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