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
|
/* Determine current working directory. Linux version.
Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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 <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <bp-checks.h>
#include "kernel-features.h"
#if __ASSUME_GETCWD_SYSCALL > 0
/* Kernel 2.1.92 introduced a third way to get the current working
directory: a syscall. We've got to be careful that even when
compiling under 2.1.92+ the libc still runs under older kernels. */
extern int __syscall_getcwd (char *__unbounded buf, unsigned long size);
# define no_syscall_getcwd 0
# define have_new_dcache 1
/* This is a trick since we don't define generic_getcwd. */
# define generic_getcwd getcwd
#else
/* The "proc" filesystem provides an easy method to retrieve the value.
For each process, the corresponding directory contains a symbolic link
named `cwd'. Reading the content of this link immediate gives us the
information. But we have to take care for systems which do not have
the proc filesystem mounted. Use the POSIX implementation in this case. */
static char *generic_getcwd (char *buf, size_t size) internal_function;
# if __NR_getcwd
/* Kernel 2.1.92 introduced a third way to get the current working
directory: a syscall. We've got to be careful that even when
compiling under 2.1.92+ the libc still runs under older kernels. */
extern int __syscall_getcwd (char *__unbounded buf, unsigned long size);
static int no_syscall_getcwd;
static int have_new_dcache;
# else
# define no_syscall_getcwd 1
static int have_new_dcache = 1;
# endif
#endif
char *
__getcwd (char *buf, size_t size)
{
int save_errno;
char *path;
int n;
char *result;
size_t alloc_size = size;
if (no_syscall_getcwd && !have_new_dcache)
return generic_getcwd (buf, size);
if (size == 0)
{
if (buf != NULL)
{
__set_errno (EINVAL);
return NULL;
}
alloc_size = PATH_MAX;
}
if (buf != NULL)
path = buf;
else
{
path = malloc (alloc_size);
if (path == NULL)
return NULL;
}
save_errno = errno;
#if defined __NR_getcwd || __LINUX_GETCWD_SYSCALL > 0
if (!no_syscall_getcwd)
{
int retval;
retval = INLINE_SYSCALL (getcwd, 2, CHECK_STRING (path), alloc_size);
if (retval >= 0)
{
if (buf == NULL && size == 0)
/* Ensure that the buffer is only as large as necessary. */
buf = realloc (path, (size_t) retval);
if (buf == NULL)
/* Either buf was NULL all along, or `realloc' failed but
we still have the original string. */
buf = path;
return buf;
}
# if __ASSUME_GETCWD_SYSCALL
/* It should never happen that the `getcwd' syscall failed because
the buffer is too small if we allocated the buffer ourselves
large enough. */
assert (errno != ERANGE || buf != NULL || size != 0);
if (buf == NULL)
free (path);
return NULL;
# else
if (errno == ENOSYS)
{
no_syscall_getcwd = 1;
have_new_dcache = 1; /* Now we will try the /proc method. */
}
else if (errno != ERANGE || buf != NULL)
{
if (buf == NULL)
free (path);
return NULL;
}
__set_errno (save_errno);
# endif
}
#endif
n = __readlink ("/proc/self/cwd", path, alloc_size - 1);
if (n != -1)
{
if (path[0] == '/')
{
if (n >= alloc_size - 1)
{
if (buf == NULL)
free (path);
return NULL;
}
path[n] = '\0';
if (buf == NULL && size == 0)
/* Ensure that the buffer is only as large as necessary. */
buf = realloc (path, (size_t) n + 1);
if (buf == NULL)
/* Either buf was NULL all along, or `realloc' failed but
we still have the original string. */
buf = path;
return buf;
}
#ifndef have_new_dcache
else
have_new_dcache = 0;
#endif
}
#if __ASSUME_GETCWD_SYSCALL == 0
/* Set to have_new_dcache only if error indicates that proc doesn't
exist. */
if (errno != EACCES && errno != ENAMETOOLONG)
have_new_dcache = 0;
#endif
/* Something went wrong. Restore the error number and use the generic
version. */
__set_errno (save_errno);
/* Don't put restrictions on the length of the path unless the user does. */
if (size == 0)
{
free (path);
path = NULL;
}
result = generic_getcwd (path, size);
if (result == NULL && buf == NULL && size != 0)
free (path);
return result;
}
weak_alias (__getcwd, getcwd)
#if __ASSUME_GETCWD_SYSCALL == 0
/* Get the code for the generic version. */
# define GETCWD_RETURN_TYPE static char * internal_function
# define __getcwd generic_getcwd
# include <sysdeps/posix/getcwd.c>
#endif
|
