fish-shell/src/path.cpp
Kurtis Rader 03571b82be cleanup env code and contains()
Switch from null terminated arrays to `wcstring_list_t` for lists of
special env var names. Rename `list_contains_string` to `contains` and
modify the latter interface to not rely on a `#define`.

Rename `list_contains_string()` to `contains()` and eliminate the
current variadic implementation. Update all callers of the removed
version to use the string list version.
2017-04-05 17:09:12 -07:00

398 lines
14 KiB
C++

// Directory utilities. This library contains functions for locating configuration directories, for
// testing if a command with a given name can be found in the PATH, and various other path-related
// issues.
#include "config.h" // IWYU pragma: keep
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <wchar.h>
#include <string>
#include <type_traits>
#include <vector>
#include "common.h"
#include "env.h"
#include "expand.h"
#include "fallback.h" // IWYU pragma: keep
#include "path.h"
#include "wutil.h" // IWYU pragma: keep
/// Unexpected error in path_get_path().
#define MISSING_COMMAND_ERR_MSG _(L"Error while searching for command '%ls'")
static bool path_get_path_core(const wcstring &cmd, wcstring *out_path,
const env_var_t &bin_path_var) {
int err = ENOENT;
debug(3, L"path_get_path( '%ls' )", cmd.c_str());
// If the command has a slash, it must be a full path.
if (cmd.find(L'/') != wcstring::npos) {
if (waccess(cmd, X_OK) != 0) {
return false;
}
struct stat buff;
if (wstat(cmd, &buff)) {
return false;
}
if (S_ISREG(buff.st_mode)) {
if (out_path) out_path->assign(cmd);
return true;
}
errno = EACCES;
return false;
}
wcstring bin_path;
if (!bin_path_var.missing()) {
bin_path = bin_path_var;
} else {
// Note that PREFIX is defined in the Makefile and is defined when this module is compiled.
// This ensures we always default to "/bin", "/usr/bin" and the bin dir defined for the fish
// programs with no duplicates.
if (!wcscmp(PREFIX L"/bin", L"/bin") || !wcscmp(PREFIX L"/bin", L"/usr/bin")) {
bin_path = L"/bin" ARRAY_SEP_STR L"/usr/bin";
} else {
bin_path = L"/bin" ARRAY_SEP_STR L"/usr/bin" ARRAY_SEP_STR PREFIX L"/bin";
}
}
std::vector<wcstring> pathsv;
tokenize_variable_array(bin_path, pathsv);
for (auto next_path : pathsv) {
if (next_path.empty()) continue;
append_path_component(next_path, cmd);
if (waccess(next_path, X_OK) == 0) {
struct stat buff;
if (wstat(next_path, &buff) == -1) {
if (errno != EACCES) {
wperror(L"stat");
}
continue;
}
if (S_ISREG(buff.st_mode)) {
if (out_path) *out_path = std::move(next_path);
return true;
}
err = EACCES;
} else {
switch (errno) {
case ENOENT:
case ENAMETOOLONG:
case EACCES:
case ENOTDIR: {
break;
}
default: {
debug(1, MISSING_COMMAND_ERR_MSG, next_path.c_str());
wperror(L"access");
break;
}
}
}
}
errno = err;
return false;
}
bool path_get_path(const wcstring &cmd, wcstring *out_path, const env_vars_snapshot_t &vars) {
return path_get_path_core(cmd, out_path, vars.get(L"PATH"));
}
bool path_get_path(const wcstring &cmd, wcstring *out_path) {
return path_get_path_core(cmd, out_path, env_get_string(L"PATH"));
}
bool path_get_cdpath(const wcstring &dir, wcstring *out, const wchar_t *wd,
const env_vars_snapshot_t &env_vars) {
int err = ENOENT;
if (dir.empty()) return false;
if (wd) {
size_t len = wcslen(wd);
assert(wd[len - 1] == L'/');
}
wcstring_list_t paths;
if (dir.at(0) == L'/') {
// Absolute path.
paths.push_back(dir);
} else if (string_prefixes_string(L"./", dir) || string_prefixes_string(L"../", dir) ||
dir == L"." || dir == L"..") {
// Path is relative to the working directory.
wcstring path;
if (wd) path.append(wd);
path.append(dir);
paths.push_back(path);
} else {
// Respect CDPATH.
env_var_t cdpaths = env_vars.get(L"CDPATH");
if (cdpaths.missing_or_empty()) cdpaths = L".";
std::vector<wcstring> cdpathsv;
tokenize_variable_array(cdpaths, cdpathsv);
for (auto next_path : cdpathsv) {
if (next_path.empty()) next_path = L".";
if (next_path == L"." && wd != NULL) {
// next_path is just '.', and we have a working directory, so use the wd instead.
