We used to have a global notion of "is the shell interactive" but soon we
will want to have multiple independent execution threads, only some of
which may be interactive. Start tracking this data per-parser.
This runs build_tools/style.fish, which runs clang-format on C++, fish_indent on fish and (new) black on python.
If anything is wrong with the formatting, we should fix the tools, but automated formatting is worth it.
This was added in 04a96f6 but not strictly required to fix#5803
(verified), with the intention of hiding invisible background jobs
(created by invoking a function within a pipeline) from the user, but
that also broke intentionally created jobs from displaying as well.
I'm thinking it can't be done without keeping track of caller context vs
job context.
Closes#5824.
Prior to this change, fish used a global flag to decide if we should check
for changes to universal variables. This flag was then checked at arbitrary
locations, potentially triggering variable updates and event handlers for
those updates; this was very hard to reason about.
Switch to triggering a universal variable update at a fixed location,
after running an external command. The common case is that the variable
file has not changed, which we can identify with just a stat() call, so
this is pretty cheap.
I did not realize builtins could safely call into the parser and inject
jobs during execution. This is much cleaner than hacking around the
required shape of a plain_statement.
While `eval` is still a function, this paves the way for changing that
in the future, and lets the proc/exec functions detect when an eval is
used to allow/disallow certain behaviors and optimizations.
Followup to 394623b.
Doing it in the parser meant only top-level jobs would be reaped after
being `disown`ed, as subjobs aren't directly handled by the parser.
This is also much cleaner, as now job removal is centralized in
`process_clean_after_marking()`.
Closes#5803.
This prevents the `disown` builtin from directly removing jobs out of
the jobs list to prevent sanity issues, as `disown` may be called within
the context of a subjob (e.g. in a function or block) in which case the
parent job might not yet be done with the reference to the child job.
Instead, a flag is set and the parser removes the job from the list only
after the entire execution chain has completed.
Closes#5720.
Prior to this fix, in every call to job_continue, fish would reclaim the
foreground pgrp. This would cause other jobs in the pipeline (which may
have another pgrp) to receive SIGTTIN / SIGTTOU.
Only reclaim the foreground pgrp if it was held at the point of job_continue.
This partially addresses #5765
Directly access the job list without the intermediate job_iterator_t,
and remove functions that are ripe for abuse by modifying a local
enumeration of the same list instead of operating on the iterators
directly (e.g. proc.cpp iterates jobs, and mid-iteration calls
parser::job_remove(j) with the job (and not the iterator to the job),
causing an invisible invalidation of the pre-existing local iterators.
Prior to this fix, the wait command used waitpid() directly. Switch it to
calling process_mark_finished_children() along with the rest of the job
machinery. This centralizes the waitpid call to a single location.
In fish we play fast and loose with status codes as set directly (e.g. on
failed redirections), vs status codes returned from waitpid(), versus the
value $status. Introduce a new value type proc_status_t to encapsulate
this logic.
This introduces "internal processes" which are backed by a pthread instead
of a normal process. Internal processes are reaped using the topic
machinery, plugging in neatly alongside the sigchld topic; this means that
process_mark_finished_children() can wait for internal and external
processes simultaneously.
Initially internal processes replace the forked process that fish uses to
write out the output of blocks and functions.
The sigchld generation expresses the idea that, if we receive a sigchld
signal, the generation will be different than when we last recorded it. A
process cannot exit before it has launched, so check the generation count
before process launch. This is an optimization that reduces failing
waitpid calls.
This is a big change to how process reaping works, reimplenting it using
topics. The idea is to simplify the logic in
process_mark_finished_children around blocking, and also prepare for
"internal processes" which do not correspond to real processes.
Before this change, fish would use waitpid() to wait for a process group,
OR would individually poll processes if the process group leader was
unreapable.
After this change, fish no longer ever calls blocking waitpid(). Instead
fish uses the topic mechanism. For each reapable process, fish checks if
it has received a SIGCHLD since last poll; if not it waits until the next
SIGCHLD, and then polls them all.
