github-mirror/fish-shell
2
0
Fork 0
mirror of https://github.com/fish-shell/fish-shell.git synced 2024-11-26 19:03:38 +08:00
Code Issues Actions 3 Packages Projects Releases Wiki Activity
a7df92e187
fish-shell/src/builtin_read.cpp
ridiculousfish 84d59accfc builtins to allow stdin to be closed 
Prior to this fix, if stdin were explicitly closed, then builtins would
silently fail. For example:

    count <&-

would just fail with status 1. Remove this limitation and allow each
builtin to handle a closed stdin how it sees fit.
2021-02-10 17:43:10 -08:00

648 lines
24 KiB
C++
Raw Blame History

// Implementation of the read builtin.
#include "config.h" // IWYU pragma: keep
#include "builtin_read.h"
#include <unistd.h>
#include <algorithm>
#include <cerrno>
#include <climits>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cwchar>
#include <memory>
#include <numeric>
#include <string>
#include <vector>
#include "builtin.h"
#include "common.h"
#include "complete.h"
#include "env.h"
#include "event.h"
#include "fallback.h" // IWYU pragma: keep
#include "highlight.h"
#include "history.h"
#include "io.h"
#include "parser.h"
#include "proc.h"
#include "reader.h"
#include "termios.h"
#include "wcstringutil.h"
#include "wgetopt.h"
#include "wutil.h" // IWYU pragma: keep
struct read_cmd_opts_t {
bool print_help = false;
int place = ENV_USER;
wcstring prompt_cmd;
const wchar_t *prompt = nullptr;
const wchar_t *prompt_str = nullptr;
const wchar_t *right_prompt = L"";
const wchar_t *commandline = L"";
// If a delimiter was given. Used to distinguish between the default
// empty string and a given empty delimiter.
bool have_delimiter = false;
wcstring delimiter;
bool tokenize = false;
bool shell = false;
bool array = false;
bool silent = false;
bool split_null = false;
bool to_stdout = false;
int nchars = 0;
bool one_line = false;
};
static const wchar_t *const short_options = L":ac:d:ghiLln:p:sStuxzP:UR:L";
static const struct woption long_options[] = {{L"array", no_argument, nullptr, 'a'},
{L"command", required_argument, nullptr, 'c'},
{L"delimiter", required_argument, nullptr, 'd'},
{L"export", no_argument, nullptr, 'x'},
{L"global", no_argument, nullptr, 'g'},
{L"help", no_argument, nullptr, 'h'},
{L"line", no_argument, nullptr, 'L'},
{L"list", no_argument, nullptr, 'a'},
{L"local", no_argument, nullptr, 'l'},
{L"nchars", required_argument, nullptr, 'n'},
{L"null", no_argument, nullptr, 'z'},
{L"prompt", required_argument, nullptr, 'p'},
{L"prompt-str", required_argument, nullptr, 'P'},
{L"right-prompt", required_argument, nullptr, 'R'},
{L"shell", no_argument, nullptr, 'S'},
{L"silent", no_argument, nullptr, 's'},
{L"tokenize", no_argument, nullptr, 't'},
{L"unexport", no_argument, nullptr, 'u'},
{L"universal", no_argument, nullptr, 'U'},
{nullptr, 0, nullptr, 0}};
static int parse_cmd_opts(read_cmd_opts_t &opts, int *optind, //!OCLINT(high ncss method)
int argc, wchar_t **argv, parser_t &parser, io_streams_t &streams) {
wchar_t *cmd = argv[0];
int opt;
wgetopter_t w;
while ((opt = w.wgetopt_long(argc, argv, short_options, long_options, nullptr)) != -1) {
switch (opt) {
case 'a': {
opts.array = true;
break;
}
case L'c': {
opts.commandline = w.woptarg;
break;
}
case 'd': {
opts.have_delimiter = true;
opts.delimiter = w.woptarg;
break;
}
case 'i': {
streams.err.append_format(_(L"%ls: usage of -i for --silent is deprecated. Please "
L"use -s or --silent instead.\n"),
cmd);
