// Functions for setting and getting environment variables.
#include "config.h" // IWYU pragma: keep
#include <errno.h>
#include <pwd.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>
#include <algorithm>
#include <iterator>
#include <mutex>
#include <set>
#include <utility>
#include <vector>
#include "builtin_bind.h"
#include "common.h"
#include "env.h"
#include "env_dispatch.h"
#include "env_universal_common.h"
#include "event.h"
#include "fallback.h" // IWYU pragma: keep
#include "fish_version.h"
#include "flog.h"
#include "global_safety.h"
#include "history.h"
#include "input.h"
#include "path.h"
#include "proc.h"
#include "reader.h"
#include "wutil.h" // IWYU pragma: keep
#define DEFAULT_TERM1 "ansi"
#define DEFAULT_TERM2 "dumb"
/// Some configuration path environment variables.
#define FISH_DATADIR_VAR L"__fish_data_dir"
#define FISH_SYSCONFDIR_VAR L"__fish_sysconf_dir"
#define FISH_HELPDIR_VAR L"__fish_help_dir"
#define FISH_BIN_DIR L"__fish_bin_dir"
#define FISH_CONFIG_DIR L"__fish_config_dir"
#define FISH_USER_DATA_DIR L"__fish_user_data_dir"
/// At init, we read all the environment variables from this array.
extern char **environ;
/// The character used to delimit path and non-path variables in exporting and in string expansion.
static const wchar_t PATH_ARRAY_SEP = L':';
static const wchar_t NONPATH_ARRAY_SEP = L' ';
bool curses_initialized = false;
/// Does the terminal have the "eat_newline_glitch".
bool term_has_xn = false;
/// Universal variables global instance. Initialized in env_init.
static latch_t<env_universal_t> s_universal_variables;
/// Getter for universal variables.
static env_universal_t *uvars() { return s_universal_variables; }
bool env_universal_barrier() { return env_stack_t::principal().universal_barrier(); }
struct electric_var_t {
enum {
freadonly = 1 << 0, // May not be modified by the user.
fcomputed = 1 << 1, // Value is dynamically computed.
fexports = 1 << 2, // Exported to child processes.
};
const wchar_t *name;
uint32_t flags;
bool readonly() const { return flags & freadonly; }
bool computed() const { return flags & fcomputed; }
bool exports() const { return flags & fexports; }
static const electric_var_t *for_name(const wcstring &name);
};
static const electric_var_t electric_variables[] = {
{L"PWD", electric_var_t::freadonly | electric_var_t::fcomputed | electric_var_t::fexports},
{L"SHLVL", electric_var_t::freadonly | electric_var_t::fexports},
{L"history", electric_var_t::freadonly | electric_var_t::fcomputed},
{L"pipestatus", electric_var_t::freadonly | electric_var_t::fcomputed},
{L"status", electric_var_t::freadonly | electric_var_t::fcomputed},
{L"version", electric_var_t::freadonly},
{L"FISH_VERSION", electric_var_t::freadonly},
{L"fish_pid", electric_var_t::freadonly},
{L"hostname", electric_var_t::freadonly},
{L"_", electric_var_t::freadonly},
{L"fish_private_mode", electric_var_t::freadonly},
{L"umask", electric_var_t::fcomputed},
};
const electric_var_t *electric_var_t::for_name(const wcstring &name) {
for (const auto &var : electric_variables) {
if (name == var.name) {
return &var;
}
}
return nullptr;
}
/// Check if a variable may not be set using the set command.
static bool is_read_only(const wcstring &key) {
if (const auto *ev = electric_var_t::for_name(key)) {
return ev->readonly();
}
// Hack.
return in_private_mode() && key == L"fish_history";
}
/// Return true if a variable should become a path variable by default. See #436.
static bool variable_should_auto_pathvar(const wcstring &name) {
return string_suffixes_string(L"PATH", name);
}
// This is a big dorky lock we take around everything that might read from or modify an env_node_t.
// Fine grained locking is annoying here because env_nodes may be shared between env_stacks, so each
// node would need its own lock.
static std::mutex env_lock;
/// Some env vars contain a list of paths where an empty path element is equivalent to ".".
/// Unfortunately that convention causes problems for fish scripts. So this function replaces the
/// empty path element with an explicit ".". See issue #3914.
void fix_colon_delimited_var(const wcstring &var_name, env_stack_t &vars) {
const auto paths = vars.get(var_name);
if (paths.missing_or_empty()) return;
// See if there's any empties.
const wcstring empty = wcstring();
const wcstring_list_t &strs = paths->as_list();
if (contains(strs, empty)) {
// Copy the list and replace empties with L"."
wcstring_list_t newstrs = strs;
std::replace(newstrs.begin(), newstrs.end(), empty, wcstring(L"."));
int retval = vars.set(var_name, ENV_DEFAULT | ENV_USER, std::move(newstrs));
if (retval != ENV_OK) {
FLOGF(error, L"fix_colon_delimited_var failed unexpectedly with retval %d", retval);
}
}
}
const wcstring_list_t &env_var_t::as_list() const { return *vals_; }
wchar_t env_var_t::get_delimiter() const {
return is_pathvar() ? PATH_ARRAY_SEP : NONPATH_ARRAY_SEP;
}
/// Return a string representation of the var.
wcstring env_var_t::as_string() const { return join_strings(*vals_, get_delimiter()); }
void env_var_t::to_list(wcstring_list_t &out) const { out = *vals_; }
env_var_t::env_var_flags_t env_var_t::flags_for(const wchar_t *name) {
env_var_flags_t result = 0;
if (is_read_only(name)) result |= flag_read_only;
return result;
}
/// \return a singleton empty list, to avoid unnecessary allocations in env_var_t.
std::shared_ptr<const wcstring_list_t> env_var_t::empty_list() {
static const auto s_empty_result = std::make_shared<const wcstring_list_t>();
return s_empty_result;
}
environment_t::~environment_t() = default;
wcstring environment_t::get_pwd_slash() const {
// Return "/" if PWD is missing.
