Commit Graph

2529 Commits

Author SHA1 Message Date
Jilles Tjoelker
11535bdf04 sh: Avoid side effects from builtins in optimized command substitution.
Change the criterion for builtins to be safe to execute in the same process
in optimized command substitution from a blacklist of only cd, . and eval to
a whitelist.

This avoids clobbering the main shell environment such as by $(exit 4) and
$(set -x).

The builtins jobid, jobs, times and trap can still show information not
available in a child process; this is deliberately permitted. (Changing
traps is not.)

For some builtins, whether they are safe depends on the arguments passed to
them. Some of these are always considered unsafe to keep things simple; this
only harms efficiency a little in the rare case they are used alone in a
command substitution.
2010-12-30 22:33:55 +00:00
Jilles Tjoelker
685a270543 sh: Properly restore exception handler in fc.
If SIGINT arrived at exactly the right moment (unlikely), an exception
handler in a no longer active stack frame would be called.

Because the old handler was not used in the normal path, clang thought it
was a dead value and if an exception happened it would longjmp() to garbage.
This caused builtins/fc1.0 to fail if histedit.c was compiled with clang.

MFC after:	1 week
2010-12-29 19:39:51 +00:00
Jilles Tjoelker
acd7984f96 sh: Don't do optimized command substitution if expansions have side effects.
Before considering to execute a command substitution in the same process,
check if any of the expansions may have a side effect; if so, execute it in
a new process just like happens if it is not a single simple command.

Although the check happens at run time, it is a static check that does not
depend on current state. It is triggered by:
- expanding $! (which may cause the job to be remembered)
- ${var=value} default value assignment
- assignment operators in arithmetic
- parameter substitutions in arithmetic except ${#param}, $$, $# and $?
- command substitutions in arithmetic

This means that $((v+1)) does not prevent optimized command substitution,
whereas $(($v+1)) does, because $v might expand to something containing
assignment operators.

Scripts should not depend on these exact details for correctness. It is also
imaginable to have the shell fork if and when a side effect is encountered
or to create a new temporary namespace for variables.

Due to the $! change, the construct $(jobs $!) no longer works. The value of
$! should be stored in a variable outside command substitution first.
2010-12-28 21:27:08 +00:00
Jilles Tjoelker
45b71cd16e sh: Make expansion errors in optimized command substitution non-fatal.
Command substitutions consisting of a single simple command are executed in
the main shell process but this should be invisible apart from performance
and very few exceptions such as $(trap).
2010-12-28 13:28:24 +00:00
Jilles Tjoelker
ff802dc7bb sh: Simplify "stack string" code slightly.
Maintain a pointer to the end of the stack string area instead of how much
space is left. This simplifies the macros in memalloc.h. The places where
the new variable must be updated are only where the memory area is created,
destroyed or resized.
2010-12-27 22:18:27 +00:00
Jilles Tjoelker
78962f36d2 sh: Fix integer overflow check, it checked an uninitialized variable. 2010-12-26 13:41:53 +00:00
Jilles Tjoelker
d8f32e7287 sh: Allow arbitrary large numbers in CHECKSTRSPACE.
Reduce "stack string" API somewhat and simplify code.
Add a check for integer overflow of the "stack string" length (probably
incomplete).
2010-12-26 13:25:47 +00:00
Jilles Tjoelker
12dfb7a554 sh(1): Explain why it is a bad idea to use aliases in scripts. 2010-12-21 22:48:56 +00:00
Jilles Tjoelker
0a62a9caa9 sh: Add kill builtin.
This allows specifying a %job (which is equivalent to the corresponding
process group).

Additionally, it improves reliability of kill from sh in high-load
situations and ensures "kill" finds the correct utility regardless of PATH,
as required by POSIX (unless the undocumented %builtin mechanism is used).

Side effect: fatal errors (any error other than kill(2) failure) now return
exit status 2 instead of 1. (This is consistent with other sh builtins, but
not in NetBSD.)

Code size increases about 1K on i386.

