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: fread.c,v 1.26 2001/02/28 20:54:03 ca Exp $") 19 #include <string.h> 20 #include <errno.h> 21 #include <sm/io.h> 22 #include <sm/assert.h> 23 #include "local.h" 24 25 /* 26 ** SM_IO_READ -- read data from the file pointer 27 ** 28 ** Parameters: 29 ** fp -- file pointer to read from 30 ** timeout -- time to complete the read 31 ** buf -- location to place read data 32 ** size -- size of each chunk of data 33 ** 34 ** Returns: 35 ** Failure: returns 0 (zero) _and_ sets errno 36 ** Success: returns the number of whole chunks read. 37 ** 38 ** A read returning 0 (zero) is only an indication of error when errno 39 ** has been set. 40 */ 41 42 size_t 43 sm_io_read(fp, timeout, buf, size) 44 SM_FILE_T *fp; 45 int timeout; 46 void *buf; 47 size_t size; 48 { 49 register size_t resid = size; 50 register char *p; 51 register int r; 52 53 SM_REQUIRE_ISA(fp, SmFileMagic); 54 55 if (fp->f_read == NULL) 56 { 57 errno = ENODEV; 58 return 0; 59 } 60 61 /* 62 ** The ANSI standard requires a return value of 0 for a count 63 ** or a size of 0. Peculiarily, it imposes no such requirements 64 ** on fwrite; it only requires read to be broken. 65 */ 66 67 if (resid == 0) 68 return 0; 69 if (fp->f_r < 0) 70 fp->f_r = 0; 71 p = buf; 72 while ((int) resid > (r = fp->f_r)) 73 { 74 (void) memcpy((void *) p, (void *) fp->f_p, (size_t) r); 75 fp->f_p += r; 76 /* fp->f_r = 0 ... done in sm_refill */ 77 p += r; 78 resid -= r; 79 if ((fp->f_flags & SMNOW) != 0 && r > 0) 80 { 81 /* 82 ** Take whatever we have available. Spend no more time 83 ** trying to get all that has been requested. 84 ** This is needed on some file types (such as 85 ** SASL) that would jam when given extra, untimely 86 ** reads. 87 */ 88 89 fp->f_r -= r; 90 return size - resid; 91 } 92 if (sm_refill(fp, timeout) != 0) 93 { 94 /* no more input: return partial result */ 95 return size - resid; 96 } 97 } 98 (void) memcpy((void *) p, (void *) fp->f_p, resid); 99 fp->f_r -= resid; 100 fp->f_p += resid; 101 return size; 102 } 103