// See https://github.com/fish-shell/fish-shell/issues/5080
auto pwd_var = get(L"PWD");
wcstring pwd;
if (!pwd_var.missing_or_empty()) {
pwd = pwd_var->as_string();
}
if (!string_suffixes_string(L"/", pwd)) {
pwd.push_back(L'/');
}
return pwd;
}
null_environment_t::~null_environment_t() = default;
maybe_t<env_var_t> null_environment_t::get(const wcstring &key, env_mode_flags_t mode) const {
UNUSED(key);
UNUSED(mode);
return none();
}
wcstring_list_t null_environment_t::get_names(int flags) const {
UNUSED(flags);
return {};
}
/// Set up the USER variable.
static void setup_user(bool force) {
auto &vars = env_stack_t::globals();
if (force || vars.get(L"USER").missing_or_empty()) {
struct passwd userinfo;
struct passwd *result;
char buf[8192];
int retval = getpwuid_r(getuid(), &userinfo, buf, sizeof(buf), &result);
if (!retval && result) {
const wcstring uname = str2wcstring(userinfo.pw_name);
vars.set_one(L"USER", ENV_GLOBAL | ENV_EXPORT, uname);
}
}
}
/// Various things we need to initialize at run-time that don't really fit any of the other init
/// routines.
void misc_init() {
// If stdout is open on a tty ensure stdio is unbuffered. That's because those functions might
// be intermixed with `write()` calls and we need to ensure the writes are not reordered. See
// issue #3748.
if (isatty(STDOUT_FILENO)) {
fflush(stdout);
setvbuf(stdout, NULL, _IONBF, 0);
}
}
/// Ensure the content of the magic path env vars is reasonable. Specifically, that empty path
/// elements are converted to explicit "." to make the vars easier to use in fish scripts.
static void init_path_vars() {
// Do not replace empties in MATHPATH - see #4158.
fix_colon_delimited_var(L"PATH", env_stack_t::globals());
fix_colon_delimited_var(L"CDPATH", env_stack_t::globals());
}
/// Make sure the PATH variable contains something.
static void setup_path() {
auto &vars = env_stack_t::globals();
const auto path = vars.get(L"PATH");
if (path.missing_or_empty()) {
#if defined(_CS_PATH)
// _CS_PATH: colon-separated paths to find POSIX utilities
std::string cspath;
cspath.resize(confstr(_CS_PATH, nullptr, 0));
confstr(_CS_PATH, &cspath[0], cspath.length());
#else
std::string cspath = "/usr/bin:/bin"; // I doubt this is even necessary
#endif
vars.set_one(L"PATH", ENV_GLOBAL | ENV_EXPORT, str2wcstring(cspath));
}
}
void env_init(const struct config_paths_t *paths /* or NULL */) {
env_stack_t &vars = env_stack_t::principal();
// Import environment variables. Walk backwards so that the first one out of any duplicates wins
// (See issue #2784).
wcstring key, val;
const char *const *envp = environ;
size_t i = 0;
while (envp && envp[i]) i++;
while (i--) {
const wcstring key_and_val = str2wcstring(envp[i]); // like foo=bar
size_t eql = key_and_val.find(L'=');
if (eql == wcstring::npos) {
// No equal-sign found so treat it as a defined var that has no value(s).
if (!electric_var_t::for_name(key_and_val)) {
vars.set_empty(key_and_val, ENV_EXPORT | ENV_GLOBAL);
}
} else {
key.assign(key_and_val, 0, eql);
val.assign(key_and_val, eql + 1, wcstring::npos);
if (!electric_var_t::for_name(key)) {
vars.set(key, ENV_EXPORT | ENV_GLOBAL, {val});
}
}
}
// Set the given paths in the environment, if we have any.
if (paths != NULL) {
vars.set_one(FISH_DATADIR_VAR, ENV_GLOBAL, paths->data);
vars.set_one(FISH_SYSCONFDIR_VAR, ENV_GLOBAL, paths->sysconf);
vars.set_one(FISH_HELPDIR_VAR, ENV_GLOBAL, paths->doc);
vars.set_one(FISH_BIN_DIR, ENV_GLOBAL, paths->bin);
}
wcstring user_config_dir;
path_get_config(user_config_dir);
vars.set_one(FISH_CONFIG_DIR, ENV_GLOBAL, user_config_dir);
wcstring user_data_dir;
path_get_data(user_data_dir);
vars.set_one(FISH_USER_DATA_DIR, ENV_GLOBAL, user_data_dir);
init_path_vars();
// Set up the USER and PATH variables
setup_path();
// Some `su`s keep $USER when changing to root.
// This leads to issues later on (and e.g. in prompts),
// so we work around it by resetting $USER.
// TODO: Figure out if that su actually checks if username == "root"(as the man page says) or
// UID == 0.
uid_t uid = getuid();
setup_user(uid == 0);
// Set up $IFS - this used to be in share/config.fish, but really breaks if it isn't done.
vars.set_one(L"IFS", ENV_GLOBAL, L"\n \t");
// Set up the version variable.
wcstring version = str2wcstring(get_fish_version());
vars.set_one(L"version", ENV_GLOBAL, version);
vars.set_one(L"FISH_VERSION", ENV_GLOBAL, version);
// Set the $fish_pid variable.
vars.set_one(L"fish_pid", ENV_GLOBAL, to_string(getpid()));
// Set the $hostname variable
wcstring hostname = L"fish";
get_hostname_identifier(hostname);
vars.set_one(L"hostname", ENV_GLOBAL, hostname);
// Set up SHLVL variable. Not we can't use vars.get() because SHLVL is read-only, and therefore
// was not inherited from the environment.
wcstring nshlvl_str = L"1";
if (const char *shlvl_var = getenv("SHLVL")) {
const wchar_t *end;
// TODO: Figure out how to handle invalid numbers better. Shouldn't we issue a diagnostic?
long shlvl_i = fish_wcstol(str2wcstring(shlvl_var).c_str(), &end);
if (!errno && shlvl_i >= 0) {
nshlvl_str = to_string(shlvl_i + 1);
}
}
vars.set_one(L"SHLVL", ENV_GLOBAL | ENV_EXPORT, nshlvl_str);
// Set up the HOME variable.