Obtained from:	NetBSD
2010-12-21 22:47:34 +00:00
Jilles Tjoelker
5fe9123ff5 sh: Add a function to print warnings (with command name and newline).
This is like error() but without raising an exception.
It is particularly useful as a replacement for the warnx macro in
bltin/bltin.h.
2010-12-21 20:47:06 +00:00
Jilles Tjoelker
6a6760db7f sh: Make warnings in the printf builtin non-fatal, like in the program.
The #define for warnx now behaves much like the libc function (except that
it uses sh command name and output).

Also, it now uses C99 __VA_ARGS__ so there is no need for three different
macros for 0, 1 or 2 parameters.
2010-12-20 23:06:57 +00:00
Jilles Tjoelker
79357531c8 sh: arith: Disallow decimal constants starting with 0 (containing 8 or 9).
Constants in arithmetic starting with 0 should be octal only.

This avoids the following highly puzzling result:
  $ echo $((018-017))
  3
by making it an error instead.
2010-12-18 23:03:51 +00:00
Ulrich Spörlein
f6b767b026 Remove dead code.
c is assigned 0 and *loc is pointing to NULL, so c!=0 cannot be true,
and dereferencing loc would be a bad idea anyway.

Coverity Prevent:	CID 5113
Reviewed by:		jilles
2010-12-18 22:16:15 +00:00
Jilles Tjoelker
fa0951d63a sh: Fix corruption of command substitutions with special chars after newline
The CTLESC byte to protect a special character was output before instead of
after a newline directly preceding the special character.

The special handling of newlines is because command substitutions discard
all trailing newlines.
2010-12-16 23:28:20 +00:00
Ulrich Spörlein
326b41010a Remove duplicate check, turning dead code into live code.
Coverity CID:	5114
Reviewed by:	jilles
2010-12-13 10:48:49 +00:00
Jilles Tjoelker
b036c75b4c sh: Various simplifications to jobs.c:
* Prefer kill(-X) to killpg(X).
* Remove some dead code.
* No additional SIGINT is needed if int_pending() is already true.

No functional change is intended.
2010-12-12 22:59:34 +00:00
Jilles Tjoelker
9f5a68a002 sh: Remove the herefd hack.
The herefd hack wrote out partial here documents while expanding them. It
seems unnecessary complication given that other expansions just allocate
memory. It causes bugs because the stack is also used for intermediate
results such as arithmetic expressions. Such places should disable herefd
for the duration but not all of them do, and I prefer removing the need for
disabling herefd to disabling it everywhere needed.

Here documents larger than 1024 bytes will use a bit more CPU time and
memory.

Additionally this allows a later change to expand here documents in the
current shell environment. (This is faster for small here documents but also
changes behaviour.)

Obtained from:	dash
2010-12-12 00:07:27 +00:00
Jilles Tjoelker
f7dea8517f sh: Replace some macros and repeated code in expand.c with functions.
No functional change is intended, but the binary is about 1K smaller on
i386.
2010-12-11 22:13:29 +00:00
Jilles Tjoelker
6903c6832e sh: Use vsnprintf() rather than crafting our own in fmtstr().
Add INTOFF/INTON as longjmp out of vsnprintf may cause memory leaks or
undefined behaviour.
2010-12-11 17:47:27 +00:00
Jilles Tjoelker
c67712a089 sh: Improve internal-representation-to-text code to avoid binary output.
The code to translate the internal representation to text did not know about
various additions to the internal representation since the original ash and
therefore wrote binary stuff to the terminal.

The code is used in the jobs command and similar output.

Note that the output is far from complete and mostly serves for recognition
purposes.
2010-12-06 23:49:27 +00:00
Jilles Tjoelker
fa9e5d05a3 sh: POSIX says there should not be a space between Done and (exitstatus).
(On the other hand, (core dumped) does need a space and so does [1] +.)
2010-12-05 22:56:46 +00:00
Jilles Tjoelker
1bb49f9524 sh: Improve jobs output of pipelines.
If describing the status of a pipeline, write all elements of the pipeline
and show the status of the last process (which would also end up in $?).
Only write one report per job, not one for every process that exits.

To keep some earlier behaviour, if any process started by the shell in a
foreground job terminates because of a signal, write a message about the
signal (at most one message per job, however).

