From: Richard M. Stallman Date: Wed, 21 Aug 1996 20:18:00 +0000 (+0000) Subject: Conditionalize the changes below on not __linux__. X-Git-Tag: emacs-20.1~4051 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=d7b43eaa00c71f48a19134bf89751820f1ccf17b;p=emacs.git 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. --- diff --git a/src/unexalpha.c b/src/unexalpha.c index 48b4059fcaf..2adfd1fa57e 100644 --- a/src/unexalpha.c +++ b/src/unexalpha.c @@ -31,6 +31,10 @@ Boston, MA 02111-1307, USA. */ #include #include #include +#ifndef __linux__ +# include +# include +#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__ */ /*