mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-24 11:29:10 +00:00
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
parent
27d73120d4
commit
2e06076f23
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=39887
@ -23,7 +23,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: bootstrap.h,v 1.8 1998/09/26 10:51:37 dfr Exp $
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* $Id: bootstrap.h,v 1.9 1998/09/30 19:25:26 peter Exp $
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*/
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#include <sys/types.h>
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@ -193,6 +193,8 @@ extern int elf_loadmodule(char *filename, vm_offset_t dest, struct loaded_module
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#define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */
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#define MODINFOMD_ELFHDR 0x0002 /* ELF header */
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#define MODINFOMD_ELFSSYM 0x0003 /* ELF start of symbols */
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#define MODINFOMD_ELFESYM 0x0004 /* ELF end of symbols */
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#define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */
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#define KLD_IDENT_SYMNAME "kld_identifier_"
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@ -24,7 +24,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: load_aout.c,v 1.6 1998/09/26 10:51:38 dfr Exp $
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* $Id: load_elf.c,v 1.1 1998/09/30 19:38:26 peter Exp $
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*/
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#include <sys/param.h>
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@ -39,7 +39,7 @@
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#include "bootstrap.h"
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static int elf_loadimage(int fd, vm_offset_t *loadaddr, Elf_Ehdr *ehdr, int kernel);
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static int elf_loadimage(struct loaded_module *mp, int fd, vm_offset_t *loadaddr, Elf_Ehdr *ehdr, int kernel);
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#if 0
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static vm_offset_t elf_findkldident(struct loaded_module *mp, Elf_Ehdr *ehdr);
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static int elf_fixupkldmod(struct loaded_module *mp, Elf_Ehdr *ehdr);
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@ -152,7 +152,7 @@ elf_loadmodule(char *filename, vm_offset_t dest, struct loaded_module **result)
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printf("%s at %p\n", filename, (void *) addr);
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mp->m_size = elf_loadimage(fd, &addr, &ehdr, kernel);
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mp->m_size = elf_loadimage(mp, fd, &addr, &ehdr, kernel);
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if (mp->m_size == 0)
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goto ioerr;
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mp->m_addr = addr; /* save the aligned load address */
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@ -185,15 +185,23 @@ elf_loadmodule(char *filename, vm_offset_t dest, struct loaded_module **result)
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* the Elf header, load the image at (addr)
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*/
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static int
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elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
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elf_loadimage(struct loaded_module *mp, int fd, vm_offset_t *addr,
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Elf_Ehdr *ehdr, int kernel)
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{
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int i;
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int i, j;
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Elf_Phdr *phdr;
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Elf_Shdr *shdr;
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Elf_Ehdr local_ehdr;
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int ret;
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vm_offset_t firstaddr;
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vm_offset_t lastaddr;
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vm_offset_t off;
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void *buf;
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size_t resid, chunk;
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vm_offset_t dest;
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char *secname;
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vm_offset_t shdrpos;
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vm_offset_t ssym, esym;
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ret = 0;
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firstaddr = lastaddr = 0;
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@ -225,29 +233,27 @@ elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
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if (phdr[i].p_type != PT_LOAD)
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continue;
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printf("segment %d: 0x%lx@0x%lx -> 0x%lx-0x%lx\n", i,
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printf("Segment: 0x%lx@0x%lx -> 0x%lx-0x%lx",
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(long)phdr[i].p_filesz, (long)phdr[i].p_offset,
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(long)(phdr[i].p_vaddr + off),
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(long)(phdr[i].p_vaddr + off + phdr[i].p_filesz - 1));
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(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
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if (lseek(fd, phdr[i].p_offset, SEEK_SET) == -1) {
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printf("elf_loadexec: cannot seek\n");
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printf("\nelf_loadexec: cannot seek\n");
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goto out;
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}
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if (archsw.arch_readin(fd, phdr[i].p_vaddr + off, phdr[i].p_filesz) !=
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phdr[i].p_filesz) {
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printf("elf_loadexec: archsw.readin failed\n");
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printf("\nelf_loadexec: archsw.readin failed\n");
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goto out;
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}
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/* clear space from oversized segments; eg: bss */
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if (phdr[i].p_filesz < phdr[i].p_memsz) {
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size_t resid, chunk;
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vm_offset_t dest;
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printf(".. extended: clearing 0x%lx-0x%lx\n",
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printf(" (bss: 0x%lx-0x%lx)",
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(long)(phdr[i].p_vaddr + off + phdr[i].p_filesz),
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(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
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/* no archsw.arch_bzero */
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buf = malloc(PAGE_SIZE);
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bzero(buf, PAGE_SIZE);
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resid = phdr[i].p_memsz - phdr[i].p_filesz;
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@ -260,6 +266,7 @@ elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
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}
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free(buf);
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}
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printf("\n");
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if (firstaddr < (phdr[i].p_vaddr + off))
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firstaddr = phdr[i].p_vaddr + off;
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@ -267,6 +274,112 @@ elf_loadimage(int fd, vm_offset_t *addr, Elf_Ehdr *ehdr, int kernel)
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lastaddr = phdr[i].p_vaddr + off + phdr[i].p_memsz;
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}
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/*
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* Now grab the symbol tables. This isn't easy if we're reading a
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* .gz file. I think the rule is going to have to be that you must
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* strip a file to remove symbols before gzipping it so that we do not
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* try to lseek() on it. The layout is a bit wierd, but it's what
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* the NetBSD-derived ddb/db_elf.c wants.
