// Support for dispatching on environment changes.
#include "config.h" // IWYU pragma: keep
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <stddef.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <cstring>
#include <cwchar>
#if HAVE_CURSES_H
#include <curses.h>
#elif HAVE_NCURSES_H
#include <ncurses.h>
#elif HAVE_NCURSES_CURSES_H
#include <ncurses/curses.h>
#endif
#if HAVE_TERM_H
#include <term.h>
#elif HAVE_NCURSES_TERM_H
#include <ncurses/term.h>
#endif
#include <assert.h>
#include <algorithm>
#include <functional>
#include <memory>
#include <string>
#include <unordered_map>
#include <utility>
#include "common.h"
#include "complete.h"
#include "env.h"
#include "env_dispatch.h"
#include "env_universal_common.h"
#include "event.h"
#include "fallback.h" // IWYU pragma: keep
#include "flog.h"
#include "function.h"
#include "global_safety.h"
#include "history.h"
#include "input_common.h"
#include "maybe.h"
#include "output.h"
#include "parser.h"
#include "proc.h"
#include "reader.h"
#include "screen.h"
#include "termsize.h"
#include "wutil.h" // IWYU pragma: keep
#define DEFAULT_TERM1 "ansi"
#define DEFAULT_TERM2 "dumb"
/// List of all locale environment variable names that might trigger (re)initializing the locale
/// subsystem.
static const wcstring_list_t locale_variables({L"LANG", L"LANGUAGE", L"LC_ALL", L"LC_ADDRESS",
L"LC_COLLATE", L"LC_CTYPE", L"LC_IDENTIFICATION",
L"LC_MEASUREMENT", L"LC_MESSAGES", L"LC_MONETARY",
L"LC_NAME", L"LC_NUMERIC", L"LC_PAPER",
L"LC_TELEPHONE", L"LC_TIME", L"LOCPATH"});
/// List of all curses environment variable names that might trigger (re)initializing the curses
/// subsystem.
static const wcstring_list_t curses_variables({L"TERM", L"TERMINFO", L"TERMINFO_DIRS"});
class var_dispatch_table_t {
using named_callback_t = std::function<void(const wcstring &, env_stack_t &)>;
std::unordered_map<wcstring, named_callback_t> named_table_;
using anon_callback_t = std::function<void(env_stack_t &)>;
std::unordered_map<wcstring, anon_callback_t> anon_table_;
bool observes_var(const wcstring &name) {
return named_table_.count(name) || anon_table_.count(name);
}
public:
/// Add a callback for the given variable, which expects the name.
/// We must not already be observing this variable.
void add(wcstring name, named_callback_t cb) {
assert(!observes_var(name) && "Already observing that variable");
named_table_.emplace(std::move(name), std::move(cb));
}
/// Add a callback for the given variable, which ignores the name.
/// We must not already be observing this variable.
void add(wcstring name, anon_callback_t cb) {
assert(!observes_var(name) && "Already observing that variable");
anon_table_.emplace(std::move(name), std::move(cb));
}
void dispatch(const wcstring &key, env_stack_t &vars) const {
auto named = named_table_.find(key);
if (named != named_table_.end()) {
named->second(key, vars);
}
auto anon = anon_table_.find(key);
if (anon != anon_table_.end()) {
anon->second(vars);
}
}
};
// Forward declarations.
static void init_curses(const environment_t &vars);
static void init_locale(const environment_t &vars);
static void update_fish_color_support(const environment_t &vars);
/// True if we think we can set the terminal title.
static relaxed_atomic_bool_t can_set_term_title{false};
// Run those dispatch functions which want to be run at startup.
static void run_inits(const environment_t &vars);
// return a new-ly allocated dispatch table, running those dispatch functions which should be
// initialized.
static std::unique_ptr<const var_dispatch_table_t> create_dispatch_table();
// A pointer to the variable dispatch table. This is allocated with new() and deliberately leaked to
// avoid shutdown destructors. This is set during startup and should not be modified after.
static latch_t<const var_dispatch_table_t> s_var_dispatch_table;
void env_dispatch_init(const environment_t &vars) {
run_inits(vars);
// Note this deliberately leaks; the dispatch table is immortal.