// TODO: if next_path starts with ./ we need to replace the . with the wd.
next_path = wd;
}
expand_tilde(next_path);
if (next_path.empty()) continue;
wcstring whole_path = next_path;
append_path_component(whole_path, dir);
paths.push_back(whole_path);
}
}
bool success = false;
for (wcstring_list_t::const_iterator iter = paths.begin(); iter != paths.end(); ++iter) {
struct stat buf;
const wcstring &dir = *iter;
if (wstat(dir, &buf) == 0) {
if (S_ISDIR(buf.st_mode)) {
success = true;
if (out) out->assign(dir);
break;
} else {
err = ENOTDIR;
}
}
}
if (!success) errno = err;
return success;
}
bool path_can_be_implicit_cd(const wcstring &path, wcstring *out_path, const wchar_t *wd,
const env_vars_snapshot_t &vars) {
wcstring exp_path = path;
expand_tilde(exp_path);
bool result = false;
if (string_prefixes_string(L"/", exp_path) || string_prefixes_string(L"./", exp_path) ||
string_prefixes_string(L"../", exp_path) || string_suffixes_string(L"/", exp_path) ||
exp_path == L"..") {
// These paths can be implicit cd, so see if you cd to the path. Note that a single period
// cannot (that's used for sourcing files anyways).
result = path_get_cdpath(exp_path, out_path, wd, vars);
}
return result;
}
// If the given path looks like it's relative to the working directory, then prepend that working
// directory. This operates on unescaped paths only (so a ~ means a literal ~).
wcstring path_apply_working_directory(const wcstring &path, const wcstring &working_directory) {
if (path.empty() || working_directory.empty()) return path;
// We're going to make sure that if we want to prepend the wd, that the string has no leading
// "/".
bool prepend_wd = path.at(0) != L'/' && path.at(0) != HOME_DIRECTORY;
if (!prepend_wd) {
// No need to prepend the wd, so just return the path we were given.
return path;
}
// Remove up to one "./".
wcstring path_component = path;
if (string_prefixes_string(L"./", path_component)) {
path_component.erase(0, 2);
}
// Removing leading /s.
while (string_prefixes_string(L"/", path_component)) {
path_component.erase(0, 1);
}
// Construct and return a new path.
wcstring new_path = working_directory;
append_path_component(new_path, path_component);
return new_path;
}
/// We separate this from path_create() for two reasons. First it's only caused if there is a
/// problem, and thus is not central to the behavior of that function. Second, we only want to issue
/// the message once. If the current shell starts a new fish shell (e.g., by running `fish -c` from
/// a function) we don't want that subshell to issue the same warnings.
static void maybe_issue_path_warning(const wcstring &which_dir, const wcstring &custom_error_msg,
bool using_xdg, const wcstring &xdg_var, const wcstring &path,
int saved_errno) {
wcstring warning_var_name = L"_FISH_WARNED_" + which_dir;
if (env_exist(warning_var_name.c_str(), ENV_GLOBAL | ENV_EXPORT)) {
return;
}
env_set(warning_var_name, L"1", ENV_GLOBAL | ENV_EXPORT);
debug(0, custom_error_msg.c_str());
if (path.empty()) {
debug(0, _(L"Unable to locate the %ls directory."), which_dir.c_str());
debug(0, _(L"Please set the %ls or HOME environment variable "
L"before starting fish."),
xdg_var.c_str());
} else {
const wchar_t *env_var = using_xdg ? xdg_var.c_str() : L"HOME";
debug(0, _(L"Unable to locate %ls directory derived from $%ls: '%ls'."), which_dir.c_str(),
env_var, path.c_str());
debug(0, _(L"The error was '%s'."), strerror(saved_errno));
debug(0, _(L"Please set $%ls to a directory where you have write access."), env_var);
}
fputwc(L'\n', stderr);
}
static void path_create(wcstring &path, const wcstring &xdg_var, const wcstring &which_dir,
const wcstring &custom_error_msg) {
bool path_done = false;
bool using_xdg = false;
int saved_errno = 0;
// The vars we fetch must be exported. Allowing them to be universal doesn't make sense and
// allowing that creates a lock inversion that deadlocks the shell since we're called before
// uvars are available.