// Unlike $USER, it doesn't seem that `su`s pass this along
// if the target user is root, unless "--preserve-environment" is used.
// Since that is an explicit choice, we should allow it to enable e.g.
// env HOME=(mktemp -d) su --preserve-environment fish
if (vars.get(L"HOME").missing_or_empty()) {
auto user_var = vars.get(L"USER");
if (!user_var.missing_or_empty()) {
char *unam_narrow = wcs2str(user_var->as_string());
struct passwd userinfo;
struct passwd *result;
char buf[8192];
int retval = getpwnam_r(unam_narrow, &userinfo, buf, sizeof(buf), &result);
if (retval || !result) {
// Maybe USER is set but it's bogus. Reset USER from the db and try again.
setup_user(true);
user_var = vars.get(L"USER");
if (!user_var.missing_or_empty()) {
unam_narrow = wcs2str(user_var->as_string());
retval = getpwnam_r(unam_narrow, &userinfo, buf, sizeof(buf), &result);
}
}
if (!retval && result && userinfo.pw_dir) {
const wcstring dir = str2wcstring(userinfo.pw_dir);
vars.set_one(L"HOME", ENV_GLOBAL | ENV_EXPORT, dir);
} else {
// We cannot get $HOME. This triggers warnings for history and config.fish already,
// so it isn't necessary to warn here as well.
vars.set_empty(L"HOME", ENV_GLOBAL | ENV_EXPORT);
}
free(unam_narrow);
} else {
// If $USER is empty as well (which we tried to set above), we can't get $HOME.
vars.set_empty(L"HOME", ENV_GLOBAL | ENV_EXPORT);
}
}
// initialize the PWD variable if necessary
// Note we may inherit a virtual PWD that doesn't match what getcwd would return; respect that
// if and only if it matches getcwd (#5647). Note we treat PWD as read-only so it was not set in
// vars.
const char *incoming_pwd_cstr = getenv("PWD");
wcstring incoming_pwd = incoming_pwd_cstr ? str2wcstring(incoming_pwd_cstr) : wcstring{};
if (!incoming_pwd.empty() && paths_are_same_file(incoming_pwd, L".")) {
vars.set_one(L"PWD", ENV_EXPORT | ENV_GLOBAL, incoming_pwd);
} else {
vars.set_pwd_from_getcwd();
}
vars.set_termsize(); // initialize the terminal size variables
// Set fish_bind_mode to "default".
vars.set_one(FISH_BIND_MODE_VAR, ENV_GLOBAL, DEFAULT_BIND_MODE);
// Allow changes to variables to produce events.
env_dispatch_init(vars);
init_input();
// Complain about invalid config paths.
path_emit_config_directory_errors(vars);
// Set up universal variables. The empty string means to use the default path.
s_universal_variables.emplace(L"");
callback_data_list_t callbacks;
s_universal_variables->initialize(callbacks);
env_universal_callbacks(&env_stack_t::principal(), callbacks);
}
static int set_umask(const wcstring_list_t &list_val) {
long mask = -1;
if (list_val.size() == 1 && !list_val.front().empty()) {
mask = fish_wcstol(list_val.front().c_str(), NULL, 8);
}
if (errno || mask > 0777 || mask < 0) return ENV_INVALID;
// Do not actually create a umask variable. On env_stack_t::get() it will be calculated.
umask(mask);
return ENV_OK;
}
namespace {
struct query_t {
// Whether any scopes were specified.
bool has_scope;
// Whether to search local, global, universal scopes.
bool local;
bool global;
bool universal;
// Whether export or unexport was specified.
bool has_export_unexport;
// Whether to search exported and unexported variables.
bool exports;
bool unexports;
// Whether pathvar or unpathvar was set.
bool has_pathvar_unpathvar;
bool pathvar;
bool unpathvar;
// Whether this is a "user" set.
bool user;
explicit query_t(env_mode_flags_t mode) {
has_scope = mode & (ENV_LOCAL | ENV_GLOBAL | ENV_UNIVERSAL);
local = !has_scope || (mode & ENV_LOCAL);
global = !has_scope || (mode & ENV_GLOBAL);
universal = !has_scope || (mode & ENV_UNIVERSAL);
has_export_unexport = mode & (ENV_EXPORT | ENV_UNEXPORT);
exports = !has_export_unexport || (mode & ENV_EXPORT);
unexports = !has_export_unexport || (mode & ENV_UNEXPORT);
// note we don't use pathvar for searches, so these don't default to true if unspecified.
has_pathvar_unpathvar = mode & (ENV_PATHVAR | ENV_UNPATHVAR);
pathvar = mode & ENV_PATHVAR;
unpathvar = mode & ENV_UNPATHVAR;
user = mode & ENV_USER;
}
bool export_matches(const env_var_t &var) const {
if (has_export_unexport) {
return var.exports() ? exports : unexports;
} else {
return true;
}
}
};
// Struct representing one level in the function variable stack.
class env_node_t {
public:
/// Variable table.
var_table_t env;
/// Does this node imply a new variable scope? If yes, all non-global variables below this one
/// in the stack are invisible. If new_scope is set for the global variable node, the universe
/// will explode.
const bool new_scope;
/// Does this node contain any variables which are exported to subshells
/// or does it redefine any variables to not be exported?
