Add support for reading ELF relocatable object file format modules.

1 files changed, 602 insertions, 0 deletions

diff --git a/usr.sbin/kldxref/ef_obj.c b/usr.sbin/kldxref/ef_obj.c
new file mode 100644
index 0000000..0406f6a
--- /dev/null
+++ b/usr.sbin/kldxref/ef_obj.c
@@ -0,0 +1,602 @@
+/*
+ * Copyright (c) 2000, Boris Popov
+ * Copyright (c) 1998-2000 Doug Rabson
+ * Copyright (c) 2004 Peter Wemm
+ * 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 Boris Popov.
+ * 4. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/linker.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <machine/elf.h>
+#define FREEBSD_ELF
+#include <link.h>
+
+#include <err.h>
+
+#include "ef.h"
+
+typedef struct {
+	void		*addr;
+	Elf_Off		size;
+	int		flags;
+	int		sec;	/* Original section */
+	char		*name;
+} Elf_progent;
+
+typedef struct {
+	Elf_Rel		*rel;
+	int		nrel;
+	int		sec;
+} Elf_relent;
+
+typedef struct {
+	Elf_Rela	*rela;
+	int		nrela;
+	int		sec;
+} Elf_relaent;
+
+struct ef_file {
+	char		*ef_name;
+	int		ef_fd;
+	Elf_Ehdr	ef_hdr;
+	struct elf_file *ef_efile;
+
+	caddr_t		address;
+	Elf_Off		size;
+	Elf_Shdr	*e_shdr;
+
+	Elf_progent	*progtab;
+	int		nprogtab;
+
+	Elf_relaent	*relatab;
+	int		nrela;
+
+	Elf_relent	*reltab;
+	int		nrel;
+
+	Elf_Sym		*ddbsymtab;	/* The symbol table we are using */
+	long		ddbsymcnt;	/* Number of symbols */
+	caddr_t		ddbstrtab;	/* String table */
+	long		ddbstrcnt;	/* number of bytes in string table */
+
+	caddr_t		shstrtab;	/* Section name string table */
+	long		shstrcnt;	/* number of bytes in string table */
+
+	int		ef_verbose;
+};
+
+static int ef_obj_get_type(elf_file_t ef);
+static int ef_obj_close(elf_file_t ef);
+static int ef_obj_read(elf_file_t ef, Elf_Off offset, size_t len, void* dest);
+static int ef_obj_read_entry(elf_file_t ef, Elf_Off offset, size_t len,
+    void **ptr);
+static int ef_obj_seg_read(elf_file_t ef, Elf_Off offset, size_t len,
+    void *dest);
+static int ef_obj_seg_read_rel(elf_file_t ef, Elf_Off offset, size_t len,
+    void *dest);
+static int ef_obj_seg_read_entry(elf_file_t ef, Elf_Off offset, size_t len,
+    void **ptr);
+static int ef_obj_seg_read_entry_rel(elf_file_t ef, Elf_Off offset, size_t len,
+    void **ptr);
+static Elf_Addr ef_obj_symaddr(elf_file_t ef, Elf_Word symidx);
+static int ef_obj_lookup_set(elf_file_t ef, const char *name, long *startp,
+    long *stopp, long *countp);
+static int ef_obj_lookup_symbol(elf_file_t ef, const char* name, Elf_Sym** sym);
+
+static struct elf_file_ops ef_obj_file_ops = {
+	ef_obj_get_type,
+	ef_obj_close,
+	ef_obj_read,
+	ef_obj_read_entry,
+	ef_obj_seg_read,
+	ef_obj_seg_read_rel,
+	ef_obj_seg_read_entry,
+	ef_obj_seg_read_entry_rel,
+	ef_obj_symaddr,
+	ef_obj_lookup_set,
+	ef_obj_lookup_symbol
+};
+
+static int
+ef_obj_get_type(elf_file_t ef)
