1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * SMB root file system support
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (c) 2019 Paulo Alcantara <palcantara@suse.de>
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun #include <linux/init.h>
8*4882a593Smuzhiyun #include <linux/fs.h>
9*4882a593Smuzhiyun #include <linux/types.h>
10*4882a593Smuzhiyun #include <linux/ctype.h>
11*4882a593Smuzhiyun #include <linux/string.h>
12*4882a593Smuzhiyun #include <linux/root_dev.h>
13*4882a593Smuzhiyun #include <linux/kernel.h>
14*4882a593Smuzhiyun #include <linux/in.h>
15*4882a593Smuzhiyun #include <linux/inet.h>
16*4882a593Smuzhiyun #include <net/ipconfig.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #define DEFAULT_MNT_OPTS \
19*4882a593Smuzhiyun "vers=1.0,cifsacl,mfsymlinks,rsize=1048576,wsize=65536,uid=0,gid=0," \
20*4882a593Smuzhiyun "hard,rootfs"
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun static char root_dev[2048] __initdata = "";
23*4882a593Smuzhiyun static char root_opts[1024] __initdata = DEFAULT_MNT_OPTS;
24*4882a593Smuzhiyun
parse_srvaddr(char * start,char * end)25*4882a593Smuzhiyun static __be32 __init parse_srvaddr(char *start, char *end)
26*4882a593Smuzhiyun {
27*4882a593Smuzhiyun /* TODO: ipv6 support */
28*4882a593Smuzhiyun char addr[sizeof("aaa.bbb.ccc.ddd")];
29*4882a593Smuzhiyun int i = 0;
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun while (start < end && i < sizeof(addr) - 1) {
32*4882a593Smuzhiyun if (isdigit(*start) || *start == '.')
33*4882a593Smuzhiyun addr[i++] = *start;
34*4882a593Smuzhiyun start++;
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun addr[i] = '\0';
37*4882a593Smuzhiyun return in_aton(addr);
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /* cifsroot=//<server-ip>/<share>[,options] */
cifs_root_setup(char * line)41*4882a593Smuzhiyun static int __init cifs_root_setup(char *line)
42*4882a593Smuzhiyun {
43*4882a593Smuzhiyun char *s;
44*4882a593Smuzhiyun int len;
45*4882a593Smuzhiyun __be32 srvaddr = htonl(INADDR_NONE);
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun ROOT_DEV = Root_CIFS;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun if (strlen(line) > 3 && line[0] == '/' && line[1] == '/') {
50*4882a593Smuzhiyun s = strchr(&line[2], '/');
51*4882a593Smuzhiyun if (!s || s[1] == '\0')
52*4882a593Smuzhiyun return 1;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun /* make s point to ',' or '\0' at end of line */
55*4882a593Smuzhiyun s = strchrnul(s, ',');
56*4882a593Smuzhiyun /* len is strlen(unc) + '\0' */
57*4882a593Smuzhiyun len = s - line + 1;
58*4882a593Smuzhiyun if (len > sizeof(root_dev)) {
59*4882a593Smuzhiyun pr_err("Root-CIFS: UNC path too long\n");
60*4882a593Smuzhiyun return 1;
61*4882a593Smuzhiyun }
62*4882a593Smuzhiyun strlcpy(root_dev, line, len);
63*4882a593Smuzhiyun srvaddr = parse_srvaddr(&line[2], s);
64*4882a593Smuzhiyun if (*s) {
65*4882a593Smuzhiyun int n = snprintf(root_opts,
66*4882a593Smuzhiyun sizeof(root_opts), "%s,%s",
67*4882a593Smuzhiyun DEFAULT_MNT_OPTS, s + 1);
68*4882a593Smuzhiyun if (n >= sizeof(root_opts)) {
69*4882a593Smuzhiyun pr_err("Root-CIFS: mount options string too long\n");
70*4882a593Smuzhiyun root_opts[sizeof(root_opts)-1] = '\0';
71*4882a593Smuzhiyun return 1;
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun }
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun root_server_addr = srvaddr;
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun return 1;
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun __setup("cifsroot=", cifs_root_setup);
82*4882a593Smuzhiyun
cifs_root_data(char ** dev,char ** opts)83*4882a593Smuzhiyun int __init cifs_root_data(char **dev, char **opts)
84*4882a593Smuzhiyun {
85*4882a593Smuzhiyun if (!root_dev[0] || root_server_addr == htonl(INADDR_NONE)) {
86*4882a593Smuzhiyun pr_err("Root-CIFS: no SMB server address\n");
87*4882a593Smuzhiyun return -1;
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun *dev = root_dev;
91*4882a593Smuzhiyun *opts = root_opts;
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun return 0;
94*4882a593Smuzhiyun }
95