getdents.c revision 3f54fd611f536639ec30dd53c48e5ec1897cc7d9
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2011 AT&T Intellectual Property *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
#include "dirlib.h"
#if _dir_ok || _lib_getdents
NoN(getdents)
#else
/*
* getdents
*
* read directory entries into directory block
*
* NOTE: directory entries must fit within DIRBLKSIZ boundaries
*/
#ifndef MAXNAMLEN
#define MAXNAMLEN 255
#endif
#if _lib_dirread
extern int dirread(int, char*, int);
#endif
#if _lib_getdirentries
extern int getdirentries(int, char*, int, long*);
#endif
ssize_t
getdents(int fd, void* buf, size_t siz)
{
struct stat st;
if (siz < DIRBLKSIZ)
{
errno = EINVAL;
return(-1);
}
if (fstat(fd, &st)) return(-1);
if (!S_ISDIR(st.st_mode))
{
#ifdef ENOTDIR
errno = ENOTDIR;
#else
errno = EBADF;
#endif
return(-1);
}
#if _lib_getdirentries
{
long off;
return(getdirentries(fd, buf, siz, &off));
}
#else
#if _lib_dirread
{
register char* sp; /* system */
register struct dirent* up; /* user */
char* u;
int n;
int m;
int i;
m = (siz * 6) / 10;
m = roundof(m, 8);
sp = (char*)buf + siz - m - 1;
if (!(n = dirread(fd, sp, m))) return(0);
if (n > 0)
{
up = (struct dirent*)buf;
sp[n] = 0;
while (sp < (char*)buf + siz - m + n)
{
i = 0;
while (*sp >= '0' && *sp <= '9')
i = 10 * i + *sp++ - '0';
while (*sp && *sp != '\t') sp++;
if (*sp++)
{
up->d_fileno = i;
u = up->d_name;
while ((*u = *sp++) && u < up->d_name + MAXNAMLEN) u++;
*u = 0;
up->d_reclen = sizeof(struct dirent) - sizeof(up->d_name) + (up->d_namlen = u - up->d_name) + 1;
up->d_reclen = roundof(up->d_reclen, 8);
up = (struct dirent*)((char*)up + up->d_reclen);
}
}
return((char*)up - (char*)buf);
}
}
#else
#if _mem_d_reclen_direct
return(read(fd, buf, siz));
#else
{
#define MAXREC roundof(sizeof(*up)-sizeof(up->d_name)+sizeof(sp->d_name)+1,8)
register struct direct* sp; /* system */
register struct dirent* up; /* user */
register char* s;
register char* u;
int n;
int m;
char tmp[sizeof(sp->d_name) + 1];
/*
* we assume sizeof(struct dirent) > sizeof(struct direct)
*/
up = (struct dirent*)buf;
n = (siz / MAXREC) * sizeof(struct direct);
if ((!(m = n & ~511) || m < MAXREC) && (!(m = n & ~255) || m < MAXREC)) m = n;
do
{
if ((n = read(fd, (char*)buf + siz - m, m)) <= 0) break;
sp = (struct direct*)((char*)buf + siz - m);
while (sp < (struct direct*)((char*)buf + siz - m + n))
{
if (sp->d_ino)
{
up->d_fileno = sp->d_ino;
s = sp->d_name;
u = tmp;
while (s < sp->d_name + sizeof(sp->d_name) && *s)
*u++ = *s++;
*u = 0;
strcpy(up->d_name, tmp);
up->d_reclen = sizeof(struct dirent) - sizeof(up->d_name) + (up->d_namlen = u - tmp) + 1;
up->d_reclen = roundof(up->d_reclen, 8);
up = (struct dirent*)((char*)up + up->d_reclen);
}
sp++;
}
} while (up == (struct dirent*)buf);
return((char*)up - (char*)buf);
}
#endif
#endif
#endif
}
#endif