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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Kenneth Myhra <kennethmyhra@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Format.h>
#include <AK/Optional.h>
#include <AK/String.h>
#include <AK/StringUtils.h>
#include <AK/Vector.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
/* the new mode will be computed using the boolean function(for each bit):
|current mode|removal mask|applying mask|result |
| 0 | 0 | 0 | 0 |
| 0 | 0 | 1 | 1 |
| 0 | 1 | 0 | 0 |
| 0 | 1 | 1 | 1 | ---> find the CNF --> find the minimal CNF
| 1 | 0 | 0 | 1 |
| 1 | 0 | 1 | 1 |
| 1 | 1 | 0 | 0 |
| 1 | 1 | 1 | 1 |
*/
class Mask {
private:
mode_t removal_mask; // the bits that will be removed
mode_t applying_mask; // the bits that will be set
public:
Mask()
: removal_mask(0)
, applying_mask(0)
{
}
Mask& operator|=(const Mask& other)
{
removal_mask |= other.removal_mask;
applying_mask |= other.applying_mask;
return *this;
}
mode_t& get_removal_mask() { return removal_mask; }
mode_t& get_applying_mask() { return applying_mask; }
void set_mode(mode_t mode)
{
this->applying_mask = mode;
this->removal_mask = ~mode;
}
};
Optional<Mask> string_to_mode(char access_scope, StringView access_string);
Optional<Mask> apply_permission(char access_scope, char permission, char operation);
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
TRY(Core::System::pledge("stdio rpath fattr", nullptr));
if (arguments.strings.size() < 3) {
warnln("usage: chmod <octal-mode> <path...>");
warnln(" chmod [[ugoa][+-=][rwx...],...] <path...>");
return 1;
}
Mask mask;
/* compute a mask */
auto mode_string = arguments.strings[1];
if (mode_string[0] >= '0' && mode_string[0] <= '7') {
mode_t mode = AK::StringUtils::convert_to_uint_from_octal<u16>(mode_string).value_or(01000);
if (mode > 0777) {
warnln("chmod: invalid mode: {}", mode_string);
return 1;
}
mask.set_mode(mode);
} else {
auto access_strings = arguments.strings[1].split_view(',');
for (auto access_string : access_strings) {
Optional<Mask> tmp_mask;
switch (access_string[0]) {
case 'u':
tmp_mask = string_to_mode('u', access_string);
break;
case 'g':
tmp_mask = string_to_mode('g', access_string);
break;
case 'o':
tmp_mask = string_to_mode('o', access_string);
break;
case 'a':
tmp_mask = string_to_mode('a', access_string);
break;
case '=':
case '+':
case '-':
tmp_mask = string_to_mode('a', access_string);
break;
}
if (!tmp_mask.has_value()) {
warnln("chmod: invalid mode: {}", arguments.strings[1]);
return 1;
}
mask |= tmp_mask.value();
}
}
/* set the mask for each file's permissions */
size_t i = 2;
while (i < arguments.strings.size()) {
auto current_access = TRY(Core::System::stat(arguments.strings[i]));
/* found the minimal CNF by The Quine–McCluskey algorithm and use it */
mode_t mode = mask.get_applying_mask()
| (current_access.st_mode & ~mask.get_removal_mask());
TRY(Core::System::chmod(arguments.strings[i++], mode));
}
return 0;
}
Optional<Mask> string_to_mode(char access_scope, StringView access_string)
{
auto get_operation = [](StringView s) {
for (auto c : s) {
if (c == '+' || c == '-' || c == '=')
return c;
}
return ' ';
};
auto operation = get_operation(access_string);
if (operation == ' ') {
return {};
}
Mask mask;
if (operation == '=') {
switch (access_scope) {
case 'u':
mask.get_removal_mask() = (S_IRUSR | S_IWUSR | S_IXUSR);
break;
case 'g':
mask.get_removal_mask() = (S_IRGRP | S_IWGRP | S_IXGRP);
break;
case 'o':
mask.get_removal_mask() = (S_IROTH | S_IWOTH | S_IXOTH);
break;
case 'a':
mask.get_removal_mask() = (S_IRUSR | S_IWUSR | S_IXUSR
| S_IRGRP | S_IWGRP | S_IXGRP
| S_IROTH | S_IWOTH | S_IXOTH);
break;
}
operation = '+';
}
for (size_t i = 1; i < access_string.length(); i++) {
char permission = access_string[i];
if (permission == '+' || permission == '-' || permission == '=')
continue;
Optional<Mask> tmp_mask;
tmp_mask = apply_permission(access_scope, permission, operation);
if (!tmp_mask.has_value()) {
return {};
}
mask |= tmp_mask.value();
}
return mask;
}
Optional<Mask> apply_permission(char access_scope, char permission, char operation)
{
if (permission != 'r' && permission != 'w' && permission != 'x') {
return {};
}
Mask mask;
mode_t tmp_mask = 0;
switch (access_scope) {
case 'u':
switch (permission) {
case 'r':
tmp_mask = S_IRUSR;
break;
case 'w':
tmp_mask = S_IWUSR;
break;
case 'x':
tmp_mask = S_IXUSR;
break;
}
break;
case 'g':
switch (permission) {
case 'r':
tmp_mask = S_IRGRP;
break;
case 'w':
tmp_mask = S_IWGRP;
break;
case 'x':
tmp_mask = S_IXGRP;
break;
}
break;
case 'o':
switch (permission) {
case 'r':
tmp_mask = S_IROTH;
break;
case 'w':
tmp_mask = S_IWOTH;
break;
case 'x':
tmp_mask = S_IXOTH;
break;
}
break;
case 'a':
mask |= apply_permission('u', permission, operation).value();
mask |= apply_permission('g', permission, operation).value();
mask |= apply_permission('o', permission, operation).value();
break;
}
if (operation == '+') {
mask.get_applying_mask() |= tmp_mask;
} else {
mask.get_removal_mask() |= tmp_mask;
}
return mask;
}
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