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, 448 insertions, 0 deletions

diff --git a/sys/kern/link_aout.c b/sys/kern/link_aout.c
new file mode 100644
index 0000000..5fd3f87
--- /dev/null
+++ b/sys/kern/link_aout.c
@@ -0,0 +1,448 @@
+/*-
+ * 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/proc.h>
+#include <sys/namei.h>
+#include <sys/fcntl.h>
+#include <sys/vnode.h>
+#include <sys/linker.h>
+#include <a.out.h>
+#include <link.h>
+#include <machine/reloc.h>
+#include <sys/imgact_aout.h>
+
+static int		link_aout_load_file(const char*, linker_file_t*);
+
+static int		link_aout_lookup_symbol(linker_file_t, const char*,
+						caddr_t*, size_t*);
+static void		link_aout_unload(linker_file_t);
+
+static struct linker_class_ops link_aout_class_ops = {
+    link_aout_load_file,
+};
+
+static struct linker_file_ops link_aout_file_ops = {
+    link_aout_lookup_symbol,
+    link_aout_unload,
+};
+
+typedef struct aout_file {
+    char*		address;	/* Load address */
+    struct _dynamic*	dynamic;	/* Symbol table etc. */
+} *aout_file_t;
+
+static int		load_dependancies(linker_file_t lf);
+static int		relocate_file(linker_file_t lf);
+
+/*
+ * The kernel symbol table starts here.
+ */
+extern struct _dynamic _DYNAMIC;
+
+static void
+link_aout_init(void* arg)
+{
+    struct _dynamic* dp = &_DYNAMIC;
+
+    linker_add_class("a.out", NULL, &link_aout_class_ops);
+
+    if (dp) {
+	aout_file_t af;
+
+	af = malloc(sizeof(struct aout_file), M_LINKER, M_NOWAIT);
+	if (af == NULL)
+	    panic("link_aout_init: Can't create linker structures for kernel");
+
+	af->address = 0;
+	af->dynamic = dp;
+	linker_kernel_file =
+	    linker_make_file(kernelname, af, &link_aout_file_ops);
+	if (linker_kernel_file == NULL)
+	    panic("link_aout_init: Can't create linker structures for kernel");
+	/*
+	 * XXX there must be a better way of getting these constants.
+	 */
+	linker_kernel_file->address = (caddr_t) 0xf0100000;
+	linker_kernel_file->size = -0xf0100000;
+	linker_current_file = linker_kernel_file;
+    }
+}
+
+SYSINIT(link_aout, SI_SUB_KMEM, SI_ORDER_THIRD, link_aout_init, 0);
+
+int
+link_aout_load_file(const char* filename, linker_file_t* result)
+{
+    struct nameidata nd;
+    struct vnode* file;
+    struct proc* p = curproc;	/* XXX */
+    int error = 0;
+    int resid;
+    struct iovec aiov;
+    struct uio auio;
+    struct exec header;
+    aout_file_t af;
+    linker_file_t lf;
+
+    NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p);
+    error = vn_open(&nd, FREAD, 0);
+    if (error)
+	return error;
+
+    /*
+     * Read the a.out header from the file.
+     */
+    error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) &header, sizeof header, 0,
+		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
+    if (error)
+	goto out;
+
+    if (N_BADMAG(header) || !(N_GETFLAG(header) & EX_DYNAMIC))
+	goto out;
+
+    /*
+     * We have an a.out file, so make some space to read it in.
+     */
+    af = malloc(sizeof(struct aout_file), M_LINKER, M_WAITOK);
+    af->address = malloc(header.a_text + header.a_data + header.a_bss,
+			 M_LINKER, M_WAITOK);
+    
+    /*
+     * Read the text and data sections and zero the bss.
+     */
+    error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) af->address,
+		    header.a_text + header.a_data, 0,
+		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
+    if (error)
+	goto out;
+    bzero(af->address + header.a_text + header.a_data, header.a_bss);
+
+    /*
+     * Assume _DYNAMIC is the first data item.
