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Commit d7b43eaa authored by Richard M. Stallman's avatar Richard M. Stallman
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Conditionalize the changes below on not __linux__. 

Include reloc.h and elf_abi.h.
(rel_dyn_section, dynstr_section, dynsym_section): New variables.
(old_data_scnhdr): New variable.
(CHECK_SCNHDR): Compare just 8 chars of section name.
(unexec): Check for rel_dyn_section, dynsym_section, dynstr_section.
Do call update_dynamic_symbols.
(update_dynamic_symbols): Finish it up and take away #if 0.
parent 18aa68c3
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Showing with 91 additions and 60 deletions
src/unexalpha.c
View file @ d7b43eaa
......@@ -31,6 +31,10 @@ Boston, MA 02111-1307, USA. */
#include <aouthdr.h>
#include <scnhdr.h>
#include <syms.h>
#ifndef __linux__
# include <reloc.h>
# include <elf_abi.h>
#endif
static void fatal_unexec ();
static void mark_x ();
......@@ -52,11 +56,14 @@ static void mark_x ();
extern int errno;
extern char *strerror ();
void *sbrk();
void *sbrk ();
#define EEOF -1
static struct scnhdr *text_section;
static struct scnhdr *rel_dyn_section;
static struct scnhdr *dynstr_section;
static struct scnhdr *dynsym_section;
static struct scnhdr *init_section;
static struct scnhdr *finit_section;
static struct scnhdr *rdata_section;
......@@ -71,6 +78,8 @@ static struct scnhdr *sdata_section;
static struct scnhdr *sbss_section;
static struct scnhdr *bss_section;
static struct scnhdr old_data_scnhdr;
static unsigned long Brk;
struct headers {
......@@ -157,7 +166,7 @@ unexec (new_name, a_name, data_start, bss_start, entry_address)
#define CHECK_SCNHDR(ptr, name, flags) \
ptr = NULL; \
for (i = 0; i < nhdr.fhdr.f_nscns && !ptr; i++) \
if (strcmp (nhdr.section[i].s_name, name) == 0) \
if (strncmp (nhdr.section[i].s_name, name, 8) == 0) \
{ \
if (nhdr.section[i].s_flags != flags) \
fprintf (stderr, "unexec: %x flags (%x expected) in %s section.\n", \
......@@ -167,6 +176,15 @@ unexec (new_name, a_name, data_start, bss_start, entry_address)
CHECK_SCNHDR (text_section, _TEXT, STYP_TEXT);
CHECK_SCNHDR (init_section, _INIT, STYP_INIT);
#ifdef _REL_DYN
CHECK_SCNHDR (rel_dyn_section, _REL_DYN, STYP_REL_DYN);
#endif /* _REL_DYN */
#ifdef _DYNSYM
CHECK_SCNHDR (dynsym_section, _DYNSYM, STYP_DYNSYM);
#endif /* _REL_DYN */
#ifdef _DYNSTR
CHECK_SCNHDR (dynstr_section, _DYNSTR, STYP_DYNSTR);
#endif /* _REL_DYN */
#ifdef _FINI
CHECK_SCNHDR (finit_section, _FINI, STYP_FINI);
#endif /* _FINI */
......@@ -200,6 +218,8 @@ unexec (new_name, a_name, data_start, bss_start, entry_address)
Brk = brk;
bcopy (data_section, &old_data_scnhdr, sizeof (old_data_scnhdr));
nhdr.aout.dsize = brk - DATA_START;
nhdr.aout.bsize = 0;
if (entry_address == 0)
......@@ -341,15 +361,8 @@ unexec (new_name, a_name, data_start, bss_start, entry_address)
stat.st_size - ohdr.fhdr.f_symptr - cbHDRR,
"writing symbol table of %s", new_name);
#if 0
/* Not needed for now */
update_dynamic_symbols (oldptr, new_name, new, newsyms,
((pHDRR) (oldptr + ohdr.fhdr.f_symptr))->issExtMax,
((pHDRR) (oldptr + ohdr.fhdr.f_symptr))->cbExtOffset,
((pHDRR) (oldptr + ohdr.fhdr.f_symptr))->cbSsExtOffset);
#ifndef __linux__
update_dynamic_symbols (oldptr, new_name, new, nhdr.aout);
#endif
#undef symhdr
......@@ -364,69 +377,87 @@ unexec (new_name, a_name, data_start, bss_start, entry_address)
}
#if 0
/* Not needed for now */
