1 /*
2 * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
3 *
4 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
5 */
6
7 #include <_lfs_64.h>
8 #include <sys/syscall.h>
9
10 #ifdef __NR_getdents64
11
12 #include <assert.h>
13 #include <errno.h>
14 #include <dirent.h>
15 #include <stddef.h>
16 #include <stdint.h>
17 #include <string.h>
18 #include <unistd.h>
19 #include <sys/param.h>
20 #include <bits/wordsize.h>
21 #include <bits/uClibc_alloc.h>
22
23 struct kernel_dirent64
24 {
25 uint64_t d_ino;
26 int64_t d_off;
27 unsigned short d_reclen;
28 unsigned char d_type;
29 char d_name[256];
30 };
31
32 # define __NR___syscall_getdents64 __NR_getdents64
_syscall3(int,__syscall_getdents64,int,fd,unsigned char *,dirp,size_t,count)33 static __inline__ _syscall3(int, __syscall_getdents64, int, fd, unsigned char *, dirp, size_t, count)
34
35 ssize_t __getdents64 (int fd, char *buf, size_t nbytes)
36 {
37 struct dirent64 *dp;
38 off64_t last_offset = -1;
39 ssize_t retval;
40 size_t red_nbytes;
41 struct kernel_dirent64 *skdp, *kdp;
42 const size_t size_diff = (offsetof (struct dirent64, d_name)
43 - offsetof (struct kernel_dirent64, d_name));
44
45 red_nbytes = MIN (nbytes - ((nbytes /
46 (offsetof (struct dirent64, d_name) + 14)) * size_diff),
47 nbytes - size_diff);
48
49 dp = (struct dirent64 *) buf;
50 skdp = kdp = stack_heap_alloc(red_nbytes);
51
52 retval = __syscall_getdents64(fd, (unsigned char *)kdp, red_nbytes);
53 if (retval == -1) {
54 stack_heap_free(skdp);
55 return -1;
56 }
57
58 while ((char *) kdp < (char *) skdp + retval) {
59 const size_t alignment = __alignof__ (struct dirent64);
60 /* Since kdp->d_reclen is already aligned for the kernel structure
61 this may compute a value that is bigger than necessary. */
62 size_t new_reclen = ((kdp->d_reclen + size_diff + alignment - 1)
63 & ~(alignment - 1));
64 if ((char *) dp + new_reclen > buf + nbytes) {
65 /* Our heuristic failed. We read too many entries. Reset
66 the stream. */
67 assert (last_offset != -1);
68 lseek64(fd, last_offset, SEEK_SET);
69
70 if ((char *) dp == buf) {
71 /* The buffer the user passed in is too small to hold even
72 one entry. */
73 stack_heap_free(skdp);
74 __set_errno (EINVAL);
75 return -1;
76 }
77 break;
78 }
79
80 last_offset = kdp->d_off;
81 dp->d_ino = kdp->d_ino;
82 dp->d_off = kdp->d_off;
83 dp->d_reclen = new_reclen;
84 dp->d_type = kdp->d_type;
85 memcpy (dp->d_name, kdp->d_name,
86 kdp->d_reclen - offsetof (struct kernel_dirent64, d_name));
87 dp = (struct dirent64 *) ((char *) dp + new_reclen);
88 kdp = (struct kernel_dirent64 *) (((char *) kdp) + kdp->d_reclen);
89 }
90 stack_heap_free(skdp);
91 return (char *) dp - buf;
92 }
93
94 #if __WORDSIZE == 64 || !defined __NR_getdents
95 /* since getdents doesnt give us d_type but getdents64 does, try and
96 * use getdents64 as much as possible */
97 strong_alias(__getdents64,__getdents)
98 #endif
99
100 #endif
101