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/***************************************************************
SYS-GETDENTS.C
Linux/i386/ILP32 implementation of __cpu_sys_getdents().
PART OF : CPU - library .
USAGE : Internal only .
Copyright (C) 2026 by Andrew V.Kosteltsev.
All Rights Reserved.
***************************************************************/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <dirent.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
#include <libmcpu.h>
#include <cpu-sysdeps.h>
#define __CPU_HOST_DIRENT_BUFFER 4096U
struct __cpu_linux_dirent64
{
uint64_t d_ino;
int64_t d_off;
unsigned short d_reclen;
unsigned char d_type;
char d_name[];
};
static int
__cpu_dirent_utf8_valid( const unsigned char *s, size_t n )
{
size_t i = 0;
while( i < n )
{
unsigned int c = s[i++];
if( c < 0x80U ) continue;
if( c >= 0xc2U && c <= 0xdfU )
{
if( i >= n || ( s[i] & 0xc0U ) != 0x80U ) return( 0 );
++i; continue;
}
if( c == 0xe0U )
{
if( i + 1 >= n || s[i] < 0xa0U || s[i] > 0xbfU ||
( s[i + 1] & 0xc0U ) != 0x80U ) return( 0 );
i += 2; continue;
}
if( c >= 0xe1U && c <= 0xecU )
{
if( i + 1 >= n || ( s[i] & 0xc0U ) != 0x80U ||
( s[i + 1] & 0xc0U ) != 0x80U ) return( 0 );
i += 2; continue;
}
if( c == 0xedU )
{
if( i + 1 >= n || s[i] < 0x80U || s[i] > 0x9fU ||
( s[i + 1] & 0xc0U ) != 0x80U ) return( 0 );
i += 2; continue;
}
if( c >= 0xeeU && c <= 0xefU )
{
if( i + 1 >= n || ( s[i] & 0xc0U ) != 0x80U ||
( s[i + 1] & 0xc0U ) != 0x80U ) return( 0 );
i += 2; continue;
}
if( c == 0xf0U )
{
if( i + 2 >= n || s[i] < 0x90U || s[i] > 0xbfU ||
( s[i + 1] & 0xc0U ) != 0x80U ||
( s[i + 2] & 0xc0U ) != 0x80U ) return( 0 );
i += 3; continue;
}
if( c >= 0xf1U && c <= 0xf3U )
{
if( i + 2 >= n || ( s[i] & 0xc0U ) != 0x80U ||
( s[i + 1] & 0xc0U ) != 0x80U ||
( s[i + 2] & 0xc0U ) != 0x80U ) return( 0 );
i += 3; continue;
}
if( c == 0xf4U )
{
if( i + 2 >= n || s[i] < 0x80U || s[i] > 0x8fU ||
( s[i + 1] & 0xc0U ) != 0x80U ||
( s[i + 2] & 0xc0U ) != 0x80U ) return( 0 );
i += 3; continue;
}
return( 0 );
}
return( 1 );
}
static __mpu_uint64_t
__cpu_dirent_type( unsigned char type )
{
switch( type )
{
#ifdef DT_FIFO
case DT_FIFO: return( __CPU_DT_FIFO );
#endif
#ifdef DT_CHR
case DT_CHR: return( __CPU_DT_CHR );
#endif
#ifdef DT_DIR
case DT_DIR: return( __CPU_DT_DIR );
#endif
#ifdef DT_BLK
case DT_BLK: return( __CPU_DT_BLK );
#endif
#ifdef DT_REG
case DT_REG: return( __CPU_DT_REG );
#endif
#ifdef DT_LNK
case DT_LNK: return( __CPU_DT_LNK );
#endif
#ifdef DT_SOCK
case DT_SOCK: return( __CPU_DT_SOCK );
#endif
default: return( __CPU_DT_UNKNOWN );
}
}
__mpu_int64_t
__cpu_sys_getdents( int fd, struct __cpu_dirent *dirp, __mpu_uint64_t count )
{
unsigned char hostbuf[__CPU_HOST_DIRENT_BUFFER];
struct stat st;