+{
+
+	return (EFT_KLD);
+}
+
+static int
+ef_obj_lookup_symbol(elf_file_t ef, const char* name, Elf_Sym** sym)
+{
+	Elf_Sym *symp;
+	const char *strp;
+	int i;
+
+	for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
+		strp = ef->ddbstrtab + symp->st_name;
+		if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
+			*sym = symp;
+			return 0;
+		}
+	}
+	return ENOENT;
+}
+
+static int
+ef_obj_lookup_set(elf_file_t ef, const char *name, long *startp, long *stopp,
+    long *countp)
+{
+	int i;
+
+	for (i = 0; i < ef->nprogtab; i++) {
+		if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
+		    strcmp(ef->progtab[i].name + 4, name) == 0) {
+			*startp = (char *)ef->progtab[i].addr - ef->address;
+			*stopp = (char *)ef->progtab[i].addr +
+			    ef->progtab[i].size - ef->address;
+			*countp = (*stopp - *startp) / sizeof(void *);
+			return (0);
+		}
+	}
+	return (ESRCH);
+}
+
+static Elf_Addr
+ef_obj_symaddr(elf_file_t ef, Elf_Word symidx)
+{
+	const Elf_Sym *sym;
+
+	if (symidx >= ef->ddbsymcnt)
+		return (0);
+	sym = ef->ddbsymtab + symidx;
+
+	if (sym->st_shndx != SHN_UNDEF)
+		return (sym->st_value - (Elf_Addr)ef->address);
+	return (0);
+}
+
+static int
+ef_obj_read(elf_file_t ef, Elf_Off offset, size_t len, void *dest)
+{
+	ssize_t r;
+
+	if (offset != (Elf_Off)-1) {
+		if (lseek(ef->ef_fd, offset, SEEK_SET) == -1)
+			return EIO;
+	}
+
+	r = read(ef->ef_fd, dest, len);
+	if (r != -1 && (size_t)r == len)
+		return 0;
+	else
+		return EIO;
+}
+
+static int
+ef_obj_read_entry(elf_file_t ef, Elf_Off offset, size_t len, void **ptr)
+{
+	int error;
+
+	*ptr = malloc(len);
+	if (*ptr == NULL)
+		return ENOMEM;
+	error = ef_obj_read(ef, offset, len, *ptr);
+	if (error)
+		free(*ptr);
+	return error;
+}
+
+static int
+ef_obj_seg_read(elf_file_t ef, Elf_Off offset, size_t len, void *dest)
+{
+
+	if (offset + len > ef->size) {
+		if (ef->ef_verbose)
+			warnx("ef_seg_read_rel(%s): bad offset/len (%lx:%ld)",
+			    ef->ef_name, (long)offset, (long)len);
+		return (EFAULT);
+	}
+	bcopy(ef->address + offset, dest, len);
+	return (0);
+}
+
+static int
+ef_obj_seg_read_rel(elf_file_t ef, Elf_Off offset, size_t len, void *dest)
+{
+	char *memaddr;
+	Elf_Rel *r;
+	Elf_Rela *a;
+	Elf_Off secoff;
+	int error, i, sec;
+	
+	if (offset + len > ef->size) {
+		if (ef->ef_verbose)
+			warnx("ef_seg_read_rel(%s): bad offset/len (%lx:%ld)",
+			    ef->ef_name, (long)offset, (long)len);
+		return (EFAULT);
+	}
+	bcopy(ef->address + offset, dest, len);
+
+	/* Find out which section contains the data. */
+	memaddr = ef->address + offset;
+	sec = -1;
+	for (i = 0; i < ef->nprogtab; i++) {
+		if (ef->progtab[i].addr == NULL)
+			continue;
+		if (memaddr < (char *)ef->progtab[i].addr || memaddr + len >
+		     (char *)ef->progtab[i].addr + ef->progtab[i].size)