+     */
+    af->dynamic = (struct _dynamic*) (af->address + header.a_text);
+    if (af->dynamic->d_version != LD_VERSION_BSD) {
+	free(af->address, M_LINKER);
+	free(af, M_LINKER);
+	goto out;
+    }
+    (long) af->dynamic->d_un.d_sdt += af->address;
+
+    lf = linker_make_file(filename, af, &link_aout_file_ops);
+    if (lf == NULL) {
+	free(af->address, M_LINKER);
+	free(af, M_LINKER);
+	error = ENOMEM;
+	goto out;
+    }
+    lf->address = af->address;
+    lf->size = header.a_text + header.a_data + header.a_bss;
+
+    if ((error = load_dependancies(lf)) != 0
+	|| (error = relocate_file(lf)) != 0) {
+	linker_file_unload(lf);
+	goto out;
+    }
+
+    *result = lf;
+
+out:
+    VOP_UNLOCK(nd.ni_vp, 0, p);
+    vn_close(nd.ni_vp, FREAD, p->p_ucred, p);
+
+    return error;
+}
+
+void
+link_aout_unload(linker_file_t file)
+{
+    aout_file_t af = file->priv;
+
+    if (af) {
+	if (af->address)
+	    free(af->address, M_LINKER);
+	free(af, M_LINKER);
+    }
+}
+
+#define AOUT_RELOC(af, type, off) (type*) ((af)->address + (off))
+
+static int
+load_dependancies(linker_file_t lf)
+{
+    aout_file_t af = lf->priv;
+    linker_file_t lfdep;
+    long off;
+    struct sod* sodp;
+    char* name;
+    char* filename = 0;
+    int error = 0;
+
+    /*
+     * All files are dependant on /kernel.
+     */
+    linker_kernel_file->refs++;
+    linker_file_add_dependancy(lf, linker_kernel_file);
+
+    off = LD_NEED(af->dynamic);
+
+    /*
+     * Load the dependancies.
+     */
+    while (off != 0) {
+	sodp = AOUT_RELOC(af, struct sod, off);
+	name = AOUT_RELOC(af, char, sodp->sod_name);
+
+	/*
+	 * Prepend pathname if dep is not an absolute filename.
+	 */
+	if (name[0] != '/') {
+	    char* p;
+	    filename = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
+	    p = lf->filename + strlen(lf->filename) - 1;
+	    while (p >= lf->filename && *p != '/')
+		p--;
+	    if (p >= lf->filename) {
+		strncpy(filename, lf->filename, p - lf->filename);
+		filename[p - lf->filename] = '\0';
+		strcat(filename, "/");
+		strcat(filename, name);
+		name = filename;
+	    }
+	}
+	error = linker_load_file(name, &lfdep);
+	if (error)
+	    goto out;
+	error = linker_file_add_dependancy(lf, lfdep);
+	if (error)
+	    goto out;
+	off = sodp->sod_next;
+    }
+
+out:
+    if (filename)
+	free(filename, M_TEMP);
+    return error;
+}
+
+/*
+ * XXX i386 dependant.
