1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
/* A slightly more convenient wrapper for gethostname
Copyright (C) 1996 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
/* Return the name of the localhost. This is just a wrapper for gethostname,
which takes care of allocating a big enough buffer, and caches the result
after the first call (so the result should be copied before modification).
If something goes wrong, 0 is returned, and errno set. */
char *
localhost ()
{
static char *buf = 0;
static size_t buf_len = 0;
if (! buf)
{
do {
errno = 0;
if (buf) {
char *new;
buf_len += buf_len;
new = realloc (buf, buf_len);
if (! new)
{
free (buf);
buf = 0;
errno = ENOMEM;
return 0;
}
else
buf = new;
} else {
buf_len = 128; /* Initial guess */
buf = malloc (buf_len);
if (! buf)
{
errno = ENOMEM;
return 0;
}
}
} while ((gethostname(buf, buf_len) == 0 && !memchr (buf, '\0', buf_len))
|| errno == ENAMETOOLONG);
if (errno)
/* gethostname failed, abort. */
{
free (buf);
buf = 0;
}
}
return buf;
}
|