// Via this construct we can avoid invoking destructors at shutdown.
s_var_dispatch_table = create_dispatch_table();
}
/// Properly sets all timezone information.
static void handle_timezone(const wchar_t *env_var_name, const environment_t &vars) {
const auto var = vars.get(env_var_name, ENV_DEFAULT);
FLOGF(env_dispatch, L"handle_timezone() current timezone var: |%ls| => |%ls|", env_var_name,
!var ? L"MISSING" : var->as_string().c_str());
const std::string &name = wcs2string(env_var_name);
if (var.missing_or_empty()) {
unsetenv_lock(name.c_str());
} else {
const std::string value = wcs2string(var->as_string());
setenv_lock(name.c_str(), value.c_str(), 1);
}
tzset();
}
/// Update the value of g_guessed_fish_emoji_width
static void guess_emoji_width(const environment_t &vars) {
if (auto width_str = vars.get(L"fish_emoji_width")) {
int new_width = fish_wcstol(width_str->as_string().c_str());
g_fish_emoji_width = std::max(0, new_width);
FLOGF(term_support, "'fish_emoji_width' preference: %d, overwriting default",
g_fish_emoji_width);
return;
}
wcstring term;
if (auto term_var = vars.get(L"TERM_PROGRAM")) {
term = term_var->as_string();
}
double version = 0;
if (auto version_var = vars.get(L"TERM_PROGRAM_VERSION")) {
std::string narrow_version = wcs2string(version_var->as_string());
version = strtod(narrow_version.c_str(), nullptr);
}
if (term == L"Apple_Terminal" && version >= 400) {
// Apple Terminal on High Sierra
g_guessed_fish_emoji_width = 2;
FLOGF(term_support, "default emoji width: 2 for %ls", term.c_str());
} else if (term == L"iTerm.app") {
// iTerm2 defaults to Unicode 8 sizes.
// See https://gitlab.com/gnachman/iterm2/wikis/unicodeversionswitching
g_guessed_fish_emoji_width = 1;
FLOGF(term_support, "default emoji width: 1");
} else {
// Default to whatever system wcwidth says to U+1F603,
// but only if it's at least 1.
int w = wcwidth(L'😃');
g_guessed_fish_emoji_width = w > 0 ? w : 1;
FLOGF(term_support, "default emoji width: %d", g_guessed_fish_emoji_width);
}
}
/// React to modifying the given variable.
void env_dispatch_var_change(const wcstring &key, env_stack_t &vars) {
ASSERT_IS_MAIN_THREAD();
// Do nothing if not yet fully initialized.
if (!s_var_dispatch_table) return;
s_var_dispatch_table->dispatch(key, vars);
}
/// Universal variable callback function. This function makes sure the proper events are triggered
/// when an event occurs.
static void universal_callback(env_stack_t *stack, const callback_data_t &cb) {
const wchar_t *op = cb.is_erase() ? L"ERASE" : L"SET";
env_dispatch_var_change(cb.key, *stack);
// TODO: eliminate this principal_parser. Need to rationalize how multiple threads work here.
