chgrp.cpp

#include <cstdio>
#include <cstring>
#include <grp.h>
#include <string>

#include <cfbox/args.hpp>
#include <cfbox/fs_util.hpp>
#include <cfbox/help.hpp>
#include <cfbox/error.hpp>

namespace {

constexpr cfbox::help::HelpEntry HELP = {
    .name    = "chgrp",
    .version = CFBOX_VERSION_STRING,
    .one_line = "change group ownership",
    .usage   = "chgrp [-R] [-v] GROUP FILE...",
    .options = "  -R          operate on files and directories recursively\n"
               "  -v          output a diagnostic for every file processed",
    .extra   = "",
};

} // namespace

auto chgrp_main(int argc, char* argv[]) -> int {
    auto parsed = cfbox::args::parse(argc, argv, {
        cfbox::args::OptSpec{'R', false, "recursive"},
        cfbox::args::OptSpec{'v', false, "verbose"},
    });

    if (parsed.has_long("help"))    { cfbox::help::print_help(HELP); return 0; }
    if (parsed.has_long("version")) { cfbox::help::print_version(HELP); return 0; }

    bool recursive = parsed.has('R');
    bool verbose = parsed.has('v');
    const auto& pos = parsed.positional();

    if (pos.size() < 2) {
        CFBOX_ERR("chgrp", "missing operand");
        return 2;
    }

    std::string group_name(pos[0]);
    gid_t gid;
    auto* gr = getgrnam(group_name.c_str());
    if (gr) {
        gid = gr->gr_gid;
    } else {
        gid = static_cast<gid_t>(std::strtoul(group_name.c_str(), nullptr, 10));
    }

    auto chgrp_one = [&](const std::string& path) -> int {
        auto result = cfbox::fs::chown(path, static_cast<uid_t>(-1), gid);
        if (!result) {
            CFBOX_ERR("chgrp", "%s: %s", path.c_str(), result.error().msg.c_str());
            return 1;
        }
        if (verbose) std::printf("group of '%s' changed\n", path.c_str());
        return 0;
    };

    int rc = 0;
    for (size_t i = 1; i < pos.size(); i++) {
        cfbox::fs::for_each_entry(pos[i], recursive, [&](const std::string& p) {
            if (chgrp_one(p) != 0) rc = 1;
        });
    }
    return rc;
}