return STATUS_INVALID_ARGS;
}
case L'g': {
opts.place |= ENV_GLOBAL;
break;
}
case 'h': {
opts.print_help = true;
break;
}
case L'L': {
opts.one_line = true;
break;
}
case L'l': {
opts.place |= ENV_LOCAL;
break;
}
case L'n': {
opts.nchars = fish_wcstoi(w.woptarg);
if (errno) {
if (errno == ERANGE) {
streams.err.append_format(_(L"%ls: Argument '%ls' is out of range\n"), cmd,
w.woptarg);
builtin_print_error_trailer(parser, streams.err, cmd);
return STATUS_INVALID_ARGS;
}
streams.err.append_format(BUILTIN_ERR_NOT_NUMBER, cmd, w.woptarg);
builtin_print_error_trailer(parser, streams.err, cmd);
return STATUS_INVALID_ARGS;
}
break;
}
case L'P': {
opts.prompt_str = w.woptarg;
break;
}
case L'p': {
opts.prompt = w.woptarg;
break;
}
case L'R': {
opts.right_prompt = w.woptarg;
break;
}
case 's': {
opts.silent = true;
break;
}
case L'S': {
opts.shell = true;
break;
}
case L't': {
opts.tokenize = true;
break;
}
case L'U': {
opts.place |= ENV_UNIVERSAL;
break;
}
case L'u': {
opts.place |= ENV_UNEXPORT;
break;
}
case L'x': {
opts.place |= ENV_EXPORT;
break;
}
case L'z': {
opts.split_null = true;
break;
}
case ':': {
builtin_missing_argument(parser, streams, cmd, argv[w.woptind - 1]);
return STATUS_INVALID_ARGS;
}
case L'?': {
builtin_unknown_option(parser, streams, cmd, argv[w.woptind - 1]);
return STATUS_INVALID_ARGS;
}
default: {
DIE("unexpected retval from wgetopt_long");
}
}
}
*optind = w.woptind;
return STATUS_CMD_OK;
}
/// Read from the tty. This is only valid when the stream is stdin and it is attached to a tty and
/// we weren't asked to split on null characters.
static int read_interactive(parser_t &parser, wcstring &buff, int nchars, bool shell, bool silent,
const wchar_t *prompt, const wchar_t *right_prompt,
const wchar_t *commandline, int in) {
int exit_res = STATUS_CMD_OK;
// Construct a configuration.
reader_config_t conf;
conf.complete_ok = shell;
conf.highlight_ok = shell;
conf.syntax_check_ok = shell;
// No autosuggestions or abbreviations in builtin_read.
conf.autosuggest_ok = false;
conf.expand_abbrev_ok = false;
conf.exit_on_interrupt = true;
conf.in_silent_mode = silent;
conf.left_prompt_cmd = prompt;
conf.right_prompt_cmd = right_prompt;
conf.in = in;
// Don't keep history.
reader_push(parser, wcstring{}, std::move(conf));
reader_get_history()->resolve_pending();
reader_set_buffer(commandline, std::wcslen(commandline));
scoped_push<bool> interactive{&parser.libdata().is_interactive, true};
event_fire_generic(parser, L"fish_read");
auto mline = reader_readline(nchars);
interactive.restore();
if (mline) {
buff = mline.acquire();
if (nchars > 0 && static_cast<size_t>(nchars) < buff.size()) {
// Line may be longer than nchars if a keybinding used `commandline -i`
// note: we're deliberately throwing away the tail of the commandline.
// It shouldn't be unread because it was produced with `commandline -i`,
// not typed.
buff.resize(nchars);
}
} else {
exit_res = STATUS_CMD_ERROR;
}
reader_pop();
return exit_res;
}
/// Bash uses 128 bytes for its chunk size. Very informal testing I did suggested that a smaller
/// chunk size performed better. However, we're going to use the bash value under the assumption
/// they've done more extensive testing.
#define READ_CHUNK_SIZE 128
/// Read from the fd in chunks until we see newline or null, as requested, is seen. This is only
/// used when the fd is seekable (so not from a tty or pipe) and we're not reading a specific number
/// of chars.
