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>
18SM_RCSID("@(#)$Id: fget.c,v 1.22 2001/08/27 18:54:14 gshapiro Exp $")
19#include <stdlib.h>
20#include <string.h>
21#include <sm/io.h>
22#include <sm/assert.h>
23#include "local.h"
24
25/*
26**  SM_IO_FGETS -- get a string from a file
27**
28**  Read at most n-1 characters from the given file.
29**  Stop when a newline has been read, or the count ('n') runs out.
30**
31**	Parameters:
32**		fp -- the file to read from
33**		timeout -- time to complete reading the string in milliseconds
34**		buf -- buffer to place read string in
35**		n -- size of 'buf'
36**
37**	Returns:
38**		success: returns value of 'buf'
39**		failure: NULL (no characters were read)
40**		timeout: NULL and errno set to EAGAIN
41**
42**	Side Effects:
43**		may move the file pointer
44*/
45
46char *
47sm_io_fgets(fp, timeout, buf, n)
48	register SM_FILE_T *fp;
49	int timeout;
50	char *buf;
51	register int n;
52{
53	register int len;
54	register char *s;
55	register unsigned char *p, *t;
56
57	SM_REQUIRE_ISA(fp, SmFileMagic);
58	if (n <= 0)		/* sanity check */
59		return NULL;
60
61	s = buf;
62	n--;			/* leave space for NUL */
63	while (n > 0)
64	{
65		/* If the buffer is empty, refill it. */
66		if ((len = fp->f_r) <= 0)
67		{
68
69			/*
70			**  Timeout is only passed if we can't get the data
71			**  from the buffer (which is counted as immediately).
72			*/
73
74			if (sm_refill(fp, timeout) != 0)
75			{
76				/* EOF/error: stop with partial or no line */
77				if (s == buf)
78					return NULL;
79				break;
80			}
81			len = fp->f_r;
82		}
83		p = fp->f_p;
84
85		/*
86		**  Scan through at most n bytes of the current buffer,
87		**  looking for '\n'.  If found, copy up to and including
88		**  newline, and stop.  Otherwise, copy entire chunk
89		**  and loop.
90		*/
91
92		if (len > n)
93			len = n;
94		t = (unsigned char *) memchr((void *) p, '\n', len);
95		if (t != NULL)
96		{
97			len = ++t - p;
98			fp->f_r -= len;
99			fp->f_p = t;
100			(void) memcpy((void *) s, (void *) p, len);
101			s[len] = 0;
102			return buf;
103		}
104		fp->f_r -= len;
105		fp->f_p += len;
106		(void) memcpy((void *) s, (void *) p, len);
107		s += len;
108		n -= len;
109	}
110	*s = 0;
111	return buf;
112}
113