event_fire(parser_t::principal_parser(), event_t::variable(cb.key, {L"VARIABLE", op, cb.key}));
}
void env_universal_callbacks(env_stack_t *stack, const callback_data_list_t &callbacks) {
for (const callback_data_t &cb : callbacks) {
universal_callback(stack, cb);
}
}
static void handle_fish_term_change(const env_stack_t &vars) {
update_fish_color_support(vars);
reader_schedule_prompt_repaint();
}
static void handle_change_ambiguous_width(const env_stack_t &vars) {
int new_width = 1;
if (auto width_str = vars.get(L"fish_ambiguous_width")) {
new_width = fish_wcstol(width_str->as_string().c_str());
}
g_fish_ambiguous_width = std::max(0, new_width);
}
static void handle_term_size_change(const env_stack_t &vars) {
termsize_container_t::shared().handle_columns_lines_var_change(vars);
}
static void handle_fish_history_change(const env_stack_t &vars) {
reader_change_history(history_session_id(vars));
}
static void handle_function_path_change(const env_stack_t &vars) {
UNUSED(vars);
function_invalidate_path();
}
static void handle_complete_path_change(const env_stack_t &vars) {
UNUSED(vars);
complete_invalidate_path();
}
static void handle_tz_change(const wcstring &var_name, const env_stack_t &vars) {
handle_timezone(var_name.c_str(), vars);
}
static void handle_locale_change(const environment_t &vars) {
init_locale(vars);
// We need to re-guess emoji width because the locale might have changed to a multibyte one.
guess_emoji_width(vars);
}
static void handle_curses_change(const environment_t &vars) {
guess_emoji_width(vars);
init_curses(vars);
}
static void handle_fish_use_posix_spawn_change(const environment_t &vars) {
// note this defaults to true
auto use_posix_spawn = vars.get(L"fish_use_posix_spawn");
g_use_posix_spawn =
use_posix_spawn.missing_or_empty() ? true : bool_from_string(use_posix_spawn->as_string());
}
/// Allow the user to override the limit on how much data the `read` command will process.
/// This is primarily for testing but could be used by users in special situations.
static void handle_read_limit_change(const environment_t &vars) {
auto read_byte_limit_var = vars.get(L"fish_read_limit");
if (!read_byte_limit_var.missing_or_empty()) {
size_t limit = fish_wcstoull(read_byte_limit_var->as_string().c_str());
if (errno) {
FLOGF(warning, "Ignoring fish_read_limit since it is not valid");
} else {
read_byte_limit = limit;
}
}
}
/// Populate the dispatch table used by `env_dispatch_var_change()` to efficiently call the
/// appropriate function to handle a change to a variable.
/// Note this returns a new-allocated value that we expect to leak.
static std::unique_ptr<const var_dispatch_table_t> create_dispatch_table() {
auto var_dispatch_table = make_unique<var_dispatch_table_t>();
for (const auto &var_name : locale_variables) {
var_dispatch_table->add(var_name, handle_locale_change);
}
for (const auto &var_name : curses_variables) {
var_dispatch_table->add(var_name, handle_curses_change);
}
var_dispatch_table->add(L"fish_term256", handle_fish_term_change);
var_dispatch_table->add(L"fish_term24bit", handle_fish_term_change);
var_dispatch_table->add(L"fish_escape_delay_ms", update_wait_on_escape_ms);
var_dispatch_table->add(L"fish_emoji_width", guess_emoji_width);
var_dispatch_table->add(L"fish_ambiguous_width", handle_change_ambiguous_width);
var_dispatch_table->add(L"LINES", handle_term_size_change);
var_dispatch_table->add(L"COLUMNS", handle_term_size_change);
var_dispatch_table->add(L"fish_complete_path", handle_complete_path_change);
var_dispatch_table->add(L"fish_function_path", handle_function_path_change);
var_dispatch_table->add(L"fish_read_limit", handle_read_limit_change);
var_dispatch_table->add(L"fish_history", handle_fish_history_change);
var_dispatch_table->add(L"TZ", handle_tz_change);
var_dispatch_table->add(L"fish_use_posix_spawn", handle_fish_use_posix_spawn_change);
// This std::move is required to avoid a build error on old versions of libc++ (#5801),
// but it causes a different warning under newer versions of GCC (observed under GCC 9.3.0,
// but not under llvm/clang 9).
