95 lines
2.1 KiB
C
95 lines
2.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* SMB root file system support
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*
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* Copyright (c) 2019 Paulo Alcantara <palcantara@suse.de>
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*/
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/types.h>
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#include <linux/ctype.h>
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#include <linux/string.h>
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#include <linux/root_dev.h>
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#include <linux/kernel.h>
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#include <linux/in.h>
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#include <linux/inet.h>
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#include <net/ipconfig.h>
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#define DEFAULT_MNT_OPTS \
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"vers=1.0,cifsacl,mfsymlinks,rsize=1048576,wsize=65536,uid=0,gid=0," \
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"hard,rootfs"
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static char root_dev[2048] __initdata = "";
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static char root_opts[1024] __initdata = DEFAULT_MNT_OPTS;
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static __be32 __init parse_srvaddr(char *start, char *end)
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{
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/* TODO: ipv6 support */
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char addr[sizeof("aaa.bbb.ccc.ddd")];
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int i = 0;
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while (start < end && i < sizeof(addr) - 1) {
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if (isdigit(*start) || *start == '.')
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addr[i++] = *start;
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start++;
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}
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addr[i] = '\0';
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return in_aton(addr);
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}
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/* cifsroot=//<server-ip>/<share>[,options] */
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static int __init cifs_root_setup(char *line)
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{
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char *s;
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int len;
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__be32 srvaddr = htonl(INADDR_NONE);
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ROOT_DEV = Root_CIFS;
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if (strlen(line) > 3 && line[0] == '/' && line[1] == '/') {
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s = strchr(&line[2], '/');
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if (!s || s[1] == '\0')
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return 1;
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/* make s point to ',' or '\0' at end of line */
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s = strchrnul(s, ',');
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/* len is strlen(unc) + '\0' */
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len = s - line + 1;
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if (len > sizeof(root_dev)) {
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pr_err("Root-CIFS: UNC path too long\n");
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return 1;
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}
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strscpy(root_dev, line, len);
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srvaddr = parse_srvaddr(&line[2], s);
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if (*s) {
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int n = snprintf(root_opts,
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sizeof(root_opts), "%s,%s",
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DEFAULT_MNT_OPTS, s + 1);
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if (n >= sizeof(root_opts)) {
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pr_err("Root-CIFS: mount options string too long\n");
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root_opts[sizeof(root_opts)-1] = '\0';
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return 1;
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}
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}
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}
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root_server_addr = srvaddr;
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return 1;
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}
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__setup("cifsroot=", cifs_root_setup);
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int __init cifs_root_data(char **dev, char **opts)
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{
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if (!root_dev[0] || root_server_addr == htonl(INADDR_NONE)) {
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pr_err("Root-CIFS: no SMB server address\n");
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return -1;
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}
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*dev = root_dev;
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*opts = root_opts;
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return 0;
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}
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