NetBSD/sbin/modload/modload.c

/*	$NetBSD: modload.c,v 1.23 1999/04/23 17:47:02 abs Exp $	*/

/*
 * Copyright (c) 1993 Terrence R. Lambert.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Terrence R. Lambert.
 * 4. The name Terrence R. Lambert may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY TERRENCE R. LAMBERT ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: modload.c,v 1.23 1999/04/23 17:47:02 abs Exp $");
#endif /* not lint */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/conf.h>
#include <sys/mount.h>
#include <sys/lkm.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <a.out.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <nlist.h>
#include "pathnames.h"

#define TRUE 1
#define FALSE 0

#ifndef DFLT_ENTRY
#define	DFLT_ENTRY	"xxxinit"
#endif	/* !DFLT_ENTRY */
#ifndef DFLT_ENTRYEXT
#define	DFLT_ENTRYEXT	"_lkmentry"
#endif	/* !DFLT_ENTRYEXT */

/*
 * Expected linker options:
 *
 * -A		executable to link against
 * -e		entry point
 * -o		output file
 * -T		address to link to in hex (assumes it's a page boundry)
 * <target>	object file
 */
#ifdef	__alpha__
#define	LINKCMD		"ld -R %s -e %s -o %s -Ttext %x %s"
#else
#define	LINKCMD		"ld -A %s -e _%s -o %s -T %x %s"
#endif

void	cleanup __P((void));
int	linkcmd __P((char *, char *, char *, u_int, char *));
int	main __P((int, char *[]));
void	usage __P((void));
int	verify_entry __P((char *, char *));

int debug = 0;
int verbose = 0;
int symtab = 1;

int
linkcmd(kernel, entry, outfile, address, object)
	char *kernel, *entry, *outfile;
	u_int address;	/* XXX */
	char *object;
{
	char cmdbuf[1024];
	int error = 0;

	if (snprintf(cmdbuf, sizeof(cmdbuf), LINKCMD, kernel, entry, outfile,
	    address, object) >= sizeof(cmdbuf))
		errx(1, "link command too long");

	if (debug)
		printf("%s\n", cmdbuf);

	switch (system(cmdbuf)) {
	case 0:				/* SUCCESS! */
		break;
	case 1:				/* uninformitive error */
		/*
		 * Someone needs to fix the return values from the NetBSD
		 * ld program -- it's totally uninformative.
		 *
		 * No such file		(4 on SunOS)
		 * Can't write output	(2 on SunOS)
		 * Undefined symbol	(1 on SunOS)
		 * etc.
		 */
	case 127:			/* can't load shell */
	case 32512:
	default:
		error = 1;
		break;
	}

	return error;
}

void
usage()
{

	fprintf(stderr, "usage:\n");
	fprintf(stderr, "modload [-d] [-v] [-A <kernel>] [-e <entry]\n");
	fprintf(stderr,
	    "[-p <postinstall>] [-o <output file>] <input file>\n");
	exit(1);
}

int fileopen = 0;
#define	DEV_OPEN	0x01
#define	MOD_OPEN	0x02
#define	PART_RESRV	0x04
int devfd, modfd;
struct lmc_resrv resrv;

void
cleanup()
{
	if (fileopen & PART_RESRV) {
		/*
		 * Free up kernel memory
		 */
		if (ioctl(devfd, LMUNRESRV, 0) == -1)
			warn("can't release slot 0x%08x memory", resrv.slot);
	}

	if (fileopen & DEV_OPEN)
		close(devfd);

	if (fileopen & MOD_OPEN)
		close(modfd);
}

int
verify_entry(entry, filename)
	char *entry, *filename;
{
	struct	nlist	names[2];
	int n;
	char *s;

	memset(names, 0, sizeof(names));
	s = malloc(strlen(entry) + 2);
	s[0] = '_';
	strcpy(s + 1, entry);
#ifdef	_AOUT_INCLUDE_
	names[0].n_un.n_name = s;
#else
	names[0].n_name = s;
#endif

	n = nlist(filename, names);
	if (n == -1)
		err(1, "nlist %s", filename);
	return n;
}

int
main(argc, argv)
	int argc;
	char *argv[];
{
	int c;
	char *kname = _PATH_UNIX;
	char *entry = DFLT_ENTRY;
	char *post = NULL;
	char *out = NULL;
	char *modobj;
	char modout[80], *p;
	struct exec info_buf;
	struct stat stb;
	u_int modsize;	/* XXX */
	u_int modentry;	/* XXX */
	struct nlist *nlp;
	int strtablen, numsyms;

	struct lmc_loadbuf ldbuf;
	int sz, bytesleft, old = FALSE;
	char buf[MODIOBUF];
 	char *symbuf;

	while ((c = getopt(argc, argv, "dvsA:e:p:o:")) != -1) {
		switch (c) {
		case 'd':
			debug = 1;
			break;	/* debug */
		case 'v':
			verbose = 1;
			break;	/* verbose */
		case 'A':
			kname = optarg;
			break;	/* kernel */
		case 'e':
			entry = optarg;
			break;	/* entry point */
		case 'p':
			post = optarg;
			break;	/* postinstall */
		case 'o':
			out = optarg;
			break;	/* output file */
		case 's':
			symtab = 0;
			break;
		case '?':
			usage();
		default:
			printf("default!\n");
			break;
		}
	}
	argc -= optind;
	argv += optind;

	if (argc != 1)
		usage();

	modobj = argv[0];

	atexit(cleanup);

