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
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/*
* fontconfig/src/fcatomic.c
*
* Copyright © 2002 Keith Packard
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of Keith Packard not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. Keith Packard makes no
* representations about the suitability of this software for any purpose. It
* is provided "as is" without express or implied warranty.
*
* THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/*
* fcatomic.c
*
* Lock cache and configuration files for atomic update
*
* Uses only regular filesystem calls so it should
* work even in the absense of functioning file locking
*
* On Unix, four files are used:
* file - the data file accessed by other apps.
* new - a new version of the data file while it's being written
* lck - the lock file
* tmp - a temporary file made unique with mkstemp
*
* Here's how it works:
* Create 'tmp' and store our PID in it
* Attempt to link it to 'lck'
* Unlink 'tmp'
* If the link succeeded, the lock is held
*
* On Windows, where there are no links, no tmp file is used, and lck
* is a directory that's mkdir'ed. If the mkdir succeeds, the lock is
* held.
*/
#include "fcint.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <time.h>
#ifdef _WIN32
#define mkdir(path,mode) _mkdir(path)
#endif
#define NEW_NAME ".NEW"
#define LCK_NAME ".LCK"
#define TMP_NAME ".TMP-XXXXXX"
FcAtomic *
FcAtomicCreate (const FcChar8 *file)
{
int file_len = strlen ((char *) file);
int new_len = file_len + sizeof (NEW_NAME);
int lck_len = file_len + sizeof (LCK_NAME);
int tmp_len = file_len + sizeof (TMP_NAME);
int total_len = (sizeof (FcAtomic) +
file_len + 1 +
new_len + 1 +
lck_len + 1 +
tmp_len + 1);
FcAtomic *atomic = malloc (total_len);
if (!atomic)
return 0;
FcMemAlloc (FC_MEM_ATOMIC, total_len);
atomic->file = (FcChar8 *) (atomic + 1);
strcpy ((char *) atomic->file, (char *) file);
atomic->new = atomic->file + file_len + 1;
strcpy ((char *) atomic->new, (char *) file);
strcat ((char *) atomic->new, NEW_NAME);
atomic->lck = atomic->new + new_len + 1;
strcpy ((char *) atomic->lck, (char *) file);
strcat ((char *) atomic->lck, LCK_NAME);
atomic->tmp = atomic->lck + lck_len + 1;
return atomic;
}
FcBool
FcAtomicLock (FcAtomic *atomic)
{
int fd = -1;
FILE *f = 0;
int ret;
struct stat lck_stat;
#ifdef HAVE_LINK
strcpy ((char *) atomic->tmp, (char *) atomic->file);
strcat ((char *) atomic->tmp, TMP_NAME);
fd = mkstemp ((char *) atomic->tmp);
if (fd < 0)
return FcFalse;
f = fdopen (fd, "w");
if (!f)
{
close (fd);
unlink ((char *) atomic->tmp);
return FcFalse;
}
ret = fprintf (f, "%ld\n", (long)getpid());
if (ret <= 0)
{
fclose (f);
unlink ((char *) atomic->tmp);
return FcFalse;
}
if (fclose (f) == EOF)
{
unlink ((char *) atomic->tmp);
return FcFalse;
}
ret = link ((char *) atomic->tmp, (char *) atomic->lck);
(void) unlink ((char *) atomic->tmp);
#else
ret = mkdir ((char *) atomic->lck, 0600);
#endif
if (ret < 0)
{
/*
* If the file is around and old (> 10 minutes),
* assume the lock is stale. This assumes that any
* machines sharing the same filesystem will have clocks
* reasonably close to each other.
*/
if (FcStat ((char *) atomic->lck, &lck_stat) >= 0)
{
time_t now = time (0);
if ((long int) (now - lck_stat.st_mtime) > 10 * 60)
{
#ifdef HAVE_LINK
if (unlink ((char *) atomic->lck) == 0)
return FcAtomicLock (atomic);
#else
if (rmdir ((char *) atomic->lck) == 0)
return FcAtomicLock (atomic);
#endif
}
}
return FcFalse;
}
(void) unlink ((char *) atomic->new);
return FcTrue;
}
FcChar8 *
FcAtomicNewFile (FcAtomic *atomic)
{
return atomic->new;
}
FcChar8 *
FcAtomicOrigFile (FcAtomic *atomic)
{
return atomic->file;
}
FcBool
FcAtomicReplaceOrig (FcAtomic *atomic)
{
#ifdef _WIN32
unlink (atomic->file);
#endif
if (rename ((char *) atomic->new, (char *) atomic->file) < 0)
return FcFalse;
return FcTrue;
}
void
FcAtomicDeleteNew (FcAtomic *atomic)
{
unlink ((char *) atomic->new);
}
void
FcAtomicUnlock (FcAtomic *atomic)
{
#ifdef HAVE_LINK
unlink ((char *) atomic->lck);
#else
rmdir ((char *) atomic->lck);
#endif
}
void
FcAtomicDestroy (FcAtomic *atomic)
{
FcMemFree (FC_MEM_ATOMIC, sizeof (FcAtomic) +
strlen ((char *) atomic->file) * 4 + 4 +
sizeof (NEW_NAME) + sizeof (LCK_NAME) +
sizeof (TMP_NAME));
free (atomic);
}
#define __fcatomic__
#include "fcaliastail.h"
#undef __fcatomic__
|
