1 /* 2 * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers. 3 * All rights reserved. 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * By using this file, you agree to the terms and conditions set 11 * forth in the LICENSE file which can be found at the top level of 12 * the sendmail distribution. 13 */ 14 15 #pragma ident "%Z%%M% %I% %E% SMI" 16 17 #include <sm/gen.h> 18 SM_RCSID("@(#)$Id: wbuf.c,v 1.19 2001/03/05 03:22:41 ca Exp $") 19 #include <errno.h> 20 #include <sm/io.h> 21 #include "local.h" 22 23 /* Note: This function is called from a macro located in <sm/io.h> */ 24 25 /* 26 ** SM_WBUF -- write character to and flush (likely now full) buffer 27 ** 28 ** Write the given character into the (probably full) buffer for 29 ** the given file. Flush the buffer out if it is or becomes full, 30 ** or if c=='\n' and the file is line buffered. 31 ** 32 ** Parameters: 33 ** fp -- the file pointer 34 ** timeout -- time to complete operation (milliseconds) 35 ** c -- int representation of the character to add 36 ** 37 ** Results: 38 ** Failure: -1 and sets errno 39 ** Success: int value of 'c' 40 */ 41 42 int 43 sm_wbuf(fp, timeout, c) 44 register SM_FILE_T *fp; 45 int timeout; 46 register int c; 47 { 48 register int n; 49 50 /* 51 ** In case we cannot write, or longjmp takes us out early, 52 ** make sure w is 0 (if fully- or un-buffered) or -bf.smb_size 53 ** (if line buffered) so that we will get called again. 54 ** If we did not do this, a sufficient number of sm_io_putc() 55 ** calls might wrap w from negative to positive. 56 */ 57 58 fp->f_w = fp->f_lbfsize; 59 if (cantwrite(fp)) 60 { 61 errno = EBADF; 62 return SM_IO_EOF; 63 } 64 c = (unsigned char)c; 65 66 /* 67 ** If it is completely full, flush it out. Then, in any case, 68 ** stuff c into the buffer. If this causes the buffer to fill 69 ** completely, or if c is '\n' and the file is line buffered, 70 ** flush it (perhaps a second time). The second flush will always 71 ** happen on unbuffered streams, where bf.smb_size==1; sm_io_flush() 72 ** guarantees that sm_io_putc() will always call sm_wbuf() by setting 73 ** w to 0, so we need not do anything else. 74 ** Note for the timeout, only one of the sm_io_flush's will get called. 75 */ 76 77 n = fp->f_p - fp->f_bf.smb_base; 78 if (n >= fp->f_bf.smb_size) 79 { 80 if (sm_io_flush(fp, timeout)) 81 return SM_IO_EOF; /* sm_io_flush() sets errno */ 82 n = 0; 83 } 84 fp->f_w--; 85 *fp->f_p++ = c; 86 if (++n == fp->f_bf.smb_size || (fp->f_flags & SMLBF && c == '\n')) 87 if (sm_io_flush(fp, timeout)) 88 return SM_IO_EOF; /* sm_io_flush() sets errno */ 89 return c; 90 } 91