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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Maxime Friess <M4x1me@pm.me>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/String.h>
#include <AK/Vector.h>
#include <errno.h>
#include <errno_numbers.h>
#include <grp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
extern "C" {
static FILE* s_stream = nullptr;
static unsigned s_line_number = 0;
static struct group s_group;
static String s_name;
static String s_passwd;
static Vector<String> s_members;
static Vector<const char*> s_members_ptrs;
void setgrent()
{
s_line_number = 0;
if (s_stream) {
rewind(s_stream);
} else {
s_stream = fopen("/etc/group", "r");
if (!s_stream) {
perror("open /etc/group");
}
}
}
void endgrent()
{
s_line_number = 0;
if (s_stream) {
fclose(s_stream);
s_stream = nullptr;
}
memset(&s_group, 0, sizeof(s_group));
s_name = {};
s_passwd = {};
s_members = {};
s_members_ptrs = {};
}
struct group* getgrgid(gid_t gid)
{
setgrent();
while (auto* gr = getgrent()) {
if (gr->gr_gid == gid)
return gr;
}
return nullptr;
}
struct group* getgrnam(const char* name)
{
setgrent();
while (auto* gr = getgrent()) {
if (!strcmp(gr->gr_name, name))
return gr;
}
return nullptr;
}
static bool parse_grpdb_entry(const String& line)
{
auto parts = line.split_view(':', true);
if (parts.size() != 4) {
warnln("getgrent(): Malformed entry on line {}: '{}' has {} parts", s_line_number, line, parts.size());
return false;
}
s_name = parts[0];
s_passwd = parts[1];
auto& gid_string = parts[2];
String members_string = parts[3];
auto gid = gid_string.to_uint();
if (!gid.has_value()) {
warnln("getgrent(): Malformed GID on line {}", s_line_number);
return false;
}
s_members = members_string.split(',');
s_members_ptrs.clear_with_capacity();
s_members_ptrs.ensure_capacity(s_members.size() + 1);
for (auto& member : s_members) {
s_members_ptrs.append(member.characters());
}
s_members_ptrs.append(nullptr);
s_group.gr_gid = gid.value();
s_group.gr_name = const_cast<char*>(s_name.characters());
s_group.gr_passwd = const_cast<char*>(s_passwd.characters());
s_group.gr_mem = const_cast<char**>(s_members_ptrs.data());
return true;
}
struct group* getgrent()
{
if (!s_stream)
setgrent();
while (true) {
if (!s_stream || feof(s_stream))
return nullptr;
if (ferror(s_stream)) {
warnln("getgrent(): Read error: {}", strerror(ferror(s_stream)));
return nullptr;
}
char buffer[1024];
++s_line_number;
char* s = fgets(buffer, sizeof(buffer), s_stream);
// Silently tolerate an empty line at the end.
if ((!s || !s[0]) && feof(s_stream))
return nullptr;
String line(s, Chomp);
if (parse_grpdb_entry(line))
return &s_group;
// Otherwise, proceed to the next line.
}
}
int initgroups(const char* user, gid_t extra_gid)
{
size_t count = 0;
gid_t gids[32];
bool extra_gid_added = false;
setgrent();
while (auto* gr = getgrent()) {
for (auto* mem = gr->gr_mem; *mem; ++mem) {
if (!strcmp(*mem, user)) {
gids[count++] = gr->gr_gid;
if (gr->gr_gid == extra_gid)
extra_gid_added = true;
break;
}
}
}
endgrent();
if (!extra_gid_added)
gids[count++] = extra_gid;
return setgroups(count, gids);
}
int putgrent(const struct group* group, FILE* stream)
{
if (!group || !stream || !group->gr_name || !group->gr_passwd) {
errno = EINVAL;
return -1;
}
auto is_valid_field = [](const char* str) {
return str && !strpbrk(str, ":\n");
};
if (!is_valid_field(group->gr_name) || !is_valid_field(group->gr_passwd)) {
errno = EINVAL;
return -1;
}
int nwritten = fprintf(stream, "%s:%s:%u:", group->gr_name, group->gr_passwd, group->gr_gid);
if (!nwritten || nwritten < 0) {
errno = ferror(stream);
return -1;
}
if (group->gr_mem) {
for (size_t i = 0; group->gr_mem[i] != nullptr; i++) {
nwritten = fprintf(stream, i == 0 ? "%s" : ",%s", group->gr_mem[i]);
if (!nwritten || nwritten < 0) {
errno = ferror(stream);
return -1;
}
}
}
nwritten = fprintf(stream, "\n");
if (!nwritten || nwritten < 0) {
errno = ferror(stream);
return -1;
}
return 0;
}
}
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