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New subshell types Busybox ash + Debian ash (dash) and some more enha…
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…ncements plus fish chdir bugfix

Signed-off-by: Slava Zanko <[email protected]>
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@kriegaex @godelzanko
kriegaex authored and godelzanko committed Nov 10, 2015
1 parent 039fd56 commit f596c91
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Showing 4 changed files with 219 additions and 32 deletions.
1 change: 1 addition & 0 deletions lib/global.c
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Original file line number Diff line number Diff line change
Expand Up @@ -97,6 +97,7 @@ mc_global_t mc_global = {
#endif /* !ENABLE_SUBSHELL */

.shell = NULL,
.shell_realpath = NULL,

.xterm_flag = FALSE,
.disable_x11 = FALSE,
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1 change: 1 addition & 0 deletions lib/global.h
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Original file line number Diff line number Diff line change
Expand Up @@ -255,6 +255,7 @@ typedef struct

/* The user's shell */
char *shell;
char *shell_realpath;

/* This flag is set by xterm detection routine in function main() */
/* It is used by function view_other_cmd() */
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47 changes: 46 additions & 1 deletion src/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,9 @@
/*** file scope variables ************************************************************************/

/*** file scope functions ************************************************************************/

static char rp_shell[PATH_MAX];

/* --------------------------------------------------------------------------------------------- */

static void
Expand Down Expand Up @@ -117,6 +120,44 @@ check_codeset (void)
mc_global.utf8_display = str_isutf8 (current_system_codepage);
}

/* --------------------------------------------------------------------------------------------- */
/**
* Get a system shell.
*
* @return newly allocated string with shell name
*/

static char *
mc_get_system_shell (void)
{
char *sh_str;
/* 3rd choice: look for existing shells supported as MC subshells. */
if (access ("/bin/bash", X_OK) == 0)
sh_str = g_strdup ("/bin/bash");
else if (access ("/bin/ash", X_OK) == 0)
sh_str = g_strdup ("/bin/ash");
else if (access ("/bin/dash", X_OK) == 0)
sh_str = g_strdup ("/bin/dash");
else if (access ("/bin/busybox", X_OK) == 0)
sh_str = g_strdup ("/bin/busybox");
else if (access ("/bin/zsh", X_OK) == 0)
sh_str = g_strdup ("/bin/zsh");
else if (access ("/bin/tcsh", X_OK) == 0)
sh_str = g_strdup ("/bin/tcsh");
/* No fish as fallback because it is so much different from other shells and
* in a way exotic (even though user-friendly by name) that we should not
* present it as a subshell without the user's explicit intention. We rather
* will not use a subshell but just a command line.
* else if (access("/bin/fish", X_OK) == 0)
* mc_global.tty.shell = g_strdup ("/bin/fish");
*/
else
/* Fallback and last resort: system default shell */
sh_str = g_strdup ("/bin/sh");

return sh_str;
}

/* --------------------------------------------------------------------------------------------- */

/** POSIX version. The only version we support. */
Expand All @@ -126,23 +167,27 @@ OS_Setup (void)
const char *shell_env;
const char *datadir_env;


shell_env = getenv ("SHELL");
if ((shell_env == NULL) || (shell_env[0] == '\0'))
{
/* 2nd choice: user login shell */
struct passwd *pwd;

pwd = getpwuid (geteuid ());
if (pwd != NULL)
mc_global.tty.shell = g_strdup (pwd->pw_shell);
}
else
/* 1st choice: SHELL environment variable */
mc_global.tty.shell = g_strdup (shell_env);

if ((mc_global.tty.shell == NULL) || (mc_global.tty.shell[0] == '\0'))
{
g_free (mc_global.tty.shell);
mc_global.tty.shell = g_strdup ("/bin/sh");
mc_global.tty.shell = mc_get_system_shell ();
}
mc_global.tty.shell_realpath = mc_realpath (mc_global.tty.shell, rp_shell);

