/* * Copyright (c) 1994 Gordon W. Ross * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * $NetBSD: dbsym.c,v 1.14 1998/02/20 09:27:21 mycroft Exp $ */ #include #ifndef lint __RCSID("$NetBSD: dbsym.c,v 1.14 1998/02/20 09:27:21 mycroft Exp $"); #endif /* Copy the symbol table into the space reserved for it. */ #include #include #include #include #include #include #include struct exec head; char *file; /* Virtual addresses of the symbols we frob. */ long db_symtab_va, db_symtabsize_va; /* Offsets relative to start of data segment. */ long db_symtab_off, db_symtabsize_off; /* value in the location at db_symtabsize_off */ int db_symtabsize_val; /* pointers to pieces of mapped file */ char *dataseg; char *symbols; char *strings; int *strtab; /* and lengths */ int strtab_len; int file_len; int data_off; int data_pgoff; void find_db_symtab __P((const char *)); int main __P((int, char **)); int main(argc,argv) int argc; char **argv; { int fd, n; int *ip; if (argc < 2) errx(1, "missing file name"); file = argv[1]; fd = open(file, O_RDWR); if (fd < 0) err(1, "open `%s'", file); n = read(fd, &head, sizeof(head)); if (n < sizeof(head)) errx(1, "reading header of `%s'", file); file_len = lseek(fd, (off_t)0, 2); if (N_BADMAG(head)) errx(1, "%s: bad magic number", file); #ifdef DEBUG printf(" text: %9d\n", head.a_text); printf(" data: %9d\n", head.a_data); printf(" bss: %9d\n", head.a_bss); printf(" syms: %9d\n", head.a_syms); printf("entry: 0x%08X\n", head.a_entry); printf("trsiz: %9d\n", head.a_trsize); printf("drsiz: %9d\n", head.a_drsize); #endif if (head.a_syms <= 0) { printf("%s: no symbols\n", file); exit(1); } if (head.a_trsize || head.a_drsize) errx(1, "%s: has relocations", file); find_db_symtab(file); /* * Map in the file from start of data to EOF. * The file offset needs to be page aligned. */ data_off = N_DATOFF(head); data_pgoff = N_PAGSIZ(head) - 1; data_pgoff &= data_off; data_off -= data_pgoff; dataseg = mmap(NULL, /* any address is ok */ file_len - data_off, /* length */ PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, fd, data_off); if ((long)dataseg == -1) { printf("%s: can not map data seg\n", file); err(1, "%s", file); } dataseg += data_pgoff; symbols = dataseg + head.a_data; strings = symbols + head.a_syms; /* Find the string table length (first word after symtab). */ strtab_len = *((int*)strings); #ifdef DEBUG printf("strtab_len: %d\n", strtab_len); #endif /* * Find value in the location: db_symtabsize */ ip = (int*) (dataseg + db_symtabsize_off); db_symtabsize_val = *ip; #ifdef DEBUG printf("db_symtabsize val: 0x%08X (%d)\n", db_symtabsize_val, db_symtabsize_val); #endif /* Is there room for the symbols + strings? */ if (db_symtabsize_val < (head.a_syms + strtab_len)) errx(1, "symbol space too small (%ld < %ld)", (long)db_symtabsize_val, (long)(head.a_syms + strtab_len)); printf("Symbols use %ld of %ld bytes available (%ld%%)\n", (long)(head.a_syms + strtab_len), (long)db_symtabsize_val, (long)((head.a_syms + strtab_len) * 100 / db_symtabsize_val)); /* * Copy the symbol table and string table. */ #ifdef DEBUG printf("copying symbol table...\n"); #endif ip = (int*) (dataseg + db_symtab_off); /* Write symtab length */ *ip++ = head.a_syms; memcpy((char*)ip, symbols, head.a_syms + strtab_len); msync(dataseg - data_pgoff, file_len - data_off, 0); #ifdef DEBUG printf("...done\n"); #endif close(fd); exit(0); } /* * Find locations of the symbols to patch. */ struct nlist wantsyms[] = { { { "_db_symtabsize" }, 0 }, { { "_db_symtab" }, 0 }, { { NULL }, 0 }, }; void find_db_symtab(file) const char *file; { int data_va; int std_entry; if (nlist(file, wantsyms)) { printf("%s: no db_symtab symbols?\n", file); exit(1); } std_entry = N_TXTADDR(head) + (head.a_entry & (N_PAGSIZ(head)-1)); data_va = N_DATADDR(head); if (head.a_entry != std_entry) { printf("%s: warning: non-standard entry point: 0x%08lx\n", file, head.a_entry); printf("\texpecting entry=0x%X\n", std_entry); data_va += (head.a_entry - std_entry); } db_symtabsize_off = wantsyms[0].n_value - data_va; db_symtab_off = wantsyms[1].n_value - data_va; #ifdef DEBUG printf(".data segment va: 0x%08X\n", data_va); printf("db_symtabsize va: 0x%08X\n", wantsyms[0].n_value); printf("db_symtab va: 0x%08X\n", wantsyms[1].n_value); printf("db_symtabsize off: 0x%08X\n", db_symtabsize_off); printf("db_symtab off: 0x%08X\n", db_symtab_off); #endif /* * Sanity check locations of db_* symbols */ if (db_symtab_off < 0 || db_symtab_off >= head.a_data) { printf("%s: db_symtab not in data segment?\n", file); exit(1); } if (db_symtabsize_off < 0 || db_symtabsize_off >= head.a_data) { printf("%s: db_symtabsize not in data segment?\n", file); exit(1); } }