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Serenity Operating System
1/*
2 * Copyright (c) 2019-2020, Jesse Buhagiar <jooster669@gmail.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26#include <AK/String.h>
27#include <LibCore/ArgsParser.h>
28#include <ctype.h>
29#include <pwd.h>
30#include <stdio.h>
31#include <sys/stat.h>
32#include <sys/types.h>
33#include <unistd.h>
34
35constexpr uid_t BASE_UID = 1000;
36constexpr gid_t USERS_GID = 100;
37constexpr const char* DEFAULT_SHELL = "/bin/Shell";
38
39int main(int argc, char** argv)
40{
41 const char* home_path = nullptr;
42 int uid = 0;
43 int gid = USERS_GID;
44 bool create_home_dir = false;
45 const char* shell = DEFAULT_SHELL;
46 const char* gecos = "";
47 const char* username = nullptr;
48
49 Core::ArgsParser args_parser;
50 args_parser.add_option(home_path, "Home directory for the new user", "home-dir", 'd', "path");
51 args_parser.add_option(uid, "User ID (uid) for the new user", "uid", 'u', "uid");
52 args_parser.add_option(gid, "Group ID (gid) for the new user", "gid", 'g', "gid");
53 args_parser.add_option(create_home_dir, "Create home directory if it does not exist", "create-home", 'm');
54 args_parser.add_option(shell, "Path to the default shell binary for the new user", "shell", 's', "path-to-shell");
55 args_parser.add_option(gecos, "GECOS name of the new user", "gecos", 'n', "general-info");
56 args_parser.add_positional_argument(username, "Login user identity (username)", "login");
57
58 args_parser.parse(argc, argv);
59
60 // Let's run a quick sanity check on username
61 if (strpbrk(username, "\\/!@#$%^&*()~+=`:\n")) {
62 fprintf(stderr, "invalid character in username, %s\n", username);
63 return 1;
64 }
65
66 // Disallow names starting with _ and -
67 if (username[0] == '_' || username[0] == '-' || !isalpha(username[0])) {
68 fprintf(stderr, "invalid username, %s\n", username);
69 return 1;
70 }
71
72 if (uid < 0) {
73 fprintf(stderr, "invalid uid %d!\n", uid);
74 return 3;
75 }
76
77 // First, let's sort out the uid for the user
78 if (uid > 0) {
79 if (getpwuid(static_cast<uid_t>(uid))) {
80 fprintf(stderr, "uid %u already exists!\n", uid);
81 return 4;
82 }
83
84 } else {
85 for (uid = BASE_UID; getpwuid(static_cast<uid_t>(uid)); uid++) {
86 }
87 }
88
89 if (gid < 0) {
90 fprintf(stderr, "invalid gid %d\n", gid);
91 return 3;
92 }
93
94 FILE* pwfile = fopen("/etc/passwd", "a");
95 if (!pwfile) {
96 perror("failed to open /etc/passwd");
97 return 1;
98 }
99
100 String home;
101 if (!home_path)
102 home = String::format("/home/%s", username);
103 else
104 home = home_path;
105
106 if (create_home_dir) {
107 if (mkdir(home.characters(), 0700) < 0) {
108 perror(String::format("failed to create directory %s", home.characters()).characters());
109 return 12;
110 }
111
112 if (chown(home.characters(), static_cast<uid_t>(uid), static_cast<gid_t>(gid)) < 0) {
113 perror(String::format("failed to chown %s to %u:%u", home.characters(), uid, gid).characters());
114
115 if (rmdir(home.characters()) < 0) {
116 perror(String::format("failed to rmdir %s", home.characters()).characters());
117 return 12;
118 }
119 return 12;
120 }
121 }
122
123 struct passwd p;
124 p.pw_name = const_cast<char*>(username);
125 p.pw_dir = const_cast<char*>(home.characters());
126 p.pw_uid = static_cast<uid_t>(uid);
127 p.pw_gid = static_cast<gid_t>(gid);
128 p.pw_shell = const_cast<char*>(shell);
129 p.pw_gecos = const_cast<char*>(gecos);
130
131 if (putpwent(&p, pwfile) < 0) {
132 perror("putpwent");
133 return 1;
134 }
135
136 fclose(pwfile);
137
138 return 0;
139}