1/*
2 * Copyright (c) 2006 Cisco Systems, Inc.  All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 *     Redistribution and use in source and binary forms, with or
11 *     without modification, are permitted provided that the following
12 *     conditions are met:
13 *
14 *      - Redistributions of source code must retain the above
15 *        copyright notice, this list of conditions and the following
16 *        disclaimer.
17 *
18 *      - Redistributions in binary form must reproduce the above
19 *        copyright notice, this list of conditions and the following
20 *        disclaimer in the documentation and/or other materials
21 *        provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 */
32
33#if HAVE_CONFIG_H
34#  include <config.h>
35#endif /* HAVE_CONFIG_H */
36
37#include <stdio.h>
38#include <stdlib.h>
39#include <unistd.h>
40#include <sys/types.h>
41#include <sys/stat.h>
42#include <fcntl.h>
43#include <string.h>
44
45#include <sys/sysctl.h>
46
47#include "ibverbs.h"
48
49static char *sysfs_path;
50
51const char *ibv_get_sysfs_path(void)
52{
53	char *env = NULL;
54
55	if (sysfs_path)
56		return sysfs_path;
57
58	/*
59	 * Only follow use path passed in through the calling user's
60	 * environment if we're not running SUID.
61	 */
62	if (getuid() == geteuid())
63		env = getenv("SYSFS_PATH");
64
65	if (env) {
66		int len;
67
68		sysfs_path = strndup(env, IBV_SYSFS_PATH_MAX);
69		len = strlen(sysfs_path);
70		while (len > 0 && sysfs_path[len - 1] == '/') {
71			--len;
72			sysfs_path[len] = '\0';
73		}
74	} else
75		sysfs_path = "/sys";
76
77	return sysfs_path;
78}
79
80int ibv_read_sysfs_file(const char *dir, const char *file,
81			char *buf, size_t size)
82{
83	char *path, *s;
84	int fd;
85	size_t len;
86
87	if (asprintf(&path, "%s/%s", dir, file) < 0)
88		return -1;
89
90	for (s = &path[0]; *s != '\0'; s++)
91		if (*s == '/')
92			*s = '.';
93
94        len = size;
95        if (sysctlbyname(&path[1], buf, &len, NULL, 0) == -1)
96		return -1;
97
98	free(path);
99
100	if (len > 0 && buf[len - 1] == '\n')
101		buf[--len] = '\0';
102
103	return len;
104}
105