Mercurial > vim
view runtime/vimrc_example.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
" An example for a vimrc file. " " Maintainer: The Vim Project <https://github.com/vim/vim> " Last Change: 2023 Aug 10 " Former Maintainer: Bram Moolenaar <Bram@vim.org> " " To use it, copy it to " for Unix: ~/.vimrc " for Amiga: s:.vimrc " for MS-Windows: $VIM\_vimrc " for Haiku: ~/config/settings/vim/vimrc " for OpenVMS: sys$login:.vimrc " When started as "evim", evim.vim will already have done these settings, bail " out. if v:progname =~? "evim" finish endif " Get the defaults that most users want. source $VIMRUNTIME/defaults.vim if has("vms") set nobackup " do not keep a backup file, use versions instead else set backup " keep a backup file (restore to previous version) if has('persistent_undo') set undofile " keep an undo file (undo changes after closing) endif endif if &t_Co > 2 || has("gui_running") " Switch on highlighting the last used search pattern. set hlsearch endif " Put these in an autocmd group, so that we can delete them easily. augroup vimrcEx au! " For all text files set 'textwidth' to 78 characters. autocmd FileType text setlocal textwidth=78 augroup END " Add optional packages. " " The matchit plugin makes the % command work better, but it is not backwards " compatible. " The ! means the package won't be loaded right away but when plugins are " loaded during initialization. if has('syntax') && has('eval') packadd! matchit endif