/* This is the directory, where MC was installed, on Unix this is DATADIR */
/* and can be overriden by the MC_DATADIR environment variable */
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202 changes: 171 additions & 31 deletions src/subshell.c
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Original file line number Diff line number Diff line change
Expand Up @@ -114,6 +114,8 @@ enum
static enum
{
BASH,
ASH_BUSYBOX, /* BusyBox default shell (ash) */
DASH, /* Debian variant of ash */
TCSH,
ZSH,
FISH
Expand Down Expand Up @@ -285,7 +287,26 @@ init_subshell_child (const char *pty_name)

break;

/* TODO: Find a way to pass initfile to TCSH and ZSH */
case ASH_BUSYBOX:
case DASH:
/* Do we have a custom init file ~/.local/share/mc/ashrc? */
init_file = mc_config_get_full_path ("ashrc");

/* Otherwise use ~/.profile */
if (access (init_file, R_OK) == -1)
{
g_free (init_file);
init_file = g_strdup (".profile");
}

/* Put init file to ENV variable used by ash */
putenv_str = g_strconcat ("ENV=", init_file, NULL);
putenv (putenv_str);
/* Do not use "g_free (putenv_str)" here, otherwise ENV will be undefined! */

break;

/* TODO: Find a way to pass initfile to TCSH, ZSH and FISH */
case TCSH:
case ZSH:
case FISH:
Expand Down Expand Up @@ -323,19 +344,18 @@ init_subshell_child (const char *pty_name)
execl (mc_global.tty.shell, "bash", "-rcfile", init_file, (char *) NULL);
break;

case TCSH:
execl (mc_global.tty.shell, "tcsh", (char *) NULL);
break;

case ZSH:
/* Use -g to exclude cmds beginning with space from history
* and -Z to use the line editor on non-interactive term */
execl (mc_global.tty.shell, "zsh", "-Z", "-g", (char *) NULL);

break;

case ASH_BUSYBOX:
case DASH:
case TCSH:
case FISH:
execl (mc_global.tty.shell, "fish", (char *) NULL);
execl (mc_global.tty.shell, mc_global.tty.shell, (char *) NULL);
break;

default:
Expand Down Expand Up @@ -746,6 +766,59 @@ pty_open_slave (const char *pty_name)
}
#endif /* !HAVE_GRANTPT */


/* --------------------------------------------------------------------------------------------- */
/**
* Get a subshell type and store in subshell_type variable
*
* @return TRUE if subtype was gotten, FALSE otherwise
*/

static gboolean
init_subshell_type (void)
{
gboolean result = TRUE;

/* Find out what type of shell we have. Also consider real paths (resolved symlinks)
* because e.g. csh might point to tcsh, ash to dash or busybox, sh to anything. */

if (strstr (mc_global.tty.shell, "/zsh") || strstr (mc_global.tty.shell_realpath, "/zsh")
|| getenv ("ZSH_VERSION"))
/* Also detects ksh symlinked to zsh */
subshell_type = ZSH;
else if (strstr (mc_global.tty.shell, "/tcsh")
|| strstr (mc_global.tty.shell_realpath, "/tcsh"))
/* Also detects csh symlinked to tcsh */
subshell_type = TCSH;
else if (strstr (mc_global.tty.shell, "/fish")
|| strstr (mc_global.tty.shell_realpath, "/fish"))
subshell_type = FISH;
else if (strstr (mc_global.tty.shell, "/dash")
|| strstr (mc_global.tty.shell_realpath, "/dash"))
/* Debian ash (also found if symlinked to by ash/sh) */
subshell_type = DASH;
else if (strstr (mc_global.tty.shell_realpath, "/busybox"))
{
/* If shell is symlinked to busybox, assume it is an ash, even though theoretically
* it could also be a hush (a mini shell for non-MMU systems deactivated by default).
* For simplicity's sake we assume that busybox always contains an ash, not a hush.
* On embedded platforms or on server systems, /bin/sh often points to busybox.
* Sometimes even bash is symlinked to busybox (CONFIG_FEATURE_BASH_IS_ASH option),
* so we need to check busybox symlinks *before* checking for the name "bash"
* in order to avoid that case. */
subshell_type = ASH_BUSYBOX;
}
else if (strstr (mc_global.tty.shell, "/bash") || getenv ("BASH"))
/* If bash is not symlinked to busybox, it is safe to assume it is a real bash */
subshell_type = BASH;
else
{
mc_global.tty.use_subshell = FALSE;
result = FALSE;
}
return result;
}

