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1// SPDX-License-Identifier: GPL-2.02/*3 * SMB root file system support4 *5 * Copyright (c) 2019 Paulo Alcantara <palcantara@suse.de>6 */7#include <linux/init.h>8#include <linux/fs.h>9#include <linux/types.h>10#include <linux/ctype.h>11#include <linux/string.h>12#include <linux/root_dev.h>13#include <linux/kernel.h>14#include <linux/in.h>15#include <linux/inet.h>16#include <net/ipconfig.h>17 18#define DEFAULT_MNT_OPTS \19 "vers=1.0,cifsacl,mfsymlinks,rsize=1048576,wsize=65536,uid=0,gid=0," \20 "hard,rootfs"21 22static char root_dev[2048] __initdata = "";23static char root_opts[1024] __initdata = DEFAULT_MNT_OPTS;24 25static __be32 __init parse_srvaddr(char *start, char *end)26{27 /* TODO: ipv6 support */28 char addr[sizeof("aaa.bbb.ccc.ddd")];29 int i = 0;30 31 while (start < end && i < sizeof(addr) - 1) {32 if (isdigit(*start) || *start == '.')33 addr[i++] = *start;34 start++;35 }36 addr[i] = '\0';37 return in_aton(addr);38}39 40/* cifsroot=//<server-ip>/<share>[,options] */41static int __init cifs_root_setup(char *line)42{43 char *s;44 int len;45 __be32 srvaddr = htonl(INADDR_NONE);46 47 ROOT_DEV = Root_CIFS;48 49 if (strlen(line) > 3 && line[0] == '/' && line[1] == '/') {50 s = strchr(&line[2], '/');51 if (!s || s[1] == '\0')52 return 1;53 54 /* make s point to ',' or '\0' at end of line */55 s = strchrnul(s, ',');56 /* len is strlen(unc) + '\0' */57 len = s - line + 1;58 if (len > sizeof(root_dev)) {59 pr_err("Root-CIFS: UNC path too long\n");60 return 1;61 }62 strscpy(root_dev, line, len);63 srvaddr = parse_srvaddr(&line[2], s);64 if (*s) {65 int n = snprintf(root_opts,66 sizeof(root_opts), "%s,%s",67 DEFAULT_MNT_OPTS, s + 1);68 if (n >= sizeof(root_opts)) {69 pr_err("Root-CIFS: mount options string too long\n");70 root_opts[sizeof(root_opts)-1] = '\0';71 return 1;72 }73 }74 }75 76 root_server_addr = srvaddr;77 78 return 1;79}80 81__setup("cifsroot=", cifs_root_setup);82 83int __init cifs_root_data(char **dev, char **opts)84{85 if (!root_dev[0] || root_server_addr == htonl(INADDR_NONE)) {86 pr_err("Root-CIFS: no SMB server address\n");87 return -1;88 }89 90 *dev = root_dev;91 *opts = root_opts;92 93 return 0;94}95