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
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/* $OpenBSD: backupfile.c,v 1.21 2013/11/26 13:19:07 deraadt Exp $ */
/*
* backupfile.c -- make Emacs style backup file names Copyright (C) 1990 Free
* Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* without restriction.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE.
*/
/*
* David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs.
*/
#include <ctype.h>
#include <dirent.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "backupfile.h"
#define ISDIGIT(c) (isascii (c) && isdigit (c))
/* Which type of backup file names are generated. */
enum backup_type backup_type = none;
/*
* The extension added to file names to produce a simple (as opposed to
* numbered) backup file name.
*/
char *simple_backup_suffix = "~";
static char *concat(const char *, const char *);
static char *make_version_name(const char *, int);
static int max_backup_version(const char *, const char *);
static int version_number(const char *, const char *, size_t);
static int argmatch(const char *, const char **);
static void invalid_arg(const char *, const char *, int);
/*
* Return the name of the new backup file for file FILE, allocated with
* malloc. Return 0 if out of memory. FILE must not end with a '/' unless it
* is the root directory. Do not call this function if backup_type == none.
*/
char *
find_backup_file_name(const char *file)
{
char *dir, *base_versions;
int highest_backup;
if (backup_type == simple)
return concat(file, simple_backup_suffix);
base_versions = concat(basename(file), ".~");
if (base_versions == NULL)
return NULL;
dir = dirname(file);
if (dir == NULL) {
free(base_versions);
return NULL;
}
highest_backup = max_backup_version(base_versions, dir);
free(base_versions);
if (backup_type == numbered_existing && highest_backup == 0)
return concat(file, simple_backup_suffix);
return make_version_name(file, highest_backup + 1);
}
/*
* Return the number of the highest-numbered backup file for file FILE in
* directory DIR. If there are no numbered backups of FILE in DIR, or an
* error occurs reading DIR, return 0. FILE should already have ".~" appended
* to it.
*/
static int
max_backup_version(const char *file, const char *dir)
{
DIR *dirp;
struct dirent *dp;
int highest_version, this_version;
size_t file_name_length;
dirp = opendir(dir);
if (dirp == NULL)
return 0;
highest_version = 0;
file_name_length = strlen(file);
while ((dp = readdir(dirp)) != NULL) {
if (dp->d_namlen <= file_name_length)
continue;
this_version = version_number(file, dp->d_name, file_name_length);
if (this_version > highest_version)
highest_version = this_version;
}
closedir(dirp);
return highest_version;
}
/*
* Return a string, allocated with malloc, containing "FILE.~VERSION~".
* Return 0 if out of memory.
*/
static char *
make_version_name(const char *file, int version)
{
char *backup_name;
if (asprintf(&backup_name, "%s.~%d~", file, version) == -1)
return NULL;
return backup_name;
}
/*
* If BACKUP is a numbered backup of BASE, return its version number;
* otherwise return 0. BASE_LENGTH is the length of BASE. BASE should
* already have ".~" appended to it.
*/
static int
version_number(const char *base, const char *backup, size_t base_length)
{
int version;
const char *p;
version = 0;
if (!strncmp(base, backup, base_length) &&
ISDIGIT((unsigned char)backup[base_length])) {
for (p = &backup[base_length]; ISDIGIT((unsigned char)*p); ++p)
version = version * 10 + *p - '0';
if (p[0] != '~' || p[1])
version = 0;
}
return version;
}
/*
* Return the newly-allocated concatenation of STR1 and STR2. If out of
* memory, return 0.
*/
static char *
concat(const char *str1, const char *str2)
{
char *newstr;
if (asprintf(&newstr, "%s%s", str1, str2) == -1)
return NULL;
return newstr;
}
/*
* If ARG is an unambiguous match for an element of the null-terminated array
* OPTLIST, return the index in OPTLIST of the matched element, else -1 if it
* does not match any element or -2 if it is ambiguous (is a prefix of more
* than one element).
*/
static int
argmatch(const char *arg, const char **optlist)
{
int i; /* Temporary index in OPTLIST. */
size_t arglen; /* Length of ARG. */
int matchind = -1; /* Index of first nonexact match. */
int ambiguous = 0; /* If nonzero, multiple nonexact match(es). */
arglen = strlen(arg);
/* Test all elements for either exact match or abbreviated matches. */
for (i = 0; optlist[i]; i++) {
if (!strncmp(optlist[i], arg, arglen)) {
if (strlen(optlist[i]) == arglen)
/* Exact match found. */
return i;
else if (matchind == -1)
/* First nonexact match found. */
matchind = i;
else
/* Second nonexact match found. */
ambiguous = 1;
}
}
if (ambiguous)
return -2;
else
return matchind;
}
/*
* Error reporting for argmatch. KIND is a description of the type of entity
* that was being matched. VALUE is the invalid value that was given. PROBLEM
* is the return value from argmatch.
*/
static void
invalid_arg(const char *kind, const char *value, int problem)
{
fprintf(stderr, "patch: ");
if (problem == -1)
fprintf(stderr, "invalid");
else /* Assume -2. */
fprintf(stderr, "ambiguous");
fprintf(stderr, " %s `%s'\n", kind, value);
}
static const char *backup_args[] = {
"never", "simple", "nil", "existing", "t", "numbered", 0
};
static enum backup_type backup_types[] = {
simple, simple, numbered_existing,
numbered_existing, numbered, numbered
};
/*
* Return the type of backup indicated by VERSION. Unique abbreviations are
* accepted.
*/
enum backup_type
get_version(const char *version)
{
int i;
if (version == NULL || *version == '\0')
return numbered_existing;
i = argmatch(version, backup_args);
if (i >= 0)
return backup_types[i];
invalid_arg("version control type", version, i);
exit(2);
}
|
