Implement persistent history storage:
the strategy is simple at start: loads the existing .sh_history file
at exit dump it.
The implementation respects the HISTFILE variable and its POSIX
definition: ~/.sh_history is used if HISTFILE is not set.
to avoid sh to create the history file, set HISTSIZE to 0 or HISTFILE to
en empty value
Co-authored-by: pstef
Reviewed by: jilles
Differential Revision: https://reviews.freebsd.org/D29493
If job control is not enabled, a background job (... &) ignores SIGINT and
SIGQUIT, but this can be reverted using the trap builtin in the same shell
environment.
Using the set builtin to change options would also revert SIGINT and SIGQUIT
to their previous dispositions.
This broke due to r317298. Calling setsignal() reverts the effect of
ignoresig().
Reported by: bdrewery
MFC after: 1 week
INTOFF postpones SIGINT processing and INTON enables it again. This is
important so an interactive shell can return to the top level prompt when
Ctrl+C is pressed.
Given that INTON is automatically done when a builtin completes, the part
where onsig() ignores suppressint when in_dotrap is true is both unnecessary
and unsafe. If the trap is for some other signal than SIGINT, arbitrary code
could have been interrupted.
Historically, INTOFF remained in effect for longer.
Reviewed by: bdrewery
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D25270
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
The parser considered 'trap exit INT' to reset the default for both EXIT and
INT. This beahvior is not POSIX compliant. This was avoided if a value was
specified for 'exit', but then disallows exiting with the signal received. A
possible workaround is using ' exit'.
However POSIX does allow this type of behavior if the parameters are all
integers. Fix the handling for this and clarify its support in the manpage
since it is specifically allowed by POSIX.
Differential Revision: https://reviews.freebsd.org/D2325
Reviewed by: jilles
MFC after: 2 weeks
The SIGWINCH handler triggers breakage in libedit which is hard to fix; see
PR bin/169773.
Also, window size changes while a program is in foreground (and it rather
than sh will receive SIGWINCH) will now be picked up automatically.
Downside: it is now certain that a resize is only processed after pressing
<Enter>. If libedit is fixed, sh will most likely have to be changed also.
PR: bin/180146
If job control is not enabled, background jobs started with ... & ignore
SIGINT and SIGQUIT so that they are not affected by such signals that are
intended for the foreground job. However, this should not prevent
reassigning a different action for these signals (as if the shell invocation
inherited these signal actions from its parent).
Austin group issue #751
Example:
{ trap - INT; exec sleep 10; } & wait
A Ctrl+C should terminate the sleep command.
The change in r238888 was incomplete. It was still possible for a trapped
signal to arrive before the shell went to sleep (sigsuspend()) because a
check was missing or because the signal arrived before in_waitcmd was set.
On SMP, this bug sometimes caused the builtins/wait4.0 test to take 1 second
to execute; it then might or might not fail. On UP, the test almost always
failed.
It now passes WARNS=7 with clang on i386.
GCC 4.2.1 does not understand setjmp() properly so will always trigger
-Wuninitialized. I will not add the volatile keywords to suppress this.
This ensures 'return' in a trap returns the correct status to the caller.
If evalskip is not set or if it is overridden by a previous evalskip, keep
the old behaviour of restoring the exit status from before the trap.
When waiting for child processes using "wait" or if "set -T" is in effect, a
signal interrupts the wait. Make sure there is no window where the signal
handler may be invoked (setting a flag) just before going to sleep.
There is a similar race condition in the shell language, but scripts can
avoid it by exiting from the trap handler or enforcing synchronization using
a fifo.
If SIGCHLD is not trapped, a signal handler must be installed for it. Only
install this handler for the duration of the wait to avoid triggering
unexpected [EINTR] errors elsewhere.
Note that for some reason only SIGINT and SIGQUIT interrupt a "wait"
command. This remains the case.
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
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.
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.
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'.
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.
* 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.
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 $?'.
Example:
sh -c '(trap "echo trapped" EXIT; sleep 3)'
now correctly prints "trapped".
With this check, it is no longer necessary to check for -T
explicitly in that case.
This is a useful bugfix by itself and also important because I plan to
skip forking more often.
PR: bin/113860 (part of)
PR: bin/74404 (part of)
Reviewed by: stefanf
Approved by: ed (mentor)
would always terminate if eval returned with a non-zero exit status regardless
if the status was actually tested. Unfortunately a new file-scope variable
is needed, the alternative would only be to add a new parameter to all
built-ins.
PR: 134881
and linting procedure:
1. Remove useless sub-expression:
- if (*start || (!ifsspc && start > string && (nulonly || 1))) {
+ if (*start || (!ifsspc && start > string)) {
The sub-expression "(nulonly || 1)" always evaluates to true and
according to CVS logs seems to be just a left-over from some
debugging and introduced by accident. Removing the sub-expression
doesn't change semantics and a code inspection showed that the
variable "nulonly" is also not necessary here in any way (and the
expression would require fixing instead of removing).
2. Remove dead code:
- if (backslash && c == '\\') {
- if (read(STDIN_FILENO, &c, 1) != 1) {
- status = 1;
- break;
- }
- STPUTC(c, p);
- } else if (ap[1] != NULL && strchr(ifs, c) != NULL) {
+ if (ap[1] != NULL && strchr(ifs, c) != NULL) {
Inspection of the control and data flow showed that variable
"backslash" is always false (0) when the "if"-expression is
evaluated, hence the whole block is effectively dead code.
Additionally, the skipping of characters after a backslash is already
performed correctly a few lines above, so this code is also not
needed at all. According to the CVS logs and the ASH 0.2 sources,
this code existed in this way already since its early days.
3. Cleanup Style:
- ! trap[signo][0] == '\0' &&
+ ! (trap[signo][0] == '\0') &&
The expression wants to ensure the trap is not assigned the empty
string. But the "!" operator has higher precedence than "==", so the
comparison should be put into parenthesis to form the intended way of
expression. Nevertheless the code was effectively not really broken
as both particular NUL comparisons are semantically equal, of course.
But the parenthesized version is a lot more intuitive.
4. Remove shadowing variable declaration:
- char *q;
The declaration of symbol "q" hides another identical declaration of
"q" in the same context. As the other "q" is already reused multiple
times and also can be reused again without negative side-effects,
just remove the shadowing declaration.
5. Just small cosmetics:
- if (ifsset() != 0)
+ if (ifsset())
The ifsset() macro is already coded by returning the boolean result
of a comparison operator, so no need to compare this boolean result
again against a numerical value. This also aligns the macros usage to
the remaining existing code.
Reviewed by: stefanf@
itself does that if you set EL_SIGNAL. Instead, set a flag and check it
before calling el_gets(). This is safer, but slower to respond to changes.
Pointed out by: mp
