This is the kernel linker. To use it, you will first need to apply

the patches in freefall:/home/dfr/ld.diffs to your ld sources and set
BINFORMAT to aoutkld when linking the kernel.

Library changes and userland utilities will appear in a later commit.

1 files changed, 562 insertions, 0 deletions

diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c
new file mode 100644
index 0000000..2a4e6cd
--- /dev/null
+++ b/sys/kern/kern_linker.c
@@ -0,0 +1,562 @@
+/*-
+ * Copyright (c) 1997 Doug Rabson
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
+ *
+ *	$Id$
+ */
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/sysctl.h>
+#include <sys/queue.h>
+#include <sys/libkern.h>
+#include <sys/malloc.h>
+#include <sys/sysproto.h>
+#include <sys/sysent.h>
+#include <sys/proc.h>
+#include <sys/lock.h>
+#include <machine/cpu.h>
+#include <sys/module.h>
+#include <sys/linker.h>
+
+static struct lock lock;	/* lock for the file list */
+static linker_class_list_t classes;
+static linker_file_list_t files;
+static int next_file_id = 1;
+
+static void
+linker_init(void* arg)
+{
+    lockinit(&lock, PVM, "klink", 0, 0);
+    TAILQ_INIT(&classes);
+    TAILQ_INIT(&files);
+}
+
+SYSINIT(linker, SI_SUB_KMEM, SI_ORDER_SECOND, linker_init, 0);
+
+int
+linker_add_class(const char* desc, void* priv,
+		 struct linker_class_ops* ops)
+{
+    linker_class_t lc;
+
+    lc = malloc(sizeof(struct linker_class), M_LINKER, M_NOWAIT);
+    if (!lc)
+	return ENOMEM;
+
+    lc->desc = desc;
+    lc->priv = priv;
+    lc->ops = ops;
+    TAILQ_INSERT_HEAD(&classes, lc, link);
+
+    return 0;
+}
+
+static void
+linker_file_sysinit(linker_file_t lf)
+{
+    struct linker_set* sysinits;
+    struct sysinit** sipp;
+    struct sysinit** xipp;
+    struct sysinit* save;
+    int rval[2];		/* SI_TYPE_KTHREAD support*/
+
+    linker_current_file = lf;
+
+    KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
+		   lf->filename));
+
+    sysinits = (struct linker_set*)
+	linker_file_lookup_symbol(lf, "sysinit_set", 0);
+    if (!sysinits)
+	return;
+
+    /*
+     * Perform a bubble sort of the system initialization objects by
+     * their subsystem (primary key) and order (secondary key).
+     *
+     * Since some things care about execution order, this is the
+     * operation which ensures continued function.
+     */
+    for( sipp = (struct sysinit **)sysinits->ls_items; *sipp; sipp++) {
+	for( xipp = sipp + 1; *xipp; xipp++) {
+	    if( (*sipp)->subsystem < (*xipp)->subsystem ||
+		( (*sipp)->subsystem == (*xipp)->subsystem &&
+		  (*sipp)->order < (*xipp)->order))
+		continue;	/* skip*/
+	    save = *sipp;
+	    *sipp = *xipp;
+	    *xipp = save;
+	}
+    }
+
+
+    /*
+     * Traverse the (now) ordered list of system initialization tasks.
+     * Perform each task, and continue on to the next task.
+     *
+     * The last item on the list is expected to be the scheduler,
+     * which will not return.