bool exportv = false;
/// Pointer to next level.
const std::shared_ptr<env_node_t> next;
env_node_t(bool is_new_scope, std::shared_ptr<env_node_t> next_scope)
: new_scope(is_new_scope), next(std::move(next_scope)) {}
maybe_t<env_var_t> find_entry(const wcstring &key) {
auto it = env.find(key);
if (it != env.end()) return it->second;
return none();
}
};
} // namespace
using env_node_ref_t = std::shared_ptr<env_node_t>;
class env_scoped_impl_t : public environment_t {
/// A struct wrapping up parser-local variables. These are conceptually variables that differ in
/// different fish internal processes.
struct perproc_data_t {
wcstring pwd{};
statuses_t statuses{statuses_t::just(0)};
};
public:
env_scoped_impl_t(env_node_ref_t locals, env_node_ref_t globals)
: locals_(std::move(locals)), globals_(std::move(globals)) {
assert(locals_ && globals_ && "Nodes cannot be null");
}
maybe_t<env_var_t> get(const wcstring &key, env_mode_flags_t mode = ENV_DEFAULT) const override;
wcstring_list_t get_names(int flags) const override;
perproc_data_t &perproc_data() { return perproc_data_; }
const perproc_data_t &perproc_data() const { return perproc_data_; }
std::shared_ptr<environment_t> snapshot() const;
virtual ~env_scoped_impl_t() = default;
std::shared_ptr<const null_terminated_array_t<char>> export_array();
env_scoped_impl_t(env_scoped_impl_t &&) = delete;
env_scoped_impl_t(const env_scoped_impl_t &) = delete;
void operator=(env_scoped_impl_t &&) = delete;
void operator=(const env_scoped_impl_t &) = delete;
protected:
// A linked list of scopes.
env_node_ref_t locals_{};
// Global scopes. There is no parent here.
env_node_ref_t globals_{};
// Per process data.
perproc_data_t perproc_data_{};
// Exported variable array used by execv.
std::shared_ptr<const null_terminated_array_t<char>> export_array_{};
/// \return true if the local scope exports.
bool local_scope_exports() const {
for (auto cursor = locals_; cursor; cursor = cursor->next) {
if (cursor->exportv) return true;
}
return false;
}
private:
// These "try" methods return true on success, false on failure. On a true return, \p result is
// populated. A maybe_t<maybe_t<...>> is a bridge too far.
// These may populate result with none() if a variable is present which does not match the
// query.
maybe_t<env_var_t> try_get_computed(const wcstring &key) const;
maybe_t<env_var_t> try_get_local(const wcstring &key) const;
maybe_t<env_var_t> try_get_global(const wcstring &key) const;
maybe_t<env_var_t> try_get_universal(const wcstring &key) const;
/// \return a newly allocated export array.
std::shared_ptr<const null_terminated_array_t<char>> create_export_array() const;
};
/// Get the exported variables into a variable table.
static void get_exported(const env_node_ref_t &n, var_table_t &table) {
if (!n) return;
// Allow parent scopes to populate first, since we may want to overwrite those results.
get_exported(n->next, table);
for (const auto &kv : n->env) {
const wcstring &key = kv.first;
const env_var_t &var = kv.second;
if (var.exports()) {
// Export the variable. Don't use std::map::insert here, since we need to overwrite
// existing values from previous scopes.
table[key] = var;
} else {
// We need to erase from the map if we are not exporting, since a lower scope may have
// exported. See #2132.
table.erase(key);
}
}
}
std::shared_ptr<const null_terminated_array_t<char>> env_scoped_impl_t::create_export_array()
const {
var_table_t table;
debug(4, L"create_export_array() recalc");
var_table_t vals;
get_exported(this->globals_, vals);
get_exported(this->locals_, vals);
if (uvars()) {
const wcstring_list_t uni = uvars()->get_names(true, false);
for (const wcstring &key : uni) {
auto var = uvars()->get(key);
if (!var.missing_or_empty()) {
// Note that std::map::insert does NOT overwrite a value already in the map,
// which we depend on here.
vals.insert(std::pair<wcstring, env_var_t>(key, *var));
}
}
}
// Dorky way to add our single exported computed variable.
vals[L"PWD"] = env_var_t(L"PWD", perproc_data().pwd);
// Construct the export list: a list of strings of the form key=value.
std::vector<std::string> export_list;
export_list.reserve(vals.size());
for (const auto &kv : vals) {
std::string str = wcs2string(kv.first);
str.push_back('=');
str.append(wcs2string(kv.second.as_string()));
export_list.push_back(std::move(str));
}
return std::make_shared<null_terminated_array_t<char>>(export_list);
}
std::shared_ptr<const null_terminated_array_t<char>> env_scoped_impl_t::export_array() {
ASSERT_IS_NOT_FORKED_CHILD();
if (!export_array_) {
export_array_ = create_export_array();
}
return export_array_;
}
maybe_t<env_var_t> env_scoped_impl_t::try_get_computed(const wcstring &key) const {
const electric_var_t *ev = electric_var_t::for_name(key);
if (!(ev && ev->computed())) {
return none();
}
if (key == L"PWD") {
return env_var_t(perproc_data().pwd, env_var_t::flag_export);
} else if (key == L"history") {
// Big hack. We only allow getting the history on the main thread. Note that history_t
// may ask for an environment variable, so don't take the lock here (we don't need it).
if (!is_main_thread()) {
return none();
}
history_t *history = reader_get_history();
if (!history) {
history = &history_t::history_with_name(history_session_id(*this));
}
wcstring_list_t result;
if (history) history->get_history(result);
return env_var_t(L"history", std::move(result));
} else if (key == L"pipestatus") {
const auto &js = perproc_data().statuses;
wcstring_list_t result;
result.reserve(js.pipestatus.size());
for (int i : js.pipestatus) {
result.push_back(to_string(i));
}
return env_var_t(L"pipestatus", std::move(result));
} else if (key == L"status") {
const auto &js = perproc_data().statuses;
return env_var_t(L"status", to_string(js.status));
} else if (key == L"umask") {
// note umask() is an absurd API: you call it to set the value and it returns the old
// value. Thus we have to call it twice, to reset the value. The env_lock protects
// against races. Guess what the umask is; if we guess right we don't need to reset it.
mode_t guess = 022;
mode_t res = umask(guess);
if (res != guess) umask(res);
return env_var_t(L"umask", format_string(L"0%0.3o", res));
}
// We should never get here unless the electric var list is out of sync with the above code.
