1*38c8a9a5SSteve French // SPDX-License-Identifier: GPL-2.0
2*38c8a9a5SSteve French /*
3*38c8a9a5SSteve French * SMB root file system support
4*38c8a9a5SSteve French *
5*38c8a9a5SSteve French * Copyright (c) 2019 Paulo Alcantara <palcantara@suse.de>
6*38c8a9a5SSteve French */
7*38c8a9a5SSteve French #include <linux/init.h>
8*38c8a9a5SSteve French #include <linux/fs.h>
9*38c8a9a5SSteve French #include <linux/types.h>
10*38c8a9a5SSteve French #include <linux/ctype.h>
11*38c8a9a5SSteve French #include <linux/string.h>
12*38c8a9a5SSteve French #include <linux/root_dev.h>
13*38c8a9a5SSteve French #include <linux/kernel.h>
14*38c8a9a5SSteve French #include <linux/in.h>
15*38c8a9a5SSteve French #include <linux/inet.h>
16*38c8a9a5SSteve French #include <net/ipconfig.h>
17*38c8a9a5SSteve French
18*38c8a9a5SSteve French #define DEFAULT_MNT_OPTS \
19*38c8a9a5SSteve French "vers=1.0,cifsacl,mfsymlinks,rsize=1048576,wsize=65536,uid=0,gid=0," \
20*38c8a9a5SSteve French "hard,rootfs"
21*38c8a9a5SSteve French
22*38c8a9a5SSteve French static char root_dev[2048] __initdata = "";
23*38c8a9a5SSteve French static char root_opts[1024] __initdata = DEFAULT_MNT_OPTS;
24*38c8a9a5SSteve French
parse_srvaddr(char * start,char * end)25*38c8a9a5SSteve French static __be32 __init parse_srvaddr(char *start, char *end)
26*38c8a9a5SSteve French {
27*38c8a9a5SSteve French /* TODO: ipv6 support */
28*38c8a9a5SSteve French char addr[sizeof("aaa.bbb.ccc.ddd")];
29*38c8a9a5SSteve French int i = 0;
30*38c8a9a5SSteve French
31*38c8a9a5SSteve French while (start < end && i < sizeof(addr) - 1) {
32*38c8a9a5SSteve French if (isdigit(*start) || *start == '.')
33*38c8a9a5SSteve French addr[i++] = *start;
34*38c8a9a5SSteve French start++;
35*38c8a9a5SSteve French }
36*38c8a9a5SSteve French addr[i] = '\0';
37*38c8a9a5SSteve French return in_aton(addr);
38*38c8a9a5SSteve French }
39*38c8a9a5SSteve French
40*38c8a9a5SSteve French /* cifsroot=//<server-ip>/<share>[,options] */
cifs_root_setup(char * line)41*38c8a9a5SSteve French static int __init cifs_root_setup(char *line)
42*38c8a9a5SSteve French {
43*38c8a9a5SSteve French char *s;
44*38c8a9a5SSteve French int len;
45*38c8a9a5SSteve French __be32 srvaddr = htonl(INADDR_NONE);
46*38c8a9a5SSteve French
47*38c8a9a5SSteve French ROOT_DEV = Root_CIFS;
48*38c8a9a5SSteve French
49*38c8a9a5SSteve French if (strlen(line) > 3 && line[0] == '/' && line[1] == '/') {
50*38c8a9a5SSteve French s = strchr(&line[2], '/');
51*38c8a9a5SSteve French if (!s || s[1] == '\0')
52*38c8a9a5SSteve French return 1;
53*38c8a9a5SSteve French
54*38c8a9a5SSteve French /* make s point to ',' or '\0' at end of line */
55*38c8a9a5SSteve French s = strchrnul(s, ',');
56*38c8a9a5SSteve French /* len is strlen(unc) + '\0' */
57*38c8a9a5SSteve French len = s - line + 1;
58*38c8a9a5SSteve French if (len > sizeof(root_dev)) {
59*38c8a9a5SSteve French pr_err("Root-CIFS: UNC path too long\n");
60*38c8a9a5SSteve French return 1;
61*38c8a9a5SSteve French }
62*38c8a9a5SSteve French strscpy(root_dev, line, len);
63*38c8a9a5SSteve French srvaddr = parse_srvaddr(&line[2], s);
64*38c8a9a5SSteve French if (*s) {
65*38c8a9a5SSteve French int n = snprintf(root_opts,
66*38c8a9a5SSteve French sizeof(root_opts), "%s,%s",
67*38c8a9a5SSteve French DEFAULT_MNT_OPTS, s + 1);
68*38c8a9a5SSteve French if (n >= sizeof(root_opts)) {
69*38c8a9a5SSteve French pr_err("Root-CIFS: mount options string too long\n");
70*38c8a9a5SSteve French root_opts[sizeof(root_opts)-1] = '\0';
71*38c8a9a5SSteve French return 1;
72*38c8a9a5SSteve French }
73*38c8a9a5SSteve French }
74*38c8a9a5SSteve French }
75*38c8a9a5SSteve French
76*38c8a9a5SSteve French root_server_addr = srvaddr;
77*38c8a9a5SSteve French
78*38c8a9a5SSteve French return 1;
79*38c8a9a5SSteve French }
80*38c8a9a5SSteve French
81*38c8a9a5SSteve French __setup("cifsroot=", cifs_root_setup);
82*38c8a9a5SSteve French
cifs_root_data(char ** dev,char ** opts)83*38c8a9a5SSteve French int __init cifs_root_data(char **dev, char **opts)
84*38c8a9a5SSteve French {
85*38c8a9a5SSteve French if (!root_dev[0] || root_server_addr == htonl(INADDR_NONE)) {
86*38c8a9a5SSteve French pr_err("Root-CIFS: no SMB server address\n");
87*38c8a9a5SSteve French return -1;
88*38c8a9a5SSteve French }
89*38c8a9a5SSteve French
90*38c8a9a5SSteve French *dev = root_dev;
91*38c8a9a5SSteve French *opts = root_opts;
92*38c8a9a5SSteve French
93*38c8a9a5SSteve French return 0;
94*38c8a9a5SSteve French }
95