/* * 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> /* With newer versions of linux, the getdents syscall returns d_type * information after the name field. Someday, we should add support for * that instead of always calling getdents64 ... * * 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; #if ! defined __UCLIBC_HAS_LFS__ || ! defined __NR_getdents64 libc_hidden_proto(memcpy) libc_hidden_proto(lseek) #define __NR___syscall_getdents __NR_getdents static inline _syscall3(int, __syscall_getdents, int, fd, unsigned char *, kdirp, size_t, count); 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; } #elif __WORDSIZE == 32 libc_hidden_proto(memmove) 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