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/*
* UNG's Not GNU
*
* Copyright (c) 2020 Jakob Kaivo <jkk@ung.org>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#define _POSIX_C_SOURCE 200809L
#include <fcntl.h>
#include <dirent.h>
#include <limits.h>
#include <pwd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#ifndef LINE_MAX
#define LINE_MAX _POSIX2_LINE_MAX
#endif
#ifndef O_SEARCH
#define O_SEARCH 0
#endif
#define USERS_DIRECTORY "/var/secure/users"
static DIR *users_dir = NULL;
struct user {
struct passwd pw;
char gecos[LINE_MAX];
char password[LINE_MAX];
};
enum selection { UID, NAME, ALL };
static struct user *user_read(char *name)
{
static struct user u = { 0 };
int user = openat(dirfd(users_dir), name, O_SEARCH);
if (user == -1) {
return NULL;
}
struct stat st;
if (fstat(user, &st) != 0) {
close(user);
return NULL;
}
u.pw.pw_name = name;
u.pw.pw_uid = st.st_uid;
u.pw.pw_gid = st.st_gid;
u.pw.pw_dir = "/"; // TODO: read symlink at userfd, home
u.pw.pw_shell = "/bin/sh"; // TOOD: read symlink at userfd, shell
strcpy(u.gecos, name); // TODO: read file at userfd, gecos
strcpy(u.password, "--"); // TODO: read file at userfd, password
close(user);
return &u;
}
static char *user_uid(uid_t uid)
{
char *name = NULL;
struct dirent *de;
while ((de = readdir(users_dir)) != NULL) {
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
continue;
}
struct stat st;
if (fstatat(dirfd(users_dir), de->d_name, &st, 0) != 0) {
continue;
}
if (st.st_uid == uid) {
name = de->d_name;
break;
}
}
return name;
}
static struct user *user_find(enum selection sel, char *name, uid_t uid)
{
if (sel == UID) {
name = user_uid(uid);
}
return user_read(name);
}
static void user_print(const struct user *u)
{
if (u == NULL) {
return;
}
printf("%s:%s:%jd:%jd:%s:%s:%s\n", u->pw.pw_name, u->password,
(intmax_t)u->pw.pw_uid, (intmax_t)u->pw.pw_gid,
u->gecos, u->pw.pw_dir, u->pw.pw_shell);
}
int main(int argc, char *argv[])
{
char *name = getlogin();
uid_t uid = getuid();
enum selection sel = NAME;;
enum { LIST, PASSWORD } action = LIST;
int c;
while ((c = getopt(argc, argv, "LN:U:p")) != -1) {
switch (c) {
case 'L':
sel = ALL;
break;
case 'N':
sel = NAME;
name = optarg;
break;
case 'U':
sel = UID;
uid = atoi(optarg);
break;
case 'p':
action = PASSWORD;
break;
default:
return 1;
}
}
if (action == PASSWORD && sel == ALL) {
fprintf(stderr, "user: -L and -p are incompatible\n");
return 1;
}
users_dir = opendir(USERS_DIRECTORY);
if (users_dir == NULL) {
fprintf(stderr, "user: no users directory\n");
return 1;
}
if (action == PASSWORD) {
printf("TODO: interactively change password\n");
return 0;
}
if (sel == ALL) {
struct dirent *de = NULL;
while ((de = readdir(users_dir)) != NULL) {
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
continue;
}
user_print(user_read(de->d_name));
}
return 0;
}
struct user *u = user_find(sel, name, uid);
if (u == NULL) {
fprintf(stderr, "user: not found\n");
return 1;
}
user_print(u);
}
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