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 #include <sm/gen.h> 16 SM_RCSID("@(#)$Id: wbuf.c,v 1.21 2001/09/11 04:04:49 gshapiro Exp $") 17 #include <errno.h> 18 #include <sm/io.h> 19 #include "local.h" 20 21 /* Note: This function is called from a macro located in <sm/io.h> */ 22 23 /* 24 ** SM_WBUF -- write character to and flush (likely now full) buffer 25 ** 26 ** Write the given character into the (probably full) buffer for 27 ** the given file. Flush the buffer out if it is or becomes full, 28 ** or if c=='\n' and the file is line buffered. 29 ** 30 ** Parameters: 31 ** fp -- the file pointer 32 ** timeout -- time to complete operation (milliseconds) 33 ** c -- int representation of the character to add 34 ** 35 ** Results: 36 ** Failure: -1 and sets errno 37 ** Success: int value of 'c' 38 */ 39 40 int 41 sm_wbuf(fp, timeout, c) 42 register SM_FILE_T *fp; 43 int timeout; 44 register int c; 45 { 46 register int n; 47 48 /* 49 ** In case we cannot write, or longjmp takes us out early, 50 ** make sure w is 0 (if fully- or un-buffered) or -bf.smb_size 51 ** (if line buffered) so that we will get called again. 52 ** If we did not do this, a sufficient number of sm_io_putc() 53 ** calls might wrap w from negative to positive. 54 */ 55 56 fp->f_w = fp->f_lbfsize; 57 if (cantwrite(fp)) 58 { 59 errno = EBADF; 60 return SM_IO_EOF; 61 } 62 c = (unsigned char)c; 63 64 /* 65 ** If it is completely full, flush it out. Then, in any case, 66 ** stuff c into the buffer. If this causes the buffer to fill 67 ** completely, or if c is '\n' and the file is line buffered, 68 ** flush it (perhaps a second time). The second flush will always 69 ** happen on unbuffered streams, where bf.smb_size==1; sm_io_flush() 70 ** guarantees that sm_io_putc() will always call sm_wbuf() by setting 71 ** w to 0, so we need not do anything else. 72 ** Note for the timeout, only one of the sm_io_flush's will get called. 73 */ 74 75 n = fp->f_p - fp->f_bf.smb_base; 76 if (n >= fp->f_bf.smb_size) 77 { 78 if (sm_io_flush(fp, timeout)) 79 return SM_IO_EOF; /* sm_io_flush() sets errno */ 80 n = 0; 81 } 82 fp->f_w--; 83 *fp->f_p++ = c; 84 if (++n == fp->f_bf.smb_size || (fp->f_flags & SMLBF && c == '\n')) 85 if (sm_io_flush(fp, timeout)) 86 return SM_IO_EOF; /* sm_io_flush() sets errno */ 87 return c; 88 } 89