+			continue;
+		sec = ef->progtab[i].sec;
+		secoff = memaddr - (char *)ef->progtab[i].addr;
+		break;
+	}
+
+	if (sec == -1)
+		return (EFAULT);
+
+	/* Now do the relocations. */
+	for (i = 0; i < ef->nrel; i++) {
+		if (ef->reltab[i].sec != sec)
+			continue;
+		for (r = ef->reltab[i].rel;
+		     r < &ef->reltab[i].rel[ef->reltab[i].nrel]; r++) {
+			error = ef_reloc(ef->ef_efile, r, EF_RELOC_REL, secoff,
+			    len, dest);
+			if (error != 0)
+				return (error);
+		}
+	}
+	for (i = 0; i < ef->nrela; i++) {
+		if (ef->relatab[i].sec != sec)
+			continue;
+		for (a = ef->relatab[i].rela;
+		     a < &ef->relatab[i].rela[ef->relatab[i].nrela]; a++) {
+			error = ef_reloc(ef->ef_efile, a, EF_RELOC_RELA, secoff,
+			    len, dest);
+			if (error != 0)
+				return (error);
+		}
+	}
+	return (0);
+}
+
+static int
+ef_obj_seg_read_entry(elf_file_t ef, Elf_Off offset, size_t len, void **ptr)
+{
+	int error;
+
+	*ptr = malloc(len);
+	if (*ptr == NULL)
+		return ENOMEM;
+	error = ef_obj_seg_read(ef, offset, len, *ptr);
+	if (error)
+		free(*ptr);
+	return error;
+}
+
+static int
+ef_obj_seg_read_entry_rel(elf_file_t ef, Elf_Off offset, size_t len,
+    void **ptr)
+{
+	int error;
+
+	*ptr = malloc(len);
+	if (*ptr == NULL)
+		return ENOMEM;
+	error = ef_obj_seg_read_rel(ef, offset, len, *ptr);
+	if (error)
+		free(*ptr);
+	return error;
+}
+
+int
+ef_obj_open(const char *filename, struct elf_file *efile, int verbose)
+{
+	elf_file_t ef;
+	Elf_Ehdr *hdr;
+	Elf_Shdr *shdr;
+	Elf_Sym *es;
+	char *mapbase;
+	size_t mapsize;
+	int alignmask, error, fd, pb, ra, res, rl;
+	int i, j, nbytes, nsym, shstrindex, symstrindex, symtabindex;
+
+	if (filename == NULL)
+		return EFTYPE;
+	if ((fd = open(filename, O_RDONLY)) == -1)
+		return errno;
+
+	ef = malloc(sizeof(*ef));
+	if (ef == NULL) {
+		close(fd);
+		return (ENOMEM);
+	}
+
+	efile->ef_ef = ef;
+	efile->ef_ops = &ef_obj_file_ops;
+
+	bzero(ef, sizeof(*ef));
+	ef->ef_verbose = verbose;
+	ef->ef_fd = fd;
+	ef->ef_name = strdup(filename);
+	ef->ef_efile = efile;
+	hdr = (Elf_Ehdr *)&ef->ef_hdr;
+
+	res = read(fd, hdr, sizeof(*hdr));
+	error = EFTYPE;
+	if (res != sizeof(*hdr))
+		goto out;
+	if (!IS_ELF(*hdr))
+		goto out;
+	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
+	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
+	    hdr->e_ident[EI_VERSION] != EV_CURRENT ||
+	    hdr->e_version != EV_CURRENT || hdr->e_machine != ELF_TARG_MACH ||
+	    hdr->e_type != ET_REL)
+		goto out;
+
+	nbytes = hdr->e_shnum * hdr->e_shentsize;
+	if (nbytes == 0 || hdr->e_shoff == 0 ||
+	    hdr->e_shentsize != sizeof(Elf_Shdr))
+		goto out;
+
+	if (ef_obj_read_entry(ef, hdr->e_shoff, nbytes, (void**)&shdr) != 0) {
+		printf("ef_read_entry failed\n");
+		goto out;
+	}
+	ef->e_shdr = shdr;
+
+	/* Scan the section header for information and table sizing. */
