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[/] [or1k/] [trunk/] [linux/] [uClibc/] [libc/] [sysdeps/] [linux/] [common/] [getdents64.c] - Rev 1765
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/* Copyright (C) 1993, 1995-2002 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 <features.h> #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 <sysdep.h> #include <sys/param.h> #include <sys/types.h> #include <sys/syscall.h> #if defined __UCLIBC_HAS_LFS__ && defined __NR_getdents64 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) struct kernel_dirent64 { uint64_t d_ino; int64_t d_off; unsigned short d_reclen; unsigned char d_type; char d_name[256]; }; #define __NR___syscall_getdents64 __NR_getdents64 static inline _syscall3(int, __syscall_getdents64, int, fd, unsigned char *, dirp, size_t, count); ssize_t __getdents64 (int fd, char *buf, size_t nbytes) { struct dirent64 *dp; off64_t last_offset = -1; ssize_t retval; size_t red_nbytes; struct kernel_dirent64 *skdp, *kdp; const size_t size_diff = (offsetof (struct dirent64, d_name) - offsetof (struct kernel_dirent64, d_name)); red_nbytes = MIN (nbytes - ((nbytes / (offsetof (struct dirent64, d_name) + 14)) * size_diff), nbytes - size_diff); dp = (struct dirent64 *) buf; skdp = kdp = alloca (red_nbytes); retval = __syscall_getdents64(fd, (char *)kdp, red_nbytes); if (retval == -1) return -1; while ((char *) kdp < (char *) skdp + retval) { const size_t alignment = __alignof__ (struct dirent64); /* 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); lseek64(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_dirent64, d_name)); dp = (struct dirent64 *) ((char *) dp + new_reclen); kdp = (struct kernel_dirent64 *) (((char *) kdp) + kdp->d_reclen); } return (char *) dp - buf; } #else ssize_t __getdents (int fd, char *buf, size_t nbytes); ssize_t __getdents64 (int fd, char *buf, size_t nbytes) { return(__getdents(fd, buf, nbytes)); } #endif /* __UCLIBC_HAS_LFS__ */