ladybird/Userland/chroot.cpp
Sergey Bugaev 3847d00727 Kernel+Userland: Support remounting filesystems :^)
This makes it possible to change flags of a mount after the fact, with the
caveats outlined in the man page.
2020-05-29 07:53:30 +02:00

89 lines
3.1 KiB
C++

/*
* Copyright (c) 2020, Sergey Bugaev <bugaevc@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/StringView.h>
#include <LibCore/ArgsParser.h>
#include <stdio.h>
#include <unistd.h>
int main(int argc, char** argv)
{
const char* path = nullptr;
const char* program = "/bin/Shell";
int flags = -1;
Core::ArgsParser args_parser;
args_parser.add_positional_argument(path, "New root directory", "path");
args_parser.add_positional_argument(program, "Program to run", "program", Core::ArgsParser::Required::No);
Core::ArgsParser::Option option {
true,
"Mount options",
"options",
'o',
"options",
[&flags](const char* s) {
flags = 0;
Vector<StringView> parts = StringView(s).split_view(',');
for (auto& part : parts) {
if (part == "defaults")
continue;
else if (part == "nodev")
flags |= MS_NODEV;
else if (part == "noexec")
flags |= MS_NOEXEC;
else if (part == "nosuid")
flags |= MS_NOSUID;
else if (part == "ro")
flags |= MS_RDONLY;
else if (part == "remount")
flags |= MS_REMOUNT;
else if (part == "bind")
fprintf(stderr, "Ignoring -o bind, as it doesn't make sense for chroot\n");
else
return false;
}
return true;
}
};
args_parser.add_option(move(option));
args_parser.parse(argc, argv);
if (chroot_with_mount_flags(path, flags) < 0) {
perror("chroot");
return 1;
}
if (chdir("/") < 0) {
perror("chdir(/)");
return 1;
}
execl(program, program, nullptr);
perror("execl");
return 1;
}