+	nsym = 0;
+	symtabindex = -1;
+	symstrindex = -1;
+	for (i = 0; i < hdr->e_shnum; i++) {
+		switch (shdr[i].sh_type) {
+		case SHT_PROGBITS:
+		case SHT_NOBITS:
+			ef->nprogtab++;
+			break;
+		case SHT_SYMTAB:
+			nsym++;
+			symtabindex = i;
+			symstrindex = shdr[i].sh_link;
+			break;
+		case SHT_REL:
+			ef->nrel++;
+			break;
+		case SHT_RELA:
+			ef->nrela++;
+			break;
+		case SHT_STRTAB:
+			break;
+		}
+	}
+
+	if (ef->nprogtab == 0) {
+		warnx("%s: file has no contents", filename);
+		goto out;
+	}
+	if (nsym != 1) {
+		warnx("%s: file has no valid symbol table", filename);
+		goto out;
+	}
+	if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
+	    shdr[symstrindex].sh_type != SHT_STRTAB) {
+		warnx("%s: file has invalid symbol strings", filename);
+		goto out;
+	}
+
+	/* Allocate space for tracking the load chunks */
+	if (ef->nprogtab != 0)
+		ef->progtab = calloc(ef->nprogtab, sizeof(*ef->progtab));
+	if (ef->nrel != 0)
+		ef->reltab = calloc(ef->nrel, sizeof(*ef->reltab));
+	if (ef->nrela != 0)
+		ef->relatab = calloc(ef->nrela, sizeof(*ef->relatab));
+	if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
+	    (ef->nrel != 0 && ef->reltab == NULL) ||
+	    (ef->nrela != 0 && ef->relatab == NULL)) {
+		printf("malloc failed\n");
+		error = ENOMEM;
+		goto out;
+	}
+
+	ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
+	if (ef_obj_read_entry(ef, shdr[symtabindex].sh_offset,
+	    shdr[symtabindex].sh_size, (void**)&ef->ddbsymtab) != 0) {
+		printf("ef_read_entry failed\n");
+		goto out;
+	}
+
+	ef->ddbstrcnt = shdr[symstrindex].sh_size;
+	if (ef_obj_read_entry(ef, shdr[symstrindex].sh_offset,
+	    shdr[symstrindex].sh_size, (void**)&ef->ddbstrtab) != 0) {
+		printf("ef_read_entry failed\n");
+		goto out;
+	}
+
+	/* Do we have a string table for the section names?  */
+	shstrindex = -1;
+	if (hdr->e_shstrndx != 0 &&
+	    shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
+		shstrindex = hdr->e_shstrndx;
+		ef->shstrcnt = shdr[shstrindex].sh_size;
+		if (ef_obj_read_entry(ef, shdr[shstrindex].sh_offset,
+		    shdr[shstrindex].sh_size, (void**)&ef->shstrtab) != 0) {
+			printf("ef_read_entry failed\n");
+			goto out;
+		}
+	}
+
+	/* Size up code/data(progbits) and bss(nobits). */
+	alignmask = 0;
+	mapsize = 0;
+	for (i = 0; i < hdr->e_shnum; i++) {
+		switch (shdr[i].sh_type) {
+		case SHT_PROGBITS:
+		case SHT_NOBITS:
+			alignmask = shdr[i].sh_addralign - 1;
+			mapsize += alignmask;
+			mapsize &= ~alignmask;
+			mapsize += shdr[i].sh_size;
+			break;
+		}
+	}
+
+	/* We know how much space we need for the text/data/bss/etc. */
+	ef->address = malloc(mapsize);
+	ef->size = mapsize;
+	if (ef->address == NULL) {
+		printf("malloc failed\n");
+		goto out;
+	}
+	mapbase = ef->address;
+
+	/*
