2 * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
4 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
15 #include <sys/param.h>
16 #include <sys/types.h>
17 #include <sys/syscall.h>
18 #include <bits/kernel_types.h>
20 /* With newer versions of linux, the getdents syscall returns d_type
21 * information after the name field. Someday, we should add support for
22 * that instead of always calling getdents64 ...
24 * See __ASSUME_GETDENTS32_D_TYPE in glibc's kernel-features.h for specific
25 * version / arch details.
29 # define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
36 unsigned short int d_reclen;
40 ssize_t __getdents (int fd, char *buf, size_t nbytes) attribute_hidden;
42 #if ! defined __UCLIBC_HAS_LFS__ || ! defined __NR_getdents64
44 /* Experimentally off - libc_hidden_proto(memcpy) */
45 libc_hidden_proto(lseek)
47 #define __NR___syscall_getdents __NR_getdents
48 static __inline__ _syscall3(int, __syscall_getdents, int, fd, unsigned char *, kdirp, size_t, count);
50 ssize_t __getdents (int fd, char *buf, size_t nbytes)
53 off_t last_offset = -1;
56 struct kernel_dirent *skdp, *kdp;
57 const size_t size_diff = (offsetof (struct dirent, d_name)
58 - offsetof (struct kernel_dirent, d_name));
60 red_nbytes = MIN (nbytes - ((nbytes /
61 (offsetof (struct dirent, d_name) + 14)) * size_diff),
64 dp = (struct dirent *) buf;
65 skdp = kdp = alloca (red_nbytes);
67 retval = __syscall_getdents(fd, (unsigned char *)kdp, red_nbytes);
71 while ((char *) kdp < (char *) skdp + retval) {
72 const size_t alignment = __alignof__ (struct dirent);
73 /* Since kdp->d_reclen is already aligned for the kernel structure
74 this may compute a value that is bigger than necessary. */
75 size_t new_reclen = ((kdp->d_reclen + size_diff + alignment - 1)
77 if ((char *) dp + new_reclen > buf + nbytes) {
78 /* Our heuristic failed. We read too many entries. Reset
80 assert (last_offset != -1);
81 lseek(fd, last_offset, SEEK_SET);
83 if ((char *) dp == buf) {
84 /* The buffer the user passed in is too small to hold even
92 last_offset = kdp->d_off;
93 dp->d_ino = kdp->d_ino;
94 dp->d_off = kdp->d_off;
95 dp->d_reclen = new_reclen;
96 dp->d_type = DT_UNKNOWN;
97 memcpy (dp->d_name, kdp->d_name,
98 kdp->d_reclen - offsetof (struct kernel_dirent, d_name));
99 dp = (struct dirent *) ((char *) dp + new_reclen);
100 kdp = (struct kernel_dirent *) (((char *) kdp) + kdp->d_reclen);
102 return (char *) dp - buf;
105 #if defined __UCLIBC_HAS_LFS__ && ! defined __NR_getdents64
106 attribute_hidden strong_alias(__getdents,__getdents64)
109 #elif __WORDSIZE == 32
111 /* Experimentally off - libc_hidden_proto(memmove) */
113 extern __typeof(__getdents) __getdents64 attribute_hidden;
114 ssize_t __getdents (int fd, char *buf, size_t nbytes)
117 struct dirent64 *dp64;
118 ssize_t ret = __getdents64 (fd, buf, nbytes);
123 dp64 = (struct dirent64 *) buf;
125 while ((void *) dp64 < (void *) buf) {
126 dp = (struct dirent *) dp64;
127 dp->d_ino = dp64->d_ino;
128 dp->d_off = dp64->d_off;
129 dp->d_reclen = dp64->d_reclen;
130 dp->d_type = dp64->d_type;
131 memmove (dp->d_name, dp64->d_name, dp->d_reclen - offsetof (struct dirent64, d_name));
132 memmove (dp64, dp, dp->d_reclen);
133 dp64 = ((void *) dp64) + dp->d_reclen;