+     */
+    for( sipp = (struct sysinit **)sysinits->ls_items; *sipp; sipp++) {
+	if( (*sipp)->subsystem == SI_SUB_DUMMY)
+	    continue;	/* skip dummy task(s)*/
+
+	switch( (*sipp)->type) {
+	case SI_TYPE_DEFAULT:
+	    /* no special processing*/
+	    (*((*sipp)->func))( (*sipp)->udata);
+	    break;
+
+	case SI_TYPE_KTHREAD:
+	    /* kernel thread*/
+	    if (fork(&proc0, NULL, rval))
+		panic("fork kernel process");
+	    cpu_set_fork_handler(pfind(rval[0]), (*sipp)->func, (*sipp)->udata);
+	    break;
+
+	default:
+	    panic( "linker_file_sysinit: unrecognized init type");
+	}
+    }
+}
+
+int
+linker_load_file(const char* filename, linker_file_t* result)
+{
+    linker_class_t lc;
+    linker_file_t lf;
+    int error = 0;
+
+    lf = linker_find_file_by_name(filename);
+    if (lf) {
+	KLD_DPF(FILE, ("linker_load_file: file %s is already loaded, incrementing refs\n", filename));
+	*result = lf;
+	lf->refs++;
+	goto out;
+    }
+
+    lf = NULL;
+    for (lc = TAILQ_FIRST(&classes); lc; lc = TAILQ_NEXT(lc, link)) {
+	KLD_DPF(FILE, ("linker_load_file: trying to load %s as %s\n",
+		       filename, lc->desc));
+	if (error = lc->ops->load_file(filename, &lf))
+	    goto out;
+	if (lf) {
+	    linker_file_sysinit(lf);
+
+	    *result = lf;
+	    goto out;
+	}
+    }
+
+    error = ENOEXEC;		/* format not recognised */
+
+out:
+    return error;
+}
+
+linker_file_t
+linker_find_file_by_name(const char* filename)
+{
+    linker_file_t lf = 0;
+
+    lockmgr(&lock, LK_SHARED, 0, curproc);
+    for (lf = TAILQ_FIRST(&files); lf; lf = TAILQ_NEXT(lf, link))
+	if (!strcmp(lf->filename, filename))
+	    break;
+    lockmgr(&lock, LK_RELEASE, 0, curproc);
+
+    return lf;
+}
+
+linker_file_t
+linker_find_file_by_id(int fileid)
+{
+    linker_file_t lf = 0;
+
+    lockmgr(&lock, LK_SHARED, 0, curproc);
+    for (lf = TAILQ_FIRST(&files); lf; lf = TAILQ_NEXT(lf, link))
+	if (lf->id == fileid)
+	    break;
+    lockmgr(&lock, LK_RELEASE, 0, curproc);
+
+    return lf;
+}
+
+linker_file_t
+linker_make_file(const char* filename, void* priv, struct linker_file_ops* ops)
+{
+    linker_file_t lf = 0;
+    int namelen;
+
+    KLD_DPF(FILE, ("linker_make_file: new file, filename=%s\n", filename));
+    lockmgr(&lock, LK_EXCLUSIVE|LK_RETRY, 0, curproc);
+    namelen = strlen(filename) + 1;
+    lf = malloc(sizeof(struct linker_file) + namelen, M_LINKER, M_WAITOK);
+    if (!lf)
+	goto out;
+
+    lf->refs = 1;
+    lf->userrefs = 0;
+    lf->filename = (char*) (lf + 1);
+    strcpy(lf->filename, filename);
+    lf->id = next_file_id++;
+    lf->ndeps = 0;
+    lf->deps = NULL;
+    STAILQ_INIT(&lf->common);
+    TAILQ_INIT(&lf->modules);
+
+    lf->priv = priv;
+    lf->ops = ops;
+    TAILQ_INSERT_TAIL(&files, lf, link);
+
+out:
+    lockmgr(&lock, LK_RELEASE, 0, curproc);
+    return lf;
+}
+
+int
+linker_file_unload(linker_file_t file)
+{
+    module_t mod, next;
+    struct common_symbol* cp;
+    int error = 0;
+    int i;
+
+    KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", lf->refs));
+    lockmgr(&lock, LK_EXCLUSIVE|LK_RETRY, 0, curproc);
+    if (file->refs == 1) {
+	KLD_DPF(FILE, ("linker_file_unload: file is unloading, informing modules\n"));
+	/*
+	 * Inform any modules associated with this file.
+	 */
+	for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
+	    next = module_getfnext(mod);
+
+	    /*
+	     * Give the module a chance to veto the unload.
