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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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
27#include <AK/String.h>
28#include <AK/Vector.h>
29#include <pwd.h>
30#include <stdio.h>
31#include <stdlib.h>
32#include <sys/mman.h>
33#include <unistd.h>
34
35extern "C" {
36
37#define PWDB_STR_MAX_LEN 256
38
39struct passwd_with_strings : public passwd {
40 char name_buffer[PWDB_STR_MAX_LEN];
41 char passwd_buffer[PWDB_STR_MAX_LEN];
42 char gecos_buffer[PWDB_STR_MAX_LEN];
43 char dir_buffer[PWDB_STR_MAX_LEN];
44 char shell_buffer[PWDB_STR_MAX_LEN];
45};
46
47static FILE* __pwdb_stream = nullptr;
48static unsigned __pwdb_line_number = 0;
49static struct passwd_with_strings* __pwdb_entry = nullptr;
50
51void setpwent()
52{
53 __pwdb_line_number = 0;
54 if (__pwdb_stream) {
55 rewind(__pwdb_stream);
56 } else {
57 __pwdb_stream = fopen("/etc/passwd", "r");
58 if (!__pwdb_stream) {
59 perror("open /etc/passwd");
60 }
61 assert(__pwdb_stream);
62 __pwdb_entry = (struct passwd_with_strings*)mmap_with_name(nullptr, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0, "setpwent");
63 }
64}
65
66void endpwent()
67{
68 __pwdb_line_number = 0;
69 if (__pwdb_stream) {
70 fclose(__pwdb_stream);
71 __pwdb_stream = nullptr;
72 }
73 if (__pwdb_entry) {
74 munmap(__pwdb_entry, getpagesize());
75 __pwdb_entry = nullptr;
76 }
77}
78
79struct passwd* getpwuid(uid_t uid)
80{
81 setpwent();
82 while (auto* pw = getpwent()) {
83 if (pw->pw_uid == uid)
84 return pw;
85 }
86 return nullptr;
87}
88
89struct passwd* getpwnam(const char* name)
90{
91 setpwent();
92 while (auto* pw = getpwent()) {
93 if (!strcmp(pw->pw_name, name))
94 return pw;
95 }
96 return nullptr;
97}
98
99struct passwd* getpwent()
100{
101 if (!__pwdb_stream)
102 setpwent();
103
104 assert(__pwdb_stream);
105 if (feof(__pwdb_stream))
106 return nullptr;
107
108next_entry:
109 char buffer[1024];
110 ++__pwdb_line_number;
111 char* s = fgets(buffer, sizeof(buffer), __pwdb_stream);
112 if (!s)
113 return nullptr;
114 assert(__pwdb_stream);
115 if (feof(__pwdb_stream))
116 return nullptr;
117 String line(s, Chomp);
118 auto parts = line.split(':', true);
119 if (parts.size() != 7) {
120 fprintf(stderr, "getpwent(): Malformed entry on line %u\n", __pwdb_line_number);
121 goto next_entry;
122 }
123 auto& e_name = parts[0];
124 auto& e_passwd = parts[1];
125 auto& e_uid_string = parts[2];
126 auto& e_gid_string = parts[3];
127 auto& e_gecos = parts[4];
128 auto& e_dir = parts[5];
129 auto& e_shell = parts[6];
130 bool ok;
131 uid_t e_uid = e_uid_string.to_uint(ok);
132 if (!ok) {
133 fprintf(stderr, "getpwent(): Malformed UID on line %u\n", __pwdb_line_number);
134 goto next_entry;
135 }
136 gid_t e_gid = e_gid_string.to_uint(ok);
137 if (!ok) {
138 fprintf(stderr, "getpwent(): Malformed GID on line %u\n", __pwdb_line_number);
139 goto next_entry;
140 }
141 __pwdb_entry->pw_uid = e_uid;
142 __pwdb_entry->pw_gid = e_gid;
143 __pwdb_entry->pw_name = __pwdb_entry->name_buffer;
144 __pwdb_entry->pw_passwd = __pwdb_entry->passwd_buffer;
145 __pwdb_entry->pw_gecos = __pwdb_entry->gecos_buffer;
146 __pwdb_entry->pw_dir = __pwdb_entry->dir_buffer;
147 __pwdb_entry->pw_shell = __pwdb_entry->shell_buffer;
148 strncpy(__pwdb_entry->name_buffer, e_name.characters(), PWDB_STR_MAX_LEN);
149 strncpy(__pwdb_entry->passwd_buffer, e_passwd.characters(), PWDB_STR_MAX_LEN);
150 strncpy(__pwdb_entry->gecos_buffer, e_gecos.characters(), PWDB_STR_MAX_LEN);
151 strncpy(__pwdb_entry->dir_buffer, e_dir.characters(), PWDB_STR_MAX_LEN);
152 strncpy(__pwdb_entry->shell_buffer, e_shell.characters(), PWDB_STR_MAX_LEN);
153 return __pwdb_entry;
154}
155
156int putpwent(const struct passwd* p, FILE* stream)
157{
158 if (!p || !stream || !p->pw_name || !p->pw_dir || !p->pw_gecos || !p->pw_shell) {
159 errno = EINVAL;
160 return -1;
161 }
162
163 auto is_valid_field = [](const char* str) {
164 return str && !strpbrk(str, ":\n");
165 };
166
167 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)) {
168 errno = EINVAL;
169 return -1;
170 }
171
172 int nwritten = fprintf(stream, "%s:x:%u:%u:%s,,,:%s:%s\n", p->pw_name, p->pw_uid, p->pw_gid, p->pw_gecos, p->pw_dir, p->pw_shell);
173 if (!nwritten || nwritten < 0) {
174 errno = ferror(stream);
175 return -1;
176 }
177
178 return 0;
179}
180}