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First shot at loading elf symbols. Things are a bit strange because 

of the ..umm.. "wierd" way binutils lays out the file.  The section
headers are nearly at the end of the file and this is a problem when
loading from a .gz file which can't seek backwards (or has a limited
reverse seek, ~2K from memory).

This is intended to be compatable with the ddb/db_elf.c code and the
alpha/libalpha/elf_freebsd.c layout.  I've studied these (which are NetBSD
derived) but did it a bit differently.  Naturally the process is similar
since it's supposed to end up with the same result.
This commit is contained in:
Peter Wemm 1998-10-02 08:04:56 +00:00
parent 27d73120d4
commit 2e06076f23
5 changed files with 162 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
sys/boot/common/bootstrap.h
View File

@ -23,7 +23,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: bootstrap.h,v 1.8 1998/09/26 10:51:37 dfr Exp $
* $Id: bootstrap.h,v 1.9 1998/09/30 19:25:26 peter Exp $
*/
#include <sys/types.h>
@ -193,6 +193,8 @@ extern int elf_loadmodule(char *filename, vm_offset_t dest, struct loaded_module
#define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */
#define MODINFOMD_ELFHDR 0x0002 /* ELF header */
#define MODINFOMD_ELFSSYM 0x0003 /* ELF start of symbols */
#define MODINFOMD_ELFESYM 0x0004 /* ELF end of symbols */
#define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */
#define KLD_IDENT_SYMNAME "kld_identifier_"

