Commit Graph

2558 Commits

Author SHA1 Message Date
Jilles Tjoelker
2fd7d6aab6 test: Note that this is used both as a normal program and a shell builtin.
MFC after:	1 week
2011-02-15 22:17:47 +00:00
Jilles Tjoelker
e9749129ad sh: Detect dividing the smallest integer by -1.
This overflows and on some architectures such as amd64 it generates SIGFPE.
Generate an error on all architectures.
2011-02-12 23:44:05 +00:00
Rebecca Cran
f68fbfedc1 Fix typos.
PR:	docs/131625
Submitted by:	Andrew Wright <andrew at qemg.org>
MFC after:	1 month
2011-02-12 20:28:15 +00:00
Jilles Tjoelker
075b72ef01 sh(1): Update description of arithmetic. 2011-02-08 23:19:40 +00:00
Jilles Tjoelker
6262b84eee sh: Import arithmetic expression code from dash.
New features:
* proper lazy evaluation of || and &&
* ?: ternary operator
* executable is considerably smaller (8K on i386) because lex and yacc are
  no longer used

Differences from dash:
* arith_t instead of intmax_t
* imaxdiv() not used
* unset or null variables default to 0
* let/exp builtin (undocumented, will probably be removed later)

Obtained from:	dash
2011-02-08 23:18:06 +00:00
Jilles Tjoelker
b15e9aa322 sh: Fix two things about {(...)} <redir:
* In {(...) <redir1;} <redir2, do not drop redir1.
* Maintain the difference between (...) <redir and {(...)} <redir:
  In (...) <redir, the redirection is performed in the child, while in
  {(...)} <redir it should be performed in the parent (like {(...); :;}
  <redir)
2011-02-05 15:02:19 +00:00
Jilles Tjoelker
c059d82290 sh: Remove clearcmdentry()'s now unused argument. 2011-02-05 14:08:51 +00:00
Jilles Tjoelker
ef0cb80dd4 sh: Forget all cached command locations on any PATH change.
POSIX requires this and it is simpler than the previous code that remembered
command locations when appending directories to PATH.

In particular,
  PATH=$PATH
is no longer a no-op but discards all cached command locations.
2011-02-05 14:01:46 +00:00
Jilles Tjoelker
604e8224f8 sh: Do not try to execute binary files as scripts.
If execve() returns an [ENOEXEC] error, check if the file is binary before
trying to execute it using sh. A file is considered binary if at least one
of the first 256 bytes is '\0'.

In particular, trying to execute ELF binaries for the wrong architecture now
fails with an "Exec format error" message instead of syntax errors and
potentially strange results.
2011-02-05 12:54:59 +00:00
Jilles Tjoelker
3835f47c7e sh: Remove special code for shell scripts without magic number.
These are called "shell procedures" in the source.

If execve() failed with [ENOEXEC], the shell would reinitialize itself
and execute the program as a script. This requires a fair amount of code
which is not frequently used (most scripts have a #! magic number).
Therefore just execute a new instance of sh (_PATH_BSHELL) to run the
script.
2011-02-04 22:47:55 +00:00
Jilles Tjoelker
12dacf622b Make sys_signame upper case.
This matches the constants from <signal.h> with 'SIG' removed, which POSIX
requires kill and trap to accept and 'kill -l' to write.

'kill -l', 'trap', 'trap -l' output is now upper case.

In Turkish locales, signal names with an upper case 'I' are now accepted,
while signal names with a lower case 'i' are no longer accepted, and the
output of 'killall -l' now contains proper capital 'I' without dot instead
of a dotted capital 'I'.
2011-02-04 16:40:50 +00:00
Jilles Tjoelker
834d160b3a sh: Return only 126 or 127 for execve() failures.
Do not return 2 for errors other than [EACCES] or [ENOENT].
2011-02-03 23:38:11 +00:00
Jilles Tjoelker
3e0b768c63 sh: Remove comment mentioning herefd, which is gone. 2011-02-02 21:48:53 +00:00
Jilles Tjoelker
b9f696953d sh: Send messages about signals to stderr.
This is required by POSIX and seems to make more sense.

See also r217557.
2011-01-30 22:57:52 +00:00
Jilles Tjoelker
cff1d84937 sh: Clean up some old comments:
* There is no plan for an alternative to the command "set".
* Attempting to unset a readonly variable has not raised an error for quite
  a while, so the order of unsetting a variable and a function with the same
  name does not matter.

MFC after:	1 week
2011-01-25 20:56:18 +00:00
Konstantin Belousov
f5f3977b8d Document P_FOLLOWFORK.
MFC after:	2 weeks
2011-01-25 11:04:16 +00:00
Jilles Tjoelker
0d5ccb45d8 sh: Fix signal messages being sent to the wrong file sometimes.
When a foreground job exits on a signal, a message is printed to stdout
about this. The buffer was not flushed after this which could result in the
message being written to the wrong file if the next command was a builtin
and had stdout redirected.

