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touch: Support custom timestamps

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Previously, `touch` remained limited to creating files and updating
their current access and modifications time to the current time. It's
now capable of accepting two different timestamp formats with flags `-d`
and `-t` and referencing timestamps of other files with flag `-r`.

`touch` can also update only the last access time with `-a`, only the
last access time with `-m`, or update both as usual. `touch` updates
both left unspecified.

With `-c`, `touch` does not create a file if it doesn't already exist.
This commit is contained in:
Ariel Don 2022-05-02 13:56:15 -05:00 • committed by Andreas Kling
parent 244357472a
commit a2c34554cd
1 changed files with 216 additions and 16 deletions
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232
Userland/Utilities/touch.cpp
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@ -1,51 +1,251 @@
/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, Ariel Don <ariel@arieldon.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/CheckedFormatString.h>
#include <AK/GenericLexer.h>
#include <AK/Time.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/Stream.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <LibTimeZone/TimeZone.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <time.h>
static bool file_exists(String const& path)
static String program_name;
template<typename... Parameters>
[[noreturn]] static void err(CheckedFormatString<Parameters...>&& fmtstr, Parameters const&... parameters)
{
struct stat st;
int rc = stat(path.characters(), &st);
if (rc < 0) {
if (errno == ENOENT)
return false;
}
if (rc == 0) {
return true;
}
perror("stat");
warn("{}: ", program_name);
warnln(move(fmtstr), parameters...);
exit(1);
}
inline static bool validate_timestamp(unsigned year, unsigned month, unsigned day, unsigned hour, unsigned minute, unsigned second)
{
return (year >= 1970) && (month >= 1 && month <= 12) && (day >= 1 && day <= static_cast<unsigned>(days_in_month(year, month))) && (hour <= 23) && (minute <= 59) && (second <= 59);
}
static void parse_time(StringView input_time, timespec& atime, timespec& mtime)
{
// Parse [[CC]YY]MMDDhhmm[.SS] format, where brackets signify optional
// parameters.
if (input_time.length() < 8)
err("invalid time format '{}' -- too short", input_time);
else if (input_time.length() > 15)
err("invalid time format '{}' -- too long", input_time);
Vector<u8> parameters;
GenericLexer lexer(input_time);
unsigned year, month, day, hour, minute, second;
auto lex_number = [&]() {
auto literal = lexer.consume(2);
if (literal.length() < 2)
err("invalid time format '{}' -- expected 2 digits per parameter", input_time);
auto maybe_parameter = literal.to_uint();
if (maybe_parameter.has_value())
parameters.append(maybe_parameter.value());
else
err("invalid time format '{}'", input_time);
};
while (!lexer.is_eof() && lexer.next_is(isdigit))
lex_number();
if (parameters.size() > 6)
err("invalid time format '{}' -- too many parameters", input_time);
if (lexer.consume_specific('.')) {
lex_number();
second = parameters.take_last();
} else {
second = 0;
}
auto current_year = seconds_since_epoch_to_year(time(nullptr));
auto current_century = current_year / 100;
if (parameters.size() == 6)
year = parameters.take_first() * 100 + parameters.take_first();
else if (parameters.size() == 5)
year = current_century * 100 + parameters.take_first();
else
year = current_year;
minute = parameters.take_last();
hour = parameters.take_last();
day = parameters.take_last();
month = parameters.take_last();
if (validate_timestamp(year, month, day, hour, minute, second))
atime = mtime = AK::Time::from_timestamp(year, month, day, hour, minute, second, 0).to_timespec();
else
err("invalid time format '{}'", input_time);
}
static void parse_datetime(StringView input_datetime, timespec& atime, timespec& mtime)
{
// Parse YYYY-MM-DDThh:mm:SS[.frac][tz] or YYYY-MM-DDThh:mm:SS[,frac][tz]
// formats, where brackets signify optional parameters.
GenericLexer lexer(input_datetime);
unsigned year, month, day, hour, minute, second, millisecond;
StringView time_zone;
auto lex_number = [&](unsigned& value, size_t n) {
auto maybe_value = lexer.consume(n).to_uint();
if (!maybe_value.has_value())
err("invalid datetime format '{}' -- expected number at index {}", input_datetime, lexer.tell());
else
value = maybe_value.value();
};
lex_number(year, 4);
if (!lexer.consume_specific('-'))
err("invalid datetime format '{}' -- expected '-' after year", input_datetime);
lex_number(month, 2);
if (!lexer.consume_specific('-'))
err("invalid datetime format '{}' -- expected '-' after month", input_datetime);
lex_number(day, 2);
// Parse the time designator -- a single 'T' or ' ' according to POSIX.
