From 8626589c42c3cdb9784be37fff88f631a5f25b6e Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Wed, 6 May 2009 22:54:58 +0000 Subject: [PATCH] * utils.c: Add include of gdb_usleep.h. (defaulted_query): Detect false EOF conditions that happen on terminals opened with the O_NONBLOCK flag when there is nothing to read. --- gdb/ChangeLog | 7 +++++++ gdb/utils.c | 21 +++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 21bf55d857a..e219552a8a6 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2009-05-06 Joel Brobecker + + * utils.c: Add include of gdb_usleep.h. + (defaulted_query): Detect false EOF conditions that happen + on terminals opened with the O_NONBLOCK flag when there is + nothing to read. + 2009-05-06 Pedro Alves * inferior.c (add_inferior): Move observer_notify_new_inferior diff --git a/gdb/utils.c b/gdb/utils.c index 99b0e7693c9..4396d145df7 100644 --- a/gdb/utils.c +++ b/gdb/utils.c @@ -67,6 +67,8 @@ #include #include +#include "gdb_usleep.h" + #if !HAVE_DECL_MALLOC extern PTR malloc (); /* ARI: PTR */ #endif @@ -1477,6 +1479,25 @@ defaulted_query (const char *ctlstr, const char defchar, va_list args) gdb_flush (gdb_stdout); answer = fgetc (stdin); + + /* We expect fgetc to block until a character is read. But + this may not be the case if the terminal was opened with + the NONBLOCK flag. In that case, if there is nothing to + read on stdin, fgetc returns EOF, but also sets the error + condition flag on stdin and errno to EAGAIN. With a true + EOF, stdin's error condition flag is not set. + + A situation where this behavior was observed is a pseudo + terminal on AIX. */ + while (answer == EOF && ferror (stdin) && errno == EAGAIN) + { + /* Not a real EOF. Wait a little while and try again until + we read something. */ + clearerr (stdin); + gdb_usleep (10000); + answer = fgetc (stdin); + } + clearerr (stdin); /* in case of C-d */ if (answer == EOF) /* C-d */ { -- 2.30.2