+	 * Now load code/data(progbits), zero bss(nobits), allocate
+	 * space for and load relocs
+	 */
+	pb = 0;
+	rl = 0;
+	ra = 0;
+	alignmask = 0;
+	for (i = 0; i < hdr->e_shnum; i++) {
+		switch (shdr[i].sh_type) {
+		case SHT_PROGBITS:
+		case SHT_NOBITS:
+			alignmask = shdr[i].sh_addralign - 1;
+			mapbase += alignmask;
+			mapbase  = (char *)((uintptr_t)mapbase & ~alignmask);
+			ef->progtab[pb].addr = (void *)(uintptr_t)mapbase;
+			if (shdr[i].sh_type == SHT_PROGBITS) {
+				ef->progtab[pb].name = "<<PROGBITS>>";
+				if (ef_obj_read(ef, shdr[i].sh_offset,
+				    shdr[i].sh_size,
+				    ef->progtab[pb].addr) != 0) {
+					printf("failed to read progbits\n");
+					goto out;
+				}
+			} else {
+				ef->progtab[pb].name = "<<NOBITS>>";
+				bzero(ef->progtab[pb].addr, shdr[i].sh_size);
+			}
+			ef->progtab[pb].size = shdr[i].sh_size;
+			ef->progtab[pb].sec = i;
+			if (ef->shstrtab && shdr[i].sh_name != 0)
+				ef->progtab[pb].name =
+				    ef->shstrtab + shdr[i].sh_name;
+
+			/* Update all symbol values with the offset. */
+			for (j = 0; j < ef->ddbsymcnt; j++) {
+				es = &ef->ddbsymtab[j];
+				if (es->st_shndx != i)
+					continue;
+				es->st_value += (Elf_Addr)ef->progtab[pb].addr;
+			}
+			mapbase += shdr[i].sh_size;
+			pb++;
+			break;
+		case SHT_REL:
+			ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
+			ef->reltab[rl].sec = shdr[i].sh_info;
+			if (ef_obj_read_entry(ef, shdr[i].sh_offset,
+			    shdr[i].sh_size, (void**)&ef->reltab[rl].rel) !=
+			    0) {
+				printf("ef_read_entry failed\n");
+				goto out;
+			}
+			rl++;
+			break;
+		case SHT_RELA:
+			ef->relatab[ra].nrela =
+			    shdr[i].sh_size / sizeof(Elf_Rela);
+			ef->relatab[ra].sec = shdr[i].sh_info;
+			if (ef_obj_read_entry(ef, shdr[i].sh_offset,
+			    shdr[i].sh_size, (void**)&ef->relatab[ra].rela) !=
+			    0) {
+				printf("ef_read_entry failed\n");
+				goto out;
+			}
+			ra++;
+			break;
+		}
+	}
+	error = 0;
+out:
+	if (error)
+		ef_obj_close(ef);
+	return error;
+}
+
+static int
+ef_obj_close(elf_file_t ef)
+{
+	int i;
+
+	close(ef->ef_fd);
+	if (ef->ef_name)
+		free(ef->ef_name);
+	if (ef->e_shdr != NULL)
+		free(ef->e_shdr);
+	if (ef->size != 0)
+		free(ef->address);
+	if (ef->nprogtab != 0)
+		free(ef->progtab);
+	if (ef->nrel != 0) {
+		for (i = 0; i < ef->nrel; i++)
+			if (ef->reltab[i].rel != NULL)
+				free(ef->reltab[i].rel);
+		free(ef->reltab);
+	}
+	if (ef->nrela != 0) {
+		for (i = 0; i < ef->nrela; i++)
+			if (ef->relatab[i].rela != NULL)
+				free(ef->relatab[i].rela);
+		free(ef->relatab);
+	}
+	if (ef->ddbsymtab != NULL)
+		free(ef->ddbsymtab);
+	if (ef->ddbstrtab != NULL)
+		free(ef->ddbstrtab);
+	if (ef->shstrtab != NULL)
+		free(ef->shstrtab);
+	ef->ef_efile->ef_ops = NULL;
+	ef->ef_efile->ef_ef = NULL;
+	free(ef);
+
+	return 0;
+}