This reverts commit 54050bd4c5.
Type job_list_t was changed from a list to a deque in
commit 54050bd4c5.
In process_clean_after_marking(), we remove jobs while iterating.
dequeues do not support that. Make it a list again.
Now jobs are aware of their parent jobs, and can interrogate those jobs,
to determine if every job in the chain is fully constructed.
Remove flags and the static stacks that manipulated them.
The parent of a job is the parent pipeline that executed the function or
block corresponding to this job. This will help simplify
process_mark_finished_children().
select_try() returned IO_ERROR to indicate that there's no file descriptors
from which to read. Name this return value properly.
Also migrate this type into proc.cpp since it's not used outside of the
header.
This was introduced in 1b1bc28c0a but did
not cause any problems until the job control refactor, which caused it
to attempt to signal the calling `exec` builtin's own (invalid) pgrp
with SIGHUP.
Also improved debugging for `j->signal()` failures by printing the
signal we tried sending in case of error, rename the function to
`hup_background_jobs`, and move it from `reader.h`/`reader.cpp` to
`proc.h`/`proc.cpp`.
When a function is encountered by exec_job, a new context is created for
its execution from the ground up, with a new job and all, ultimately
resulting in a recursive call to exec_job from the same (main) thread.
Since each time exec_job encounters a new job with external commands
that needs terminal control it creates a new pgrp and gives it control
of the terminal (tcsetpgrp & co), this effectively takes control away
from the previously spawned external commands which may be (and likely
are) expecting to still have terminal access.
This commit attempts to detect when such a situation arises by handling
recursive calls to exec_job (which can only happen if the pipeline
included a function) by borrowing the pgrp from the (necessarily still
active) parent job and spawning new external commands into it.
When a parent job spawns new jobs due to the evaluation of a new
function (which shouldn't be the case in the first place), we end up
with two distinct jobs sharing one pgrp (to fix#3952). This can lead to
early termination of a pgrp if finished parent job children are reaped
before future processes in either the parent or future child jobs can
join it.
While the parent job is under construction, require that waitpid(2)
calls for the child job be done by process id and not job pgrp.
Closes#3952.
Convert `select_try()` to return a well-defined enum describing its
state, and handle each of the three possible cases with clear reasons
why we are blocking or not blocking in each subsequent call to
`process_mark_finished_children()`.
* Use the newly-introduced signal_block_t RAII wrapper
* Remove EINTR loops as all signals are blocked
* Clean up control flow thanks to RAII wrappers
* Rename parameter to clarify what it does and update docs accordingly
* Update outdated comments referencing SIGSTOP code that was removed a
long time ago.
* Remove no-op CHECK_BLOCK() call
* Convert JOB_* enums to scoped enums
* Convert standalone job_is_* functions to member functions
* Convert standalone job_{promote, signal, continue} to member functions
* Convert standolen job_get{,_from_pid} to `job_t` static functions
* Reduce usage of JOB_* enums outside of proc.cpp by using new
`job_t::is_foo()` const helper methods instead.
This patch is only a refactor and should not change any functionality or
behavior (both observed and unobserved).
* Debug level 3: describe all commands being executed (this is, after all,
a shell and one can argue that this is the most important debug
information avaliable)
* Debug level 4: details of execution, mainly fork vs no-fork and io
handling
Also introduced j->preview() to print a short descriptor of the job
based on the head of the first process so we don't overwhelm with
needless repitition, but also so that we don't have to rely on
distinguishing between repeated, non-unique/non-monotonic job ids that
are often recycled within a single "execution cycle" (pressing enter
once).
We never insert elements into the middle of a job list, only move
elements to the top. While that can be done "efficiently" with a list, it
can be done faster with a deque, which also won't thrash the cache when
enumerating over jobs.
This speeds up enumeration in the critical path in
`process_mark_finished_children()`.
Fix#5133 changed builtins to acquire the terminal, but this regressed
caused fish to be stopped when running in background via `sudo fish`.
Fix this by only acquiring the terminal if the terminal was owned by the
builtin's pgroup.
