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+/*
+ * $Id: nfsroot.c,v 1.45 1998/03/07 10:44:46 mj Exp $
+ *
+ * Copyright (C) 1995, 1996 Gero Kuhlmann <gero@gkminix.han.de>
+ *
+ * Allow an NFS filesystem to be mounted as root. The way this works is:
+ * (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
+ * (2) Handle RPC negotiation with the system which replied to RARP or
+ * was reported as a boot server by BOOTP or manually.
+ * (3) The actual mounting is done later, when init() is running.
+ *
+ *
+ * Changes:
+ *
+ * Alan Cox : Removed get_address name clash with FPU.
+ * Alan Cox : Reformatted a bit.
+ * Gero Kuhlmann : Code cleanup
+ * Michael Rausch : Fixed recognition of an incoming RARP answer.
+ * Martin Mares : (2.0) Auto-configuration via BOOTP supported.
+ * Martin Mares : Manual selection of interface & BOOTP/RARP.
+ * Martin Mares : Using network routes instead of host routes,
+ * allowing the default configuration to be used
+ * for normal operation of the host.
+ * Martin Mares : Randomized timer with exponential backoff
+ * installed to minimize network congestion.
+ * Martin Mares : Code cleanup.
+ * Martin Mares : (2.1) BOOTP and RARP made configuration options.
+ * Martin Mares : Server hostname generation fixed.
+ * Gerd Knorr : Fixed wired inode handling
+ * Martin Mares : (2.2) "0.0.0.0" addresses from command line ignored.
+ * Martin Mares : RARP replies not tested for server address.
+ * Gero Kuhlmann : (2.3) Some bug fixes and code cleanup again (please
+ * send me your new patches _before_ bothering
+ * Linus so that I don' always have to cleanup
+ * _afterwards_ - thanks)
+ * Gero Kuhlmann : Last changes of Martin Mares undone.
+ * Gero Kuhlmann : RARP replies are tested for specified server
+ * again. However, it's now possible to have
+ * different RARP and NFS servers.
+ * Gero Kuhlmann : "0.0.0.0" addresses from command line are
+ * now mapped to INADDR_NONE.
+ * Gero Kuhlmann : Fixed a bug which prevented BOOTP path name
+ * from being used (thanks to Leo Spiekman)
+ * Andy Walker : Allow to specify the NFS server in nfs_root
+ * without giving a path name
+ * Swen Thümmler : Allow to specify the NFS options in nfs_root
+ * without giving a path name. Fix BOOTP request
+ * for domainname (domainname is NIS domain, not
+ * DNS domain!). Skip dummy devices for BOOTP.
+ * Jacek Zapala : Fixed a bug which prevented server-ip address
+ * from nfsroot parameter from being used.
+ * Olaf Kirch : Adapted to new NFS code.
+ * Jakub Jelinek : Free used code segment.
+ * Marko Kohtala : Fixed some bugs.
+ * Martin Mares : Debug message cleanup
+ * Martin Mares : Changed to use the new generic IP layer autoconfig
+ * code. BOOTP and RARP moved there.
+ * Martin Mares : Default path now contains host name instead of
+ * host IP address (but host name defaults to IP
+ * address anyway).
+ * Martin Mares : Use root_server_addr appropriately during setup.
+ * Martin Mares : Rewrote parameter parsing, now hopefully giving
+ * correct overriding.
+ * Trond Myklebust : Add in preliminary support for NFSv3 and TCP.
+ * Fix bug in root_nfs_addr(). nfs_data.namlen
+ * is NOT for the length of the hostname.
+ * Hua Qin : Support for mounting root file system via
+ * NFS over TCP.