Example:
  sh -c 'kill -9 $$'; : > foo; echo FOO:; cat foo

Reported by:	gcooper
MFC after:	1 week
2011-01-18 21:18:31 +00:00
Jilles Tjoelker
421fb02139 sh(1): Document changes to 'exit' from traps. 2011-01-16 14:11:50 +00:00
Jilles Tjoelker
ebdfd6dc4d sh: If exit is used without args from a trap action, exit on the signal.
This is useful so that it is easier to exit on a signal than to reset the
trap to default and resend the signal. It matches ksh93. POSIX says that
'exit' without args from a trap action uses the exit status from the last
command before the trap, which is different from 'exit $?' and matches this
if the previous command is assumed to have exited on the signal.

If the signal is SIGSTOP, SIGTSTP, SIGTTIN or SIGTTOU, or if the default
action for the signal is to ignore it, a normal _exit(2) is done with exit
status 128+signal_number.
2011-01-16 13:56:41 +00:00
Jilles Tjoelker
a043cc4c68 sh: Fix some things about -- in trap:
* Make 'trap --' do the same as 'trap' instead of nothing.
* Make '--' stop option processing (note that '-' action is not an option).

Side effect: The error message for an unknown option is different.
2011-01-15 21:09:00 +00:00
Jilles Tjoelker
45b3c17647 sh: Make 'trap -l' look like 'kill -l'. 2011-01-14 21:30:27 +00:00
Jilles Tjoelker
33a8413363 sh: Follow-up to r216743, grabstackblock() can be replaced with stalloc().
grabstackblock() was used only once (but it is a very often executed piece
of code).
2011-01-09 22:47:58 +00:00
Jilles Tjoelker
4b45b49a70 sh: Remove special %builtin PATH entry.
All builtins are now always found before a PATH search.

Most ash derivatives have an undocumented feature where the presence of an
entry "%builtin" in $PATH will cause builtins to be checked at that point of
the PATH search, rather than before looking at any directories as documented
in the man page (very old versions do document this feature).

I am removing this feature from sh, as it complicates the code, may violate
expectations (for example, /usr/bin/alias is very close to a forkbomb with
PATH=/usr/bin:%builtin, only /usr/bin/builtin not being another link saves
it) and appears to be unused (all the %builtin google code search finds is
in some sort of ash source code).

Note that aliases and functions took and take precedence above builtins.
Because aliases work on a lexical level they can only ever be overridden on
a lexical level (quoting or preceding 'builtin' or 'command'). Allowing
override of functions via PATH does not really fit in the model of sh and it
would work differently from %builtin if implemented.

Note: POSIX says special builtins are found before functions. We comply to
this because we do not allow functions with the same name as a special
builtin.

Silence from:	freebsd-hackers@ (message sent 20101225)
Discussed with:	dougb
2011-01-09 21:07:30 +00:00
Konstantin Belousov
50a57dfbec Move repeated MAXSLP definition from machine/vmparam.h to sys/vmmeter.h.
Update the outdated comments describing MAXSLP and the process
selection algorithm for swap out.

Comments wording and reviewed by:	alc
2011-01-09 12:50:44 +00:00
Jilles Tjoelker
70df11eaad sh: Make exit without parameters from EXIT trap POSIX-compliant.
It should use the original exit status, just like falling off the
end of the trap handler.

Outside an EXIT trap, 'exit' is still equivalent to 'exit $?'.
2011-01-08 23:08:13 +00:00
Jilles Tjoelker
e23a66ac83 sh: Do not call exitshell() from evalcommand() unless evalcommand() forked
itself.

This ensures that certain traps caused by builtins are executed.
2011-01-05 23:17:29 +00:00
Jaakko Heinonen
b38dc7ebea Increase carried_error if we skip a file due to an error. This ensures
that setfacl(1) exits with proper exit status on failure.

PR:		bin/149780
Submitted by:	Ævar Arnfjörð Bjarmason (original version)
Reviewed by:	trasz
MFC after:	3 weeks
2011-01-03 17:17:31 +00:00
Jilles Tjoelker
850460c0f1 sh: Check readonly status for assignments on regular builtins.
An error message is written, the builtin is not executed, nonzero exit
status is returned but the shell does not abort.

This was already checked for special builtins and external commands, with
the same consequences except that the shell aborts for special builtins.

Obtained from:	NetBSD
2011-01-01 13:26:18 +00:00
Jilles Tjoelker
09683f46b9 sh: Check if dup2 for redirection from/to a file succeeds.
A failure (e.g. caused by ulimit -n being set very low) is a redirection
error.

Example:
  ulimit -n 9; exec 9<.
2010-12-31 18:20:17 +00:00
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