///
/// Returns an exit status.
static int read_in_chunks(int fd, wcstring &buff, bool split_null) {
int exit_res = STATUS_CMD_OK;
std::string str;
bool eof = false;
bool finished = false;
while (!finished) {
char inbuf[READ_CHUNK_SIZE];
long bytes_read = read_blocked(fd, inbuf, READ_CHUNK_SIZE);
if (bytes_read <= 0) {
eof = true;
break;
}
const char *end = std::find(inbuf, inbuf + bytes_read, split_null ? L'\0' : L'\n');
long bytes_consumed = end - inbuf; // must be signed for use in lseek
assert(bytes_consumed <= bytes_read);
str.append(inbuf, bytes_consumed);
if (bytes_consumed < bytes_read) {
// We found a splitter. The +1 because we need to treat the splitter as consumed, but
// not append it to the string.
if (lseek(fd, bytes_consumed - bytes_read + 1, SEEK_CUR) == -1) {
wperror(L"lseek");
return STATUS_CMD_ERROR;
}
finished = true;
} else if (str.size() > read_byte_limit) {
exit_res = STATUS_READ_TOO_MUCH;
finished = true;
}
}
buff = str2wcstring(str);
if (buff.empty() && eof) {
exit_res = STATUS_CMD_ERROR;
}
return exit_res;
}
/// Read from the fd on char at a time until we've read the requested number of characters or a
/// newline or null, as appropriate, is seen. This is inefficient so should only be used when the
/// fd is not seekable.
static int read_one_char_at_a_time(int fd, wcstring &buff, int nchars, bool split_null) {
int exit_res = STATUS_CMD_OK;
bool eof = false;
size_t nbytes = 0;
while (true) {
bool finished = false;
wchar_t res = 0;
mbstate_t state = {};
while (!finished) {
char b;
if (read_blocked(fd, &b, 1) <= 0) {
eof = true;
break;
}
nbytes++;
if (MB_CUR_MAX == 1) {
res = static_cast<unsigned char>(b);
finished = true;
} else {
size_t sz = std::mbrtowc(&res, &b, 1, &state);
if (sz == static_cast<size_t>(-1)) {
std::memset(&state, 0, sizeof(state));
} else if (sz != static_cast<size_t>(-2)) {
finished = true;
}
}
}
if (nbytes > read_byte_limit) {
exit_res = STATUS_READ_TOO_MUCH;
break;
}
if (eof) break;
if (!split_null && res == L'\n') break;
if (split_null && res == L'\0') break;
buff.push_back(res);
if (nchars > 0 && static_cast<size_t>(nchars) <= buff.size()) {
break;
}
}
if (buff.empty() && eof) {
exit_res = STATUS_CMD_ERROR;
}
return exit_res;
}
/// Validate the arguments given to `read` and provide defaults where needed.
static int validate_read_args(const wchar_t *cmd, read_cmd_opts_t &opts, int argc,
const wchar_t *const *argv, parser_t &parser, io_streams_t &streams) {
if (opts.prompt && opts.prompt_str) {
streams.err.append_format(_(L"%ls: Options %ls and %ls cannot be used together\n"), cmd,
L"-p", L"-P");
builtin_print_error_trailer(parser, streams.err, cmd);
return STATUS_INVALID_ARGS;
}
if (opts.have_delimiter && opts.one_line) {
streams.err.append_format(_(L"%ls: Options %ls and %ls cannot be used together\n"), cmd,
L"--delimiter", L"--line");
return STATUS_INVALID_ARGS;
}
if (opts.one_line && opts.split_null) {
streams.err.append_format(_(L"%ls: Options %ls and %ls cannot be used together\n"), cmd,
L"-z", L"--line");
return STATUS_INVALID_ARGS;
}
if (opts.prompt_str) {
opts.prompt_cmd = L"echo " + escape_string(opts.prompt_str, ESCAPE_ALL);
opts.prompt = opts.prompt_cmd.c_str();
} else if (!opts.prompt) {
opts.prompt = DEFAULT_READ_PROMPT;
}
if ((opts.place & ENV_UNEXPORT) && (opts.place & ENV_EXPORT)) {
streams.err.append_format(BUILTIN_ERR_EXPUNEXP, cmd);
builtin_print_error_trailer(parser, streams.err, cmd);
return STATUS_INVALID_ARGS;
}
if ((opts.place & ENV_LOCAL ? 1 : 0) + (opts.place & ENV_GLOBAL ? 1 : 0) +
(opts.place & ENV_UNIVERSAL ? 1 : 0) >
1) {
streams.err.append_format(BUILTIN_ERR_GLOCAL, cmd);
builtin_print_error_trailer(parser, streams.err, cmd);
return STATUS_INVALID_ARGS;
}
if (!opts.array && argc < 1 && !opts.to_stdout) {
streams.err.append_format(BUILTIN_ERR_MIN_ARG_COUNT1, cmd, 1, argc);
return STATUS_INVALID_ARGS;
}
if (opts.array && argc != 1) {
streams.err.append_format(BUILTIN_ERR_ARG_COUNT1, cmd, 1, argc);
return STATUS_INVALID_ARGS;
}
if (opts.to_stdout && argc > 0) {
streams.err.append_format(BUILTIN_ERR_MAX_ARG_COUNT1, cmd, 0, argc);
return STATUS_INVALID_ARGS;
}
if (opts.tokenize && opts.have_delimiter) {
streams.err.append_format(BUILTIN_ERR_COMBO2, cmd,
L"--delimiter and --tokenize can not be used together");
return STATUS_INVALID_ARGS;
}
if (opts.tokenize && opts.one_line) {
streams.err.append_format(BUILTIN_ERR_COMBO2, cmd,
L"--line and --tokenize can not be used together");
return STATUS_INVALID_ARGS;
}
// Verify all variable names.