+ * Fabian Frederick: Option parser rebuilt (using parser lib)
+*/
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/in.h>
+#include <linux/major.h>
+#include <linux/utsname.h>
+#include <linux/inet.h>
+#include <linux/root_dev.h>
+#include <net/ipconfig.h>
+#include <linux/parser.h>
+
+/* Define this to allow debugging output */
+#undef NFSROOT_DEBUG
+#define NFSDBG_FACILITY NFSDBG_ROOT
+
+/* Default path we try to mount. "%s" gets replaced by our IP address */
+#define NFS_ROOT "/tftpboot/%s"
+
+/* Parameters passed from the kernel command line */
+static char nfs_root_name[256] __initdata = "";
+
+/* Address of NFS server */
+static __u32 servaddr __initdata = 0;
+
+/* Name of directory to mount */
+static char nfs_path[NFS_MAXPATHLEN] __initdata = { 0, };
+
+/* NFS-related data */
+static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
+static int nfs_port __initdata = 0; /* Port to connect to for NFS */
+static int mount_port __initdata = 0; /* Mount daemon port number */
+
+
+/***************************************************************************
+
+ Parsing of options
+
+ ***************************************************************************/
+
+enum {
+ /* Options that take integer arguments */
+ Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
+ Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
+ /* Options that take no arguments */
+ Opt_soft, Opt_hard, Opt_intr,
+ Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
+ Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
+ /* Error token */
+ Opt_err
+};
+
+static match_table_t __initdata tokens = {
+ {Opt_port, "port=%u"},
+ {Opt_rsize, "rsize=%u"},
+ {Opt_wsize, "wsize=%u"},
+ {Opt_timeo, "timeo=%u"},
+ {Opt_retrans, "retrans=%u"},
+ {Opt_acregmin, "acregmin=%u"},
+ {Opt_acregmax, "acregmax=%u"},
+ {Opt_acdirmin, "acdirmin=%u"},
+ {Opt_acdirmax, "acdirmax=%u"},
+ {Opt_soft, "soft"},
+ {Opt_hard, "hard"},
+ {Opt_intr, "intr"},
+ {Opt_nointr, "nointr"},
+ {Opt_posix, "posix"},
+ {Opt_noposix, "noposix"},
+ {Opt_cto, "cto"},
+ {Opt_nocto, "nocto"},
+ {Opt_ac, "ac"},
+ {Opt_noac, "noac"},
+ {Opt_lock, "lock"},
+ {Opt_nolock, "nolock"},
+ {Opt_v2, "nfsvers=2"},
+ {Opt_v2, "v2"},
+ {Opt_v3, "nfsvers=3"},
+ {Opt_v3, "v3"},
+ {Opt_udp, "proto=udp"},
+ {Opt_udp, "udp"},
+ {Opt_tcp, "proto=tcp"},
+ {Opt_tcp, "tcp"},
+ {Opt_err, NULL}
+
+};
+
+/*
+ * Parse option string.
+ */
+
+static int __init root_nfs_parse(char *name, char *buf)
+{
+
+ char *p;
+ substring_t args[MAX_OPT_ARGS];
+ int option;
+
+ if (!name)
+ return 1;
+
+ /* Set the NFS remote path */
+ p = strsep(&name, ",");
+ if (p[0] != '\0' && strcmp(p, "default") != 0)
+ strlcpy(buf, p, NFS_MAXPATHLEN);
+
+ while ((p = strsep (&name, ",")) != NULL) {
+ int token;
+ if (!*p)
+ continue;
+ token = match_token(p, tokens, args);
+
+ /* %u tokens only. Beware if you add new tokens! */
+ if (token < Opt_soft && match_int(&args[0], &option))
+ return 0;
+ switch (token) {
+ case Opt_port:
+ nfs_port = option;
+ break;
+ case Opt_rsize:
+ nfs_data.rsize = option;
+ break;
+ case Opt_wsize:
+ nfs_data.wsize = option;
+ break;
+ case Opt_timeo:
+ nfs_data.timeo = option;
+ break;
+ case Opt_retrans:
+ nfs_data.retrans = option;
+ break;
+ case Opt_acregmin:
+ nfs_data.acregmin = option;
+ break;
+ case Opt_acregmax:
+ nfs_data.acregmax = option;
+ break;
+ case Opt_acdirmin:
+ nfs_data.acdirmin = option;
+ break;
+ case Opt_acdirmax:
+ nfs_data.acdirmax = option;
+ break;
+ case Opt_soft:
+ nfs_data.flags |= NFS_MOUNT_SOFT;
+ break;
+ case Opt_hard:
+ nfs_data.flags &= ~NFS_MOUNT_SOFT;
+ break;
+ case Opt_intr:
+ nfs_data.flags |= NFS_MOUNT_INTR;
+ break;
+ case Opt_nointr:
+ nfs_data.flags &= ~NFS_MOUNT_INTR;
+ break;
+ case Opt_posix:
+ nfs_data.flags |= NFS_MOUNT_POSIX;
+ break;
+ case Opt_noposix:
+ nfs_data.flags &= ~NFS_MOUNT_POSIX;
+ break;
+ case Opt_cto:
+ nfs_data.flags &= ~NFS_MOUNT_NOCTO;
+ break;
+ case Opt_nocto:
+ nfs_data.flags |= NFS_MOUNT_NOCTO;
+ break;
+ case Opt_ac:
+ nfs_data.flags &= ~NFS_MOUNT_NOAC;
+ break;
+ case Opt_noac:
+ nfs_data.flags |= NFS_MOUNT_NOAC;
+ break;
+ case Opt_lock:
+ nfs_data.flags &= ~NFS_MOUNT_NONLM;
+ break;
+ case Opt_nolock:
+ nfs_data.flags |= NFS_MOUNT_NONLM;
+ break;
+ case Opt_v2:
+ nfs_data.flags &= ~NFS_MOUNT_VER3;
+ break;
+ case Opt_v3:
+ nfs_data.flags |= NFS_MOUNT_VER3;
+ break;
+ case Opt_udp:
+ nfs_data.flags &= ~NFS_MOUNT_TCP;
+ break;
+ case Opt_tcp:
+ nfs_data.flags |= NFS_MOUNT_TCP;
+ break;
+ default :
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+/*
+ * Prepare the NFS data structure and parse all options.
+ */
+static int __init root_nfs_name(char *name)
+{
+ static char buf[NFS_MAXPATHLEN] __initdata;
+ char *cp;
+
+ /* Set some default values */
+ memset(&nfs_data, 0, sizeof(nfs_data));
+ nfs_port = -1;
+ nfs_data.version = NFS_MOUNT_VERSION;
+ nfs_data.flags = NFS_MOUNT_NONLM; /* No lockd in nfs root yet */
+ nfs_data.rsize = NFS_DEF_FILE_IO_BUFFER_SIZE;
+ nfs_data.wsize = NFS_DEF_FILE_IO_BUFFER_SIZE;
+ nfs_data.acregmin = 3;
+ nfs_data.acregmax = 60;
+ nfs_data.acdirmin = 30;
+ nfs_data.acdirmax = 60;
+ strcpy(buf, NFS_ROOT);
+
+ /* Process options received from the remote server */
+ root_nfs_parse(root_server_path, buf);
+
+ /* Override them by options set on kernel command-line */
+ root_nfs_parse(name, buf);
+
+ cp = system_utsname.nodename;
+ if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
+ printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
+ return -1;
+ }
+ sprintf(nfs_path, buf, cp);
+
+ return 1;
+}
+
+
+/*
+ * Get NFS server address.
+ */
+static int __init root_nfs_addr(void)
+{
+ if ((servaddr = root_server_addr) == INADDR_NONE) {
+ printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
+ return -1;
+ }
+
+ snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
+ "%u.%u.%u.%u", NIPQUAD(servaddr));
+ return 0;
+}
+
+/*
+ * Tell the user what's going on.
+ */
+#ifdef NFSROOT_DEBUG
+static void __init root_nfs_print(void)
+{
+ printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
+ nfs_path, nfs_data.hostname);
+ printk(KERN_NOTICE "Root-NFS: rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
+ nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
+ printk(KERN_NOTICE "Root-NFS: acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
+ nfs_data.acregmin, nfs_data.acregmax,
+ nfs_data.acdirmin, nfs_data.acdirmax);
+ printk(KERN_NOTICE "Root-NFS: nfsd port = %d, mountd port = %d, flags = %08x\n",
+ nfs_port, mount_port, nfs_data.flags);
+}
+#endif
+
+
+static int __init root_nfs_init(void)
+{
+#ifdef NFSROOT_DEBUG
+ nfs_debug |= NFSDBG_ROOT;
+#endif
+
+ /*
+ * Decode the root directory path name and NFS options from
+ * the kernel command line. This has to go here in order to
+ * be able to use the client IP address for the remote root
+ * directory (necessary for pure RARP booting).
+ */
+ if (root_nfs_name(nfs_root_name) < 0 ||
+ root_nfs_addr() < 0)
+ return -1;
+
+#ifdef NFSROOT_DEBUG
+ root_nfs_print();
+#endif
+
+ return 0;
+}
+
+
+/*
+ * Parse NFS server and directory information passed on the kernel
+ * command line.
