1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/* utent.c <ndf@linux.mit.edu> */
/* Let it be known that this is very possibly the worst standard ever. HP-UX
does one thing, someone else does another, linux another... If anyone
actually has the standard, please send it to me.
Note that because of the way this stupid stupid standard works, you
have to call endutent() to close the file even if you've not called
setutent -- getutid and family use the same file descriptor.
Modified by Erik Andersen for uClibc...
*/
#include <features.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <paths.h>
#include <errno.h>
#include <string.h>
#include <utmp.h>
#include <bits/uClibc_mutex.h>
__UCLIBC_MUTEX_STATIC(utmplock, PTHREAD_MUTEX_INITIALIZER);
/* Some global crap */
static int static_fd = -1;
static struct utmp static_utmp;
static const char default_file_name[] = _PATH_UTMP;
static const char *static_ut_name = default_file_name;
/* This function must be called with the LOCK held */
static void __setutent(void)
{
if (static_fd < 0) {
#ifndef O_CLOEXEC
# define O_CLOEXEC 0
#endif
static_fd = open(static_ut_name, O_RDWR | O_CLOEXEC);
if (static_fd < 0) {
static_fd = open(static_ut_name, O_RDONLY | O_CLOEXEC);
if (static_fd < 0) {
return; /* static_fd remains < 0 */
}
}
if (O_CLOEXEC == 0) {
/* Make sure the file will be closed on exec() */
fcntl(static_fd, F_SETFD, FD_CLOEXEC);
/* thus far, {G,S}ETFD only has this single flag,
* and setting it never fails.
*int ret = fcntl(static_fd, F_GETFD, 0);
*if (ret >= 0) {
* ret = fcntl(static_fd, F_SETFD, ret | FD_CLOEXEC);
*}
*if (ret < 0) {
* static_fd = -1;
*}
*/
}
return;
}
lseek(static_fd, 0, SEEK_SET);
}
void setutent(void)
{
__UCLIBC_MUTEX_LOCK(utmplock);
__setutent();
__UCLIBC_MUTEX_UNLOCK(utmplock);
}
libc_hidden_def(setutent)
/* This function must be called with the LOCK held */
static struct utmp *__getutent(void)
{
struct utmp *ret = NULL;
if (static_fd < 0) {
__setutent();
if (static_fd < 0) {
return NULL;
}
}
if (read(static_fd, &static_utmp, sizeof(static_utmp)) == sizeof(static_utmp)) {
ret = &static_utmp;
}
return ret;
}
void endutent(void)
{
__UCLIBC_MUTEX_LOCK(utmplock);
if (static_fd >= 0)
close(static_fd);
static_fd = -1;
__UCLIBC_MUTEX_UNLOCK(utmplock);
}
struct utmp *getutent(void)
{
struct utmp *ret = NULL;
__UCLIBC_MUTEX_LOCK(utmplock);
ret = __getutent();
__UCLIBC_MUTEX_UNLOCK(utmplock);
return ret;
}
/* This function must be called with the LOCK held */
static struct utmp *__getutid(const struct utmp *utmp_entry)
{
struct utmp *lutmp;
while ((lutmp = __getutent()) != NULL) {
if ( (utmp_entry->ut_type == RUN_LVL ||
utmp_entry->ut_type == BOOT_TIME ||
utmp_entry->ut_type == NEW_TIME ||
utmp_entry->ut_type == OLD_TIME) &&
lutmp->ut_type == utmp_entry->ut_type)
{
return lutmp;
}
if ( (utmp_entry->ut_type == INIT_PROCESS ||
utmp_entry->ut_type == DEAD_PROCESS ||
utmp_entry->ut_type == LOGIN_PROCESS ||
utmp_entry->ut_type == USER_PROCESS) &&
!strncmp(lutmp->ut_id, utmp_entry->ut_id, sizeof(lutmp->ut_id)))
{
return lutmp;
}
}
return NULL;
}
struct utmp *getutid(const struct utmp *utmp_entry)
{
struct utmp *ret = NULL;
__UCLIBC_MUTEX_LOCK(utmplock);
ret = __getutid(utmp_entry);
__UCLIBC_MUTEX_UNLOCK(utmplock);
return ret;
}
libc_hidden_def(getutid)
struct utmp *getutline(const struct utmp *utmp_entry)
{
struct utmp *lutmp = NULL;
__UCLIBC_MUTEX_LOCK(utmplock);
while ((lutmp = __getutent()) != NULL) {
if ((lutmp->ut_type == USER_PROCESS || lutmp->ut_type == LOGIN_PROCESS) &&
!strcmp(lutmp->ut_line, utmp_entry->ut_line)) {
break;
}
}
__UCLIBC_MUTEX_UNLOCK(utmplock);
return lutmp;
}
struct utmp *pututline(const struct utmp *utmp_entry)
{
__UCLIBC_MUTEX_LOCK(utmplock);
/* Ignore the return value. That way, if they've already positioned
the file pointer where they want it, everything will work out. */
lseek(static_fd, (off_t) - sizeof(struct utmp), SEEK_CUR);
if (__getutid(utmp_entry) != NULL)
lseek(static_fd, (off_t) - sizeof(struct utmp), SEEK_CUR);
else
lseek(static_fd, (off_t) 0, SEEK_END);
if (write(static_fd, utmp_entry, sizeof(struct utmp)) != sizeof(struct utmp))
utmp_entry = NULL;
__UCLIBC_MUTEX_UNLOCK(utmplock);
return (struct utmp *)utmp_entry;
}
int utmpname(const char *new_ut_name)
{
__UCLIBC_MUTEX_LOCK(utmplock);
if (new_ut_name != NULL) {
if (static_ut_name != default_file_name)
free((char *)static_ut_name);
static_ut_name = strdup(new_ut_name);
if (static_ut_name == NULL) {
/* We should probably whine about out-of-memory
* errors here... Instead just reset to the default */
static_ut_name = default_file_name;
}
}
if (static_fd >= 0) {
close(static_fd);
static_fd = -1;
}
__UCLIBC_MUTEX_UNLOCK(utmplock);
return 0; /* or maybe return -(static_ut_name != new_ut_name)? */
}
|