for (int i = 0; i < argc; i++) {
if (!valid_var_name(argv[i])) {
streams.err.append_format(BUILTIN_ERR_VARNAME, cmd, argv[i]);
builtin_print_error_trailer(parser, streams.err, cmd);
return STATUS_INVALID_ARGS;
}
}
return STATUS_CMD_OK;
}
/// The read builtin. Reads from stdin and stores the values in environment variables.
maybe_t<int> builtin_read(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
wchar_t *cmd = argv[0];
int argc = builtin_count_args(argv);
wcstring buff;
int exit_res = STATUS_CMD_OK;
read_cmd_opts_t opts;
int optind;
int retval = parse_cmd_opts(opts, &optind, argc, argv, parser, streams);
if (retval != STATUS_CMD_OK) return retval;
if (!opts.to_stdout) {
argc -= optind;
argv += optind;
}
if (argc == 0) {
opts.to_stdout = true;
}
if (opts.print_help) {
builtin_print_help(parser, streams, cmd);
return STATUS_CMD_OK;
}
retval = validate_read_args(cmd, opts, argc, argv, parser, streams);
if (retval != STATUS_CMD_OK) return retval;
// stdin may have been explicitly closed
if (streams.stdin_fd < 0) {
streams.err.append_format(_(L"%ls: stdin is closed\n"), cmd);
return STATUS_CMD_ERROR;
}
if (opts.one_line) {
// --line is the same as read -d \n repeated N times
opts.have_delimiter = true;
opts.delimiter = L"\n";
opts.split_null = false;
opts.shell = false;
}
wchar_t *const *var_ptr = argv;
auto vars_left = [&]() { return argv + argc - var_ptr; };
auto clear_remaining_vars = [&]() {
while (vars_left()) {
parser.vars().set_empty(*var_ptr, opts.place);
++var_ptr;
}
};
// Normally, we either consume a line of input or all available input. But if we are reading a
// line at a time, we need a middle ground where we only consume as many lines as we need to
// fill the given vars.
do {
buff.clear();
// TODO: Determine if the original set of conditions for interactive reads should be
// reinstated: if (isatty(0) && streams.stdin_fd == STDIN_FILENO && !split_null) {
int stream_stdin_is_a_tty = isatty(streams.stdin_fd);
if (stream_stdin_is_a_tty && !opts.split_null) {
// Read interactively using reader_readline(). This does not support splitting on null.
exit_res =
read_interactive(parser, buff, opts.nchars, opts.shell, opts.silent, opts.prompt,
opts.right_prompt, opts.commandline, streams.stdin_fd);
} else if (!opts.nchars && !stream_stdin_is_a_tty &&
lseek(streams.stdin_fd, 0, SEEK_CUR) != -1) {
exit_res = read_in_chunks(streams.stdin_fd, buff, opts.split_null);
} else {
exit_res =
read_one_char_at_a_time(streams.stdin_fd, buff, opts.nchars, opts.split_null);
}
if (exit_res != STATUS_CMD_OK) {
clear_remaining_vars();
return exit_res;
}
if (opts.to_stdout) {
streams.out.append(buff);
return exit_res;
}
if (opts.tokenize) {
tokenizer_t tok{buff.c_str(), TOK_ACCEPT_UNFINISHED};
wcstring out;
if (opts.array) {
// Array mode: assign each token as a separate element of the sole var.