#if __GNUC__ > 4
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wredundant-move"
#endif
return std::move(var_dispatch_table);
#if __GNUC__ > 4
#pragma GCC diagnostic pop
#endif
}
static void run_inits(const environment_t &vars) {
// This is the subset of those dispatch functions which want to be run at startup.
init_locale(vars);
init_curses(vars);
guess_emoji_width(vars);
update_wait_on_escape_ms(vars);
handle_read_limit_change(vars);
handle_fish_use_posix_spawn_change(vars);
}
/// Updates our idea of whether we support term256 and term24bit (see issue #10222).
static void update_fish_color_support(const environment_t &vars) {
// Detect or infer term256 support. If fish_term256 is set, we respect it;
// otherwise infer it from the TERM variable or use terminfo.
wcstring term;
bool support_term256 = false;
bool support_term24bit = false;
if (auto term_var = vars.get(L"TERM")) term = term_var->as_string();
if (auto fish_term256 = vars.get(L"fish_term256")) {
// $fish_term256
support_term256 = bool_from_string(fish_term256->as_string());
FLOGF(term_support, L"256 color support determined by '$fish_term256'");
} else if (term.find(L"256color") != wcstring::npos) {
// TERM is *256color*: 256 colors explicitly supported
support_term256 = true;
FLOGF(term_support, L"256 color support enabled for TERM=%ls", term.c_str());
} else if (term.find(L"xterm") != wcstring::npos) {
// Assume that all 'xterm's can handle 256, except for Terminal.app from Snow Leopard
wcstring term_program;
if (auto tp = vars.get(L"TERM_PROGRAM")) term_program = tp->as_string();
if (term_program == L"Apple_Terminal") {
auto tpv = vars.get(L"TERM_PROGRAM_VERSION");
if (tpv && fish_wcstod(tpv->as_string().c_str(), nullptr) > 299) {
// OS X Lion is version 299+, it has 256 color support (see github Wiki)
support_term256 = true;
FLOGF(term_support, L"256 color support enabled for TERM=%ls on Terminal.app",
term.c_str());
}
} else {
support_term256 = true;
FLOGF(term_support, L"256 color support enabled for TERM=%ls", term.c_str());
}
} else if (cur_term != nullptr) {
// See if terminfo happens to identify 256 colors
support_term256 = (max_colors >= 256);
FLOGF(term_support, L"256 color support: %d colors per terminfo entry for %ls", max_colors,
term.c_str());
}
// Handle $fish_term24bit
if (auto fish_term24bit = vars.get(L"fish_term24bit")) {
support_term24bit = bool_from_string(fish_term24bit->as_string());
FLOGF(term_support, L"'fish_term24bit' preference: 24-bit color %ls",
support_term24bit ? L"enabled" : L"disabled");
} else {
if (vars.get(L"STY") || string_prefixes_string(L"eterm", term)) {
// Screen and emacs' ansi-term swallow truecolor sequences,
// so we ignore them unless force-enabled.
FLOGF(term_support, L"Truecolor support: disabling for eterm/screen");
support_term24bit = false;
} else if (cur_term != nullptr && max_colors >= 32767) {
// $TERM wins, xterm-direct reports 32767 colors, we assume that's the minimum
// as xterm is weird when it comes to color.
FLOGF(term_support, L"Truecolor support: Enabling per terminfo for %ls with %d colors",
term.c_str(), max_colors);
support_term24bit = true;
} else {
if (auto ct = vars.get(L"COLORTERM")) {
// If someone set $COLORTERM, that's the sort of color they want.
if (ct->as_string() == L"truecolor" || ct->as_string() == L"24bit") {
FLOGF(term_support, L"Truecolor support: Enabling per $COLORTERM='%ls'",
ct->as_string().c_str());
support_term24bit = true;
}
} else if (vars.get(L"KONSOLE_VERSION") || vars.get(L"KONSOLE_PROFILE_NAME")) {
// All konsole versions that use $KONSOLE_VERSION are new enough to support this,
// so no check is necessary.