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*/
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lastaddr = roundup(lastaddr, sizeof(long));
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chunk = ehdr->e_shnum * ehdr->e_shentsize;
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shdr = malloc(chunk);
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if (shdr == NULL)
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goto nosyms;
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ssym = lastaddr;
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printf("Symbols: ELF Ehdr @ 0x%x; ", lastaddr);
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lastaddr += sizeof(*ehdr);
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lastaddr = roundup(lastaddr, sizeof(long));
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/* Copy out executable header modified for base offsets */
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local_ehdr = *ehdr;
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local_ehdr.e_phoff = 0;
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local_ehdr.e_phentsize = 0;
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local_ehdr.e_phnum = 0;
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local_ehdr.e_shoff = lastaddr - ssym;
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archsw.arch_copyin(&local_ehdr, ssym, sizeof(*ehdr));
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if (lseek(fd, ehdr->e_shoff, SEEK_SET) == -1) {
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printf("elf_loadimage: cannot lseek() to section headers\n");
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lastaddr = ssym; /* wind back */
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ssym = 0;
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goto nosyms;
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}
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if (read(fd, shdr, chunk) != chunk) {
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printf("elf_loadimage: read section headers failed\n");
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lastaddr = ssym; /* wind back */
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ssym = 0;
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goto nosyms;
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}
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shdrpos = lastaddr;
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printf("Section table: 0x%x@0x%x\n", chunk, shdrpos);
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lastaddr += chunk;
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lastaddr = roundup(lastaddr, sizeof(long));
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for (i = 0; i < ehdr->e_shnum; i++) {
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switch(shdr[i].sh_type) {
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/*
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* These are the symbol tables. Their names are relative to
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* an arbitary string table.
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*/
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case SHT_SYMTAB: /* Symbol table */
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secname = "symtab";
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break;
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case SHT_DYNSYM: /* Dynamic linking symbol table */
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secname = "dynsym";
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break;
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/*
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* And here are the string tables. These can be referred to from
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* a number of sources, including the dynsym, the section table
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* names itself, etc.
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*/
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case SHT_STRTAB: /* String table */
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secname = "strtab";
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break;
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default: /* Skip it */
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continue;
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}
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for (j = 0; j < ehdr->e_phnum; j++) {
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if (phdr[j].p_type != PT_LOAD)
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continue;
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if (shdr[i].sh_offset >= phdr[j].p_offset &&
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(shdr[i].sh_offset + shdr[i].sh_size <=
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phdr[j].p_offset + phdr[j].p_filesz)) {
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shdr[i].sh_offset = 0;
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shdr[i].sh_size = 0;
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break;
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}
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}
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if (shdr[i].sh_offset == 0 || shdr[i].sh_size == 0)
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continue; /* alread loaded in a PT_LOAD above */
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printf("%s: 0x%x@0x%x -> 0x%x-0x%x\n", secname,
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shdr[i].sh_size, shdr[i].sh_offset,
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lastaddr, lastaddr + shdr[i].sh_size);
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if (lseek(fd, shdr[i].sh_offset, SEEK_SET) == -1) {
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printf("\nelf_loadimage: could not seek for symbols - skipped!\n");
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shdr[i].sh_offset = 0;
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shdr[i].sh_size = 0;
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continue;
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}
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if (archsw.arch_readin(fd, lastaddr, shdr[i].sh_size) !=
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shdr[i].sh_size) {
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printf("\nelf_loadimage: could not read symbols - skipped!\n");
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shdr[i].sh_offset = 0;
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shdr[i].sh_size = 0;
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continue;
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}
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/* Reset offsets relative to ssym */
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shdr[i].sh_offset = lastaddr - ssym;
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lastaddr += shdr[i].sh_size;
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lastaddr = roundup(lastaddr, sizeof(long));
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}
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archsw.arch_copyin(shdr, lastaddr, sizeof(*ehdr));
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esym = lastaddr;
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mod_addmetadata(mp, MODINFOMD_ELFSSYM, sizeof(ssym), &ssym);
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mod_addmetadata(mp, MODINFOMD_ELFESYM, sizeof(esym), &esym);
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nosyms:
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ret = lastaddr - firstaddr;
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*addr = firstaddr;
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out:
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@ -23,7 +23,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: aout_freebsd.c,v 1.6 1998/09/29 09:11:49 peter Exp $
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* $Id: elf_freebsd.c,v 1.1 1998/09/30 19:48:09 peter Exp $
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*/
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#include <sys/param.h>