const env_var_t xdg_dir = env_get_string(xdg_var, ENV_GLOBAL | ENV_EXPORT);
if (!xdg_dir.missing_or_empty()) {
using_xdg = true;
path = xdg_dir + L"/fish";
if (create_directory(path) != -1) {
path_done = true;
} else {
saved_errno = errno;
}
} else {
const env_var_t home = env_get_string(L"HOME", ENV_GLOBAL | ENV_EXPORT);
if (!home.missing_or_empty()) {
path = home + (which_dir == L"config" ? L"/.config/fish" : L"/.local/share/fish");
if (create_directory(path) != -1) {
path_done = true;
} else {
saved_errno = errno;
}
}
}
if (!path_done) {
maybe_issue_path_warning(which_dir, custom_error_msg, using_xdg, xdg_var, path,
saved_errno);
path.clear();
}
return;
}
/// Cache the config path.
bool path_get_config(wcstring &path) {
static bool config_path_done = false;
static wcstring config_path(L"");
if (!config_path_done) {
path_create(config_path, L"XDG_CONFIG_HOME", L"config",
_(L"Your personal settings will not be saved."));
config_path_done = true;
}
path = config_path;
return !config_path.empty();
}
/// Cache the data path.
bool path_get_data(wcstring &path) {
static bool data_path_done = false;
static wcstring data_path(L"");
if (!data_path_done) {
data_path_done = true;
path_create(data_path, L"XDG_DATA_HOME", L"data", _(L"Your history will not be saved."));
}
path = data_path;
return !data_path.empty();
}
void path_make_canonical(wcstring &path) {
// Ignore trailing slashes, unless it's the first character.
size_t len = path.size();
while (len > 1 && path.at(len - 1) == L'/') len--;
// Turn runs of slashes into a single slash.
size_t trailing = 0;
bool prev_was_slash = false;
for (size_t leading = 0; leading < len; leading++) {
wchar_t c = path.at(leading);
bool is_slash = (c == '/');
if (!prev_was_slash || !is_slash) {
// This is either the first slash in a run, or not a slash at all.
path.at(trailing++) = c;
}
prev_was_slash = is_slash;
}
assert(trailing <= len);
if (trailing < len) path.resize(trailing);
}
bool paths_are_equivalent(const wcstring &p1, const wcstring &p2) {
if (p1 == p2) return true;
size_t len1 = p1.size(), len2 = p2.size();
// Ignore trailing slashes after the first character.
while (len1 > 1 && p1.at(len1 - 1) == L'/') len1--;
while (len2 > 1 && p2.at(len2 - 1) == L'/') len2--;
// Start walking
size_t idx1 = 0, idx2 = 0;
while (idx1 < len1 && idx2 < len2) {
wchar_t c1 = p1.at(idx1), c2 = p2.at(idx2);
// If the characters are different, the strings are not equivalent.
if (c1 != c2) break;
idx1++;
idx2++;
// If the character was a slash, walk forwards until we hit the end of the string, or a
// non-slash. Note the first condition is invariant within the loop.
while (c1 == L'/' && idx1 < len1 && p1.at(idx1) == L'/') idx1++;
while (c2 == L'/' && idx2 < len2 && p2.at(idx2) == L'/') idx2++;
}
// We matched if we consumed all of the characters in both strings.
return idx1 == len1 && idx2 == len2;
}
bool path_is_valid(const wcstring &path, const wcstring &working_directory) {
bool path_is_valid;
// Some special paths are always valid.
if (path.empty()) {
path_is_valid = false;
} else if (path == L"." || path == L"./") {
path_is_valid = true;
} else if (path == L".." || path == L"../") {
path_is_valid = (!working_directory.empty() && working_directory != L"/");
} else if (path.at(0) != '/') {
// Prepend the working directory. Note that we know path is not empty here.
wcstring tmp = working_directory;
tmp.append(path);
path_is_valid = (0 == waccess(tmp, F_OK));
} else {
// Simple check.
path_is_valid = (0 == waccess(path, F_OK));
}
return path_is_valid;
}
bool paths_are_same_file(const wcstring &path1, const wcstring &path2) {
if (paths_are_equivalent(path1, path2)) return true;
struct stat s1, s2;
if (wstat(path1, &s1) == 0 && wstat(path2, &s2) == 0) {
return s1.st_ino == s2.st_ino && s1.st_dev == s2.st_dev;
}
return false;
}