/* The following function updates the values of some symbols
that are used by the dynamic loader:
_edata
_end
*/
#ifndef __linux__
update_dynamic_symbols (old, new_name, new, newsyms, nsyms, symoff, stroff)
update_dynamic_symbols (old, new_name, new, aout)
char *old; /* Pointer to old executable */
char *new_name; /* Name of new executable */
int new; /* File descriptor for new executable */
long newsyms; /* Offset of Symbol table in new executable */
int nsyms; /* Number of symbol table entries */
long symoff; /* Offset of External Symbols in old file */
long stroff; /* Offset of string table in old file */
struct aouthdr aout; /* a.out info from the file header */
{
long i;
int found = 0;
EXTR n_end, n_edata;
typedef struct dynrel_info {
char * addr;
unsigned type:8;
unsigned index:24;
unsigned info:8;
unsigned pad:8;
} dr_info;
int nsyms = rel_dyn_section->s_size / sizeof (struct dynrel_info);
int i;
dr_info * rd_base = (dr_info *) (old + rel_dyn_section->s_scnptr);
Elf32_Sym * ds_base = (Elf32_Sym *) (old + dynsym_section->s_scnptr);
/* We go through the symbol table entries until we have found the two
symbols. */
for (i = 0; i < nsyms; i++) {
register Elf32_Sym x;
/* cbEXTR is the size of an external symbol table entry */
if (rd_base[i].index == 0)
continue;
for (i = 0; i < nsyms && found < 2; i += cbEXTR)
{
register pEXTR x = (pEXTR) (old + symoff + i);
char *s;
s = old + stroff + x->asym.iss; /* name of the symbol */
if (!strcmp(s,"_edata"))
{
found++;
bcopy (x, &n_edata, cbEXTR);
n_edata.asym.value = Brk;
SEEK (new, newsyms + cbHDRR + i,
"seeking to symbol _edata in %s", new_name);
WRITE (new, &n_edata, cbEXTR,
"writing symbol table entry for _edata into %s", new_name);
}
else if (!strcmp(s,"_end"))
{
found++;
bcopy (x, &n_end, cbEXTR);
n_end.asym.value = Brk;
SEEK (new, newsyms + cbHDRR + i,
"seeking to symbol _end in %s", new_name);
WRITE (new, &n_end, cbEXTR,
"writing symbol table entry for _end into %s", new_name);
}
x = ds_base[rd_base[i].index];
#if 0
fprintf (stderr, "Object inspected: %s, addr = %lx, shndx = %x",
old + dynstr_section->s_scnptr + x.st_name, rd_base[i].addr, x.st_shndx);
#endif
if ((ELF32_ST_BIND (x.st_info) == STB_GLOBAL)
&& (x.st_shndx == 0)
/* && (x.st_value == NULL) */
) {
/* OK, this is probably a reference to an object in a shared
library, so copy the old value. This is done in several steps:
1. reladdr is the address of the location in question relative to
the start of the data section,
2. oldref is the addr is the mapped in temacs executable,
3. newref is the address of the location in question in the
undumped executable,
4. len is the size of the object reference in bytes --
currently only 4 (long) and 8 (quad) are supported.
*/
register unsigned long reladdr = rd_base[i].addr - old_data_scnhdr.s_vaddr;
char * oldref = old + old_data_scnhdr.s_scnptr + reladdr;
unsigned long newref = aout.tsize + reladdr;
int len;
#if 0
fprintf (stderr, "...relocated\n");
#endif
if (rd_base[i].type == R_REFLONG)
len = 4;
else if (rd_base[i].type == R_REFQUAD)
len = 8;
else
fatal_unexec ("unrecognized relocation type in .dyn.rel section (symbol #%d)", i);
SEEK (new, newref, "seeking to dynamic symbol in %s", new_name);
WRITE (new, oldref, len, "writing old dynrel info in %s", new_name);
}
#if 0
else
fprintf (stderr, "...not relocated\n");
#endif
}
}
#endif
#endif /* !__linux__ */
/*
......
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