +1783,12 @@ fputs_maybe_filtered (const char *linebuffer, struct ui_file *stream,

 		     newline -- if chars_per_line is right, we

 		     probably just overflowed anyway; if it's wrong,

 		     let us keep going.  */

-		  fputc_unfiltered ('\n', stream);

+		  /* XXX: The ideal thing would be to call

+		     'stream->putc' here, but we can't because it

+		     currently calls 'fputc_unfiltered', which ends up

+		     calling us, which generates an infinite

+		     recursion.  */

+		  stream->puts ("\n");

 		}

 	      else

 		{

@@ -1828,7 +1833,12 @@ fputs_maybe_filtered (const char *linebuffer, struct ui_file *stream,

 	  wrap_here ((char *) 0);	/* Spit out chars, cancel

 					   further wraps.  */

 	  lines_printed++;

-	  fputc_unfiltered ('\n', stream);

+	  /* XXX: The ideal thing would be to call

+	     'stream->putc' here, but we can't because it

+	     currently calls 'fputc_unfiltered', which ends up

+	     calling us, which generates an infinite

+	     recursion.  */

+	  stream->puts ("\n");

 	  lineptr++;

 	}

     }

@@ -1923,10 +1933,7 @@ fputs_highlighted (const char *str, const compiled_regex &highlight,

 int

 putchar_unfiltered (int c)

 {

-  char buf = c;

-

-  ui_file_write (gdb_stdout, &buf, 1);

-  return c;

+  return fputc_unfiltered (c, gdb_stdout);

 }

 /* Write character C to gdb_stdout using GDB's paging mechanism and return C.

@@ -1941,9 +1948,11 @@ putchar_filtered (int c)

 int

 fputc_unfiltered (int c, struct ui_file *stream)

 {

-  char buf = c;

+  char buf[2];

-  ui_file_write (stream, &buf, 1);

+  buf[0] = c;

+  buf[1] = 0;

+  fputs_unfiltered (buf, stream);

   return c;

 }