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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@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/String.h>
#include <AK/TemporaryChange.h>
#include <AK/Vector.h>
#include <errno_numbers.h>
#include <pwd.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 passwd s_passwd_entry;
static String s_name;
static String s_passwd;
static String s_gecos;
static String s_dir;
static String s_shell;
void setpwent()
{
s_line_number = 0;
if (s_stream) {
rewind(s_stream);
} else {
s_stream = fopen("/etc/passwd", "r");
if (!s_stream) {
perror("open /etc/passwd");
}
}
}
void endpwent()
{
s_line_number = 0;
if (s_stream) {
fclose(s_stream);
s_stream = nullptr;
}
memset(&s_passwd_entry, 0, sizeof(s_passwd_entry));
s_name = {};
s_passwd = {};
s_gecos = {};
s_dir = {};
s_shell = {};
}
struct passwd* getpwuid(uid_t uid)
{
setpwent();
while (auto* pw = getpwent()) {
if (pw->pw_uid == uid)
return pw;
}
return nullptr;
}
struct passwd* getpwnam(const char* name)
{
setpwent();
while (auto* pw = getpwent()) {
if (!strcmp(pw->pw_name, name))
return pw;
}
return nullptr;
}
static bool parse_pwddb_entry(const String& line)
{
auto parts = line.split_view(':', true);
if (parts.size() != 7) {
fprintf(stderr, "getpwent(): Malformed entry on line %u\n", s_line_number);
return false;
}
s_name = parts[0];
s_passwd = parts[1];
auto& uid_string = parts[2];
auto& gid_string = parts[3];
s_gecos = parts[4];
s_dir = parts[5];
s_shell = parts[6];
auto uid = uid_string.to_uint();
if (!uid.has_value()) {
fprintf(stderr, "getpwent(): Malformed UID on line %u\n", s_line_number);
return false;
}
auto gid = gid_string.to_uint();
if (!gid.has_value()) {
fprintf(stderr, "getpwent(): Malformed GID on line %u\n", s_line_number);
return false;
}
s_passwd_entry.pw_name = const_cast<char*>(s_name.characters());
s_passwd_entry.pw_passwd = const_cast<char*>(s_passwd.characters());
s_passwd_entry.pw_uid = uid.value();
s_passwd_entry.pw_gid = gid.value();
s_passwd_entry.pw_gecos = const_cast<char*>(s_gecos.characters());
s_passwd_entry.pw_dir = const_cast<char*>(s_dir.characters());
s_passwd_entry.pw_shell = const_cast<char*>(s_shell.characters());
return true;
}
struct passwd* getpwent()
{
if (!s_stream)
setpwent();
while (true) {
if (!s_stream || feof(s_stream))
return nullptr;
if (ferror(s_stream)) {
fprintf(stderr, "getpwent(): Read error: %s\n", 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_pwddb_entry(line))
return &s_passwd_entry;
// Otherwise, proceed to the next line.
}
}
static void construct_pwd(struct passwd* pwd, char* buf, struct passwd** result)
{
auto* buf_name = &buf[0];
auto* buf_passwd = &buf[s_name.length() + 1];
auto* buf_gecos = &buf[s_name.length() + 1 + s_gecos.length() + 1];
auto* buf_dir = &buf[s_gecos.length() + 1 + s_name.length() + 1 + s_gecos.length() + 1];
auto* buf_shell = &buf[s_dir.length() + 1 + s_gecos.length() + 1 + s_name.length() + 1 + s_gecos.length() + 1];
bool ok = true;
ok = ok || s_name.copy_characters_to_buffer(buf_name, s_name.length() + 1);
ok = ok || s_passwd.copy_characters_to_buffer(buf_passwd, s_passwd.length() + 1);
ok = ok || s_gecos.copy_characters_to_buffer(buf_gecos, s_gecos.length() + 1);
ok = ok || s_dir.copy_characters_to_buffer(buf_dir, s_dir.length() + 1);
ok = ok || s_shell.copy_characters_to_buffer(buf_shell, s_shell.length() + 1);
VERIFY(ok);
*result = pwd;
pwd->pw_name = buf_name;
pwd->pw_passwd = buf_passwd;
pwd->pw_gecos = buf_gecos;
pwd->pw_dir = buf_dir;
pwd->pw_shell = buf_shell;
}
int getpwnam_r(const char* name, struct passwd* pwd, char* buf, size_t buflen, struct passwd** result)
{
// FIXME: This is a HACK!
TemporaryChange name_change { s_name, {} };
TemporaryChange passwd_change { s_passwd, {} };
TemporaryChange gecos_change { s_gecos, {} };
TemporaryChange dir_change { s_dir, {} };
TemporaryChange shell_change { s_shell, {} };
setpwent();
bool found = false;
while (auto* pw = getpwent()) {
if (!strcmp(pw->pw_name, name)) {
found = true;
break;
}
}
if (!found) {
*result = nullptr;
return 0;
}
const auto total_buffer_length = s_name.length() + s_passwd.length() + s_gecos.length() + s_dir.length() + s_shell.length() + 5;
if (buflen < total_buffer_length)
return ERANGE;
construct_pwd(pwd, buf, result);
return 0;
}
int getpwuid_r(uid_t uid, struct passwd* pwd, char* buf, size_t buflen, struct passwd** result)
{
// FIXME: This is a HACK!
TemporaryChange name_change { s_name, {} };
TemporaryChange passwd_change { s_passwd, {} };
TemporaryChange gecos_change { s_gecos, {} };
TemporaryChange dir_change { s_dir, {} };
TemporaryChange shell_change { s_shell, {} };
setpwent();
bool found = false;
while (auto* pw = getpwent()) {
if (pw->pw_uid == uid) {
found = true;
break;
}
}
if (!found) {
*result = nullptr;
return 0;
}
const auto total_buffer_length = s_name.length() + s_passwd.length() + s_gecos.length() + s_dir.length() + s_shell.length() + 5;
if (buflen < total_buffer_length)
return ERANGE;
construct_pwd(pwd, buf, result);
return 0;
}
int putpwent(const struct passwd* p, FILE* stream)
{
if (!p || !stream || !p->pw_passwd || !p->pw_name || !p->pw_dir || !p->pw_gecos || !p->pw_shell) {
errno = EINVAL;
return -1;
}
auto is_valid_field = [](const char* str) {
return str && !strpbrk(str, ":\n");
};
if (!is_valid_field(p->pw_name) || !is_valid_field(p->pw_dir) || !is_valid_field(p->pw_gecos) || !is_valid_field(p->pw_shell)) {
errno = EINVAL;
return -1;
}
int nwritten = fprintf(stream, "%s:%s:%u:%u:%s,,,:%s:%s\n", p->pw_name, p->pw_passwd, p->pw_uid, p->pw_gid, p->pw_gecos, p->pw_dir, p->pw_shell);
if (!nwritten || nwritten < 0) {
errno = ferror(stream);
return -1;
}
return 0;
}
}
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