DIE("unrecognized computed var name");
}
maybe_t<env_var_t> env_scoped_impl_t::try_get_local(const wcstring &key) const {
auto cursor = locals_;
while (cursor) {
auto where = cursor->env.find(key);
if (where != cursor->env.end()) {
return where->second;
}
cursor = cursor->next;
}
return none();
}
maybe_t<env_var_t> env_scoped_impl_t::try_get_global(const wcstring &key) const {
auto where = globals_->env.find(key);
if (where != globals_->env.end()) {
return where->second;
}
return none();
}
maybe_t<env_var_t> env_scoped_impl_t::try_get_universal(const wcstring &key) const {
if (!uvars()) return none();
auto var = uvars()->get(key);
if (var) {
return var;
}
return none();
}
maybe_t<env_var_t> env_scoped_impl_t::get(const wcstring &key, env_mode_flags_t mode) const {
const query_t query(mode);
maybe_t<env_var_t> result = try_get_computed(key);
if (!result && query.local) {
result = try_get_local(key);
}
if (!result && query.global) {
result = try_get_global(key);
}
if (!result && query.universal) {
result = try_get_universal(key);
}
// If the user requested only exported or unexported variables, enforce that here.
if (result && !query.export_matches(*result)) {
result = none();
}
return result;
}
wcstring_list_t env_scoped_impl_t::get_names(int flags) const {
const query_t query(flags);
std::set<wcstring> names;
// Helper to add the names of variables from \p envs to names, respecting show_exported and
// show_unexported.
auto add_keys = [&](const var_table_t &envs) {
for (const auto &kv : envs) {
if (query.export_matches(kv.second)) {
names.insert(kv.first);
}
}
};
if (query.local) {
for (auto cursor = locals_; cursor != nullptr; cursor = cursor->next) {
add_keys(cursor->env);
}
}
if (query.global) {
add_keys(globals_->env);
// Add electrics.
for (const auto &ev : electric_variables) {
if (ev.exports() ? query.exports : query.unexports) {
names.insert(ev.name);
}
}
}
if (query.universal && uvars()) {
const wcstring_list_t uni_list = uvars()->get_names(query.exports, query.unexports);
names.insert(uni_list.begin(), uni_list.end());
}
return wcstring_list_t(names.begin(), names.end());
}
/// Recursive helper to snapshot a series of nodes.
static env_node_ref_t copy_node_chain(const env_node_ref_t &node) {
if (node == nullptr) {
return nullptr;
}
auto next = copy_node_chain(node->next);
auto result = std::make_shared<env_node_t>(node->new_scope, next);
// Copy over variables.
// Note assigning env is a potentially big copy.
result->exportv = node->exportv;
result->env = node->env;
return result;
}
std::shared_ptr<environment_t> env_scoped_impl_t::snapshot() const {
auto ret = std::make_shared<env_scoped_impl_t>(copy_node_chain(locals_), globals_);
ret->perproc_data_ = this->perproc_data_;
return ret;
}
/// A mutable subclass of env_scoped_impl_t.
class env_stack_impl_t final : public env_scoped_impl_t {
public:
using env_scoped_impl_t::env_scoped_impl_t;
/// Set a variable under the name \p key, using the given \p mode, setting its value to \p val.
int set(const wcstring &key, env_mode_flags_t mode, wcstring_list_t val,
bool *out_needs_uvar_sync);
/// Remove a variable under the name \p key.
int remove(const wcstring &key, int var_mode, bool *out_needs_uvar_sync);
/// Push a new shadowing local scope.
void push_shadowing();
/// Push a new non-shadowing (inner) local scope.
void push_nonshadowing();
/// Pop the variable stack.
/// \return the popped node.
env_node_ref_t pop();
/// Mark that our export list needs to be regenerated.
void mark_changed_exported() { export_array_.reset(); }
/// \return a new impl representing global variables, with a single local scope.
static std::unique_ptr<env_stack_impl_t> create() {
static const auto s_global_node = std::make_shared<env_node_t>(false, nullptr);
auto local = std::make_shared<env_node_t>(false, nullptr);
return make_unique<env_stack_impl_t>(std::move(local), s_global_node);
}
virtual ~env_stack_impl_t() = default;
private:
// The scopes of caller functions, which are currently shadowed.
std::vector<env_node_ref_t> shadowed_locals_;
/// A restricted set of variable flags.
struct var_flags_t {
// if set, whether we should become a path variable; otherwise guess based on the name.
maybe_t<bool> pathvar{};
// if set, the new export value; otherwise inherit any existing export value.
maybe_t<bool> exports{};
// whether the variable is exported by some parent.
bool parent_exports{};
};
/// Find the first node in the chain starting at \p node which contains the given key \p key.
static env_node_ref_t find_in_chain(const env_node_ref_t &node, const wcstring &key) {
for (auto cursor = node; cursor; cursor = cursor->next) {
if (cursor->env.count(key)) {
return cursor;
}
}
return nullptr;
}
/// Remove a variable from the chain \p node, updating the export bit as necessary.
