expr(1) should usually not be used as various forms of parameter expansion
and arithmetic expansion replicate most of its functionality in an easier
way.
getopt(1) should not be used at all in new code. Instead, getopts(1) or
entirely manual parsing should be used.
MFC after: 1 week
This makes it impossible to use locale-specific characters in variable
names.
Names containing locale-specific characters make scripts only work with the
correct locale setting. Also, they did not even work in many practical cases
because multibyte character sets such as utf-8 are not supported.
This also avoids weirdness if LC_CTYPE is changed in the middle of a script.
This Almquist extension was disabled long ago.
In pathname generation, components starting with '!!' were treated as
containing wildcards, causing unnecessary readdir (which could fail, causing
pathname generation to fail while it should not).
In our implementation and most others, a break or continue in a dot script
can break or continue a loop outside the dot script. This should cause all
further commands in the dot script to be skipped. However, cmdloop() did not
know about this and continued to parse and execute commands from the dot
script.
As described in the man page, a return in a dot script in a function returns
from the function, not only from the dot script. There was a similar issue
as with break and continue. In various other shells, the return appears to
return from the dot script, but POSIX seems not very clear about this.
The buffer for generated pathnames could be too small in some cases. It
happened to be always at least PATH_MAX long, so there was never an overflow
if the resulting pathnames would be usable.
This bug may be abused if a script subjects input from an untrusted source
to pathname generation, which a bad idea anyhow. Most shell scripts do not
work on untrusted data. secteam@ says no advisory is necessary.
PR: bin/148733
Reported by: Changming Sun snnn119 at gmail com
MFC after: 10 days
This makes a difference if there is a command substitution.
To make this work, evalstring() has been changed to set exitstatus to 0 if
no command was executed (the string contained only whitespace).
Example:
eval $(false); echo $?
should print 0.
This simply sets a flag in libedit. It has a shortcoming in that it does not
apply to multi-line commands.
Note that a configuration option for this is not going to happen, but always
having this seems better than not having it. NetBSD has done the same.
PR: bin/54683
Obtained from: NetBSD
MFC after: 1 month
If an ; or & token was followed by an EOF token, pending here-documents were
left uninitialized. Execution would crash, either in the main shell process
for literal here-documents or in a child process for expanded
here-documents. In the latter case the problem is hard to detect apart from
the core dumps and log messages.
Side effect: slightly different retries on inputs where EOF is not
persistent.
Note that tools/regression/bin/sh/parser/heredoc6.0 still causes a similar
crash in a child process. The text passed to eval is malformed and should be
rejected.
simplecmd() only handles simple commands and function definitions, neither
of which involves the ! keyword. The initial token on entry to simplecmd()
is one of the following: TSEMI, TAND, TOR, TNL, TEOF, TWORD, TRP.
Unless $! has been referenced for a particular job or $! still contains that
job's pid, forget about it after it has terminated. If $! has been
referenced, remember the job until the wait builtin has reported its
completion (either with the pid as parameter or without parameters).
In interactive mode, jobs are forgotten after termination has been reported,
which happens before primary prompts and through the jobs builtin. Even
then, though, remember a job if $! has been referenced.
This is similar to what is suggested by POSIX and should fix most memory
leaks (which also tend to cause sh to use more CPU time) with long running
scripts that start background jobs.
Caveats:
* Repeatedly referencing $! without ever doing 'wait', like
while :; do foo & echo started foo: $!; sleep 60; done
will still use a lot of memory and CPU time in the long run.
* The jobs and jobid builtins do not cause a job to be remembered for longer
like expanding $! does.
PR: bin/55346
The LINENO code uses snprintf() and relied on "myhistedit.h" to pull in the
necessary <stdio.h>.
Compiling with -DNO_HISTORY disables all editing and history support and
allows linking without -ledit -ltermcap. This may be useful for embedded
systems.
MFC after: 2 weeks
This uses the new libedit completion function with quoting support.
Unlike NetBSD, there is no 'set +o tabcomplete' option to disable
completion. I do not see any reason for such a special treatment, as
completion is rather useful and it is possible to do
bind ^I ed-insert
to disable completion and insert a tab character instead.
Submitted by: Guy Yur
is enabled.
This already worked if without job control.
In either case, this depends on it that a process that terminates due to
SIGINT exits on it (so not with status 1, or worse, 0).
Example:
sleep 5; echo continued
This does not print "continued" any more if sleep is aborted via ctrl+c.
MFC after: 1 month
Example (in interactive mode):
cat <<EOF && )
The next command typed caused sh to segfault, because the state for the here
document was not reset.
Like parser_temp, this uses the fact that the parser is not re-entered.
If a command substitution contains a newline token, this no longer starts
here documents of outer commands. This way, we follow POSIX's idea of the
command substitution being a separate script more closely. It also matches
other shells better and is consistent with newline characters in quotes not
starting here documents.
The extension tested in parser/heredoc3.0 ($(cat <<EOF)\ntext\nEOF\n)
continues to be supported.
In particular, this change allows things like
cat <<EOF && echo `pwd`
(a `` command substitution after a here document)
which formerly silently used an empty file as the here document, because the
EOF of the inner command "pwd" also forced an empty here document.
Although "--" historically has not been required to be recognized for
certain special builtins that do not take options in POSIX, some other
implementations recognize options for them, requiring scripts to use "--" or
avoid operands starting with "-".
Operands starting with "-" can be avoided with eval by prepending a space,
and cannot occur with break, continue, exit, return and shift as they only
take numbers, nor with times as it does not take operands. With . and exec,
avoiding "-" is not so easy as it may require reimplementing the PATH
search; therefore the current proposal for POSIX is to require recognition
of "--" for them.