FLOGF(term_support, L"Truecolor support: Enabling for Konsole");
support_term24bit = true;
} else if (auto it = vars.get(L"ITERM_SESSION_ID")) {
// Supporting versions of iTerm include a colon here.
// We assume that if this is iTerm, it can't also be st, so having this check
// inside is okay.
if (it->as_string().find(L':') != wcstring::npos) {
FLOGF(term_support, L"Truecolor support: Enabling for ITERM");
support_term24bit = true;
}
} else if (string_prefixes_string(L"st-", term)) {
FLOGF(term_support, L"Truecolor support: Enabling for st");
support_term24bit = true;
} else if (auto vte = vars.get(L"VTE_VERSION")) {
if (fish_wcstod(vte->as_string().c_str(), nullptr) > 3600) {
FLOGF(term_support, L"Truecolor support: Enabling for VTE version %ls",
vte->as_string().c_str());
support_term24bit = true;
}
}
}
}
color_support_t support = (support_term256 ? color_support_term256 : 0) |
(support_term24bit ? color_support_term24bit : 0);
output_set_color_support(support);
}
// Try to initialize the terminfo/curses subsystem using our fallback terminal name. Do not set
// `TERM` to our fallback. We're only doing this in the hope of getting a minimally functional
// shell. If we launch an external command that uses TERM it should get the same value we were
// given, if any.
static bool initialize_curses_using_fallback(const char *term) {
// If $TERM is already set to the fallback name we're about to use there isn't any point in
// seeing if the fallback name can be used.
auto &vars = env_stack_t::globals();
auto term_var = vars.get(L"TERM");
if (term_var.missing_or_empty()) return false;
auto term_env = wcs2string(term_var->as_string());
if (term_env == DEFAULT_TERM1 || term_env == DEFAULT_TERM2) return false;
if (is_interactive_session()) FLOGF(warning, _(L"Using fallback terminal type '%s'."), term);
int err_ret;
if (setupterm(const_cast<char *>(term), STDOUT_FILENO, &err_ret) == OK) return true;
if (is_interactive_session()) {
FLOGF(warning, _(L"Could not set up terminal using the fallback terminal type '%s'."),
term);
}
return false;
}
/// This is a pretty lame heuristic for detecting terminals that do not support setting the
/// title. If we recognise the terminal name as that of a virtual terminal, we assume it supports
/// setting the title. If we recognise it as that of a console, we assume it does not support
/// setting the title. Otherwise we check the ttyname and see if we believe it is a virtual
/// terminal.
///
/// One situation in which this breaks down is with screen, since screen supports setting the
/// terminal title if the underlying terminal does so, but will print garbage on terminals that
/// don't. Since we can't see the underlying terminal below screen there is no way to fix this.
static const wchar_t *const title_terms[] = {L"xterm", L"screen", L"tmux",
L"nxterm", L"rxvt", L"alacritty"};
static bool does_term_support_setting_title(const environment_t &vars) {
const auto term_var = vars.get(L"TERM");
if (term_var.missing_or_empty()) return false;
const wcstring term_str = term_var->as_string();
const wchar_t *term = term_str.c_str();
bool recognized = contains(title_terms, term_var->as_string());
if (!recognized) recognized = !std::wcsncmp(term, L"xterm-", const_strlen(L"xterm-"));
if (!recognized) recognized = !std::wcsncmp(term, L"screen-", const_strlen(L"screen-"));
if (!recognized) recognized = !std::wcsncmp(term, L"tmux-", const_strlen(L"tmux-"));
if (!recognized) {
if (std::wcscmp(term, L"linux") == 0) return false;
if (std::wcscmp(term, L"dumb") == 0) return false;
// NetBSD
if (std::wcscmp(term, L"vt100") == 0) return false;
if (std::wcscmp(term, L"wsvt25") == 0) return false;
char buf[PATH_MAX];
int retval = ttyname_r(STDIN_FILENO, buf, PATH_MAX);
if (retval != 0 || std::strstr(buf, "tty") || std::strstr(buf, "/vc/")) return false;
}
return true;
}
/// Initialize the curses subsystem.
