Modified the patch to print warning only once when null byte is ignored.
----- Original Message -----
> From: "Siteshwar Vashisht" <svashi...@redhat.com>
> To: bug-bash@gnu.org
> Sent: Friday, July 28, 2017 3:59:15 PM
> Subject: read builtin goes into uninterruptible loop if input only contains
> zeros
>
> Configuration Information [Automatically generated, do not change]:
> Machine: x86_64
> OS: linux-gnu
> Compiler: gcc
> Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
> -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-unknown-linux-gnu'
> -DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/local/share/locale'
> -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H -I. -I. -I./include -I./lib -g
> -O0 -Wno-parentheses -Wno-format-security
> uname output: Linux localhost.localdomain 4.11.6-201.fc25.x86_64 #1 SMP Tue
> Jun 20 20:21:11 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
> Machine Type: x86_64-unknown-linux-gnu
>
> Bash Version: 4.4
> Patch Level: 12
> Release Status: release
>
> Description:
> read builtin goes into uninterruptible loop if input comes from
> /dev/zero.
>
> Repeat-By:
> read -N 1 _ < /dev/zero
>
> Fix:
> Attached patch fixes the bug.
>
>
> --
> --
> Siteshwar Vashisht
>
--
--
Siteshwar Vashisht
From 87f9e379ef4618d434ebc376d7d63a98ad620273 Mon Sep 17 00:00:00 2001
From: Siteshwar Vashisht <svashi...@redhat.com>
Date: Fri, 28 Jul 2017 15:51:07 +0200
Subject: [PATCH] Make read builtin interruptible if input contains zeros
---
builtins/read.def | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/builtins/read.def b/builtins/read.def
index 33821f3..4865c36 100644
--- a/builtins/read.def
+++ b/builtins/read.def
@@ -194,6 +194,7 @@ read_builtin (list)
struct stat tsb;
SHELL_VAR *var;
TTYSTRUCT ttattrs, ttset;
+ int nullbyte;
#if defined (ARRAY_VARS)
WORD_LIST *alist;
#endif
@@ -243,6 +244,7 @@ read_builtin (list)
nr = nchars = input_is_tty = input_is_pipe = unbuffered_read = have_timeout = 0;
delim = '\n'; /* read until newline */
ignore_delim = 0;
+ nullbyte = 0;
reset_internal_getopt ();
while ((opt = internal_getopt (list, "ersa:d:i:n:p:t:u:N:")) != -1)
@@ -609,7 +611,7 @@ read_builtin (list)
break;
}
- CHECK_ALRM;
+ check_signals();
#if defined (READLINE)
}
@@ -662,7 +664,14 @@ read_builtin (list)
break;
if (c == '\0' && delim != '\0')
- continue; /* skip NUL bytes in input */
+ {
+ if (nullbyte == 0)
+ {
+ internal_warning ("read_builtin: ignored null byte in input");
+ nullbyte = 1;
+ }
+ continue; /* skip NUL bytes in input */
+ }
if ((skip_ctlesc == 0 && c == CTLESC) || (skip_ctlnul == 0 && c == CTLNUL))
{
--
2.9.4