	/*
	 * Open the virtual device device driver for exclusive use (needed
	 * to write the new module to it as our means of getting it in the
	 * kernel).
	 */
	if ((devfd = open(_PATH_LKM, O_RDWR, 0)) == -1)
		err(3, _PATH_LKM);
	fileopen |= DEV_OPEN;

	strcpy(modout, modobj);

	p = strrchr(modout, '.');
	if (!p || strcmp(p, ".o"))
		errx(2, "module object must end in .o");
	*p = '\0';
	if (out == NULL)
		out = modout;

	/*
	 * Verify that the entry point for the module exists.
	 */
	if (verify_entry(entry, modobj)) {
		/*
		 * Try <modobj>_init if entry is DFLT_ENTRY.
		 */
		if (entry == DFLT_ENTRY) {
			if ((p = strrchr(modout, '/')))
				p++;
			else
				p = modout;
			entry = (char *)malloc(strlen(p) +
			    strlen(DFLT_ENTRYEXT) + 1);
			strcpy(entry, p);
			strcat(entry, DFLT_ENTRYEXT);
			if (verify_entry(entry, modobj))
				errx(1, "entry point _%s not found in %s",
				    entry, modobj);
		} else
			errx(1, "entry point _%s not found in %s", entry,
			    modobj);
	}

	/*
	 * Prelink to get file size
	 */
	if (linkcmd(kname, entry, out, 0, modobj))
		errx(1, "can't prelink `%s' creating `%s'", modobj, out);

	/*
	 * Pre-open the 0-linked module to get the size information
	 */
	if ((modfd = open(out, O_RDONLY, 0)) == -1)
		err(4, out);
	fileopen |= MOD_OPEN;

	/*
	 * Get the load module post load size... do this by reading the
	 * header and doing page counts.
	 */
	if (read(modfd, &info_buf, sizeof(struct exec)) == -1)
		err(3, "read `%s'", out);
	/*
	 * stat for filesize to figure out string table size
	 */
	if (fstat(modfd, &stb) == -1)
	    err(3, "fstat `%s'", out);

	/*
	 * Close the dummy module -- we have our sizing information.
	 */
	close(modfd);
	fileopen &= ~MOD_OPEN;

	/*
	 * Magic number...
	 */
	if (N_BADMAG(info_buf))
		errx(4, "not an a.out format file");

	/*
	 * Calculate the size of the module
	 */
 	modsize = info_buf.a_text + info_buf.a_data + info_buf.a_bss;

	/*
	 * Reserve the required amount of kernel memory -- this may fail
	 * to be successful.
	 */
	resrv.size = modsize;	/* size in bytes */
	resrv.name = modout;	/* objname w/o ".o" */
	resrv.slot = -1;	/* returned */
	resrv.addr = 0;		/* returned */
	strtablen = stb.st_size - N_STROFF(info_buf);
	if (symtab) {
	    /* XXX TODO:  grovel through symbol table looking
	       for just the symbol table stuff from the new module,
	       and skip the stuff from the kernel. */
	    resrv.sym_size = info_buf.a_syms + strtablen;
	    resrv.sym_symsize = info_buf.a_syms;
	} else
	    resrv.sym_size = resrv.sym_symsize = 0;

	if (ioctl(devfd, LMRESERV, &resrv) == -1) {
	    if (symtab)
		warn("not loading symbols: kernel does not support symbol table loading");
	doold:
	    symtab = 0;
	    if (ioctl(devfd, LMRESERV_O, &resrv) == -1)
		err(9, "can't reserve memory");
	    old = TRUE;
	}
	fileopen |= PART_RESRV;

	/*
	 * Relink at kernel load address
	 */
	if (linkcmd(kname, entry, out, resrv.addr, modobj))
		errx(1, "can't link `%s' creating `%s' bound to 0x%08lx",
		    modobj, out, (long) resrv.addr);

	/*
	 * Open the relinked module to load it...
	 */
	if ((modfd = open(out, O_RDONLY, 0)) == -1)
		err(4, out);
	fileopen |= MOD_OPEN;

	/*
	 * Reread the header to get the actual entry point *after* the
	 * relink.
	 */
	if (read(modfd, &info_buf, sizeof(struct exec)) == -1)
		err(3, "read `%s'", out);

