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: fget.c,v 1.24 2001/09/11 04:04:48 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 
44 char *
45 sm_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