/* --------------------------------------------------------------------------------------------- */
/*** public functions ****************************************************************************/
/* --------------------------------------------------------------------------------------------- */
Expand All @@ -765,6 +838,7 @@ init_subshell (void)
{
/* This must be remembered across calls to init_subshell() */
static char pty_name[BUF_SMALL];
/* Must be considerably longer than BUF_SMALL (128) to support fancy shell prompts */
char precmd[BUF_MEDIUM];

switch (check_sid ())
Expand All @@ -786,23 +860,8 @@ init_subshell (void)

if (mc_global.tty.subshell_pty == 0)
{ /* First time through */
/* Find out what type of shell we have */

if (strstr (mc_global.tty.shell, "/zsh") || getenv ("ZSH_VERSION"))
subshell_type = ZSH;
else if (strstr (mc_global.tty.shell, "/tcsh"))
subshell_type = TCSH;
else if (strstr (mc_global.tty.shell, "/csh"))
subshell_type = TCSH;
else if (strstr (mc_global.tty.shell, "/bash") || getenv ("BASH"))
subshell_type = BASH;
else if (strstr (mc_global.tty.shell, "/fish"))
subshell_type = FISH;
else
{
mc_global.tty.use_subshell = FALSE;
if (!init_subshell_type ())
return;
}

/* Open a pty for talking to the subshell */

Expand Down Expand Up @@ -848,7 +907,7 @@ init_subshell (void)
return;
}
}
else /* subshell_type is BASH or ZSH */ if (pipe (subshell_pipe))
else if (pipe (subshell_pipe)) /* subshell_type is BASH, ASH_BUSYBOX, DASH or ZSH */
{
perror (__FILE__ ": couldn't create pipe");
mc_global.tty.use_subshell = FALSE;
Expand Down Expand Up @@ -876,33 +935,107 @@ init_subshell (void)
init_subshell_child (pty_name);
}

/* Set up 'precmd' or equivalent for reading the subshell's CWD */
/* Set up `precmd' or equivalent for reading the subshell's CWD
*
* Attention! Never forget that these are *one-liners* even though the concatenated
* substrings contain line breaks and indentation for better understanding of the
* shell code. It is vital that each one-liner ends with a line feed character ("\n" ).
*/

switch (subshell_type)
{
case BASH:
g_snprintf (precmd, sizeof (precmd),
" PROMPT_COMMAND=${PROMPT_COMMAND:+$PROMPT_COMMAND\n}'pwd>&%d;kill -STOP $$'\n",
subshell_pipe[WRITE]);
" PROMPT_COMMAND=${PROMPT_COMMAND:+$PROMPT_COMMAND\n}'pwd>&%d;kill -STOP $$'\n"
"PS1='\\u@\\h:\\w\\$ '\n", subshell_pipe[WRITE]);
break;