We continue to accept other strings starting with "-" as operands to . and
exec, and also "--" if it is alone to . (which would otherwise be invalid
anyway).
* Move the "environment variables" that do not need exporting to be
effective or that are set by the shell without exporting to a new section
"Special Variables".
* Add special variables LINENO and PPID.
* Add environment variables LANG, LC_* and PWD; also describe ENV under
environment variables.
This prevents accumulating huge amounts of zombies if a script executes
many background commands but no external commands or subshells.
Note that zombies will not be reaped during long calculations (within
the shell process) or read builtins, but those actions do not create
more zombies.
The terminated background commands will also still be remembered by the
shell.
PR: bin/55346
These are git commits 36f0fa8fcbc8c7b2b194addd29100fb40e73e4e9 and
d6d06ff5c2ea0fa44becc5ef4340e5f2f15073e4 in dash.
Because this is the first code I'm importing from dash to expand.c, add the
Herbert Xu copyright notice which is in dash's expand.c.
When pathname expanding *\/, the CTLESC representing the quoted state was
erroneously taken as part of the * pathname component. This CTLESC was then
seen by the pattern matching code as escaping the '\0' terminating the
string.
The code is slightly different because dash converts the CTLESC characters
to backslashes and removes all the other CTL* characters to allow
substituting glob(3).
The effect of the bug was also slightly different from dash (where nothing
matched at all). Because a CTLESC can escape a '\0' in some way, whether
files were included despite the bug depended on memory that should not be
read. In particular, on many machines /*\/ expanded to a strict subset of
what /*/ expanded to.
Example:
echo /*"/null"
This should print /dev/null, not /*/null.
PR: bin/146378
Obtained from: dash
This allows doing things like LC_ALL=C some_builtin to run a builtin under a
different locale, just like is possible with external programs. The
immediate reason is that this allows making printf(1) a builtin without
breaking things like LC_NUMERIC=C printf '%f\n' 1.2
This change also affects special builtins, as even though the assignment is
persistent, the export is only to the builtin (unless the variable was
already exported).
Note: for this to work for builtins that also exist as external programs
such as /bin/test, the setlocale() call must be under #ifndef SHELL. The
shell will do the setlocale() calls which may not agree with the environment
variables.
Unset PWD if it is incorrect and no value for it can be determined.
This preserves the logical current directory across shell invocations.
Example (assuming /home is a symlink):
$ cd
$ pwd
/home/foo
$ sh
$ pwd
/home/foo
Formerly the second pwd would show the physical path (symlinks resolved).
These do pretty much nothing (except that parentheses are ignored), but
people seem to use them and allowing them does not hurt much.
Single-quotes seem not to be used and cause silently different behaviour
with ksh93 character constants.
This makes sh a bit more friendly in single user mode, make buildenv, chroot
and the like, and matches other shells.
The -o emacs can be overridden on the command line or in the ENV file.
Note that the following sentence
> Enclosing the full parameter expansion string in double-quotes does not
> cause the following four varieties of pattern characters to be quoted,
> whereas quoting characters within the braces has this effect.
is now true, but used to be incorrect.
This applies to word in ${v-word}, ${v+word}, ${v=word}, ${v?word} (which
inherits quoting from the outside) and in ${v%word}, ${v%%word}, ${v#word},
${v##word} (which does not inherit any quoting).
In all cases tilde expansion is only attempted at the start of word, even if
word contains spaces. This agrees with POSIX and other shells.
This is the last part of the patch tested in the exp-run.
Exp-run done by: erwin (with some other sh(1) changes)
Note that this depends on r206145 for allowing pattern match characters to
have their special meaning inside a double-quoted expansion like "${v%pat}".
PR: bin/117748
Exp-run done by: erwin (with some other sh(1) changes)
They will be treated like normal characters, resulting in a runtime
arithmetic expression error.
Exp-run done by: erwin (with some other sh(1) changes)
* remove the backslash from \} inside double quotes inside +-=?
substitutions, e.g. "${$+\}a}"
* maintain separate double-quote state for ${v#...} and ${v%...};
single and double quotes are special inside, even in a double-quoted
string or here document
* keep track of correct order of substitutions and arithmetic
This is different from dash's approach, which does not track individual
double quotes in the parser, trying to fix this up during expansion.
This treats single quotes inside "${v#...}" incorrectly, however.
This is similar to NetBSD's approach (as submitted in PR bin/57554), but
recognizes the difference between +-=? and #% substitutions hinted at in
POSIX and is more refined for arithmetic expansion and here documents.
PR: bin/57554
Exp-run done by: erwin (with some other sh(1) changes)
The old approach was wrong because PS2 was not used and seems unlikely to
parse extensions (ksh93's ${ COMMAND} may well fail to parse).
Exp-run done by: erwin (with some other sh(1) changes)
Redirection errors on subshells already did not abort the shell because
the redirection is executed in the subshell.
Other shells seem to agree that these redirection errors should not abort
the shell.
Also ensure that the redirections will be cleaned up properly in cases like
command eval '{ shift x; } 2>/dev/null'
Example:
{ echo bad; } </var/empty/x; echo good
Although simple commands without a command word (only assignments and/or
redirections) are much like special builtins, POSIX and most shells seem to
agree that redirection errors should not abort the shell in this case. Of
course, the assignments persist and assignment errors are fatal.
To get the old behaviour portably, use the ':' special builtin.
To get the new behaviour portably, given that there are no assignments, use
the 'true' regular builtin.
Make parsebackq a function instead of an emulated nested function.
This puts the setjmp usage in a smaller function where it is easier to avoid
bad optimizations.
* avoid unnecessary fork
* allow executing builtins via command
* executing a special builtin via command removes its special properties
Obtained from: NetBSD (parts)