139
sys/boot/common/load_elf.c
View File

@ -24,7 +24,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: load_aout.c,v 1.6 1998/09/26 10:51:38 dfr Exp $
* $Id: load_elf.c,v 1.1 1998/09/30 19:38:26 peter Exp $
*/
#include <sys/param.h>
@ -39,7 +39,7 @@
#include "bootstrap.h"
static int elf_loadimage(int fd, vm_offset_t *loadaddr, Elf_Ehdr *ehdr, int kernel);
static int elf_loadimage(struct loaded_module *mp, int fd, vm_offset_t *loadaddr, Elf_Ehdr *ehdr, int kernel);
#if 0
static vm_offset_t elf_findkldident(struct loaded_module *mp, Elf_Ehdr *ehdr);
static int elf_fixupkldmod(struct loaded_module *mp, Elf_Ehdr *ehdr);
@ -152,7 +152,7 @@ elf_loadmodule(char *filename, vm_offset_t dest, struct loaded_module **result)
printf("%s at %p\n", filename, (void *) addr);
mp->m_size = elf_loadimage(fd, &addr, &ehdr, kernel);
mp->m_size = elf_loadimage(mp, fd, &addr, &ehdr, kernel);
if (mp->m_size == 0)
goto ioerr;
mp->m_addr = addr; /* save the aligned load address */
@ -185,15 +185,23 @@ elf_loadmodule(char *filename, vm_offset_t dest, struct loaded_module **result)
* the Elf header, load the image at (addr)
*/
static int
elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
elf_loadimage(struct loaded_module *mp, int fd, vm_offset_t *addr,
Elf_Ehdr *ehdr, int kernel)
{
int i;
int i, j;
Elf_Phdr *phdr;
Elf_Shdr *shdr;
Elf_Ehdr local_ehdr;
int ret;
vm_offset_t firstaddr;
vm_offset_t lastaddr;
vm_offset_t off;
void *buf;
size_t resid, chunk;
vm_offset_t dest;
char *secname;
vm_offset_t shdrpos;
vm_offset_t ssym, esym;
ret = 0;
firstaddr = lastaddr = 0;
@ -225,29 +233,27 @@ elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
if (phdr[i].p_type != PT_LOAD)
continue;
printf("segment %d: 0x%lx@0x%lx -> 0x%lx-0x%lx\n", i,
printf("Segment: 0x%lx@0x%lx -> 0x%lx-0x%lx",
(long)phdr[i].p_filesz, (long)phdr[i].p_offset,
(long)(phdr[i].p_vaddr + off),
(long)(phdr[i].p_vaddr + off + phdr[i].p_filesz - 1));
(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
if (lseek(fd, phdr[i].p_offset, SEEK_SET) == -1) {
printf("elf_loadexec: cannot seek\n");
printf("\nelf_loadexec: cannot seek\n");
goto out;
}
if (archsw.arch_readin(fd, phdr[i].p_vaddr + off, phdr[i].p_filesz) !=
phdr[i].p_filesz) {
printf("elf_loadexec: archsw.readin failed\n");
printf("\nelf_loadexec: archsw.readin failed\n");
goto out;
}
/* clear space from oversized segments; eg: bss */
if (phdr[i].p_filesz < phdr[i].p_memsz) {
size_t resid, chunk;
vm_offset_t dest;
printf(".. extended: clearing 0x%lx-0x%lx\n",
printf(" (bss: 0x%lx-0x%lx)",
(long)(phdr[i].p_vaddr + off + phdr[i].p_filesz),
(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
/* no archsw.arch_bzero */
buf = malloc(PAGE_SIZE);
bzero(buf, PAGE_SIZE);
resid = phdr[i].p_memsz - phdr[i].p_filesz;
@ -260,6 +266,7 @@ elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
}
free(buf);
}
printf("\n");
if (firstaddr < (phdr[i].p_vaddr + off))
firstaddr = phdr[i].p_vaddr + off;
@ -267,6 +274,112 @@ elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
lastaddr = phdr[i].p_vaddr + off + phdr[i].p_memsz;
}
/*
* Now grab the symbol tables. This isn't easy if we're reading a
* .gz file. I think the rule is going to have to be that you must
* strip a file to remove symbols before gzipping it so that we do not
* try to lseek() on it. The layout is a bit wierd, but it's what
* the NetBSD-derived ddb/db_elf.c wants.
*/
lastaddr = roundup(lastaddr, sizeof(long));
chunk = ehdr->e_shnum * ehdr->e_shentsize;
shdr = malloc(chunk);
if (shdr == NULL)
goto nosyms;
ssym = lastaddr;
printf("Symbols: ELF Ehdr @ 0x%x; ", lastaddr);
lastaddr += sizeof(*ehdr);
lastaddr = roundup(lastaddr, sizeof(long));
/* Copy out executable header modified for base offsets */
local_ehdr = *ehdr;
local_ehdr.e_phoff = 0;
local_ehdr.e_phentsize = 0;
local_ehdr.e_phnum = 0;
local_ehdr.e_shoff = lastaddr - ssym;
archsw.arch_copyin(&local_ehdr, ssym, sizeof(*ehdr));
if (lseek(fd, ehdr->e_shoff, SEEK_SET) == -1) {
printf("elf_loadimage: cannot lseek() to section headers\n");
lastaddr = ssym; /* wind back */
ssym = 0;
goto nosyms;
}
if (read(fd, shdr, chunk) != chunk) {
printf("elf_loadimage: read section headers failed\n");
lastaddr = ssym; /* wind back */
ssym = 0;
goto nosyms;
}
shdrpos = lastaddr;
printf("Section table: 0x%x@0x%x\n", chunk, shdrpos);
lastaddr += chunk;
lastaddr = roundup(lastaddr, sizeof(long));
for (i = 0; i < ehdr->e_shnum; i++) {
switch(shdr[i].sh_type) {
/*
* These are the symbol tables. Their names are relative to
* an arbitary string table.
*/
case SHT_SYMTAB: /* Symbol table */
secname = "symtab";
break;
case SHT_DYNSYM: /* Dynamic linking symbol table */
secname = "dynsym";
break;
/*
* And here are the string tables. These can be referred to from
* a number of sources, including the dynsym, the section table
* names itself, etc.
*/
case SHT_STRTAB: /* String table */
secname = "strtab";
break;
default: /* Skip it */
continue;
}
for (j = 0; j < ehdr->e_phnum; j++) {
if (phdr[j].p_type != PT_LOAD)
continue;
if (shdr[i].sh_offset >= phdr[j].p_offset &&
(shdr[i].sh_offset + shdr[i].sh_size <=
phdr[j].p_offset + phdr[j].p_filesz)) {
shdr[i].sh_offset = 0;
shdr[i].sh_size = 0;
break;
}
}
if (shdr[i].sh_offset == 0 || shdr[i].sh_size == 0)
continue; /* alread loaded in a PT_LOAD above */
printf("%s: 0x%x@0x%x -> 0x%x-0x%x\n", secname,
shdr[i].sh_size, shdr[i].sh_offset,
lastaddr, lastaddr + shdr[i].sh_size);
if (lseek(fd, shdr[i].sh_offset, SEEK_SET) == -1) {
printf("\nelf_loadimage: could not seek for symbols - skipped!\n");
shdr[i].sh_offset = 0;
shdr[i].sh_size = 0;
continue;
}
if (archsw.arch_readin(fd, lastaddr, shdr[i].sh_size) !=
shdr[i].sh_size) {
printf("\nelf_loadimage: could not read symbols - skipped!\n");
shdr[i].sh_offset = 0;
shdr[i].sh_size = 0;
continue;
}
/* Reset offsets relative to ssym */
shdr[i].sh_offset = lastaddr - ssym;
lastaddr += shdr[i].sh_size;
lastaddr = roundup(lastaddr, sizeof(long));
}
archsw.arch_copyin(shdr, lastaddr, sizeof(*ehdr));
esym = lastaddr;
mod_addmetadata(mp, MODINFOMD_ELFSSYM, sizeof(ssym), &ssym);
mod_addmetadata(mp, MODINFOMD_ELFESYM, sizeof(esym), &esym);
nosyms:
ret = lastaddr - firstaddr;
*addr = firstaddr;
out:

14
sys/boot/i386/libi386/elf32_freebsd.c
View File

@ -23,7 +23,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: aout_freebsd.c,v 1.6 1998/09/29 09:11:49 peter Exp $
* $Id: elf_freebsd.c,v 1.1 1998/09/30 19:48:09 peter Exp $
*/
#include <sys/param.h>
@ -61,6 +61,7 @@ elf_exec(struct loaded_module *mp)
int major, bootdevnr;
vm_offset_t addr, entry;
u_int pad;
vm_offset_t ssym, esym, *symptr;
if ((md = mod_findmetadata(mp, MODINFOMD_ELFHDR)) == NULL)
return(EFTYPE); /* XXX actually EFUCKUP */
@ -82,6 +83,13 @@ elf_exec(struct loaded_module *mp)
}
free(currdev);
if ((md = mod_findmetadata(mp, MODINFOMD_ELFSSYM)) != NULL)
ssym = *((vm_offset_t *)&(md->md_data));
if ((md = mod_findmetadata(mp, MODINFOMD_ELFESYM)) != NULL)
esym = *((vm_offset_t *)&(md->md_data));
if (ssym == 0 || esym == 0)
ssym = esym = 0; /* sanity */
/* legacy bootinfo structure */
bi.bi_version = BOOTINFO_VERSION;
bi.bi_kernelname = 0; /* XXX char * -> kernel name */
@ -93,8 +101,8 @@ elf_exec(struct loaded_module *mp)
bi.bi_vesa = 0; /* XXX correct value? */
bi.bi_basemem = getbasemem();
bi.bi_extmem = getextmem();
bi.bi_symtab = 0; /* Let kld use _DYNAMIC */
bi.bi_esymtab = 0;
bi.bi_symtab = ssym;
bi.bi_esymtab = esym;
/* Device data is kept in the kernel argv array */
argv[0] = bi_getboothowto(mp->m_args); /* boothowto */

