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.
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.
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.
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
* avoid unnecessary fork
* allow executing builtins via command
* executing a special builtin via command removes its special properties
Obtained from: NetBSD (parts)
- correctly handle error output in $(builtin 2>&1), clarify out1/out2 vs
output/errout in the code
- treat all builtins as regular builtins so errors do not abort the shell
and variable assignments do not persist
- respect the caller's INTOFF
Some bugs still exist:
- expansion errors may still abort the shell
- some side effects of expansions and builtins persist
This also fixes that trying to execute a non-regular file with a command
name without '/' returns 127 instead of 126.
The fix is rather simplistic: treat CMDUNKNOWN as if the command were found
as an external program. The resulting fork is a bit wasteful but executing
unknown commands should not be very frequent.
PR: bin/137659
Empty pairs of braces are represented by a NULL node pointer, just like
empty lines at the top level.
Support for empty pairs of braces may be removed later. They make the code
more complex, have inconsistent behaviour (may or may not change $?), are
not specified by POSIX and are not allowed by some other shells like bash,
dash and ksh93.
Reported by: kan
Add a reference count to function definitions.
Memory may leak if multiple SIGINTs arrive in interactive mode,
this will be fixed later by changing SIGINT handling.
PR: bin/137640
either -v or -V) if a file with a slash in the name doesn't exist (if there is
no slash we already did that).
Additionally, suppress the error message for command -v for files with a slash.
PR: 107674
Submitted by: Martin Kammerhofer
demanded by POSIX.
- A redirection error is only fatal (meaning the execution of a shell script is
terminated) for special built-ins. Previously it was fatal for all shell
builtins, causing problems like the one reported in PR 88845.
- Variable assignments remain in effect for special built-ins.
- Option or operand errors are only fatal for special built-ins.
This change also makes errors from 'fc' non-fatal (I could not find any reasons
for this behaviour).
Somewhat independently from the above down-grade the error handling in the
shift built-in if the operand is bigger than $# from an error() call (which is
now fatal) to a return 1. I'm not sure if this should be considered a POSIX
"operand error", however this change is needed for now as we trigger that error
while building libncurses. Comparing with other shells, zsh does the same as
our sh before this change (write a diagnostic, return 1), bash behaves as our
sh after this commit (no diagnostic, return 1) and ksh93 and NetBSD's sh treat
it as a fatal error.
considered an error according to the Open Group Base Specification.
PR: standards/45738
Submitted by: Matthias Andree <matthias.andree@web.de>
MFC after: 3 days
- Removed dead declarations
- Made objects that should have been declared as static, static.
The changes use STATIC instead of static, following the existing
convention in the rest of the code.
Approved by: schweikh (mentor)
MFC after: 2 weeks
o Old-style K&R declarations have been converted to new C89 style
o register has been removed
o prototype for main() has been removed (gcc3 makes it an error)
o int main(int argc, char *argv[]) is the preferred main definition.
o Attempt to not break style(9) conformance for declarations more than
they already are.
o Change
int
foo() {
...
to
int
foo(void)
{
...
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
face of aliases. Note, bash doesn't do aliases while running scripts, but
"real" ksh does..
Also:
Reduce redundant .Nm macros in (unused) bltin/echo.1
nuke error2, it's hardly used.
More -Wall cleanups
dont do certain history operations if NO_HISTORY defined
handle quad_t's from resource limits
Submitted by: Steve Price <sprice@hiwaay.net> (minor tweaks by me)
merge of parallel duplicate work by Steve Price and myself. :-]
There are some changes to the build that are my fault... mkinit.c was
trying (poorly) to duplicate some of the work that make(1) is designed to
do. The Makefile hackery is my fault too, the depend list was incomplete
because of some explicit OBJS+= entries, so mkdep wasn't picking up their
source file #includes.
This closes a pile of /bin/sh PR's, but not all of them..
Submitted by: Steve Price <steve@bonsai.hiwaay.net>, peter