+ */
+static long
+read_relocation(struct relocation_info* r, char* addr)
+{
+    int length = r->r_length;
+    if (length == 0)
+	return *(u_char*) addr;
+    else if (length == 1)
+	return *(u_short*) addr;
+    else if (length == 2)
+	return *(u_int*) addr;
+    else
+	printf("link_aout: unsupported relocation size %d\n", r->r_length);
+    return 0;
+}
+
+static void
+write_relocation(struct relocation_info* r, char* addr, long value)
+{
+    int length = r->r_length;
+    if (length == 0)
+	*(u_char*) addr = value;
+    else if (length == 1)
+	*(u_short*) addr = value;
+    else if (length == 2)
+	*(u_int*) addr = value;
+    else
+	printf("link_aout: unsupported relocation size %d\n", r->r_length);
+}
+
+static int
+relocate_file(linker_file_t lf)
+{
+    aout_file_t af = lf->priv;
+    struct relocation_info* rel;
+    struct relocation_info* erel;
+    struct relocation_info* r;
+    struct nzlist* symbolbase;
+    char* stringbase;
+    struct nzlist* np;
+    char* sym;
+    long relocation;
+
+    rel = AOUT_RELOC(af, struct relocation_info, LD_REL(af->dynamic));
+    erel = AOUT_RELOC(af, struct relocation_info,
+		      LD_REL(af->dynamic) + LD_RELSZ(af->dynamic));
+    symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
+    stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
+
+    for (r = rel; r < erel; r++) {
+	char* addr;
+
+	if (r->r_address == 0)
+	    break;
+
+	addr = AOUT_RELOC(af, char, r->r_address);
+	if (r->r_extern) {
+	    np = &symbolbase[r->r_symbolnum];
+	    sym = &stringbase[np->nz_strx];
+
+	    if (sym[0] != '_') {
+		printf("link_aout: bad symbol name %s\n", sym);
+		relocation = 0;
+	    } else
+		relocation = (long)
+		    linker_file_lookup_symbol(lf, sym + 1,
+					      np->nz_type != (N_SETV+N_EXT));
+	    if (!relocation) {
+		printf("link_aout: symbol %s not found\n", sym);
+		return ENOENT;
+	    }
+	    
+	    relocation += read_relocation(r, addr);
+
+	    if (r->r_jmptable) {
+		printf("link_aout: can't cope with jump table relocations\n");
+		continue;
+	    }
+
+	    if (r->r_pcrel)
+		relocation -= (long) af->address;
+
+	    if (r->r_copy) {
+		printf("link_aout: can't cope with copy relocations\n");
+		continue;
+	    }
+	    
+	    write_relocation(r, addr, relocation);
+	} else {
+	    write_relocation(r, addr,
+			     (long)(read_relocation(r, addr) + af->address));
+	}
+	
+    }
+
+    return 0;
+}
+
+static long
+symbol_hash_value(aout_file_t af, const char* name)
+{
+    long hashval;
+    const char* p;
+
+    hashval = '_';		/* fake a starting '_' for C symbols */
+    for (p = name; *p; p++)
+	hashval = (hashval << 1) + *p;
+
+    return (hashval & 0x7fffffff) % LD_BUCKETS(af->dynamic);
+}
+
+int
+link_aout_lookup_symbol(linker_file_t file, const char* name,
+			caddr_t* address, size_t* size)
+{
+    aout_file_t af = file->priv;
+    int buckets;
+    long hashval;
+    struct rrs_hash* hashbase;
+    struct nzlist* symbolbase;
+    char* stringbase;
+    struct rrs_hash* hp;
+    struct nzlist* np;
+    char* cp;
+
+    if (LD_BUCKETS(af->dynamic) == 0)
+	return NULL;
+
+    hashbase = AOUT_RELOC(af, struct rrs_hash, LD_HASH(af->dynamic));
+    symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
+    stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
+
+restart:
+    hashval = symbol_hash_value(af, name);
+    hp = &hashbase[hashval];
+    if (hp->rh_symbolnum == -1)
+	return ENOENT;
+
+    while (hp) {
+	np = (struct nzlist *) &symbolbase[hp->rh_symbolnum];
+	cp = stringbase + np->nz_strx;
+	/*
+	 * Note: we fake the leading '_' for C symbols.
+	 */
+	if (cp[0] == '_' && !strcmp(cp + 1, name))
+	    break;
+
+	if (hp->rh_next == 0)
+	    hp = NULL;
+	else
+	    hp = &hashbase[hp->rh_next];
+    }
+
+    if (hp == NULL)
+	/*
+	 * Not found.
+	 */
+	return ENOENT;
+
+    /*
+     * Check for an aliased symbol, whatever that is.
+     */
+    if (np->nz_type == N_INDR+N_EXT) {
+	name = stringbase + (++np)->nz_strx + 1; /* +1 for '_' */
+	goto restart;
+    }
+
+    /*
+     * Check this is an actual definition of the symbol.
+     */
+    if (np->nz_value == 0)
+	return ENOENT;
+
+    if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
+	if (np->nz_other == AUX_FUNC)
+	    /* weak function */
+	    return ENOENT;
+	*address = 0;
+	*size = np->nz_value;
+    } else {
+	*address = AOUT_RELOC(af, char, np->nz_value);
+	*size = np->nz_size;
+    }
+
+    return 0;
+}