Also, do not write messages about signals in the wait builtin in
non-interactive shells. Only true foreground jobs now write such messages
(for example, "Terminated").
2010-12-05 22:37:01 +00:00
Jilles Tjoelker
ff304d3732 sh: Avoid marking a job as done before it is fully created.
In r208489, I added code to reap zombies when forking new processes, to
limit the amount of zombies. However, this can lead to marking a job as done
or stopped if it consists of multiple processes and the first process ends
very quickly. Fix this by only checking for zombies before forking the first
process of a job and not marking any jobs without processes as done or
stopped.
2010-12-05 21:53:29 +00:00
Jilles Tjoelker
5af61b5251 sh: jobs -p: Do not ask the kernel for the pgid.
The getpgid() call will fail if the first process in the job has already
terminated, resulting in output of "-1".

The pgid of a job is always the pid of the first process in the job and
other code already relies on this.
2010-12-05 16:09:03 +00:00
Ulrich Spörlein
cded07a878 Move most of the remaining USD/PSD/SMM papers into share/doc 2010-12-04 10:11:20 +00:00
Jilles Tjoelker
25f6b31fac sh(1): Clean up documentation of built-in commands.
Make sure all built-in commands are in the subsection named such, except
exp, let and wordexp which are deliberately undocumented. The text said only
built-ins that really need to be a built-in were documented there but in
fact almost all of them were already documented.
2010-12-03 23:24:27 +00:00
Jilles Tjoelker
b97d13b399 sh(1): Document that command's -p option also works with -v/-V.
This was implemented in r201343.
2010-12-01 23:26:32 +00:00
Jilles Tjoelker
9d37e15722 sh: Code size optimizations to "stack string" memory allocation:
* Prefer one CHECKSTRSPACE with multiple USTPUTC to multiple STPUTC.
* Add STPUTS macro (based on function) and use it instead of loops that add
  nul-terminated strings to the stack string.

No functional change is intended, but code size is about 1K less on i386.
2010-11-23 22:17:39 +00:00
Jilles Tjoelker
0bee28331e sh: Pass multiple bytes at a time to lex.
This speeds up the expansion/arith6.0 test considerably.
2010-11-23 20:46:06 +00:00
Jilles Tjoelker
ae7f47355d sh: Fix confusing behaviour if chdir succeeded but getcwd failed in cd -P.
If getcwd fails, do not treat this as an error, but print a warning and
unset PWD. This is similar to the behaviour when starting the shell in a
directory whose name cannot be determined.
2010-11-22 23:49:06 +00:00
Rebecca Cran
1161d4202c Fix some more warnings found by clang. 2010-11-22 20:10:48 +00:00
Jilles Tjoelker
467fdf32f8 sh: Remove the check that alpha/name/in_name chars are not CTL* bytes.
Since is_alpha/is_name/is_in_name were made ASCII-only, this can no longer
happen.

Additionally, the check was wrong because it did not include the new
CTLQUOTEEND.
2010-11-20 14:30:28 +00:00
Jilles Tjoelker
aeb5d06504 sh: Code size optimizations to buffered output.
This is mainly less use of the outc macro.

No functional change is intended, but code size is about 2K less on i386.
2010-11-20 14:14:52 +00:00
Jilles Tjoelker
9897c45f31 sh: Add printf builtin.
This was removed in 2001 but I think it is appropriate to add it back:
* I do not want to encourage people to write fragile and non-portable echo
  commands by making printf much slower than echo.
* Recent versions of Autoconf use it a lot.
* Almost no software still wants to support systems that do not have
  printf(1) at all.
* In many other shells printf is already a builtin.

Side effect: printf is now always the builtin version (which behaves
identically to /usr/bin/printf) and cannot be overridden via PATH (except
via the undocumented %builtin mechanism).

Code size increases about 5K on i386. Embedded folks might want to replace
/usr/bin/printf with a hard link to /usr/bin/alias.
2010-11-19 12:56:13 +00:00
Jilles Tjoelker
c3f57269e6 sh: Add binary buffered output for use by the printf builtin. 2010-11-14 15:31:59 +00:00
Jilles Tjoelker
d79326ecc8 sh: Update the suspend example for the change of the job control flag
from -j to -m, many years ago.