/// \return true if the variable was found and removed.
bool remove_from_chain(env_node_ref_t node, const wcstring &key) {
for (auto cursor = node; cursor; cursor = cursor->next) {
auto iter = cursor->env.find(key);
if (iter != cursor->env.end()) {
if (iter->second.exports()) {
mark_changed_exported();
}
cursor->env.erase(iter);
return true;
}
}
return false;
}
/// Try setting\p key as an electric or readonly variable.
/// \return an error code, or none() if not an electric or readonly variable.
/// \p val will not be modified upon a none() return.
maybe_t<int> try_set_electric(const wcstring &key, const query_t &query, wcstring_list_t &val);
/// Set a universal value.
void set_universal(const wcstring &key, wcstring_list_t val, const query_t &query);
/// Set a variable in a given node \p node.
void set_in_node(env_node_ref_t node, const wcstring &key, wcstring_list_t &&val,
const var_flags_t &flags);
// Implement the default behavior of 'set' by finding the node for an unspecified scope.
env_node_ref_t resolve_unspecified_scope() {
for (auto cursor = locals_; cursor; cursor = cursor->next) {
if (cursor->new_scope) return cursor;
}
return globals_;
}
/// Get a pointer to an existing variable, or nullptr.
/// This is used for inheriting pathvar and export status.
const env_var_t *find_variable(const wcstring &key) const {
env_node_ref_t node = find_in_chain(locals_, key);
if (!node) node = find_in_chain(globals_, key);
if (node) {
auto iter = node->env.find(key);
assert(iter != node->env.end() && "Node should contain key");
return &iter->second;
}
return nullptr;
}
};
void env_stack_impl_t::push_nonshadowing() {
locals_ = std::make_shared<env_node_t>(false, locals_);
}
void env_stack_impl_t::push_shadowing() {
// Propagate local exported variables.
// TODO: this should take all local exported variables, not just those in the top scope.
auto node = std::make_shared<env_node_t>(true, nullptr);
for (const auto &var : locals_->env) {
if (var.second.exports()) {
node->env.insert(var);
node->exportv = true;
}
}
this->shadowed_locals_.push_back(std::move(locals_));
this->locals_ = std::move(node);
}
env_node_ref_t env_stack_impl_t::pop() {
bool changed_exports = locals_->exportv;
auto popped = std::move(locals_);
if (popped->next) {
// Pop the inner scope.
locals_ = popped->next;
changed_exports = changed_exports || local_scope_exports();
} else {
// Exhausted the inner scopes, put back a shadowing scope.
assert(!shadowed_locals_.empty() && "Attempt to pop last local scope");
locals_ = std::move(shadowed_locals_.back());
shadowed_locals_.pop_back();
changed_exports = changed_exports || local_scope_exports();
}
if (changed_exports) mark_changed_exported();
assert(locals_ && "Attempt to pop first local scope");
return popped;
}
/// Apply the pathvar behavior, splitting about colons.
static wcstring_list_t colon_split(const wcstring_list_t &val) {
wcstring_list_t split_val;
split_val.reserve(val.size());
for (const wcstring &str : val) {
vec_append(split_val, split_string(str, PATH_ARRAY_SEP));
}
return split_val;
}
void env_stack_impl_t::set_in_node(env_node_ref_t node, const wcstring &key, wcstring_list_t &&val,
const var_flags_t &flags) {
env_var_t &var = node->env[key];
// Use an explicit exports, or inherit from the existing variable.
bool res_exports = flags.exports.has_value() ? *flags.exports : var.exports();
// Pathvar is inferred from the name. If set, split our entry about colons.
bool res_pathvar =
flags.pathvar.has_value() ? *flags.pathvar : variable_should_auto_pathvar(key);
if (res_pathvar) {
val = colon_split(val);
}
var = var.setting_vals(std::move(val))
.setting_exports(res_exports)
.setting_pathvar(res_pathvar)
.setting_read_only(is_read_only(key));
// Perhaps mark that this node contains an exported variable, or shadows an exported variable.
// If so regenerate the export list.
if (res_exports || flags.parent_exports) {
node->exportv = true;
mark_changed_exported();
}
}
maybe_t<int> env_stack_impl_t::try_set_electric(const wcstring &key, const query_t &query,
wcstring_list_t &val) {
const electric_var_t *ev = electric_var_t::for_name(key);
if (!ev) {
return none();
}
// If a variable is electric, it may only be set in the global scope.
if (query.has_scope && !query.global) {
return ENV_SCOPE;
}
// If the variable is read-only, the user may not set it.
if (query.user && ev->readonly()) {
return ENV_PERM;
}
// Be picky about exporting.
if (query.has_export_unexport) {
if (ev->exports() ? query.unexports : query.exports) {
return ENV_SCOPE;
}
}
// Handle computed mutable electric variables.
if (key == L"umask") {
return set_umask(val);
} else if (key == L"PWD") {
assert(val.size() == 1 && "Should have exactly one element in PWD");
wcstring &pwd = val.front();
if (pwd != perproc_data().pwd) {
perproc_data().pwd = std::move(pwd);
mark_changed_exported();
}
return ENV_OK;
}
// Decide on the mode and set it in the global scope.
var_flags_t flags{};
flags.exports = ev->exports();
flags.parent_exports = ev->exports();
flags.pathvar = false;
set_in_node(globals_, key, std::move(val), flags);
return ENV_OK;
}
/// Set a universal variable, inheriting as applicable from the given old variable.
void env_stack_impl_t::set_universal(const wcstring &key, wcstring_list_t val,
const query_t &query) {
ASSERT_IS_MAIN_THREAD();
if (!uvars()) return;
auto oldvar = uvars()->get(key);
// Resolve whether or not to export.
bool exports = false;
if (query.has_export_unexport) {
exports = query.exports;
} else if (oldvar) {
exports = oldvar->exports();
}
// Resolve whether to be a path variable.