static void init_curses(const environment_t &vars) {
for (const auto &var_name : curses_variables) {
std::string name = wcs2string(var_name);
const auto var = vars.get(var_name, ENV_EXPORT);
if (var.missing_or_empty()) {
FLOGF(term_support, L"curses var %s missing or empty", name.c_str());
unsetenv_lock(name.c_str());
} else {
std::string value = wcs2string(var->as_string());
FLOGF(term_support, L"curses var %s='%s'", name.c_str(), value.c_str());
setenv_lock(name.c_str(), value.c_str(), 1);
}
}
int err_ret;
if (setupterm(nullptr, STDOUT_FILENO, &err_ret) == ERR) {
auto term = vars.get(L"TERM");
if (is_interactive_session()) {
FLOGF(warning, _(L"Could not set up terminal."));
if (term.missing_or_empty()) {
FLOGF(warning, _(L"TERM environment variable not set."));
} else {
FLOGF(warning, _(L"TERM environment variable set to '%ls'."),
term->as_string().c_str());
FLOGF(warning, _(L"Check that this terminal type is supported on this system."));
}
}
if (!initialize_curses_using_fallback(DEFAULT_TERM1)) {
initialize_curses_using_fallback(DEFAULT_TERM2);
}
}
can_set_term_title = does_term_support_setting_title(vars);
term_has_xn =
tigetflag(const_cast<char *>("xenl")) == 1; // does terminal have the eat_newline_glitch
update_fish_color_support(vars);
// Invalidate the cached escape sequences since they may no longer be valid.
layout_cache_t::shared.clear();
curses_initialized = true;
}
/// Initialize the locale subsystem.
static void init_locale(const environment_t &vars) {
// We have to make a copy because the subsequent setlocale() call to change the locale will
// invalidate the pointer from the this setlocale() call.
char *old_msg_locale = strdup(setlocale(LC_MESSAGES, nullptr));
for (const auto &var_name : locale_variables) {
const auto var = vars.get(var_name, ENV_EXPORT);
const std::string &name = wcs2string(var_name);
if (var.missing_or_empty()) {
FLOGF(env_locale, L"locale var %s missing or empty", name.c_str());
unsetenv_lock(name.c_str());
} else {
const std::string value = wcs2string(var->as_string());
FLOGF(env_locale, L"locale var %s='%s'", name.c_str(), value.c_str());
setenv_lock(name.c_str(), value.c_str(), 1);
}
}
char *locale = setlocale(LC_ALL, "");
fish_setlocale();
FLOGF(env_locale, L"init_locale() setlocale(): '%s'", locale);
const char *new_msg_locale = setlocale(LC_MESSAGES, nullptr);
FLOGF(env_locale, L"old LC_MESSAGES locale: '%s'", old_msg_locale);
FLOGF(env_locale, L"new LC_MESSAGES locale: '%s'", new_msg_locale);
#ifdef HAVE__NL_MSG_CAT_CNTR
if (std::strcmp(old_msg_locale, new_msg_locale) != 0) {
// Make change known to GNU gettext.
extern int _nl_msg_cat_cntr;
_nl_msg_cat_cntr++;
}
#endif
free(old_msg_locale);
}
/// Returns true if we think the terminal supports setting its title.
bool term_supports_setting_title() { return can_set_term_title; }
/// Miscellaneous variables.
bool g_use_posix_spawn = false;
// Limit `read` to 100 MiB (bytes not wide chars) by default. This can be overridden by the
// fish_read_limit variable.
size_t read_byte_limit = 100 * 1024 * 1024;