if (!lexer.consume_specific('T') && !lexer.consume_specific(' '))
err("invalid datetime format '{}' -- expected 'T' or ' ' for time designator", input_datetime);
lex_number(hour, 2);
if (!lexer.consume_specific(':'))
err("invalid datetime format '{}' -- expected ':' after hour", input_datetime);
lex_number(minute, 2);
if (!lexer.consume_specific(':'))
err("invalid datetime format '{}' -- expected ':' after minute", input_datetime);
lex_number(second, 2);
millisecond = 0;
if (!lexer.is_eof()) {
if (lexer.consume_specific(',') || lexer.consume_specific('.')) {
auto fractional_second = lexer.consume_while(isdigit);
if (fractional_second.is_empty())
err("invalid datetime format '{}' -- expected floating seconds", input_datetime);
for (u8 i = 0; i < 3 && i < fractional_second.length(); ++i) {
unsigned n = fractional_second[i] - '0';
switch (i) {
case 0:
millisecond += 100 * n;
break;
case 1:
millisecond += 10 * n;
break;
case 2:
millisecond += n;
break;
default:
VERIFY_NOT_REACHED();
}
}
}
time_zone = lexer.consume_all();
if (!time_zone.is_empty() && time_zone != "Z")
err("invalid datetime format '{}' -- failed to parse time zone", input_datetime);
}
if (validate_timestamp(year, month, day, hour, minute, second)) {
auto timestamp = AK::Time::from_timestamp(year, month, day, hour, minute, second, millisecond);
auto time = timestamp.to_timespec();
if (time_zone.is_empty() && TimeZone::system_time_zone() != "UTC") {
auto offset = TimeZone::get_time_zone_offset(TimeZone::system_time_zone(), timestamp);
if (offset.has_value())
time.tv_sec -= offset.value().seconds;
else
err("failed to get the system time zone");
}
atime = mtime = time;
} else {
err("invalid datetime format '{}'", input_datetime);
}
}
static void reference_time(StringView reference_path, timespec& atime, timespec& mtime)
{
auto maybe_buffer = Core::System::stat(reference_path);
if (maybe_buffer.is_error())
err("failed to reference times of '{}': {}", reference_path, maybe_buffer.release_error());
auto buffer = maybe_buffer.release_value();
atime.tv_sec = buffer.st_atime;
atime.tv_nsec = buffer.st_atim.tv_nsec;
mtime.tv_sec = buffer.st_mtime;
mtime.tv_nsec = buffer.st_mtim.tv_nsec;
}
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
TRY(Core::System::pledge("stdio rpath cpath fattr"));
program_name = arguments.strings[0];
Vector<String> paths;
timespec times[2];
auto& atime = times[0];
auto& mtime = times[1];
bool update_atime = false;
bool update_mtime = false;
bool no_create_file = false;
String input_datetime = "";
String input_time = "";
String reference_path = "";
Core::ArgsParser args_parser;
args_parser.set_general_help("Create a file, or update its mtime (time of last modification).");
args_parser.set_general_help("Create a file or update file access time and/or modification time.");
args_parser.add_ignored(nullptr, 'f');
args_parser.add_option(update_atime, "Change access time of file", nullptr, 'a');
args_parser.add_option(no_create_file, "Do not create a file if it does not exist", nullptr, 'c');
args_parser.add_option(update_mtime, "Change modification time of file", nullptr, 'm');
args_parser.add_option(input_datetime, "Use specified datetime instead of current time", nullptr, 'd', "datetime");
args_parser.add_option(input_time, "Use specified time instead of current time", nullptr, 't', "time");
args_parser.add_option(reference_path, "Use time of file specified by reference path instead of current time", nullptr, 'r', "reference");
args_parser.add_positional_argument(paths, "Files to touch", "path", Core::ArgsParser::Required::Yes);
args_parser.parse(arguments);
if (input_datetime.is_empty() + input_time.is_empty() + reference_path.is_empty() < 2)
err("cannot specify a time with more than one option");
if (!input_datetime.is_empty())
parse_datetime(input_datetime, atime, mtime);
else if (!input_time.is_empty())
parse_time(input_time, atime, mtime);
else if (!reference_path.is_empty())
reference_time(reference_path, atime, mtime);
else
atime.tv_nsec = mtime.tv_nsec = UTIME_NOW;
// According to POSIX, if neither -a nor -m are specified, then the program
// should behave as if both are specified.
if (!update_atime && !update_mtime)
update_atime = update_mtime = true;
if (update_atime && !update_mtime)
mtime.tv_nsec = UTIME_OMIT;
if (update_mtime && !update_atime)
atime.tv_nsec = UTIME_OMIT;
for (auto path : paths) {
if (file_exists(path)) {
if (auto result = Core::System::utime(path, {}); result.is_error())
warnln("{}", result.release_error());
} else {
if (Core::Stream::File::exists(path)) {
if (utimensat(AT_FDCWD, path.characters(), times, 0) == -1)
err("failed to touch '{}': {}", path, strerror(errno));
} else if (!no_create_file) {
int fd = TRY(Core::System::open(path, O_CREAT, 0100644));
if (futimens(fd, times) == -1)
err("failed to touch '{}': {}", path, strerror(errno));
TRY(Core::System::close(fd));
}
}