// Here we fall back to the auto-pathvar behavior.
bool pathvar = false;
if (query.has_pathvar_unpathvar) {
pathvar = query.pathvar;
} else if (oldvar) {
pathvar = oldvar->is_pathvar();
} else {
pathvar = variable_should_auto_pathvar(key);
}
// Split about ':' if it's a path variable.
if (pathvar) {
wcstring_list_t split_val;
for (const wcstring &str : val) {
vec_append(split_val, split_string(str, PATH_ARRAY_SEP));
}
val = std::move(split_val);
}
// Construct and set the new variable.
env_var_t::env_var_flags_t varflags = 0;
if (exports) varflags |= env_var_t::flag_export;
if (pathvar) varflags |= env_var_t::flag_pathvar;
env_var_t new_var{val, varflags};
uvars()->set(key, new_var);
if (new_var.exports() || (oldvar && oldvar->exports())) {
mark_changed_exported();
}
}
int env_stack_impl_t::set(const wcstring &key, env_mode_flags_t mode, wcstring_list_t val,
bool *out_needs_uvar_sync) {
const query_t query(mode);
// Handle electric and read-only variables.
if (auto ret = try_set_electric(key, query, val)) {
return *ret;
}
// Resolve as much of our flags as we can. Note these contain maybes, and we may defer the final
// decision until the set_in_node call. Also note that we only inherit pathvar, not export. For
// example, if you have a global exported variable, a local variable with the same name will not
// automatically be exported. But if you have a global pathvar, a local variable with the same
// name will be a pathvar. This is historical.
var_flags_t flags{};
if (const env_var_t *existing = find_variable(key)) {
flags.pathvar = existing->is_pathvar();
flags.parent_exports = existing->exports();
}
if (query.has_export_unexport) {
flags.exports = query.exports;
}
if (query.has_pathvar_unpathvar) {
flags.pathvar = query.pathvar;
}
if (query.has_scope) {
// The user requested a particular scope.
if (query.universal) {
set_universal(key, std::move(val), query);
*out_needs_uvar_sync = true;
} else if (query.global) {
set_in_node(globals_, key, std::move(val), flags);
} else if (query.local) {
set_in_node(locals_, key, std::move(val), flags);
} else {
DIE("Unknown scope");
}
} else if (env_node_ref_t node = find_in_chain(locals_, key)) {
// Existing local variable.
set_in_node(node, key, std::move(val), flags);
} else if (env_node_ref_t node = find_in_chain(globals_, key)) {
// Existing global variable.
set_in_node(node, key, std::move(val), flags);
} else if (uvars() && uvars()->get(key)) {
// Existing universal variable.
set_universal(key, std::move(val), query);
*out_needs_uvar_sync = true;
} else {
// Unspecified scope with no existing variables.
auto node = resolve_unspecified_scope();
assert(node && "Should always resolve some scope");
set_in_node(node, key, std::move(val), flags);
}
return ENV_OK;
}
int env_stack_impl_t::remove(const wcstring &key, int mode, bool *out_needs_uvar_sync) {
const query_t query(mode);
// Users can't remove read-only keys.
if (query.user && is_read_only(key)) {
return ENV_SCOPE;
}
// Helper to remove from uvars.
auto remove_from_uvars = [&] {
if (!uvars()) return false;
auto flags = uvars()->get_flags(key);
if (!flags) return false;
if (*flags & env_var_t::flag_export) {
this->mark_changed_exported();
}
*out_needs_uvar_sync = true;
return uvars()->remove(key);
};
if (query.has_scope) {
// The user requested erasing from a particular scope.
if (query.universal) {
return remove_from_uvars() ? ENV_OK : ENV_NOT_FOUND;
} else if (query.global) {
return remove_from_chain(globals_, key) ? ENV_OK : ENV_NOT_FOUND;
} else if (query.local) {
return remove_from_chain(locals_, key) ? ENV_OK : ENV_NOT_FOUND;
} else {
DIE("Unknown scope");
}
} else if (remove_from_chain(locals_, key)) {
return ENV_OK;
} else if (remove_from_chain(globals_, key)) {
return ENV_OK;
} else if (remove_from_uvars()) {
return ENV_OK;
} else {
return ENV_NOT_FOUND;
}
}
bool env_stack_t::universal_barrier() {
ASSERT_IS_MAIN_THREAD();
if (!uvars()) return false;
callback_data_list_t callbacks;
bool changed = uvars()->sync(callbacks);
if (changed) {
universal_notifier_t::default_notifier().post_notification();
}
env_universal_callbacks(this, callbacks);
return changed || !callbacks.empty();
}
statuses_t env_stack_t::get_last_statuses() const {
return acquire_impl()->perproc_data().statuses;
}
int env_stack_t::get_last_status() const { return acquire_impl()->perproc_data().statuses.status; }
void env_stack_t::set_last_statuses(statuses_t s) {
acquire_impl()->perproc_data().statuses = std::move(s);
}
/// If they don't already exist initialize the `COLUMNS` and `LINES` env vars to reasonable
/// defaults. They will be updated later by the `get_current_winsize()` function if they need to be
/// adjusted.
void env_stack_t::set_termsize() {
auto &vars = env_stack_t::globals();
auto cols = get(L"COLUMNS");
if (cols.missing_or_empty()) vars.set_one(L"COLUMNS", ENV_GLOBAL, DFLT_TERM_COL_STR);
auto rows = get(L"LINES");
if (rows.missing_or_empty()) vars.set_one(L"LINES", ENV_GLOBAL, DFLT_TERM_ROW_STR);
}
/// Update the PWD variable directory from the result of getcwd().