+	     */
+	    if (error = module_unload(mod)) {
+		KLD_DPF(FILE, ("linker_file_unload: module %x vetoes unload\n",
+			       mod));
+		lockmgr(&lock, LK_RELEASE, 0, curproc);
+		goto out;
+	    }
+
+	    module_release(mod);
+	}
+    }
+
+    file->refs--;
+    if (file->refs > 0) {
+	lockmgr(&lock, LK_RELEASE, 0, curproc);
+	goto out;
+    }
+
+    TAILQ_REMOVE(&files, file, link);
+    lockmgr(&lock, LK_RELEASE, 0, curproc);
+    
+    for (i = 0; i < file->ndeps; i++)
+	linker_file_unload(file->deps[i]);
+    free(file->deps, M_LINKER);
+
+    for (cp = STAILQ_FIRST(&file->common); cp;
+	 cp = STAILQ_FIRST(&file->common)) {
+	STAILQ_REMOVE(&file->common, cp, common_symbol, link);
+	free(cp, M_LINKER);
+    }
+
+    file->ops->unload(file);
+    free(file, M_LINKER);
+
+out:
+    return error;
+}
+
+int
+linker_file_add_dependancy(linker_file_t file, linker_file_t dep)
+{
+    linker_file_t* newdeps;
+
+    newdeps = malloc((file->ndeps + 1) * sizeof(linker_file_t*),
+		     M_LINKER, M_WAITOK);
+    if (newdeps == NULL)
+	return ENOMEM;
+
+    if (file->deps) {
+	bcopy(file->deps, newdeps, file->ndeps * sizeof(linker_file_t*));
+	free(file->deps, M_LINKER);
+    }
+    file->deps = newdeps;
+    file->deps[file->ndeps] = dep;
+    file->ndeps++;
+
+    return 0;
+}
+
+caddr_t
+linker_file_lookup_symbol(linker_file_t file, const char* name, int deps)
+{
+    caddr_t address;
+    size_t size;
+    size_t common_size = 0;
+    int i;
+
+    KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%x, name=%s, deps=%d",
+		  file, name, deps));
+
+    if (file->ops->lookup_symbol(file, name, &address, &size) == 0)
+	if (address == 0)
+	    /*
+	     * For commons, first look them up in the dependancies and
+	     * only allocate space if not found there.
+	     */
+	    common_size = size;
+	else
+	    return address;
+
+    if (deps)
+	for (i = 0; i < file->ndeps; i++) {
+	    address = linker_file_lookup_symbol(file->deps[i], name, 0);
+	    if (address)
+		return address;
+	}
+
+    if (common_size > 0) {
+	/*
+	 * This is a common symbol which was not found in the
+	 * dependancies.  We maintain a simple common symbol table in
+	 * the file object.
+	 */
+	struct common_symbol* cp;
+
+	for (cp = STAILQ_FIRST(&file->common); cp;
+	     cp = STAILQ_NEXT(cp, link))
+	    if (!strcmp(cp->name, name))
+		return cp->address;
+
+	/*
+	 * Round the symbol size up to align.
+	 */
+	common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
+	cp = malloc(sizeof(struct common_symbol)
+		    + common_size
+		    + strlen(name) + 1,
+		    M_LINKER, M_WAITOK);
+	if (!cp)
+	    return 0;
+
+	cp->address = (caddr_t) (cp + 1);
+	cp->name = cp->address + common_size;
+	strcpy(cp->name, name);
+	bzero(cp->address, common_size);
+	STAILQ_INSERT_TAIL(&file->common, cp, link);
+
+	return cp->address;
+    }
+
+    return 0;
+}
+
+/*
+ * Syscalls.