case ASH_BUSYBOX:
/* BusyBox ash needs a somewhat complicated precmd emulation via PS1, and it is vital
* that BB be built with active CONFIG_ASH_EXPAND_PRMT, but this is the default anyway.
*
* A: This leads to a stopped subshell (=frozen mc) if user calls "ash" command
* "PS1='$(pwd>&%d; kill -STOP $$)\\u@\\h:\\w\\$ '\n",
*
* B: This leads to "sh: precmd: not found" in sub-subshell if user calls "ash" command
* "precmd() { pwd>&%d; kill -STOP $$; }; "
* "PS1='$(precmd)\\u@\\h:\\w\\$ '\n",
*
* C: This works if user calls "ash" command because in sub-subshell
* PRECMD is unfedined, thus evaluated to empty string - no damage done.
* 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 $$; }; "
* "PRECMD=precmd; "
* "PS1='$(eval $PRECMD)\\u@\\h:\\w\\$ '\n",
*/
case DASH:
/* Debian ash needs a precmd emulation via PS1, similar to BusyBox ash,
* but does not support escape sequences for user, host and cwd in prompt.
* Attention! Make sure that the buffer for precmd is big enough.
*
* We want to have a fancy dynamic prompt with user@host:cwd just like in the BusyBox
* examples above, but because replacing the home directory part of the path by "~" is
* complicated, it bloats the precmd to a size > BUF_SMALL (128).
*
* The following example is a little less fancy (home directory not replaced)
* and shows the basic workings of our prompt for easier understanding:
*
* "precmd() { "
* "echo \"$USER@$(hostname -s):$PWD\"; "
* "pwd>&%d; "
* "kill -STOP $$; "
* "}; "
* "PRECMD=precmd; "
* "PS1='$($PRECMD)$ '\n",
*/
g_snprintf (precmd, sizeof (precmd),
"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]);
break;

case ZSH:
g_snprintf (precmd, sizeof (precmd),
" _mc_precmd(){ pwd>&%d;kill -STOP $$ }; precmd_functions+=(_mc_precmd)\n",
subshell_pipe[WRITE]);
" _mc_precmd(){ pwd>&%d;kill -STOP $$ }; precmd_functions+=(_mc_precmd)\n"
"PS1='%%n@%%m:%%~%%# '\n", subshell_pipe[WRITE]);
break;

case TCSH:
g_snprintf (precmd, sizeof (precmd),
"set echo_style=both;"
"alias precmd 'echo $cwd:q >>%s;kill -STOP $$'\n", tcsh_fifo);
"set echo_style=both; "
"set prompt='%%n@%%m:%%~%%# '; "
"alias precmd 'echo $cwd:q >>%s; kill -STOP $$'\n", tcsh_fifo);
break;

case FISH:
/* Use fish_prompt_mc function for prompt, if not present then copy fish_prompt to it. */
/* We also want a fancy user@host:cwd prompt here, but fish makes it very easy to also
* use colours, which is what we will do. But first here is a simpler, uncoloured version:
* "function fish_prompt; "
* "echo (whoami)@(hostname -s):(pwd)\\$\\ ; "
* "echo \"$PWD\">&%d; "
* "kill -STOP %%self; "
* "end\n",
*
* TODO: fish prompt is shown when panel is hidden (Ctrl-O), but not when it is visible.
* Find out how to fix this.
*/
g_snprintf (precmd, sizeof (precmd),
"if not functions -q fish_prompt_mc;"
"functions -c fish_prompt fish_prompt_mc; end;"
"function fish_prompt; echo $PWD>&%d; fish_prompt_mc; kill -STOP %%self; end\n",
"function fish_prompt;"
"echo (whoami)@(hostname -s):(set_color $fish_color_cwd)(pwd)(set_color normal)\\$\\ ; "
"echo \"$PWD\">&%d; fish_prompt_mc; kill -STOP %%self; end\n",
subshell_pipe[WRITE]);
break;

Expand Down Expand Up @@ -1112,6 +1245,13 @@ subshell_name_quote (const char *s)
quote_cmd_start = "(printf \"%b\" '";
quote_cmd_end = "')";
}
/* TODO: When BusyBox printf is fixed, get rid of this "else if", see
http://lists.busybox.net/pipermail/busybox/2012-March/077460.html */
/* else if (subshell_type == ASH_BUSYBOX)
{
quote_cmd_start = "\"`echo -en '";
quote_cmd_end = "'`\"";
} */
else
{
quote_cmd_start = "\"`printf \"%b\" '";
Expand Down

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