void env_stack_t::set_pwd_from_getcwd() {
wcstring cwd = wgetcwd();
if (cwd.empty()) {
FLOG(error,
_(L"Could not determine current working directory. Is your locale set correctly?"));
return;
}
set_one(L"PWD", ENV_EXPORT | ENV_GLOBAL, cwd);
}
env_stack_t::env_stack_t(std::unique_ptr<env_stack_impl_t> impl) : impl_(std::move(impl)) {}
acquired_lock<env_stack_impl_t> env_stack_t::acquire_impl() {
return acquired_lock<env_stack_impl_t>::from_global(env_lock, impl_.get());
}
acquired_lock<const env_stack_impl_t> env_stack_t::acquire_impl() const {
return acquired_lock<const env_stack_impl_t>::from_global(env_lock, impl_.get());
}
maybe_t<env_var_t> env_stack_t::get(const wcstring &key, env_mode_flags_t mode) const {
return acquire_impl()->get(key, mode);
}
wcstring_list_t env_stack_t::get_names(int flags) const { return acquire_impl()->get_names(flags); }
int env_stack_t::set(const wcstring &key, env_mode_flags_t mode, wcstring_list_t vals) {
// Historical behavior.
if (vals.size() == 1 && (key == L"PWD" || key == L"HOME")) {
path_make_canonical(vals.front());
}
bool needs_uvar_sync = false;
auto ret = acquire_impl()->set(key, mode, std::move(vals), &needs_uvar_sync);
if (ret == ENV_OK) {
// Important to not hold the lock here.
env_dispatch_var_change(key, *this);
event_fire(event_t::variable(key, {L"VARIABLE", L"SET", key}));
}
if (needs_uvar_sync) {
universal_barrier();
}
return ret;
}
int env_stack_t::set_one(const wcstring &key, env_mode_flags_t mode, wcstring val) {
wcstring_list_t vals;
vals.push_back(std::move(val));
return set(key, mode, std::move(vals));
}
int env_stack_t::set_empty(const wcstring &key, env_mode_flags_t mode) {
return set(key, mode, {});
}
int env_stack_t::remove(const wcstring &key, int mode) {
bool needs_uvar_sync = false;
int ret = acquire_impl()->remove(key, mode, &needs_uvar_sync);
if (ret == ENV_OK) {
// Important to not hold the lock here.
env_dispatch_var_change(key, *this);
event_fire(event_t::variable(key, {L"VARIABLE", L"ERASE", key}));
}
if (needs_uvar_sync) {
universal_barrier();
}
return ret;
}
std::shared_ptr<const null_terminated_array_t<char>> env_stack_t::export_arr() {
return acquire_impl()->export_array();
}
std::shared_ptr<environment_t> env_stack_t::snapshot() const { return acquire_impl()->snapshot(); }
void env_stack_t::set_argv(wcstring_list_t argv) { set(L"argv", ENV_LOCAL, std::move(argv)); }
void env_stack_t::push(bool new_scope) {
auto impl = acquire_impl();
if (new_scope) {
impl->push_shadowing();
} else {
impl->push_nonshadowing();
}
}
void env_stack_t::pop() {
auto popped = acquire_impl()->pop();
// TODO: we would like to coalesce locale / curses changes, so that we only re-initialize once.
for (const auto &kv : popped->env) {
env_dispatch_var_change(kv.first, *this);
}
}
void env_stack_t::mark_changed_exported() { acquire_impl()->mark_changed_exported(); }
env_stack_t &env_stack_t::globals() {
static env_stack_t s_globals(env_stack_impl_t::create());
return s_globals;
}
const std::shared_ptr<env_stack_t> &env_stack_t::principal_ref() {
static const std::shared_ptr<env_stack_t> s_principal{
new env_stack_t(env_stack_impl_t::create())};
return s_principal;
}
env_stack_t::~env_stack_t() = default;
#if defined(__APPLE__) || defined(__CYGWIN__)
static int check_runtime_path(const char *path) {
UNUSED(path);
return 0;
}
#else
/// Check, and create if necessary, a secure runtime path. Derived from tmux.c in tmux
/// (http://tmux.sourceforge.net/).
static int check_runtime_path(const char *path) {
// Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
// IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
// OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
struct stat statpath;
uid_t uid = geteuid();
if (mkdir(path, S_IRWXU) != 0 && errno != EEXIST) return errno;
if (lstat(path, &statpath) != 0) return errno;
if (!S_ISDIR(statpath.st_mode) || statpath.st_uid != uid ||
(statpath.st_mode & (S_IRWXG | S_IRWXO)) != 0)
return EACCES;
return 0;
}
#endif
/// Return the path of an appropriate runtime data directory.
wcstring env_get_runtime_path() {
wcstring result;
const char *dir = getenv("XDG_RUNTIME_DIR");
// Check that the path is actually usable. Technically this is guaranteed by the fdo spec but in
// practice it is not always the case: see #1828 and #2222.
int mode = R_OK | W_OK | X_OK;
if (dir != NULL && access(dir, mode) == 0 && check_runtime_path(dir) == 0) {
result = str2wcstring(dir);
} else {
// Don't rely on $USER being set, as setup_user() has not yet been called.
// See https://github.com/fish-shell/fish-shell/issues/5180
// getpeuid() can't fail, but getpwuid sure can.
auto pwuid = getpwuid(geteuid());
const char *uname = pwuid ? pwuid->pw_name : NULL;
// /tmp/fish.user
std::string tmpdir = get_path_to_tmp_dir() + "/fish.";
if (uname) {
tmpdir.append(uname);
}
if (!uname || check_runtime_path(tmpdir.c_str()) != 0) {
FLOG(error, L"Runtime path not available.");
FLOGF(error, L"Try deleting the directory %s and restarting fish.", tmpdir.c_str());
return result;
}
result = str2wcstring(tmpdir);
}
return result;
}
static std::mutex s_setenv_lock{};
void setenv_lock(const char *name, const char *value, int overwrite) {
scoped_lock locker(s_setenv_lock);
setenv(name, value, overwrite);
}
void unsetenv_lock(const char *name) {
scoped_lock locker(s_setenv_lock);
unsetenv(name);
}