14
sys/boot/i386/libi386/elf64_freebsd.c
View File

@ -23,7 +23,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: aout_freebsd.c,v 1.6 1998/09/29 09:11:49 peter Exp $
* $Id: elf_freebsd.c,v 1.1 1998/09/30 19:48:09 peter Exp $
*/
#include <sys/param.h>
@ -61,6 +61,7 @@ elf_exec(struct loaded_module *mp)
int major, bootdevnr;
vm_offset_t addr, entry;
u_int pad;
vm_offset_t ssym, esym, *symptr;
if ((md = mod_findmetadata(mp, MODINFOMD_ELFHDR)) == NULL)
return(EFTYPE); /* XXX actually EFUCKUP */
@ -82,6 +83,13 @@ elf_exec(struct loaded_module *mp)
}
free(currdev);
if ((md = mod_findmetadata(mp, MODINFOMD_ELFSSYM)) != NULL)
ssym = *((vm_offset_t *)&(md->md_data));
if ((md = mod_findmetadata(mp, MODINFOMD_ELFESYM)) != NULL)
esym = *((vm_offset_t *)&(md->md_data));
if (ssym == 0 || esym == 0)
ssym = esym = 0; /* sanity */
/* legacy bootinfo structure */
bi.bi_version = BOOTINFO_VERSION;
bi.bi_kernelname = 0; /* XXX char * -> kernel name */
@ -93,8 +101,8 @@ elf_exec(struct loaded_module *mp)
bi.bi_vesa = 0; /* XXX correct value? */
bi.bi_basemem = getbasemem();
bi.bi_extmem = getextmem();
bi.bi_symtab = 0; /* Let kld use _DYNAMIC */
bi.bi_esymtab = 0;
bi.bi_symtab = ssym;
bi.bi_esymtab = esym;
/* Device data is kept in the kernel argv array */
argv[0] = bi_getboothowto(mp->m_args); /* boothowto */

14
sys/boot/i386/libi386/elf_freebsd.c
View File

@ -23,7 +23,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: aout_freebsd.c,v 1.6 1998/09/29 09:11:49 peter Exp $
* $Id: elf_freebsd.c,v 1.1 1998/09/30 19:48:09 peter Exp $
*/
#include <sys/param.h>
@ -61,6 +61,7 @@ elf_exec(struct loaded_module *mp)
int major, bootdevnr;
vm_offset_t addr, entry;
u_int pad;
vm_offset_t ssym, esym, *symptr;
if ((md = mod_findmetadata(mp, MODINFOMD_ELFHDR)) == NULL)
return(EFTYPE); /* XXX actually EFUCKUP */
@ -82,6 +83,13 @@ elf_exec(struct loaded_module *mp)
}
free(currdev);
if ((md = mod_findmetadata(mp, MODINFOMD_ELFSSYM)) != NULL)
ssym = *((vm_offset_t *)&(md->md_data));
if ((md = mod_findmetadata(mp, MODINFOMD_ELFESYM)) != NULL)
esym = *((vm_offset_t *)&(md->md_data));
if (ssym == 0 || esym == 0)
ssym = esym = 0; /* sanity */
/* legacy bootinfo structure */
bi.bi_version = BOOTINFO_VERSION;
bi.bi_kernelname = 0; /* XXX char * -> kernel name */
@ -93,8 +101,8 @@ elf_exec(struct loaded_module *mp)
bi.bi_vesa = 0; /* XXX correct value? */
bi.bi_basemem = getbasemem();
bi.bi_extmem = getextmem();
bi.bi_symtab = 0; /* Let kld use _DYNAMIC */
bi.bi_esymtab = 0;
bi.bi_symtab = ssym;
bi.bi_esymtab = esym;
/* Device data is kept in the kernel argv array */
argv[0] = bi_getboothowto(mp->m_args); /* boothowto */