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Simplify fallback precmd emulation

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d3m3t3r 2024-11-20 22:43:15 +00:00
parent 014cb2099f
commit 28a5e82aee
1 changed files with 46 additions and 41 deletions
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87
src/subshell/common.c
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@ -1133,6 +1133,38 @@ pty_open_slave (const char *pty_name)
static void
init_subshell_precmd (char *precmd, size_t buff_size)
{
/* Attention! Make sure that the buffer for precmd is big enough. */
/* Fallback precmd emulation that should work with virtually any shell.
* No real precmd functionality is required, no support for \x substitutions
* in PS1 is needed. For convenience, $HOME is replaced by ~ in PS1.
*
* The following example is a little less fancy (home directory not replaced)
* and shows the basic workings of our prompt for easier understanding:
*
* "precmd() { "
* "echo \"$USER@$(hostname -s):$PWD\"; "
* "pwd>&%d; "
* "kill -STOP $$; "
* "}; "
* "PRECMD=precmd; "
* "PS1='$($PRECMD)$ '\n",
*/
static const char *precmd_fallback =
" " /* Useful if the shell supports HISTCONTROL=ignorespace like functionality */
"precmd() { "
"if [ ! \"${PWD##$HOME}\" ]; then "
"MC_PWD=\"~\"; "
"else "
"[ \"${PWD##$HOME/}\" = \"$PWD\" ] && MC_PWD=\"$PWD\" || MC_PWD=\"~/${PWD##$HOME/}\"; "
"fi; "
"echo \"$USER@$(hostname -s):$MC_PWD\"; "
"pwd>&%d; "
"kill -STOP $$; "
"}; "
"PRECMD=precmd; "
"PS1='$($PRECMD)$ '\n";
switch (mc_global.shell->type)
{
case SHELL_BASH:
@ -1166,55 +1198,28 @@ init_subshell_precmd (char *precmd, size_t buff_size)
* Attention: BusyBox must be built with FEATURE_EDITING_FANCY_PROMPT to
* permit \u, \w, \h, \$ escape sequences. Unfortunately this cannot be guaranteed,
* especially on embedded systems where people try to save space, so let's use
* the dash version below. It should work on virtually all systems.
* "precmd() { pwd>&%d; kill -STOP $$; }; "
* "PRECMD=precmd; "
* "PS1='$(eval $PRECMD)\\u@\\h:\\w\\$ '\n",
* the falback version.
*/
g_snprintf (precmd, buff_size, precmd_fallback, subshell_pipe[WRITE]);
break;
case SHELL_DASH:
/* Debian ash needs a precmd emulation via PS1, similar to BusyBox ash,
* but does not support escape sequences for user, host and cwd in prompt.
* Attention! Make sure that the buffer for precmd is big enough.
*
* We want to have a fancy dynamic prompt with user@host:cwd just like in the BusyBox
* examples above, but because replacing the home directory part of the path by "~" is
* complicated, it bloats the precmd to a size > BUF_SMALL (128).
*
* The following example is a little less fancy (home directory not replaced)
* and shows the basic workings of our prompt for easier understanding:
*
* "precmd() { "
* "echo \"$USER@$(hostname -s):$PWD\"; "
* "pwd>&%d; "
* "kill -STOP $$; "
* "}; "
* "PRECMD=precmd; "
* "PS1='$($PRECMD)$ '\n",
*/
g_snprintf (precmd, buff_size,
"precmd() { "
"if [ ! \"${PWD##$HOME}\" ]; then "
"MC_PWD=\"~\"; "
"else "
"[ \"${PWD##$HOME/}\" = \"$PWD\" ] && MC_PWD=\"$PWD\" || MC_PWD=\"~/${PWD##$HOME/}\"; "
"fi; "
"echo \"$USER@$(hostname -s):$MC_PWD\"; "
"pwd>&%d; "
"kill -STOP $$; "
"}; " "PRECMD=precmd; " "PS1='$($PRECMD)$ '\n", subshell_pipe[WRITE]);
g_snprintf (precmd, buff_size, precmd_fallback, subshell_pipe[WRITE]);
break;
case SHELL_MKSH:
/* mksh doesn't support \x placeholders in PS1 and needs precmd emulation via PS1 */
g_snprintf (precmd, buff_size, precmd_fallback, subshell_pipe[WRITE]);
break;
case SHELL_KSH:
/* pdksh based variants support \x placeholders but not any "precmd" functionality. */
g_snprintf (precmd, buff_size,
" PS1='$(pwd>&%d; kill -STOP $$)\\u@\\h:\\w\\$ '\n",
subshell_pipe[WRITE]);
break;
case SHELL_MKSH:
/* mksh doesn't support \x placeholders neither any "precmd" functionality */
g_snprintf (precmd, buff_size,
" PS1='$(pwd>&%d; kill -STOP $$)${USER:=$(id -un)}@${HOSTNAME:=$(hostname -s)}:$PWD\\$ '\n",
" PS1='$(pwd>&%d; kill -STOP $$)'"
"\"${PS1:-\\u@\\h:\\w\\$ }\"\n",
subshell_pipe[WRITE]);
break;
@ -1263,11 +1268,11 @@ init_subshell_precmd (char *precmd, size_t buff_size)
* Use following technique:
*
* printf(1) with format string containing a single conversion specifier,
* "b", and an argument which contains a copy of the string passed to
* "b", and an argument which contains a copy of the string passed to
* subshell_name_quote() with all characters, except digits and letters,
* replaced by the backslash-escape sequence \0nnn, where "nnn" is the
* numeric value of the character converted to octal number.
*
*
* cd "`printf '%b' 'ABC\0nnnDEF\0nnnXYZ'`"
*
* N.B.: Use single quotes for conversion specifier to work around