This uses vfork() for simple commands and command substitutions containing a
single simple command, invoking an external program under certain conditions
(no redirections or variable assignments, non-interactive shell, no job
control). These restrictions limit the amount of code executed in a vforked
child.
There is a large speedup (for example 35%) in microbenchmarks. The
difference in buildkernel is smaller (for example 0.5%) but still
statistically significant. See
http://lists.freebsd.org/pipermail/freebsd-hackers/2012-January/037581.html
for some numbers.
The use of vfork() can be disabled by setting a variable named
SH_DISABLE_VFORK.
In the first command of a 'for', $? should be the exit status of the last
pipeline (command substitution in the word list or command before 'for'),
not always 0.
Before this fix, only the first statement of the trap was executed if
evalskip was set. This is for example the case when:
o "-e" is set for this shell
o a trap is set on EXIT
o a function returns 1 and causes the script to abort
Reviewed by: jilles
MFC after: 2 weeks
Also, rework evalcase() to not evaluate any tree. Instead, return the
NCLISTFALLTHRU node and handle it in evaltree().
Fixed bugs:
* If a ;& list with non-zero exit status is followed by an empty ;; or final
list, the exit status of the case command should be equal to the exit
status of the ;& list, not 0.
* An empty ;& case should not reset $?.
* If no pattern is matched, POSIX says the exit status shall be 0 (even if
there are command substitutions).
* If a pattern is matched and there are no command substitutions, the first
command should see the $? from before the case command, not always 0.
The errno message display added in r222292 did not take attempting to
cd to a non-directory or something that cannot be stat()ed into account.
PR: bin/164070
MFC after: 10 days
This improves performance for globs where a slash or another component
follows a component with metacharacters by eliminating unnecessary attempts
to open directories that are not.
This is not necessary: errors are already caught in evalbackcmd() and
forcelocal handles changes to variables.
Note that this depends on r223024.
MFC after: 4 weeks
Free expanded case text before executing commands.
Remove impossible evalskip checks (expanding an argument cannot set
evalskip anymore since $(break) and the like are properly executed in a
subshell environment).
For these simple utilities, it doesn't harm to make all global variables
static. In fact, this allows the compiler to perform better forms of
optimisation and analysis.
display() to calculate column widths, but was not initialized in
main(). This resulted in a division by zero.
Noticed by: Michael Butler <imb@protected-networks.net>
- In the argc == 0 case, just populate the mount list as before, but
do not calculate widths, update totals or print anything.
- In the argv > 0 case, collect information about the requested file
systems and store it in the mount list, but do not calculate
widths, update totals or print anything.
- In either case, once all the information has been collected,
iterate once through the mount list to calculate widths and totals,
then once more to print everything.
This also fixes two bugs: firstly, column widths were not calculated
correctly if more than one file system was specified on the command
line; and secondly, file systems with MNT_IGNORE were included in the
totals even if -a was not specified.
Noticed by: Paul Schenkeveld
MFC after: 3 weeks
- there's no reason the semantics of the -x flag are being explained in
the -a flag description
- be more precise regarding the relation between the -a flag and the
security.bsd.see_other_uids sysctl
- describe the format of the -t flag's argument
- 'con' no longer is a possible entry in the 'TT' column
- explain that the 'TT' column refers to pseudo-terminals via mere numbers
- add a hint in the 'tt' keyword description that a keyword 'tty' exists,
which will give the full terminal pathname
Submitted by: arundel (via docs@) (original)
MFC after: 1 week
With-MFC: 225908
As of FreeBSD 6, devices can only be opened through devfs. These device
nodes don't have major and minor numbers anymore. The st_rdev field in
struct stat is simply based a copy of st_ino.
Simply display device numbers as hexadecimal, using "%#jx". This is
allowed by POSIX, since it explicitly states things like the following
(example taken from ls(1)):
"If the file is a character special or block special file, the
size of the file may be replaced with implementation-defined
information associated with the device in question."
This makes the output of these commands more compact. For example, ls(1)
now uses approximately four columns less. While there, simplify the
column length calculation from ls(1) by calling snprintf() with a NULL
buffer.
Don't be afraid; if needed one can still obtain individual major/minor
numbers using stat(1).
Because sh executes commands in subshell environments without forking in
more and more cases (particularly from 8.0 on), it makes sense to describe
subshell environments more precisely using ideas from POSIX, together with
some FreeBSD-specific items.
In particular, the hash and times builtins may not behave as if their state
is copied for a subshell environment while leaving the parent shell
environment unchanged.
to re-establishment of 64bit arithmetic, but is committed separately, to
not obscure that conversion. This commit does not change the observed
behaviour of expr in any way. Style will be fixed in a follow-up commit.
again. This brings back the behaviour of expr in FreeBSD-4, which had been
reverted due to an assumed incompatbility with POSIX.1 for FreeBSD-5.
This issue has been discussed in the freebsd-standards list, and the
consensus was, that POSIX.1 is in fact not violated by this extension,
since it affects only cases of POSIX undefined behaviour (overflow of
signed long).
Other operating systems did upgrade their versions of expr to support
64bit range, after it had been initially brought to FreeBSD. They have
used it for a decade without problems, meanwhile.