Due to r215266, this function now actually works.
2010-11-13 22:20:46 +00:00
Jilles Tjoelker
4a7b1013fb sh: Do the additional actions if 'local -' restore changes -i/-m/-E/-V.
Example:
  f() { local -; set +m; }; f
caused failure to execute external programs because the job control tty fd
was not opened.
2010-11-13 22:10:26 +00:00
Jilles Tjoelker
61aad2fe09 echo(1): Clarify portability and mention literal "--" handling.
MFC after:	1 week
2010-11-12 22:43:40 +00:00
Jilles Tjoelker
4b985a89e7 sh(1): Document r214304 (special builtin is illegal function name). 2010-11-12 22:40:18 +00:00
Jilles Tjoelker
f35d74beed sh(1): Update for r214492. "${v+"hi}there"}".
The part hi}there is not a quoted string but nevertheless the closing brace
does not terminate the expansion.
2010-11-12 22:28:47 +00:00
Jilles Tjoelker
7f39c0011f sh: Remove unused man page for echo builtin.
The information in sh(1) about the echo builtin is equivalent, though less
extensive.

The echo(1) man page (bin/echo/echo.1) is different.

Unfortunately, sh's echo builtin and /bin/echo have gone out of sync and
this probably cannot be fixed any more.

Reported by:	uqs (list of untouched files)
MFC after:	1 week
2010-11-12 15:40:00 +00:00
Jilles Tjoelker
3fdfd0a435 sh(1): Modernize the introduction a bit.
In particular, remove the text about ksh-like features, which are usually
taken for granted nowadays. The original Bourne shell is fading away and for
most users our /bin/sh is one of the most minimalistic they know.
2010-11-12 14:40:20 +00:00
Jilles Tjoelker
47fdf870a7 test: Move tests to tools/regression/bin/test.
Convert the tests to the perl prove format.
Remove obsolete TEST.README (results of an old TEST.sh for some old Unices)
and TEST.csh (old tests without correct values, far less complete than
TEST.sh).

MFC after:	1 week
2010-11-08 23:15:10 +00:00
Jilles Tjoelker
135ff4b5b0 sh: Fix some issues with aliases and case, by importing dash checkkwd code.
This moves the function of the noaliases variable into the checkkwd
variable. This way it is properly reset on errors and aliases can be used
normally in the commands for each case (the case labels recognize the
keyword esac but no aliases).

The new code is clearer as well.

Obtained from:	dash
2010-11-02 23:44:29 +00:00
Ed Schouten
736fc28680 Add a new libc function: cfmakesane(3).
I've noticed various terminal emulators that need to obtain a sane
default termios structure use very complex `hacks'. Even though POSIX
doesn't provide any functionality for this, extend our termios API with
cfmakesane(3), which is similar to the commonly supported cfmakeraw(3),
except that it fills the termios structure with sane defaults.

Change all code in our base system to use this function, instead of
depending on <sys/ttydefaults.h> to provide TTYDEF_*.
2010-11-02 17:00:56 +00:00
Jilles Tjoelker
57a40f7d08 sh(1): Correct synopsis and make precise how $0 is set.
In particular, the extra argument to set $0 with -c was not documented.

MFC after:	1 week
2010-10-31 23:03:11 +00:00
Ulrich Spörlein
ec1e236534 Fix typo and grammar nit
Submitted by:	arundel
MFC after:	7 days (or when the bikeshed has abated)
2010-10-31 19:16:54 +00:00
Jilles Tjoelker
4c4164f9a7 sh: Reindent evaltree(). 2010-10-31 12:08:16 +00:00
Jilles Tjoelker
dca867f1c9 sh: Use iteration instead of recursion to evaluate semicolon lists.
This reduces CPU and memory usage when executing long lists (such
as long functions).
2010-10-31 12:06:02 +00:00
Ulrich Spörlein
c2c9a54067 Elaborate some more on the non-security implications of using -P
Submitted by:	delphij
Discussion at:	svn-src-all
2010-10-31 09:21:27 +00:00