fget.c revision 95154 
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>
16SM_RCSID("@(#)$Id: fget.c,v 1.1.1.1 2002/02/17 21:56:43 gshapiro Exp $")
17#include <stdlib.h>
18#include <string.h>
19#include <sm/io.h>
20#include <sm/assert.h>
21#include "local.h"
22
23/*
24**  SM_IO_FGETS -- get a string from a file
25**
26**  Read at most n-1 characters from the given file.
27**  Stop when a newline has been read, or the count ('n') runs out.
28**
29**	Parameters:
30**		fp -- the file to read from
31**		timeout -- time to complete reading the string in milliseconds
32**		buf -- buffer to place read string in
33**		n -- size of 'buf'
34**
35**	Returns:
36**		success: returns value of 'buf'
37**		failure: NULL (no characters were read)
38**		timeout: NULL and errno set to EAGAIN
39**
40**	Side Effects:
41**		may move the file pointer
42*/
43
44char *
45sm_io_fgets(fp, timeout, buf, n)
46	register SM_FILE_T *fp;
47	int timeout;
48	char *buf;
49	register int n;
50{
51	register int len;
52	register char *s;
53	register unsigned char *p, *t;
54
55	SM_REQUIRE_ISA(fp, SmFileMagic);
56	if (n <= 0)		/* sanity check */
57		return NULL;
58
59	s = buf;
60	n--;			/* leave space for NUL */
61	while (n > 0)
62	{
63		/* If the buffer is empty, refill it. */
64		if ((len = fp->f_r) <= 0)
65		{
66
67			/*
68			**  Timeout is only passed if we can't get the data
69			**  from the buffer (which is counted as immediately).
70			*/
71
72			if (sm_refill(fp, timeout) != 0)
73			{
74				/* EOF/error: stop with partial or no line */
75				if (s == buf)
76					return NULL;
77				break;
78			}
79			len = fp->f_r;
80		}
81		p = fp->f_p;
82
83		/*
84		**  Scan through at most n bytes of the current buffer,
85		**  looking for '\n'.  If found, copy up to and including
86		**  newline, and stop.  Otherwise, copy entire chunk
87		**  and loop.
88		*/
89
90		if (len > n)
91			len = n;
92		t = (unsigned char *) memchr((void *) p, '\n', len);
93		if (t != NULL)
94		{
95			len = ++t - p;
96			fp->f_r -= len;
97			fp->f_p = t;
98			(void) memcpy((void *) s, (void *) p, len);
99			s[len] = 0;
100			return buf;
101		}
102		fp->f_r -= len;
103		fp->f_p += len;
104		(void) memcpy((void *) s, (void *) p, len);
105		s += len;
106		n -= len;
107	}
108	*s = 0;
109	return buf;
110}
111