The -e option is retained, but it will only select less strict checking
of numeric parameters (leading white-space, leading "+" are allowed and
skipped, an empty string is considered to represent 0 in numeric context.)
The call of check_utility_compat() as a means of establishing backwards
compatibility with FreeBSD-4 is considered obsolete, but preserved in
this commit. It is expected to be removed in a later revision of this
file.
Reviewed by: bde, das, jilles
MFC after: 2 month (those parts that do not violate POLA)
* Shell patterns are also for ${var#pat} and the like.
* An '!' by itself will not trigger pathname generation so do not call it a
meta-character, even though it has a special meaning directly after an
'['.
* Character ranges are locale-dependent.
* A '^' will complement a character class like '!' but is non-standard.
MFC after: 1 week
POSIX requires a -h option to sh and set, to locate and remember utilities
invoked by functions as they are defined. Given that this
locate-and-remember process is optional elsewhere, it seems safe enough to
make this option do nothing.
POSIX does not specify a long name for this option. Follow ksh in calling it
"trackall".
Replacing ;; with the new control operator ;& will cause the next list to be
executed as well without checking its pattern, continuing until a list ends
with ;; or until the end of the case statement. This is like omitting
"break" in a C "switch" statement.
The sequence ;& was formerly invalid.
This feature is proposed for the next POSIX issue in Austin Group issue
#449.
The eval special builtin now runs the code with EV_EXIT if it was run
with EV_EXIT itself.
In particular, this eliminates one fork when a command substitution contains
an eval command that ends with an external program or a subshell.
This is similar to what r220978 did for functions.
Have mkbuiltins write the prototypes for the *cmd functions to builtins.h
instead of builtins.c and include builtins.h in more .c files instead of
duplicating prototypes for *cmd functions in other headers.
In optimized command substitution, save and restore any variables changed by
expansions (${var=value} and $((var=assigned))), instead of trying to
determine if an expansion may cause such changes.
If $! is referenced in optimized command substitution, do not cause jobs to
be remembered longer.
This fixes $(jobs $!) again, simplifies the man page and shortens the code.
When I added UTF-8 support in r221646, the LC_COLLATE-based ordering broke
because of sign extension of char.
Because of libc restrictions, this does not work for UTF-8. For UTF-8
locales, ranges always use character code order.
In most cases, login shells are started from the home directory, but not in
all, such as xterm -ls.
This commit depends on r222957 for read_profile() performing parameter
expansion.
PR: bin/50569
The function name expandstr() and the general idea of doing this kind of
expansion by treating the text as a here document without end marker is from
dash.
All variants of parameter expansion and arithmetic expansion also work (the
latter is not required by POSIX but it does not take extra code and many
other shells also allow it).
Command substitution is prevented because I think it causes too much code to
be re-entered (for example creating an unbounded recursion of trace lines).
Unfortunately, our LINENO is somewhat crude, otherwise PS4='$LINENO+ ' would
be quite useful.
The "exp" builtin is undocumented, non-standard and not very useful.
If exp's return value is not used, something like
VAR=$(exp EXPRESSION)
is equivalent to
VAR=$((EXPRESSION))
except that errors in the expression are fatal and quoting special
characters is not needed in the latter case.
If exp's return value is used, something like
if exp EXPRESSION >/dev/null
can be replaced by
if [ $((EXPRESSION)) -ne 0 ]
with similar differences.
The exp-run showed that "let" is close enough to bash's and ksh's builtin
that removing it would break a few ports. Therefore, "let" remains in 9.x.
PR: bin/104432
Exp-run done by: pav (with some other sh(1) changes)
CDPATH should be ignored not only for pathnames starting with '/' but also
for pathnames whose first component is '.' or '..'.
The man page already describes this behaviour.
If IFS is null, unquoted $@/$* should still expand to separate words.
This differs from quoted $@ (which does not depend on IFS) in that pathname
generation is performed and empty words are removed.
If the length of a directory in PATH together with the given filename
exceeded FILENAME_MAX (which may happen even for pathnames that work), a
static buffer was overflown.
The static buffer is unnecessary, we can use the stalloc() stack.
Obtained from: NetBSD
MFC after: 1 week
This reflects failure to determine the pathname of the new directory in the
exit status (1). Normally, cd returns successfully if it did chdir() and the
call was successful.
In POSIX, -e only has meaning with -P; because our -L is not entirely
compliant and may fall back to -P mode, -e has some effect with -L as well.
This is sometimes used with eval or old-style command substitution, and most
shells other than ash derivatives allow it.
It can also be used with scripts that violate POSIX's requirement on the
application that they end in a newline (scripts must be text files except
that line length is unlimited).
Example:
v=`cat <<EOF
foo
EOF`
echo $v
This commit does not add support for the similar construct with new-style
command substitution, like
v=$(cat <<EOF
foo
EOF)
This continues to require a newline after the terminator.
Because we have no iconv in base, support for other charsets is not
possible.
Note that \u/\U are processed using the locale that was active when the
shell started. This is necessary to avoid behaviour that depends on the
parse/execute split (for example when placing braces around an entire
script). Therefore, UTF-8 encoding is implemented manually.
