Mercurial > vim
view runtime/defaults.vim @ 34394:a400c8f9506f v9.1.0123
patch 9.1.0123: MS-Windows: system() may deadlock
Commit: https://github.com/vim/vim/commit/52ecc76c7fa1865603f27bc838efaeaa03cad77c
Author: GuyBrush <miguel.barro@live.com>
Date: Wed Feb 21 20:16:38 2024 +0100
patch 9.1.0123: MS-Windows: system() may deadlock
Problem: MS-Windows: system() may deadlock when calling binaries that
expect stdin
Solution: Ignore the SHELL_EXPAND flag
(GuyBrush)
This happens on binaries that expect stdin. For example:
:echo system("xxd")
will cause a deadlock.
SHELL_EXPAND is a flag devoted to support the linux implementation of
the backtick-expansion mechanism.
On linux backtic-expansion relies in the function mch_expand_wildchars()
(os_unix.c) that delegates on each specific shell (bash, sh, csh, zsh)
the expansion. Basically it composes a shell command that does the
expansion and redirects the output to a file and call_shell() it. On
windows backtick-expansion is performed by Vim itself.
On linux SHELL_EXPAND modifies how mch_call_shell_fork() (os_unix.c)
works. This function:
- relies on posix fork() to spawn a child process to execute a
external command.
- Child and parent process communicate using pipes (or pseudoterminal
if available).
User input (type ahead content) is processed in a loop only if
!(SHELL_EXPAND || SHELL_COOKED).
Though signals are used to detect Ctrl-C in all cases (the input
loop is not necessary to interrupt the function).
In the backtick-expansion the external command is the shell command
that provides the expansion. For the child redirection:
- SHELL_EXPAND replaces stdin, stdout & stderr to /dev/null. This is
why the shell command composed includes redirection (otherwise
output would be lost).
- !SHELL_EXPAND replaces stdin, stdout & stderr with the parent
created pipes (or pseudoterminal).
Note that the use of SIGINT signal prevents mch_call_shell_fork()
from hanging vim.
On Windows mch_system_piped() (os_win32.c) (which is only used when the
GUI is running) mimics mch_call_shell_fork() (os_unix.c).
Win32 lacks fork() and relies on CreateProcessW() and only has pipe
support (not pseudoterminal) which makes the implementation much
different.
But, the key idea is that windows lacks signals, the OS provides support
for console apps but gvim is not one. The only way of detecting a Ctrl-C
is actually processing user input (type ahead content). By ignoring the
user input under SHELL_EXPAND the function can hang gvim.
Ignoring SHELL_EXPAND flag has no consequence in Windows because as
mentioned above it is only meaningful in linux.
closes: #13988
Signed-off-by: GuyBrush <miguel.barro@live.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Wed, 21 Feb 2024 20:30:02 +0100 |
parents | 4027cefc2aab |
children |
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line source
" The default vimrc file. " " Maintainer: The Vim Project <https://github.com/vim/vim> " Last change: 2023 Aug 10 " Former Maintainer: Bram Moolenaar <Bram@vim.org> " " This is loaded if no vimrc file was found. " Except when Vim is run with "-u NONE" or "-C". " Individual settings can be reverted with ":set option&". " Other commands can be reverted as mentioned below. " When started as "evim", evim.vim will already have done these settings. if v:progname =~? "evim" finish endif " Bail out if something that ran earlier, e.g. a system wide vimrc, does not " want Vim to use these default values. if exists('skip_defaults_vim') finish endif " Use Vim settings, rather than Vi settings (much better!). " This must be first, because it changes other options as a side effect. " Avoid side effects when it was already reset. if &compatible set nocompatible endif " When the +eval feature is missing, the set command above will be skipped. " Use a trick to reset compatible only when the +eval feature is missing. silent! while 0 set nocompatible silent! endwhile " Allow backspacing over everything in insert mode. set backspace=indent,eol,start set history=200 " keep 200 lines of command line history set ruler " show the cursor position all the time set showcmd " display incomplete commands set wildmenu " display completion matches in a status line set ttimeout " time out for key codes set ttimeoutlen=100 " wait up to 100ms after Esc for special key " Show @@@ in the last line if it is truncated. set display=truncate " Show a few lines of context around the cursor. Note that this makes the " text scroll if you mouse-click near the start or end of the window. set scrolloff=5 " Do incremental searching when it's possible to timeout. if has('reltime') set incsearch endif " Do not recognize octal numbers for Ctrl-A and Ctrl-X, most users find it " confusing. set nrformats-=octal " For Win32 GUI: remove 't' flag from 'guioptions': no tearoff menu entries. if has('win32') set guioptions-=t endif " Don't use Q for Ex mode, use it for formatting. Except for Select mode. " Revert with ":unmap Q". map Q gq sunmap Q " CTRL-U in insert mode deletes a lot. Use CTRL-G u to first break undo, " so that you can undo CTRL-U after inserting a line break. " Revert with ":iunmap <C-U>". inoremap <C-U> <C-G>u<C-U> " In many terminal emulators the mouse works just fine. By enabling it you " can position the cursor, Visually select and scroll with the mouse. " Only xterm can grab the mouse events when using the shift key, for other " terminals use ":", select text and press Esc. if has('mouse') if &term =~ 'xterm' set mouse=a else set mouse=nvi endif endif " Only do this part when Vim was compiled with the +eval feature. if 1 " Enable file type detection. " Use the default filetype settings, so that mail gets 'tw' set to 72, " 'cindent' is on in C files, etc. " Also load indent files, to automatically do language-dependent indenting. " Revert with ":filetype off". filetype plugin indent on " Put these in an autocmd group, so that you can revert them with: " ":autocmd! vimStartup" augroup vimStartup autocmd! " When editing a file, always jump to the last known cursor position. " Don't do it when the position is invalid, when inside an event handler " (happens when dropping a file on gvim), for a commit or rebase message " (likely a different one than last time), and when using xxd(1) to filter " and edit binary files (it transforms input files back and forth, causing " them to have dual nature, so to speak) autocmd BufReadPost * \ let line = line("'\"") \ | if line >= 1 && line <= line("$") && &filetype !~# 'commit' \ && index(['xxd', 'gitrebase'], &filetype) == -1 \ | execute "normal! g`\"" \ | endif augroup END " Quite a few people accidentally type "q:" instead of ":q" and get confused " by the command line window. Give a hint about how to get out. " If you don't like this you can put this in your vimrc: " ":autocmd! vimHints" augroup vimHints au! autocmd CmdwinEnter * \ echohl Todo | \ echo gettext('You discovered the command-line window! You can close it with ":q".') | \ echohl None augroup END endif " Switch syntax highlighting on when the terminal has colors or when using the " GUI (which always has colors). if &t_Co > 2 || has("gui_running") " Revert with ":syntax off". syntax on " I like highlighting strings inside C comments. " Revert with ":unlet c_comment_strings". let c_comment_strings=1 endif " Convenient command to see the difference between the current buffer and the " file it was loaded from, thus the changes you made. " Only define it when not defined already. " Revert with: ":delcommand DiffOrig". if !exists(":DiffOrig") command DiffOrig vert new | set bt=nofile | r ++edit # | 0d_ | diffthis \ | wincmd p | diffthis endif if has('langmap') && exists('+langremap') " Prevent that the langmap option applies to characters that result from a " mapping. If set (default), this may break plugins (but it's backward " compatible). set nolangremap endif