1 /* 2 * Copyright (c) 2000-2001 Proofpoint, 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: fread.c,v 1.29 2013-11-22 20:51:42 ca Exp $") 17 #include <string.h> 18 #include <errno.h> 19 #include <sm/io.h> 20 #include <sm/assert.h> 21 #include "local.h" 22 23 /* 24 ** SM_IO_READ -- read data from the file pointer 25 ** 26 ** Parameters: 27 ** fp -- file pointer to read from 28 ** timeout -- time to complete the read 29 ** buf -- location to place read data 30 ** size -- size of each chunk of data 31 ** 32 ** Returns: 33 ** Failure: returns 0 (zero) _and_ sets errno 34 ** Success: returns the number of whole chunks read. 35 ** 36 ** A read returning 0 (zero) is only an indication of error when errno 37 ** has been set. 38 */ 39 40 size_t 41 sm_io_read(fp, timeout, buf, size) 42 SM_FILE_T *fp; 43 int timeout; 44 void *buf; 45 size_t size; 46 { 47 register size_t resid = size; 48 register char *p; 49 register int r; 50 51 SM_REQUIRE_ISA(fp, SmFileMagic); 52 53 if (fp->f_read == NULL) 54 { 55 errno = ENODEV; 56 return 0; 57 } 58 59 /* 60 ** The ANSI standard requires a return value of 0 for a count 61 ** or a size of 0. Peculiarily, it imposes no such requirements 62 ** on fwrite; it only requires read to be broken. 63 */ 64 65 if (resid == 0) 66 return 0; 67 if (fp->f_r < 0) 68 fp->f_r = 0; 69 p = buf; 70 while ((int) resid > (r = fp->f_r)) 71 { 72 (void) memcpy((void *) p, (void *) fp->f_p, (size_t) r); 73 fp->f_p += r; 74 /* fp->f_r = 0 ... done in sm_refill */ 75 p += r; 76 resid -= r; 77 if ((fp->f_flags & SMNOW) != 0 && r > 0) 78 { 79 /* 80 ** Take whatever we have available. Spend no more time 81 ** trying to get all that has been requested. 82 ** This is needed on some file types (such as 83 ** SASL) that would jam when given extra, untimely 84 ** reads. 85 */ 86 87 fp->f_r -= r; 88 return size - resid; 89 } 90 if (sm_refill(fp, timeout) != 0) 91 { 92 /* no more input: return partial result */ 93 return size - resid; 94 } 95 } 96 (void) memcpy((void *) p, (void *) fp->f_p, resid); 97 fp->f_r -= resid; 98 fp->f_p += resid; 99 return size; 100 } 101