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
|
/* GNU Mailutils -- a suite of utilities for electronic mail
Copyright (C) 1999-2003, 2005-2007, 2009-2012 Free Software
Foundation, Inc.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This library 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. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General
Public License along with this library. If not, see
<http://www.gnu.org/licenses/>. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <mailutils/types.h>
#include <mailutils/util.h>
#define INITIAL_READLINK_SIZE 128
int
mu_readlink (const char *name, char **pbuf, size_t *psize, size_t *plen)
{
size_t status = 0;
char *buf = *pbuf;
size_t size = *psize;
ssize_t linklen;
while (1)
{
if (!buf)
{
size = INITIAL_READLINK_SIZE;
buf = malloc (size);
}
else
{
char *p;
size_t newsize = size << 1;
if (newsize < size)
{
status = ENAMETOOLONG;
break;
}
size = newsize;
p = realloc (buf, size);
if (!p)
free (buf);
buf = p;
}
if (!buf)
{
status = ENOMEM;
break;
}
linklen = readlink (name, buf, size);
if (linklen < 0 && errno != ERANGE)
{
status = errno;
break;
}
if ((size_t) linklen < size)
{
buf[linklen++] = '\0';
status = 0;
break;
}
}
if (status)
{
if (buf)
{
free (buf);
buf = NULL;
}
size = 0;
}
*pbuf = buf;
*psize = size;
if (plen)
*plen = linklen;
return status;
}
#ifndef _POSIX_SYMLOOP_MAX
# define _POSIX_SYMLOOP_MAX 255
#endif
int
mu_unroll_symlink (const char *name, char **pout)
{
size_t symloops = 0;
struct slbuf { char *base; size_t size; } buf[2];
int idx = 0;
int status;
buf[0].base = buf[1].base = NULL;
buf[0].size = buf[1].size = 0;
while (symloops++ < _POSIX_SYMLOOP_MAX)
{
struct stat st;
size_t len;
if (lstat (name, &st) == -1)
return errno;
if (!S_ISLNK (st.st_mode))
{
if (!buf[idx].base)
{
buf[idx].base = strdup (name);
if (!buf[idx].base)
return ENOMEM;
}
status = 0;
break;
}
idx = !idx;
status = mu_readlink (name, &buf[idx].base, &buf[idx].size, &len);
if (status)
break;
name = mu_normalize_path (buf[idx].base);
}
if (status)
{
free (buf[0].base);
free (buf[1].base);
}
else
{
*pout = buf[idx].base;
free (buf[!idx].base);
}
return status;
}
|
