free: called with unallocated block argument
Configuration Information [Automatically generated, do not change]: Machine: i686 OS: linux-gnu Compiler: gcc Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' -DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H -I. -I. -I./include -I./lib -g -O2 uname output: Linux Arcturus 2.6.27.15jpmr #20 SMP Sun Feb 8 12:51:35 CET 2009 i686 GNU/Linux Machine Type: i686-pc-linux-gnu Bash Version: 4.0 Patch Level: 0 Release Status: release Description: Problem with auto completion : ls[space][TAB] gives the follwing abort : malloc: /Users/chet/src/bash/src/parse.y:5561: assertion botched free: called with unallocated block argument last command: ls Aborting...Abandon If /etc/bash_completion is suppressed, problem disapears. My bash_completion is : $Id: bash_completion,v 1.872 2006/03/01 16:20:18 ianmacd Exp $ Repeat-By: ls[space] [TAB] or cd[space][TAB] and several other commands.
bash crash processing b=b+1 after array read
phil@rex:~$ unset a b X; declare -i a b=1; declare -ia X=(1 2 3);
phil@rex:~$ unset a b X; declare -i a b=1; declare -ia X=(1 2 3); (( a=X[b]
)); echo $a
2
phil@rex:~$ cd Development/pc-z80
phil@rex:~/Development/pc-z80$ chmod +x pc-crash-bash.bash
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash2
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
2
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
2
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
3
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
200
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
100
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: 100Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: 100
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: 100
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: 100
This works: 200
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: 100
This works: 200
But a 'b=b+1' after an array read crashes bash.
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: 100
This works: 200
This works: 200
But a 'b=b+1' after an array read crashes bash.
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: 100
This works: 200
This works: 200
But a 'b=b+1' after an array read crashes bash.
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ declare -ia X=({0..1000}); echo ${X[3]}
3
phil@rex:~/Development/pc-z80$ declare -ia X=({0..1000..100}); echo ${X[3]}
300
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: a=-1 b=2
This works: a=-1 b=3
This works: a=300 b=3
This works: a=300 b=4
This works: a=400 b=5
This works: a=500 b=6
This works: a=500 b=8
This works: a=500 b=10
This works: a=0 b=11
This works: a=0 b=12
This works: a=0 b=13
This works: a=0 b=14
But a 'b=b+1' after an array read crashes bash.
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ ./pc-crash-bash.bash
Howto crash bash
This works: a=-1 b=2
This works: a=-1 b=3
This works: a=300 b=3
This works: a=300 b=4
This works: a=400 b=5
This works: a=500 b=6
This works: a=500 b=8
This works: a=500 b=10
This works: a=0 b=11
This works: a=0 b=12
This works: a=0 b=13
This works: a=0 b=14
But a 'b=b+1' after an array read crashes bash.
Segmentation fault (core dumped)
phil@rex:~/Development/pc-z80$ bashbug
Processing '/etc/jupp/editorrc'...done
Processing '/etc/jupp/editorrc'...done
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-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H -I. -I../bash -I../bash/include -I../bash/lib
-D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector --param=ssp-buffer-size=4
-Wformat -Werror=format-security -Wall
uname output: Linux rex 3.7.5-030705-generic #201301280206 SMP Mon Jan 28
07:07:29 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 4.2
Patch Level: 37
Release Status: release
Description:
Within (( )), 'b=b+1' will crash bash with a segment fault if it follows an
array read such as 'a=X[b]'.
Once, a test line entered into a bash prompt crashed my terminal window as
well.
Repeat-By:
#!/bin/bash printf "Howto crash bash\n" unset a b X declare -i a=-1 b=1
declare -ia X=( {0..1000..100} ) printf "But a 'b=b+1' after an array read
crashes bash.\n" (( a=X[b], b=b+1 )); printf "This crashes: a=%d b=%d\n" $a
$b
Fix:
Don't run a command after an array read
eg.
Do this instead
#!/bin/bash printf "Howto crash bash\n" unset a b X declare -i a=-1 b=1
declare -ia X=( {0..1000..100} ) printf "But a 'b=b+1' after an array read
crashes bash.\n" (( a=X[b] )); (( b=b+1 )); printf "This crashes: a=%d
b=%d\n" $a $b
More detailed script looking at what case crashes bash:
It seems that b+=1 is ok, but b=b+1 is not.
