/* * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org> * * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. */ #include <assert.h> #include <errno.h> #include <dirent.h> #include <stddef.h> #include <stdint.h> #include <string.h> #include <unistd.h> #include <dirent.h> #include <sys/param.h> #include <sys/types.h> #include <sys/syscall.h> #include <bits/kernel_types.h> #include <bits/kernel-features.h> #include <bits/uClibc_alloc.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]; }; #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 = stack_heap_alloc(red_nbytes); retval = __syscall_getdents(fd, (unsigned char *)kdp, red_nbytes); if (retval == -1) { stack_heap_free(skdp); 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. */ stack_heap_free(skdp); __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); } stack_heap_free(skdp); return (char *) dp - buf; } #elif __WORDSIZE == 32 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 #if defined __UCLIBC_HAS_LFS__ && ! defined __NR_getdents64 strong_alias(__getdents,__getdents64) #endif #endif