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1 | /* Get a host configuration item kept as the whole contents of a file. | |
2 | Copyright (C) 1996-2024 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <https://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <fcntl.h> | |
20 | #include <hurd.h> | |
21 | #include <hurd/lookup.h> | |
22 | #include "hurdhost.h" | |
23 | #include <string.h> | |
24 | ||
25 | ssize_t | |
26 | _hurd_get_host_config (const char *item, char *buf, size_t buflen) | |
27 | { | |
28 | error_t err; | |
29 | char *data; | |
30 | mach_msg_type_number_t nread; | |
31 | vm_size_t more; | |
32 | file_t config; | |
33 | ||
34 | err = __hurd_file_name_lookup (&_hurd_ports_use, &__getdport, 0, | |
35 | item, O_RDONLY, 0, &config); | |
36 | switch (err) | |
37 | { | |
38 | case 0: /* Success; read file contents below. */ | |
39 | break; | |
40 | ||
41 | case ENOENT: /* ? Others? All errors? */ | |
42 | /* The file does not exist, so no value has been set. Rather than | |
43 | causing gethostname et al to fail with ENOENT, give an empty value | |
44 | as other systems do before sethostname has been called. */ | |
45 | if (buflen != 0) | |
46 | *buf = '\0'; | |
47 | return 0; | |
48 | ||
49 | default: | |
50 | return __hurd_fail (err); | |
51 | } | |
52 | ||
53 | data = buf; | |
54 | nread = buflen; | |
55 | err = __io_read (config, &data, &nread, -1, buflen); | |
56 | if (! err) | |
57 | /* Check if there is more in the file we didn't read. */ | |
58 | err = __io_readable (config, &more); | |
59 | __mach_port_deallocate (__mach_task_self (), config); | |
60 | if (err) | |
61 | return __hurd_fail (err); | |
62 | if (data != buf) | |
63 | { | |
64 | memcpy (buf, data, nread); | |
65 | __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread); | |
66 | } | |
67 | ||
68 | /* If the file is empty, give an empty value. */ | |
69 | if (nread == 0 && more == 0) | |
70 | { | |
71 | if (buflen != 0) | |
72 | *buf = '\0'; | |
73 | return 0; | |
74 | } | |
75 | ||
76 | /* Remove newlines in case someone wrote the file by hand. */ | |
77 | while (nread > 0 && buf[nread - 1] == '\n') | |
78 | buf[--nread] = '\0'; | |
79 | ||
80 | /* Null-terminate the result if there is enough space. */ | |
81 | if (nread < buflen) | |
82 | buf[nread] = '\0'; | |
83 | else | |
84 | if (nread != 0 && buf[nread - 1] != '\0') | |
85 | more = 1; | |
86 | ||
87 | if (more) | |
88 | /* If we didn't read the whole file, tell the caller to use a bigger | |
89 | buffer next time. */ | |
90 | return __hurd_fail (ENAMETOOLONG); | |
91 | ||
92 | return nread; | |
93 | } |