SYMTAB *Snarf_Symbols (FILE *f, struct exec *ep) { SYMTAB *tab; register SYM *sp; register SYM **nextp; int strsiz = 0; /* running total length of names read, */ /* each '\0' terminated */ int nread = 0; /* running total of bytes read from symbol table */ int max = 0; /* current maximum size of name table */ char *names = 0; /* the name table */ struct nlist_ nl; tab = (SYMTAB *)Safe_Malloc (sizeof (SYMTAB)); tab->first = 0; tab->strings = 0; nextp = &tab->first; (void)fseek (f, (long)LESYM_OFFSET(*ep), 0); while (nread < ep->a_lesyms) { if (fread ((char *)&nl, sizeof (nl), 1, f) != 1) { Free_Symbols (tab); (void)fclose (f); Primitive_Error ("corrupt symbol table in object file"); } nread += sizeof (nl); if (nl.n_length == 0) { continue; } else if (nl.n_length + strsiz + 1 > max) { max += STRING_BLOCK; names = Safe_Realloc (names, max); } if (fread (names + strsiz, 1, nl.n_length, f) != nl.n_length) { Free_Symbols (tab); (void)fclose (f); Primitive_Error ("corrupt symbol table in object file"); } else { nread += nl.n_length; names[ strsiz + nl.n_length ] = '\0'; } if ((nl.n_type & N_TYPE) != N_TEXT) { strsiz += nl.n_length +1; continue; } sp = (SYM *)Safe_Malloc (sizeof (SYM)); sp->name = (char *)strsiz; strsiz += (nl.n_length + 1); sp->value = nl.n_value; *nextp = sp; nextp = &sp->next; *nextp = 0; } tab->strings = names; for (sp = tab->first; sp; sp = sp->next) sp->name += (unsigned int)names; return tab; }
int unexec (char *new_name, char *old_name, unsigned int emacs_edata, unsigned int dummy1, unsigned int dummy2) { /* /dld.sl data */ struct dynamic *ld = 0; /* old and new state */ int old_fd; int new_fd; struct exec old_hdr; struct exec new_hdr; struct stat old_buf; /* some process specific "constants" */ unsigned long n_pagsiz; caddr_t dynamic_beg; caddr_t current_break = (caddr_t) sbrk (0); /* dynamically linked image? -- if so, find dld.sl structures */ if (dynamic_addr) { ld = (struct dynamic *) dynamic_addr; #ifdef DEBUG printf ("dl_text = %#x\n", ld->text); printf ("dl_data = %#x\n", ld->data); printf ("dl_bss = %#x\n", ld->bss); printf ("dl_end = %#x\n", ld->end); printf ("dl_dmodule = %#x\n", ld->dmodule); printf ("dl_dlt = %#x\n", ld->dlt); printf ("dl_plt = %#x\n", ld->plt); #endif } /* open the old and new files, figuring out how big the old one is so that we can map it in */ old_fd = unexec_open (old_name, O_RDONLY, 0); new_fd = unexec_open (new_name, O_RDWR | O_CREAT | O_TRUNC, 0666); /* setup the header and the statbuf for old_fd */ unexec_read (old_fd, 0, (char *) &old_hdr, sizeof (old_hdr)); unexec_fstat (old_fd, &old_buf); /* set up some important constants */ n_pagsiz = EXEC_PAGESIZE; /* setup beginning of data to copy from executable */ if (ld) dynamic_beg = ld->dmodule; else dynamic_beg = (caddr_t)EXEC_ALIGN (old_hdr.a_text) + old_hdr.a_data; /* set up the new exec */ new_hdr = old_hdr; new_hdr.a_text = MASK_DOWN (emacs_edata, n_pagsiz); new_hdr.a_data = MASK_UP (current_break, n_pagsiz) - EXEC_ALIGN(new_hdr.a_text); new_hdr.a_bss = 0; #ifdef DEBUG printf ("old text %#x\n", old_hdr.a_text); printf ("new text %#x\n", new_hdr.a_text); printf ("old data %#x\n", old_hdr.a_data); printf ("new data %#x\n", new_hdr.a_data); printf ("old bss %#x\n", old_hdr.a_bss); printf ("new bss %#x\n", new_hdr.a_bss); #endif /* set up this variable, in case we want to reset "the break" when restarting */ sbrk_of_0_at_unexec = ((unsigned long) MASK_UP (current_break, n_pagsiz)); /* Write out the first approximation to the new file. The sizes of each section will be correct, but there will be a number of corrections that will need to be made. */ { long old_datoff = DATA_OFFSET (old_hdr); long new_datoff = DATA_OFFSET (new_hdr); long old_dataddr = EXEC_ALIGN (old_hdr.a_text); long new_dataddr = EXEC_ALIGN (new_hdr.a_text); long new_mcaloff = MODCAL_OFFSET (new_hdr); long old_mcaloff = MODCAL_OFFSET (old_hdr); long newtext_size = new_hdr.a_text - old_dataddr; long newdata1_size = (unsigned long)dynamic_beg - new_dataddr; long dyn_size = (EXEC_ALIGN (old_hdr.a_text) + old_hdr.a_data) - (unsigned long)dynamic_beg; long newdata2_size = (unsigned long)current_break - ((unsigned long)dynamic_beg + dyn_size); long pad_size = MASK_UP (current_break, n_pagsiz) - ((unsigned long) current_break); #ifdef DEBUG printf ("current break is %#lx\n", current_break); printf ("old_dataddr = %#lx, dynamic_beg = %#lx\n", old_dataddr, dynamic_beg); #endif /* * First, write the text segment with new header -- copy * everything until the start of the data segment from the old * file */ #ifdef DEBUG printf ("copying %#lx bytes of text from 0\n", old_datoff); #endif unexec_copy (new_fd, old_fd, 0, 0, old_datoff); /* pad out the text segment */ #ifdef DEBUG printf ( "text pad size is %#x\n", old_dataddr - old_hdr.a_text); #endif unexec_pad (new_fd, old_dataddr - old_hdr.a_text); /* * Update debug header spoo */ if (new_hdr.a_extension > 0) { new_hdr.a_extension += LESYM_OFFSET(new_hdr) - LESYM_OFFSET(old_hdr); } /* * go back and write the new header. */ unexec_write (new_fd, 0, (char *) &new_hdr, sizeof (new_hdr)); /* * Copy the part of the data segment which becomes text from the * running image. */ #ifdef DEBUG printf ("copying %#lx bytes of new text from %#lx to position %#lx\n", newtext_size, old_dataddr, TEXT_OFFSET(new_hdr) + old_dataddr); #endif unexec_write (new_fd, TEXT_OFFSET(new_hdr) + old_dataddr, (caddr_t)old_dataddr, newtext_size); #ifdef DEBUG printf ("new DATA_OFFSET is %#lx\n", new_datoff); #endif /* * Copy the part of the old data segment which will be data * in the new executable (before the dynamic stuff) * from the running image. */ #ifdef DEBUG printf ("copying %#lx bytes of data from %#lx to position %#lx\n", newdata1_size, new_dataddr, new_datoff); #endif unexec_write (new_fd, new_datoff, (caddr_t)new_dataddr, newdata1_size); /* copy the dynamic part of the data segment from the old executable */ if (dyn_size) { #ifdef DEBUG printf ("copying %#lx bytes of dyn data from executable" " at address %#lx to position %#lx\n", dyn_size, dynamic_beg, new_datoff + newdata1_size); #endif unexec_copy (new_fd, old_fd, old_datoff + newtext_size + newdata1_size, new_datoff + newdata1_size, dyn_size); } /* copy remaining data (old bss) from the running image */ #ifdef DEBUG printf ("copying %#lx bytes of data from %#lx to position %#lx\n", newdata2_size, new_dataddr + newdata1_size + dyn_size, new_datoff + newdata1_size + dyn_size); #endif unexec_write (new_fd, new_datoff + newdata1_size + dyn_size, (caddr_t)(new_dataddr + newdata1_size + dyn_size), newdata2_size); /* pad out the data segment */ #ifdef DEBUG printf ( "pad size is %#x\n", pad_size); #endif unexec_pad (new_fd, pad_size); /* Finally, copy the rest of the junk from the old file. */ #ifdef DEBUG printf ("Copying %#lx bytes of junk from %#lx (old) to %#lx (new)\n", old_buf.st_size - old_mcaloff, old_mcaloff, new_mcaloff); #endif unexec_copy (new_fd, old_fd, old_mcaloff, new_mcaloff, old_buf.st_size - old_mcaloff); { long curpos, offset; struct _debug_header dhdr; int new_header_delta; new_header_delta = LESYM_OFFSET(new_hdr) - LESYM_OFFSET(old_hdr); if ((new_header_delta > 0) && ((offset = EXT_OFFSET(old_hdr)) > 0)) { curpos = lseek(new_fd, 0, SEEK_CUR); lseek(old_fd, offset, 0); if (read(old_fd, &dhdr, sizeof(dhdr)) == sizeof(dhdr)) { dhdr.header_offset += new_header_delta; dhdr.gntt_offset += new_header_delta; dhdr.lntt_offset += new_header_delta; dhdr.slt_offset += new_header_delta; dhdr.vt_offset += new_header_delta; dhdr.xt_offset += new_header_delta; lseek(new_fd, EXT_OFFSET(new_hdr), SEEK_SET); if (write(new_fd, &dhdr, sizeof(dhdr)) != sizeof(dhdr)) { unexec_error("Unable to write debug information to \"%s\"\n", 1, new_name); } lseek(new_fd, curpos, SEEK_SET); } else { unexec_error("Unable to read debug information from \"%s\"\n", 1, old_name); } } } } /* make the output file executable -- then quit */ unexec_fchmod (new_fd, 0755); close (old_fd); close (new_fd); return 0; }