1
2 /* Copyright 1998 by the Massachusetts Institute of Technology.
3 *
4 * Permission to use, copy, modify, and distribute this
5 * software and its documentation for any purpose and without
6 * fee is hereby granted, provided that the above copyright
7 * notice appear in all copies and that both that copyright
8 * notice and this permission notice appear in supporting
9 * documentation, and that the name of M.I.T. not be used in
10 * advertising or publicity pertaining to distribution of the
11 * software without specific, written prior permission.
12 * M.I.T. makes no representations about the suitability of
13 * this software for any purpose. It is provided "as is"
14 * without express or implied warranty.
15 */
16
17 #include "ares_setup.h"
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <string.h>
21 #include "ares.h"
22 #include "ares_nowarn.h"
23 #include "ares_private.h"
24
25 /* This is an internal function. Its contract is to read a line from
26 * a file into a dynamically allocated buffer, zeroing the trailing
27 * newline if there is one. The calling routine may call
28 * ares__read_line multiple times with the same buf and bufsize
29 * pointers; *buf will be reallocated and *bufsize adjusted as
30 * appropriate. The initial value of *buf should be NULL. After the
31 * calling routine is done reading lines, it should free *buf.
32 */
ares__read_line(FILE * fp,char ** buf,size_t * bufsize)33 int ares__read_line(FILE *fp, char **buf, size_t *bufsize)
34 {
35 char *newbuf;
36 size_t offset = 0;
37 size_t len;
38
39 if (*buf == NULL)
40 {
41 *buf = malloc(128);
42 if (!*buf)
43 return ARES_ENOMEM;
44 *bufsize = 128;
45 }
46
47 for (;;)
48 {
49 int bytestoread = aresx_uztosi(*bufsize - offset);
50
51 if (!fgets(*buf + offset, bytestoread, fp))
52 return (offset != 0) ? 0 : (ferror(fp)) ? ARES_EFILE : ARES_EOF;
53 len = offset + strlen(*buf + offset);
54 if ((*buf)[len - 1] == '\n')
55 {
56 (*buf)[len - 1] = 0;
57 break;
58 }
59 offset = len;
60 if(len < *bufsize - 1)
61 continue;
62
63 /* Allocate more space. */
64 newbuf = realloc(*buf, *bufsize * 2);
65 if (!newbuf)
66 return ARES_ENOMEM;
67 *buf = newbuf;
68 *bufsize *= 2;
69 }
70 return ARES_SUCCESS;
71 }
72