Fixes#5147
When running a builtin, if we are an interactive shell and stdin is a tty,
then acquire ownership of the terminal via tcgetpgrp() before running the
builtin, and set it back after.
Fixes#4540
This switches function execution from the function's source code to
its stored node and pstree. This means we no longer have to re-parse
the function every time we execute it.
This concerns block nodes with redirections, like
begin ... end | grep ...
Prior to this fix, we passed in a pointer to the node. Switch to passing
in the tnode and parsed source ref. This improves type safety and better
aligns with the function-node plans.
There is no more race condition between parent and child with
regards to setting the process groups. Each child sets it for themselves
and then blocks indefinitely until the parent does what it needs to for
them (having waited for them to set their process groups). They are not
SIGCONT'd until the next process in the chain (if any) starts so that
that process can join their process group and open the pipes.
This implements `status is-breakpoint` that returns true if the current
shell prompt is displayed in the context of a `breakpoint` command.
This also fixes several bugs. Most notably making `breakpoint` a no-op if
the shell isn't interactive. Also, typing `breakpoint` at an interactive
prompt should be an error rather than creating a new nested debugging
context.
Partial fix for #1310
0 is not a good default PGID, because it's possible for a kernel process
to have the PGID of 0 under Linux.
This meant that job_get_from_pid could return incorrect jobs, as the PGID
for internal, non-forked jobs was the same as kernel processes.
Avoid this by using an invalid PGID as the initial PGID.
I recently upgraded the software on my macOS server and was dismayed to
see that cppcheck reported a huge number of format string errors due to
mismatches between the format string and its arguments from calls to
`assert()`. It turns out they are due to the macOS header using `%lu`
for the line number which is obviously wrong since it is using the C
preprocessor `__LINE__` symbol which evaluates to a signed int.
I also noticed that the macOS implementation writes to stdout, rather
than stderr. It also uses `printf()` which can be a problem on some
platforms if the stream is already in wide mode which is the normal case
for fish.
So implement our own `assert()` implementation. This also eliminates
double-negative warnings that we get from some of our calls to
`assert()` on some platforms by oclint.
Also reimplement the `DIE()` macro in terms of our internal
implementation.
Rewrite `assert(0 && msg)` statements to `DIE(msg)` for clarity and to
eliminate oclint warnings about constant expressions.
Fixes#3276, albeit not in the fashion I originally envisioned.
This puts a hard upper bound of 10 MiB on the amount of data that read
will consume. This is to avoid having the shell consume an unreasonable
amount of memory, possibly causing the system to enter a OOM condition,
if the user does something non-sensical.
Fixes#3712
This commit fixes a bug which causes that
fish -c ')'; echo $status
("Illegal command name" error) returns 0. This is inconsistent with
e.g. when trying to run non-existent command:
fish -c 'invalid-command'; echo $status
("Unknown command" error) which correctly returns 127.
A new status code,
STATUS_ILLEGAL_CMD = 123
is introduced - which is returned whenever the 'Illegal command name *'
message is printed.
This commit also adds a test which checks if valid commands return 0,
while commands with illegal name return status code 123.
Fixes#3606.
I'm doing this as part of fixing issue #2980. The code for managing tty modes
and job control is a horrible mess. This is a very tiny step towards improving
the situation.
Remove the "make iwyu" build target. Move the functionality into the
recently introduced lint.fish script. Fix a lot, but not all, of the
include-what-you-use errors. Specifically, it fixes all of the IWYU errors
on my OS X server but only removes some of them on my Ubuntu 14.04 server.
Fixes#2957
This was used to cache a narrow string representation
of commands, so that if certain system calls returned errors
after fork, we could output error messages without allocating
memory. But in practice these errors are very uncommon, as are
commands that have wide characters. It is simpler to do a best-effort
output of the wide string, instead of caching a narrow string
unconditionally.
This change moves source files into a src/ directory,
and puts object files into an obj/ directory. The Makefile
and xcode project are updated accordingly.
Fixes#1866