+ */
+
+int
+kldload(struct proc* p, struct kldload_args* uap, int* retval)
+{
+    char* filename = NULL;
+    linker_file_t lf;
+    int error = 0;
+
+    *retval = -1;
+
+    if (securelevel > 0)
+	return EPERM;
+
+    if (error = suser(p->p_ucred, &p->p_acflag))
+	return error;
+
+    filename = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
+    if (error = copyinstr(SCARG(uap, file), filename, MAXPATHLEN, NULL))
+	goto out;
+
+    if (error = linker_load_file(uap->file, &lf))
+	goto out;
+
+    lf->userrefs++;
+    *retval = lf->id;
+    
+out:
+    if (filename)
+	free(filename, M_TEMP);
+    return error;
+}
+
+int
+kldunload(struct proc* p, struct kldunload_args* uap, int* retval)
+{
+    linker_file_t lf;
+    int error = 0;
+
+    if (securelevel > 0)
+	return EPERM;
+
+    if (error = suser(p->p_ucred, &p->p_acflag))
+	return error;
+
+    lf = linker_find_file_by_id(SCARG(uap, fileid));
+    if (lf) {
+	KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
+	if (lf->userrefs == 0) {
+	    printf("linkerunload: attempt to unload file which was not loaded by user\n");
+	    error = EBUSY;
+	    goto out;
+	}
+	lf->userrefs--;
+	error = linker_file_unload(lf);
+    } else
+	error = ENOENT;
+
+out:
+    return error;
+}
+
+int
+kldfind(struct proc* p, struct kldfind_args* uap, int* retval)
+{
+    char* filename = NULL;
+    linker_file_t lf;
+    int error = 0;
+
+    *retval = -1;
+
+    filename = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
+    if (error = copyinstr(SCARG(uap, file), filename, MAXPATHLEN, NULL))
+	goto out;
+
+    lf = linker_find_file_by_name(filename);
+    if (lf)
+	*retval = lf->id;
+    else
+	error = ENOENT;
+    
+out:
+    if (filename)
+	free(filename, M_TEMP);
+    return error;
+}
+
+int
+kldnext(struct proc* p, struct kldnext_args* uap, int* retval)
+{
+    linker_file_t lf;
+    int error = 0;
+
+    if (SCARG(uap, fileid) == 0) {
+	if (TAILQ_FIRST(&files))
+	    *retval = TAILQ_FIRST(&files)->id;
+	else
+	    *retval = 0;
+	return 0;
+    }
+	
+    lf = linker_find_file_by_id(SCARG(uap, fileid));
+    if (lf) {
+	if (TAILQ_NEXT(lf, link))
+	    *retval = TAILQ_NEXT(lf, link)->id;
+	else
+	    *retval = 0;
+    } else
+	error = ENOENT;
+
+    return error;
+}
+
+int
+kldstat(struct proc* p, struct kldstat_args* uap, int* retval)
+{
+    linker_file_t lf;
+    int error = 0;
+    int version;
+    struct kld_file_stat* stat;
+    int namelen;
+
+    lf = linker_find_file_by_id(SCARG(uap, fileid));
+    if (!lf) {
+	error = ENOENT;
+	goto out;
+    }
+
+    stat = SCARG(uap, stat);
+
+    /*
+     * Check the version of the user's structure.
+     */
+    if (error = copyin(&stat->version, &version, sizeof(version)))
+	goto out;
+    if (version != sizeof(struct kld_file_stat)) {
+	error = EINVAL;
+	goto out;
+    }
+
+    namelen = strlen(lf->filename) + 1;
+    if (namelen > MAXPATHLEN)
+	namelen = MAXPATHLEN;
+    if (error = copyout(lf->filename, &stat->name[0], namelen))
+	goto out;
+    if (error = copyout(&lf->refs, &stat->refs, sizeof(int)))
+	goto out;
+    if (error = copyout(&lf->id, &stat->id, sizeof(int)))
+	goto out;
+    if (error = copyout(&lf->address, &stat->address, sizeof(caddr_t)))
+	goto out;
+    if (error = copyout(&lf->size, &stat->size, sizeof(size_t)))
+	goto out;
+
+    *retval = 0;
+
+out:
+    return error;
+}
+
+int
+kldfirstmod(struct proc* p, struct kldfirstmod_args* uap, int* retval)
+{
+    linker_file_t lf;
+    int error = 0;
+
+    lf = linker_find_file_by_id(SCARG(uap, fileid));
+    if (lf) {
+	if (TAILQ_FIRST(&lf->modules))
+	    *retval = module_getid(TAILQ_FIRST(&lf->modules));
+	else
+	    *retval = 0;
+    } else
+	error = ENOENT;
+
+    return error;
+}