+ */
+static int __init nfs_root_setup(char *line)
+{
+ ROOT_DEV = Root_NFS;
+ if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
+ strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
+ } else {
+ int n = strlen(line) + sizeof(NFS_ROOT) - 1;
+ if (n >= sizeof(nfs_root_name))
+ line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
+ sprintf(nfs_root_name, NFS_ROOT, line);
+ }
+ root_server_addr = root_nfs_parse_addr(nfs_root_name);
+ return 1;
+}
+
+__setup("nfsroot=", nfs_root_setup);
+
+/***************************************************************************
+
+ Routines to actually mount the root directory
+
+ ***************************************************************************/
+
+/*
+ * Construct sockaddr_in from address and port number.
+ */
+static inline void
+set_sockaddr(struct sockaddr_in *sin, __u32 addr, __u16 port)
+{
+ sin->sin_family = AF_INET;
+ sin->sin_addr.s_addr = addr;
+ sin->sin_port = port;
+}
+
+/*
+ * Query server portmapper for the port of a daemon program.
+ */
+static int __init root_nfs_getport(int program, int version, int proto)
+{
+ struct sockaddr_in sin;
+
+ printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
+ program, version, NIPQUAD(servaddr));
+ set_sockaddr(&sin, servaddr, 0);
+ return rpc_getport_external(&sin, program, version, proto);
+}
+
+
+/*
+ * Use portmapper to find mountd and nfsd port numbers if not overriden
+ * by the user. Use defaults if portmapper is not available.
+ * XXX: Is there any nfs server with no portmapper?
+ */
+static int __init root_nfs_ports(void)
+{
+ int port;
+ int nfsd_ver, mountd_ver;
+ int nfsd_port, mountd_port;
+ int proto;
+
+ if (nfs_data.flags & NFS_MOUNT_VER3) {
+ nfsd_ver = NFS3_VERSION;
+ mountd_ver = NFS_MNT3_VERSION;
+ nfsd_port = NFS_PORT;
+ mountd_port = NFS_MNT_PORT;
+ } else {
+ nfsd_ver = NFS2_VERSION;
+ mountd_ver = NFS_MNT_VERSION;
+ nfsd_port = NFS_PORT;
+ mountd_port = NFS_MNT_PORT;
+ }
+
+ proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
+
+ if (nfs_port < 0) {
+ if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
+ printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
+ "number from server, using default\n");
+ port = nfsd_port;
+ }
+ nfs_port = htons(port);
+ dprintk("Root-NFS: Portmapper on server returned %d "
+ "as nfsd port\n", port);
+ }
+
+ if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
+ printk(KERN_ERR "Root-NFS: Unable to get mountd port "
+ "number from server, using default\n");
+ port = mountd_port;
+ }
+ mount_port = htons(port);
+ dprintk("Root-NFS: mountd port is %d\n", port);
+
+ return 0;
+}
+
+
+/*
+ * Get a file handle from the server for the directory which is to be
+ * mounted.
+ */
+static int __init root_nfs_get_handle(void)
+{
+ struct nfs_fh fh;
+ struct sockaddr_in sin;
+ int status;
+ int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
+ IPPROTO_TCP : IPPROTO_UDP;
+ int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
+ NFS_MNT3_VERSION : NFS_MNT_VERSION;
+
+ set_sockaddr(&sin, servaddr, mount_port);
+ status = nfsroot_mount(&sin, nfs_path, &fh, version, protocol);
+ if (status < 0)
+ printk(KERN_ERR "Root-NFS: Server returned error %d "
+ "while mounting %s\n", status, nfs_path);
+ else {
+ nfs_data.root.size = fh.size;
+ memcpy(nfs_data.root.data, fh.data, fh.size);
+ }
+
+ return status;
+}
+
+/*
+ * Get the NFS port numbers and file handle, and return the prepared 'data'
+ * argument for mount() if everything went OK. Return NULL otherwise.
+ */
+void * __init nfs_root_data(void)
+{
+ if (root_nfs_init() < 0
+ || root_nfs_ports() < 0
+ || root_nfs_get_handle() < 0)
+ return NULL;
+ set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, nfs_port);
+ return (void*)&nfs_data;
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.