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
|
/* chown() compatibility.
Copyright (C) 1998, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C 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 2.1 of the License, or (at your option) any later version.
The GNU C 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 the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <sys/syscall.h>
#include <stdlib.h>
/*
In Linux 2.1.x the chown functions have been changed. A new function lchown
was introduced. The new chown now follows symlinks - the old chown and the
new lchown do not follow symlinks.
This file emulates chown() under the old kernels.
*/
extern int __syscall_chown (const char *__file,
uid_t __owner, gid_t __group);
int
__chown (const char *file, uid_t owner, gid_t group)
{
int err;
int old_errno;
char link[PATH_MAX+2];
char path[2*PATH_MAX+4];
int loopct;
int filelen;
static int libc_old_chown = 0 /* -1=old linux, 1=new linux, 0=unknown */;
if (libc_old_chown == 1)
return __syscall_chown (file, owner, group);
old_errno = errno;
#ifdef __NR_lchown
if (libc_old_chown == 0)
{
err = __syscall_chown (file, owner, group);
if (err != -1 || errno != ENOSYS)
{
libc_old_chown = 1;
return err;
}
libc_old_chown = -1;
}
#endif
err = __readlink (file, link, PATH_MAX+1);
if (err == -1)
{
errno = old_errno;
return __lchown(file, owner, group);
}
filelen = strlen (file) + 1;
if (filelen > sizeof(path))
{
errno = ENAMETOOLONG;
return -1;
}
memcpy (path, file, filelen);
/* 'The system has an arbitrary limit...' In practise, we'll hit
ENAMETOOLONG before this, usually. */
for (loopct = 0; loopct < 128; loopct++)
{
int linklen;
if (err >= PATH_MAX+1)
{
errno = ENAMETOOLONG;
return -1;
}
link[err] = 0; /* Null-terminate string, just-in-case. */
linklen = strlen (link) + 1;
if (link[0] == '/')
memcpy (path, link, linklen);
else
{
filelen = strlen (path);
while (filelen > 1 && path[filelen-1] == '/')
filelen--;
while (filelen > 0 && path[filelen-1] != '/')
filelen--;
if (filelen + linklen > sizeof(path))
{
errno = ENAMETOOLONG;
return -1;
}
memcpy (path+filelen, link, linklen);
}
err = __readlink(path, link, PATH_MAX+1);
if (err == -1)
{
errno = old_errno;
return __lchown(path, owner, group);
}
}
errno = ELOOP;
return -1;
}
#include <shlib-compat.h>
versioned_symbol (libc, __chown, chown, GLIBC_2_1);
|