#!/b
declare -ia does not enfore integer type on initialisation
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-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H -I. -I../bash -I../bash/include -I../bash/lib
-D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector --param=ssp-buffer-size=4
-Wformat -Werror=format-security -Wall
uname output: Linux max 3.8.0-35-generic #50-Ubuntu SMP Tue Dec 3 01:24:59
UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 4.2
Patch Level: 45
Release Status: release
Description:
declare -ia not enforced if variable is initiated using =
Repeat-By:
unset Z; declare -ia Z=( A B C ); echo ${Z[*]}; Z=( D E F ); echo ${Z[*]}
Outputs
A B C
0 0 0
Should output:
0 0 0
0 0 0
Phil
Readline history and bash's read -e
Dear Bash and Readline Experts, I have a simple shell script that reads user commands in a loop using "read -e". -e enables readline, but not its history feature. Is there any way to get readline history with bash's read builtin? I wouldn't want to get the user's regular bash history; rather, this program would need its own history file in the user's home directory. For example: read -e --historyfile=~/.myprogname_history CMD If there's no way to do this with the read builtin, perhaps there's an existing standalone readline wrapper program that can do this? I imagine it would only need a dozen lines of code. However, it wouldn't be possible to retain the syntax of the read builtin w.r.t. variable names: CMD=`read_with_history -e --historyfile=~/.myprogname_history` If such a program doesn't yet exist, I'll write it; let me know if you would find the code useful. Searching has found some other wrappers (e.g. 3 at packages.debian.org) that solve the slightly different and more complex problem of wrapping an entire program that doesn't use readline so that it does use it for all input. That's not what I need in this case. Thanks for any advice. Phil.
++ causes 2 variables to increment
Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='i686'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H -I. -I../. -I.././include -I.././lib
-D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector-strong -Wformat
-Werror=format-security -Wall
uname output: Linux m41 4.2.0-34-generic #39-Ubuntu SMP Thu Mar 10 22:11:49
UTC 2016 i686 i686 i686 GNU/Linux
Machine Type: i686-pc-linux-gnu
Bash Version: 4.3
Patch Level: 42
Release Status: release
Description:
Odd behaviour when an undefined variable is used in arithemetic expression.
((++F[word]==M)) increments both F[word] AND M
But not always.
When M is null, M seems to be treated as 0 (as expected)
When M is assigned an integer value of an integer associative array element,
something goes wrong.
(just a guess, since as you will see, this is complex to demonstrate)
This can happen when M=1 but usually when M=2.
Repeat-By:
#!/bin/bash
p(){ # print variables
printf "F[%s]=[%d] M=[%d] I=[%s]\n" "$1" $((F[$1]*1)) $((M*1)) "$I"
}
t(){ # iterate - part of a program that counts word frequency and tracks
most frequent word
p $W
# M should not change here
((++F[$W]==M))&&I= # pre-increment F[$W]. If equal to Max then I=NULL
p $W
# but sometimes, it does!
((F[$W]>M))&&M=F[$W]&&I=$W # if F[$W]>Max then Max=F[$W]
p $W
}
unset F
unset X
unset M
unset W
unset I
W="word"
echo setup
# it always fails, but at different iterations!
# why does it fail ever?
# an example run
# run 3
#+ t
#+ p word
#+ printf 'F[%s]=[%d] M=[%d] I=[%s]\n' word 2 2 ''
# here, M=2
#F[word]=[2] M=[2] I=[]
#+ (( ++F[word]==M ))
#+ I=
#+ p word
#+ printf 'F[%s]=[%d] M=[%d] I=[%s]\n' word 3 3 ''
# without changing M, it is now 3!!
#F[word]=[3] M=[3] I=[]
#+ (( F[word]>M ))
#+ p word
#+ printf 'F[%s]=[%d] M=[%d] I=[%s]\n' word 3 3 ''
#F[word]=[3] M=[3] I=[]
#+ set +x
# only when setting M from F[$W] or F[word] causes it to fail at iteration 2
declare -iA F;F[word]=1; M=F[word] # fails run 2
#declare -iA F;F[$W]=1; M=F[$W] # fails run 2
# all other ways to initialise M fail at iteration 3
#declare -iA F; declare -iA X; F[$W]=1; X[dog]=1; M=X[dog] # fails run 3
#declare -iA F; declare -iA X; F[$W]=1; X[$W]=1; M=X[$W] # fails run 3
#declare -iA F;F[$W]=1; M=1 # fails run 3
#declare -iA F;F[$W]=1; M="1" # fails run 3
#declare -iA F;F[$W]=1; M=$((1*1)) # fails run 3
#declare -iA F;F[$W]=1; ((M=1)) # fails run 3
#declare -iA F;F[$W]=1; M=${F[$W]} # fails run 3
I=$W
p $W
echo run 2
t
echo run 3
set -x
t
set +x
echo run 4
t
Fix:
declare -i M
This seems to 'fix' this.
dead.bashbug
Description: Binary data
Re: ++ causes 2 variables to increment
Thanks Grisha,
Sorry for putting you through analysing my faulty example.
Phil
On 16 May 2016 at 05:58, Grisha Levit wrote:
>
> On Sun, May 15, 2016 at 4:42 PM, phil colbourn
> wrote:
> > # here, M=2
>>
>>
> It's not -- the value of $M here is the string "F[word]". Your print
> function reports the value of "$((M*1))", which is, in fact "2": inside the
> arithmetic expression "M" is expanded to "F[word]" which is expanded to "2".
>
> > # without changing M, it is now 3!!
>
> Exactly, M does not change, it is still "F[word]". But since F[word]
> changes, the value of $((M*1)) does change to reflect the new value of
> F[word].
>
> Instead of M=F[$W], I think you want to be doing M=${F[$W]}.
>