wcstring_list_t tokens;
while (auto t = tok.next()) {
auto text = tok.text_of(*t);
if (unescape_string(text, &out, UNESCAPE_DEFAULT)) {
tokens.push_back(out);
} else {
tokens.push_back(text);
}
}
parser.set_var_and_fire(*var_ptr++, opts.place, std::move(tokens));
} else {
maybe_t<tok_t> t;
while ((vars_left() - 1 > 0) && (t = tok.next())) {
auto text = tok.text_of(*t);
if (unescape_string(text, &out, UNESCAPE_DEFAULT)) {
parser.set_var_and_fire(*var_ptr++, opts.place, out);
} else {
parser.set_var_and_fire(*var_ptr++, opts.place, text);
}
}
// If we still have tokens, set the last variable to them.
if ((t = tok.next())) {
wcstring rest = wcstring(buff, t->offset);
parser.set_var_and_fire(*var_ptr++, opts.place, std::move(rest));
}
}
// The rest of the loop is other split-modes, we don't care about those.
continue;
}
if (!opts.have_delimiter) {
auto ifs = parser.vars().get(L"IFS");
if (!ifs.missing_or_empty()) opts.delimiter = ifs->as_string();
}
if (opts.delimiter.empty()) {
// Every character is a separate token with one wrinkle involving non-array mode where
// the final var gets the remaining characters as a single string.
size_t x = std::max(static_cast<size_t>(1), buff.size());
size_t n_splits =
(opts.array || static_cast<size_t>(vars_left()) > x) ? x : vars_left();
wcstring_list_t chars;
chars.reserve(n_splits);
int i = 0;
for (auto it = buff.begin(), end = buff.end(); it != end; ++i, ++it) {
if (opts.array || i + 1 < vars_left()) {
chars.emplace_back(1, *it);
} else {
chars.emplace_back(it, buff.end());
break;
}
}
if (opts.array) {
// Array mode: assign each char as a separate element of the sole var.
parser.set_var_and_fire(*var_ptr++, opts.place, chars);
} else {
// Not array mode: assign each char to a separate var with the remainder being
// assigned to the last var.
for (const auto &c : chars) {
parser.set_var_and_fire(*var_ptr++, opts.place, c);
}
}
} else if (opts.array) {
// The user has requested the input be split into a sequence of tokens and all the
// tokens assigned to a single var. How we do the tokenizing depends on whether the user
// specified the delimiter string or we're using IFS.
if (!opts.have_delimiter) {
// We're using IFS, so tokenize the buffer using each IFS char. This is for backward
// compatibility with old versions of fish.
wcstring_list_t tokens;
for (wcstring_range loc = wcstring_tok(buff, opts.delimiter);
loc.first != wcstring::npos; loc = wcstring_tok(buff, opts.delimiter, loc)) {
tokens.emplace_back(wcstring(buff, loc.first, loc.second));
}
parser.set_var_and_fire(*var_ptr++, opts.place, tokens);
} else {
// We're using a delimiter provided by the user so use the `string split` behavior.
wcstring_list_t splits;
split_about(buff.begin(), buff.end(), opts.delimiter.begin(), opts.delimiter.end(),
&splits);
parser.set_var_and_fire(*var_ptr++, opts.place, splits);
}
} else {
// Not array mode. Split the input into tokens and assign each to the vars in sequence.
if (!opts.have_delimiter) {
// We're using IFS, so tokenize the buffer using each IFS char. This is for backward
// compatibility with old versions of fish.
wcstring_range loc = wcstring_range(0, 0);
while (vars_left()) {
wcstring substr;
loc = wcstring_tok(buff, (vars_left() > 1) ? opts.delimiter : wcstring(), loc);
if (loc.first != wcstring::npos) {
substr = wcstring(buff, loc.first, loc.second);
}
parser.set_var_and_fire(*var_ptr++, opts.place, substr);
}
} else {
// We're using a delimiter provided by the user so use the `string split` behavior.
wcstring_list_t splits;
// We're making at most argc - 1 splits so the last variable
// is set to the remaining string.
split_about(buff.begin(), buff.end(), opts.delimiter.begin(), opts.delimiter.end(),
&splits, argc - 1);
assert(splits.size() <= static_cast<size_t>(vars_left()));
for (const auto &split : splits) {
parser.set_var_and_fire(*var_ptr++, opts.place, split);
}
}
}
} while (opts.one_line && vars_left());
if (!opts.array) {
// In case there were more args than splits
clear_remaining_vars();
}
return exit_res;
}
Reference in New Issue View Git Blame Copy Permalink