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
|
/*
* Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
*
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <dirent.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <bits/kernel_types.h>
#include <bits/kernel-features.h>
#if !(defined __UCLIBC_HAS_LFS__ && defined __NR_getdents64 && __WORDSIZE == 64)
/* If the condition above is met, __getdents is defined as an alias
* for __getdents64 (see getdents64.c). Otherwise...
*/
/* With newer versions of linux, the getdents syscall returns d_type
* information after the name field.
*
* See __ASSUME_GETDENTS32_D_TYPE in glibc's kernel-features.h for specific
* version / arch details.
*/
#ifndef offsetof
# define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
struct kernel_dirent
{
long int d_ino;
__kernel_off_t d_off;
unsigned short int d_reclen;
char d_name[256];
};
ssize_t __getdents (int fd, char *buf, size_t nbytes) attribute_hidden;
#define __NR___syscall_getdents __NR_getdents
static __always_inline _syscall3(int, __syscall_getdents, int, fd, unsigned char *, kdirp, size_t, count)
#if defined __ASSUME_GETDENTS32_D_TYPE
ssize_t __getdents (int fd, char *buf, size_t nbytes)
{
ssize_t retval;
retval = __syscall_getdents(fd, (unsigned char *)buf, nbytes);
/* The kernel added the d_type value after the name. Change
this now. */
if (retval != -1) {
union {
struct kernel_dirent k;
struct dirent u;
} *kbuf = (void *) buf;
while ((char *) kbuf < buf + retval) {
char d_type = *((char *) kbuf + kbuf->k.d_reclen - 1);
memmove (kbuf->u.d_name, kbuf->k.d_name,
strlen (kbuf->k.d_name) + 1);
kbuf->u.d_type = d_type;
kbuf = (void *) ((char *) kbuf + kbuf->k.d_reclen);
}
}
return retval;
}
#elif ! defined __UCLIBC_HAS_LFS__ || ! defined __NR_getdents64
ssize_t __getdents (int fd, char *buf, size_t nbytes)
{
struct dirent *dp;
off_t last_offset = -1;
ssize_t retval;
size_t red_nbytes;
struct kernel_dirent *skdp, *kdp;
const size_t size_diff = (offsetof (struct dirent, d_name)
- offsetof (struct kernel_dirent, d_name));
red_nbytes = MIN (nbytes - ((nbytes /
(offsetof (struct dirent, d_name) + 14)) * size_diff),
nbytes - size_diff);
dp = (struct dirent *) buf;
skdp = kdp = alloca (red_nbytes);
retval = __syscall_getdents(fd, (unsigned char *)kdp, red_nbytes);
if (retval == -1)
return -1;
while ((char *) kdp < (char *) skdp + retval) {
const size_t alignment = __alignof__ (struct dirent);
/* Since kdp->d_reclen is already aligned for the kernel structure
this may compute a value that is bigger than necessary. */
size_t new_reclen = ((kdp->d_reclen + size_diff + alignment - 1)
& ~(alignment - 1));
if ((char *) dp + new_reclen > buf + nbytes) {
/* Our heuristic failed. We read too many entries. Reset
the stream. */
assert (last_offset != -1);
lseek(fd, last_offset, SEEK_SET);
if ((char *) dp == buf) {
/* The buffer the user passed in is too small to hold even
one entry. */
__set_errno (EINVAL);
return -1;
}
break;
}
last_offset = kdp->d_off;
dp->d_ino = kdp->d_ino;
dp->d_off = kdp->d_off;
dp->d_reclen = new_reclen;
dp->d_type = DT_UNKNOWN;
memcpy (dp->d_name, kdp->d_name,
kdp->d_reclen - offsetof (struct kernel_dirent, d_name));
dp = (struct dirent *) ((char *) dp + new_reclen);
kdp = (struct kernel_dirent *) (((char *) kdp) + kdp->d_reclen);
}
return (char *) dp - buf;
}
#if defined __UCLIBC_HAS_LFS__ && ! defined __NR_getdents64
attribute_hidden strong_alias(__getdents,__getdents64)
#endif
#elif __WORDSIZE == 32
extern __typeof(__getdents) __getdents64 attribute_hidden;
ssize_t __getdents (int fd, char *buf, size_t nbytes)
{
struct dirent *dp;
struct dirent64 *dp64;
ssize_t ret = __getdents64 (fd, buf, nbytes);
if (ret <= 0)
return ret;
dp64 = (struct dirent64 *) buf;
buf += ret;
while ((void *) dp64 < (void *) buf) {
dp = (struct dirent *) dp64;
dp->d_ino = dp64->d_ino;
dp->d_off = dp64->d_off;
dp->d_reclen = dp64->d_reclen;
dp->d_type = dp64->d_type;
memmove (dp->d_name, dp64->d_name, dp->d_reclen - offsetof (struct dirent64, d_name));
memmove (dp64, dp, dp->d_reclen);
dp64 = ((void *) dp64) + dp->d_reclen;
}
return ret;
}
#endif
#endif
|