	/*
	 * Get the entry point (for initialization)
	 */
	modentry = info_buf.a_entry;			/* place to call */

	/*
	 * Seek to the text offset to start loading...
	 */
	if (lseek(modfd, N_TXTOFF(info_buf), 0) == -1)
		err(12, "lseek");

	/*
	 * Transfer the relinked module to kernel memory in chunks of
	 * MODIOBUF size at a time.
	 */
	for (bytesleft = info_buf.a_text + info_buf.a_data;
	    bytesleft > 0;
	    bytesleft -= sz) {
		sz = MIN(bytesleft, MODIOBUF);
		read(modfd, buf, sz);
		ldbuf.cnt = sz;
		ldbuf.data = buf;
		if (ioctl(devfd, LMLOADBUF, &ldbuf) == -1)
			err(11, "error transferring buffer");
	}


	if (symtab) {
	    /*
	     * Seek to the symbol table to start loading it...
	     */
	    if (lseek(modfd, N_SYMOFF(info_buf), SEEK_SET) == -1)
		err(12, "lseek");

	    /*
	     * Transfer the symbol table entries.  First, read them all in,
	     * then adjust their string table pointers, then
	     * copy in bulk.  Then copy the string table itself.
	     */

	    symbuf = malloc(info_buf.a_syms);
	    if (symbuf == 0)
		err(13, "malloc");

	    if (read(modfd, symbuf, info_buf.a_syms) != info_buf.a_syms)
		err(14, "read");
	    numsyms = info_buf.a_syms / sizeof(struct nlist);
	    for (nlp = (struct nlist *)symbuf; 
		 (char *)nlp < symbuf + info_buf.a_syms;
		 nlp++) {
		register int strx;
		strx = nlp->n_un.n_strx;
		if (strx != 0) {
		    /* If a valid name, set the name ptr to point at the
		     * loaded address for the string in the string table.
		     */
		    if (strx > strtablen)
			nlp->n_un.n_name = 0;
		    else
			nlp->n_un.n_name =
			    (char *)(strx + resrv.sym_addr + info_buf.a_syms);
		}
	    }
	    /*
	     * we've fixed the symbol table entries, now load them
	     */
	    for (bytesleft = info_buf.a_syms;
		 bytesleft > 0;
		 bytesleft -= sz) {
		sz = MIN(bytesleft, MODIOBUF);
		ldbuf.cnt = sz;
		ldbuf.data = symbuf;
		if (ioctl(devfd, LMLOADSYMS, &ldbuf) == -1)
		    err(11, "error transferring sym buffer");
		symbuf += sz;
	    }
	    free(symbuf - info_buf.a_syms);
	    /* and now read the string table and load it. */
	    for (bytesleft = strtablen;
		 bytesleft > 0;
		 bytesleft -= sz) {
		sz = MIN(bytesleft, MODIOBUF);
		read(modfd, buf, sz);
		ldbuf.cnt = sz;
		ldbuf.data = buf;
		if (ioctl(devfd, LMLOADSYMS, &ldbuf) == -1)
		    err(11, "error transferring stringtable buffer");
	    }
	}
	/*
	 * Save ourselves before disaster (potentitally) strikes...
	 */
	sync();

	/*
	 * Trigger the module as loaded by calling the entry procedure;
	 * this will do all necessary table fixup to ensure that state
	 * is maintained on success, or blow everything back to ground
	 * zero on failure.
	 */
	if (ioctl(devfd, LMREADY, &modentry) == -1) {
	  if (errno == EINVAL && !old) {
	    if (fileopen & MOD_OPEN)
	      close(modfd);
	    /* PART_RESRV is not true since the kernel cleans up
	       after a failed LMREADY */
	    fileopen &= ~(MOD_OPEN|PART_RESRV);
	    /* try using oldstyle */
	    warn("module failed to load using new version; trying old version");
	    goto doold;
	  } else
	    err(14, "error initializing module");
	}
	/*
	 * Success!
	 */
	fileopen &= ~PART_RESRV;	/* loaded */
	printf("Module loaded as ID %d\n", resrv.slot);

	/*
	 * Execute the post-install program, if specified.
	 */
	if (post) {
		struct lmc_stat sbuf;
		char id[16], type[16], offset[16];

		sbuf.id = resrv.slot;
		if (ioctl(devfd, LMSTAT, &sbuf) == -1)
			err(15, "error fetching module stats for post-install");
		(void)snprintf(id, sizeof(id), "%d", sbuf.id);
		(void)snprintf(type, sizeof(type), "0x%x", sbuf.type);
		(void)snprintf(offset, sizeof(offset), "%ld",
		    (long)sbuf.offset);
		/*
		 * XXX
		 * The modload docs say that drivers can install bdevsw &
		 * cdevsw, but the interface only supports one at a time.
		 */
		execl(post, post, id, type, offset, 0);
		err(16, "can't exec `%s'", post);
	}

	return 0;
}