off_t start;
off_t resume;
ssize_t nread;
size_t pos = 0;
size_t nrecords = 0;
size_t maxrecords;
if( !dirp ) return( -(__mpu_int64_t)__MCPU_EFAULT );
if( count < __CPU_DIRENT_SIZE ) return( -(__mpu_int64_t)__MCPU_EINVAL );
maxrecords = (size_t)( count / __CPU_DIRENT_SIZE );
if( fstat( fd, &st ) < 0 ) return( -(__mpu_int64_t)__cpu_errno_from_host( errno ) );
if( !S_ISDIR( st.st_mode ) ) return( -(__mpu_int64_t)__MCPU_ENOTDIR );
start = lseek( fd, (off_t)0, SEEK_CUR );
if( start == (off_t)-1 ) return( -(__mpu_int64_t)__cpu_errno_from_host( errno ) );
resume = start;
nread = syscall( SYS_getdents64, fd, hostbuf, sizeof( hostbuf ) );
if( nread < 0 ) return( -(__mpu_int64_t)__cpu_errno_from_host( errno ) );
if( nread == 0 ) return( 0 );
while( pos < (size_t)nread )
{
struct __cpu_linux_dirent64 *de;
const char *nul;
size_t namespace;
size_t namelen;
if( (size_t)nread - pos < offsetof( struct __cpu_linux_dirent64, d_name ) + 1U )
goto malformed;
de = (struct __cpu_linux_dirent64 *)( hostbuf + pos );
if( de->d_reclen < offsetof( struct __cpu_linux_dirent64, d_name ) + 1U ||
de->d_reclen > (size_t)nread - pos ) goto malformed;
if( nrecords >= maxrecords ) break;
namespace = de->d_reclen - offsetof( struct __cpu_linux_dirent64, d_name );
nul = (const char *)memchr( de->d_name, '\0', namespace );
if( !nul ) goto malformed;
namelen = (size_t)( nul - de->d_name );
if( namelen >= __CPU_DIRENT_NAME_SIZE )
{
if( lseek( fd, resume, SEEK_SET ) == (off_t)-1 )
return( -(__mpu_int64_t)__cpu_errno_from_host( errno ) );
return( nrecords ? (__mpu_int64_t)( nrecords * __CPU_DIRENT_SIZE )
: -(__mpu_int64_t)__MCPU_ENAMETOOLONG );
}
if( !__cpu_dirent_utf8_valid( (const unsigned char *)de->d_name, namelen ) )
{
if( lseek( fd, resume, SEEK_SET ) == (off_t)-1 )
return( -(__mpu_int64_t)__cpu_errno_from_host( errno ) );
return( nrecords ? (__mpu_int64_t)( nrecords * __CPU_DIRENT_SIZE )
: -(__mpu_int64_t)__MCPU_EILSEQ );
}
dirp[nrecords].d_ino = (__mpu_uint64_t)de->d_ino;
dirp[nrecords].d_off = (__mpu_int64_t)de->d_off;
dirp[nrecords].d_reclen = __CPU_DIRENT_SIZE;
dirp[nrecords].d_type = __cpu_dirent_type( de->d_type );
memset( dirp[nrecords].d_name, 0, __CPU_DIRENT_NAME_SIZE );
memcpy( dirp[nrecords].d_name, de->d_name, namelen );
resume = (off_t)de->d_off;
++nrecords;
pos += de->d_reclen;
}
if( pos < (size_t)nread )
{
if( lseek( fd, resume, SEEK_SET ) == (off_t)-1 )
return( -(__mpu_int64_t)__cpu_errno_from_host( errno ) );
}
return( (__mpu_int64_t)( nrecords * __CPU_DIRENT_SIZE ) );
malformed:
if( lseek( fd, start, SEEK_SET ) == (off_t)-1 )
return( -(__mpu_int64_t)__cpu_errno_from_host( errno ) );
return( -(__mpu_int64_t)__MCPU_EIO );
} /* End of __cpu_sys_getdents() */
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