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@ -61,6 +61,7 @@ elf_exec(struct loaded_module *mp)
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int major, bootdevnr;
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vm_offset_t addr, entry;
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u_int pad;
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vm_offset_t ssym, esym, *symptr;
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFHDR)) == NULL)
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return(EFTYPE); /* XXX actually EFUCKUP */
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@ -82,6 +83,13 @@ elf_exec(struct loaded_module *mp)
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}
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free(currdev);
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFSSYM)) != NULL)
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ssym = *((vm_offset_t *)&(md->md_data));
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFESYM)) != NULL)
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esym = *((vm_offset_t *)&(md->md_data));
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if (ssym == 0 || esym == 0)
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ssym = esym = 0; /* sanity */
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/* legacy bootinfo structure */
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bi.bi_version = BOOTINFO_VERSION;
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bi.bi_kernelname = 0; /* XXX char * -> kernel name */
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@ -93,8 +101,8 @@ elf_exec(struct loaded_module *mp)
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bi.bi_vesa = 0; /* XXX correct value? */
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bi.bi_basemem = getbasemem();
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bi.bi_extmem = getextmem();
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bi.bi_symtab = 0; /* Let kld use _DYNAMIC */
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bi.bi_esymtab = 0;
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bi.bi_symtab = ssym;
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bi.bi_esymtab = esym;
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/* Device data is kept in the kernel argv array */
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argv[0] = bi_getboothowto(mp->m_args); /* boothowto */
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@ -23,7 +23,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: aout_freebsd.c,v 1.6 1998/09/29 09:11:49 peter Exp $
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* $Id: elf_freebsd.c,v 1.1 1998/09/30 19:48:09 peter Exp $
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*/
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#include <sys/param.h>
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@ -61,6 +61,7 @@ elf_exec(struct loaded_module *mp)
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int major, bootdevnr;
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vm_offset_t addr, entry;
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u_int pad;
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vm_offset_t ssym, esym, *symptr;
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFHDR)) == NULL)
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return(EFTYPE); /* XXX actually EFUCKUP */
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@ -82,6 +83,13 @@ elf_exec(struct loaded_module *mp)
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}
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free(currdev);
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFSSYM)) != NULL)
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ssym = *((vm_offset_t *)&(md->md_data));
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFESYM)) != NULL)
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esym = *((vm_offset_t *)&(md->md_data));
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if (ssym == 0 || esym == 0)
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ssym = esym = 0; /* sanity */
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/* legacy bootinfo structure */
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bi.bi_version = BOOTINFO_VERSION;
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bi.bi_kernelname = 0; /* XXX char * -> kernel name */
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@ -93,8 +101,8 @@ elf_exec(struct loaded_module *mp)
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bi.bi_vesa = 0; /* XXX correct value? */
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bi.bi_basemem = getbasemem();
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bi.bi_extmem = getextmem();
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bi.bi_symtab = 0; /* Let kld use _DYNAMIC */
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bi.bi_esymtab = 0;
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bi.bi_symtab = ssym;
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bi.bi_esymtab = esym;
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/* Device data is kept in the kernel argv array */
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argv[0] = bi_getboothowto(mp->m_args); /* boothowto */
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@ -23,7 +23,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: aout_freebsd.c,v 1.6 1998/09/29 09:11:49 peter Exp $
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* $Id: elf_freebsd.c,v 1.1 1998/09/30 19:48:09 peter Exp $
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*/
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#include <sys/param.h>
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@ -61,6 +61,7 @@ elf_exec(struct loaded_module *mp)
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int major, bootdevnr;
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vm_offset_t addr, entry;
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u_int pad;
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vm_offset_t ssym, esym, *symptr;
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFHDR)) == NULL)
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return(EFTYPE); /* XXX actually EFUCKUP */
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@ -82,6 +83,13 @@ elf_exec(struct loaded_module *mp)
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}
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free(currdev);
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFSSYM)) != NULL)
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ssym = *((vm_offset_t *)&(md->md_data));
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if ((md = mod_findmetadata(mp, MODINFOMD_ELFESYM)) != NULL)
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esym = *((vm_offset_t *)&(md->md_data));
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if (ssym == 0 || esym == 0)
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ssym = esym = 0; /* sanity */
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/* legacy bootinfo structure */
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bi.bi_version = BOOTINFO_VERSION;
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bi.bi_kernelname = 0; /* XXX char * -> kernel name */
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@ -93,8 +101,8 @@ elf_exec(struct loaded_module *mp)
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bi.bi_vesa = 0; /* XXX correct value? */
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bi.bi_basemem = getbasemem();
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bi.bi_extmem = getextmem();
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bi.bi_symtab = 0; /* Let kld use _DYNAMIC */
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bi.bi_esymtab = 0;
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bi.bi_symtab = ssym;
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bi.bi_esymtab = esym;
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/* Device data is kept in the kernel argv array */
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argv[0] = bi_getboothowto(mp->m_args); /* boothowto */
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