1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * Copyright (c) 1997-2000 by Sun Microsystems, Inc. 3*0Sstevel@tonic-gate * All rights reserved. 4*0Sstevel@tonic-gate */ 5*0Sstevel@tonic-gate 6*0Sstevel@tonic-gate #ifndef LINT 7*0Sstevel@tonic-gate static const char rcsid[] = "$Id: ftruncate.c,v 8.4 1999/10/13 16:39:21 vixie Exp $"; 8*0Sstevel@tonic-gate #endif 9*0Sstevel@tonic-gate 10*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 11*0Sstevel@tonic-gate 12*0Sstevel@tonic-gate /* 13*0Sstevel@tonic-gate * ftruncate - set file size, BSD Style 14*0Sstevel@tonic-gate * 15*0Sstevel@tonic-gate * shortens or enlarges the file as neeeded 16*0Sstevel@tonic-gate * uses some undocumented locking call. It is known to work on SCO unix, 17*0Sstevel@tonic-gate * other vendors should try. 18*0Sstevel@tonic-gate * The #error directive prevents unsupported OSes 19*0Sstevel@tonic-gate */ 20*0Sstevel@tonic-gate 21*0Sstevel@tonic-gate #include "port_before.h" 22*0Sstevel@tonic-gate 23*0Sstevel@tonic-gate #if defined(M_UNIX) 24*0Sstevel@tonic-gate #define OWN_FTRUNCATE 25*0Sstevel@tonic-gate #include <stdio.h> 26*0Sstevel@tonic-gate #ifdef _XOPEN_SOURCE 27*0Sstevel@tonic-gate #undef _XOPEN_SOURCE 28*0Sstevel@tonic-gate #endif 29*0Sstevel@tonic-gate #ifdef _POSIX_SOURCE 30*0Sstevel@tonic-gate #undef _POSIX_SOURCE 31*0Sstevel@tonic-gate #endif 32*0Sstevel@tonic-gate 33*0Sstevel@tonic-gate #include <fcntl.h> 34*0Sstevel@tonic-gate 35*0Sstevel@tonic-gate #include "port_after.h" 36*0Sstevel@tonic-gate 37*0Sstevel@tonic-gate int 38*0Sstevel@tonic-gate __ftruncate(int fd, long wantsize) { 39*0Sstevel@tonic-gate long cursize; 40*0Sstevel@tonic-gate 41*0Sstevel@tonic-gate /* determine current file size */ 42*0Sstevel@tonic-gate if ((cursize = lseek(fd, 0L, 2)) == -1) 43*0Sstevel@tonic-gate return (-1); 44*0Sstevel@tonic-gate 45*0Sstevel@tonic-gate /* maybe lengthen... */ 46*0Sstevel@tonic-gate if (cursize < wantsize) { 47*0Sstevel@tonic-gate if (lseek(fd, wantsize - 1, 0) == -1 || 48*0Sstevel@tonic-gate write(fd, "", 1) == -1) { 49*0Sstevel@tonic-gate return (-1); 50*0Sstevel@tonic-gate } 51*0Sstevel@tonic-gate return (0); 52*0Sstevel@tonic-gate } 53*0Sstevel@tonic-gate 54*0Sstevel@tonic-gate /* maybe shorten... */ 55*0Sstevel@tonic-gate if (wantsize < cursize) { 56*0Sstevel@tonic-gate struct flock fl; 57*0Sstevel@tonic-gate 58*0Sstevel@tonic-gate fl.l_whence = 0; 59*0Sstevel@tonic-gate fl.l_len = 0; 60*0Sstevel@tonic-gate fl.l_start = wantsize; 61*0Sstevel@tonic-gate fl.l_type = F_WRLCK; 62*0Sstevel@tonic-gate return (fcntl(fd, F_FREESP, &fl)); 63*0Sstevel@tonic-gate } 64*0Sstevel@tonic-gate return (0); 65*0Sstevel@tonic-gate } 66*0Sstevel@tonic-gate #endif 67*0Sstevel@tonic-gate 68*0Sstevel@tonic-gate #ifndef OWN_FTRUNCATE 69*0Sstevel@tonic-gate int __bindcompat_ftruncate; 70*0Sstevel@tonic-gate #endif 71