/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ /* * Routines for preparing tdata trees for conversion into CTF data, and * for placing the resulting data into an output file. */ #include #include #include #include #include #include #include #include #include #include "ctftools.h" #include "list.h" #include "memory.h" #include "traverse.h" #include "symbol.h" typedef struct iidesc_match { int iim_fuzzy; iidesc_t *iim_ret; char *iim_name; char *iim_file; uchar_t iim_bind; } iidesc_match_t; static int burst_iitypes(void *data, void *arg) { iidesc_t *ii = data; iiburst_t *iiburst = arg; switch (ii->ii_type) { case II_GFUN: case II_SFUN: case II_GVAR: case II_SVAR: if (!(ii->ii_flags & IIDESC_F_USED)) return (0); break; default: break; } ii->ii_dtype->t_flags |= TDESC_F_ISROOT; (void) iitraverse_td(ii, iiburst->iib_tdtd); return (1); } /*ARGSUSED1*/ static int save_type_by_id(tdesc_t *tdp, tdesc_t **tdpp __unused, void *private) { iiburst_t *iiburst = private; /* * Doing this on every node is horribly inefficient, but given that * we may be suppressing some types, we can't trust nextid in the * tdata_t. */ if (tdp->t_id > iiburst->iib_maxtypeid) iiburst->iib_maxtypeid = tdp->t_id; slist_add(&iiburst->iib_types, tdp, tdesc_idcmp); return (1); } static tdtrav_cb_f burst_types_cbs[] = { NULL, save_type_by_id, /* intrinsic */ save_type_by_id, /* pointer */ save_type_by_id, /* array */ save_type_by_id, /* function */ save_type_by_id, /* struct */ save_type_by_id, /* union */ save_type_by_id, /* enum */ save_type_by_id, /* forward */ save_type_by_id, /* typedef */ tdtrav_assert, /* typedef_unres */ save_type_by_id, /* volatile */ save_type_by_id, /* const */ save_type_by_id /* restrict */ }; static iiburst_t * iiburst_new(tdata_t *td, int max) { iiburst_t *iiburst = xcalloc(sizeof (iiburst_t)); iiburst->iib_td = td; iiburst->iib_funcs = xcalloc(sizeof (iidesc_t *) * max); iiburst->iib_nfuncs = 0; iiburst->iib_objts = xcalloc(sizeof (iidesc_t *) * max); iiburst->iib_nobjts = 0; return (iiburst); } static void iiburst_types(iiburst_t *iiburst) { tdtrav_data_t tdtd; tdtrav_init(&tdtd, &iiburst->iib_td->td_curvgen, NULL, burst_types_cbs, NULL, (void *)iiburst); iiburst->iib_tdtd = &tdtd; (void) hash_iter(iiburst->iib_td->td_iihash, burst_iitypes, iiburst); } static void iiburst_free(iiburst_t *iiburst) { free(iiburst->iib_funcs); free(iiburst->iib_objts); list_free(iiburst->iib_types, NULL, NULL); free(iiburst); } /* * See if this iidesc matches the ELF symbol data we pass in. * * A fuzzy match is where we have a local symbol matching the name of a * global type description. This is common when a mapfile is used for a * DSO, but we don't accept it by default. * * A weak fuzzy match is when a weak symbol was resolved and matched to * a global type description. */ static int matching_iidesc(void *arg1, void *arg2) { iidesc_t *iidesc = arg1; iidesc_match_t *match = arg2; if (streq(iidesc->ii_name, match->iim_name) == 0) return (0); switch (iidesc->ii_type) { case II_GFUN: case II_GVAR: if (match->iim_bind == STB_GLOBAL) { match->iim_ret = iidesc; return (-1); } else if (match->iim_fuzzy && match->iim_ret == NULL) { match->iim_ret = iidesc; /* continue to look for strong match */ return (0); } break; case II_SFUN: case II_SVAR: if (match->iim_bind == STB_LOCAL && match->iim_file != NULL && streq(iidesc->ii_owner, match->iim_file)) { match->iim_ret = iidesc; return (-1); } break; default: break; } return (0); } static iidesc_t * find_iidesc(tdata_t *td, iidesc_match_t *match) { match->iim_ret = NULL; iter_iidescs_by_name(td, match->iim_name, matching_iidesc, match); return (match->iim_ret); } /* * If we have a weak symbol, attempt to find the strong symbol it will * resolve to. Note: the code where this actually happens is in * sym_process() in cmd/sgs/libld/common/syms.c * * Finding the matching symbol is unfortunately not trivial. For a * symbol to be a candidate, it must: * * - have the same type (function, object) * - have the same value (address) * - have the same size * - not be another weak symbol * - belong to the same section (checked via section index) * * If such a candidate is global, then we assume we've found it. The * linker generates the symbol table such that the curfile might be * incorrect; this is OK for global symbols, since find_iidesc() doesn't * need to check for the source file for the symbol. * * We might have found a strong local symbol, where the curfile is * accurate and matches that of the weak symbol. We assume this is a * reasonable match. * * If we've got a local symbol with a non-matching curfile, there are * two possibilities. Either this is a completely different symbol, or * it's a once-global symbol that was scoped to local via a mapfile. In * the latter case, curfile is likely inaccurate since the linker does * not preserve the needed curfile in the order of the symbol table (see * the comments about locally scoped symbols in libld's update_osym()). * As we can't tell this case from the former one, we use this symbol * iff no other matching symbol is found. * * What we really need here is a SUNW section containing weak<->strong * mappings that we can consume. */ static int check_for_weak(GElf_Sym *weak, char const *weakfile, Elf_Data *data, int nent, Elf_Data *strdata, GElf_Sym *retsym, char **curfilep) { char *curfile = NULL; char *tmpfile1 = NULL; GElf_Sym tmpsym; int candidate = 0; int i; tmpsym.st_info = 0; tmpsym.st_name = 0; if (GELF_ST_BIND(weak->st_info) != STB_WEAK) return (0); for (i = 0; i < nent; i++) { GElf_Sym sym; uchar_t type; if (gelf_getsym(data, i, &sym) == NULL) continue; type = GELF_ST_TYPE(sym.st_info); if (type == STT_FILE) curfile = (char *)strdata->d_buf + sym.st_name; if (GELF_ST_TYPE(weak->st_info) != type || weak->st_value != sym.st_value) continue; if (weak->st_size != sym.st_size) continue; if (GELF_ST_BIND(sym.st_info) == STB_WEAK) continue; if (sym.st_shndx != weak->st_shndx) continue; if (GELF_ST_BIND(sym.st_info) == STB_LOCAL && (curfile == NULL || weakfile == NULL || strcmp(curfile, weakfile) != 0)) { candidate = 1; tmpfile1 = curfile; tmpsym = sym; continue; } *curfilep = curfile; *retsym = sym; return (1); } if (candidate) { *curfilep = tmpfile1; *retsym = tmpsym; return (1); } return (0); } /* * When we've found the underlying symbol's type description * for a weak symbol, we need to copy it and rename it to match * the weak symbol. We also need to add it to the td so it's * handled along with the others later. */ static iidesc_t * copy_from_strong(tdata_t *td, GElf_Sym *sym, iidesc_t *strongdesc, const char *weakname, const char *weakfile) { iidesc_t *new = iidesc_dup_rename(strongdesc, weakname, weakfile); uchar_t type = GELF_ST_TYPE(sym->st_info); switch (type) { case STT_OBJECT: new->ii_type = II_GVAR; break; case STT_FUNC: new->ii_type = II_GFUN; break; } hash_add(td->td_iihash, new); return (new); } /* * Process the symbol table of the output file, associating each symbol * with a type description if possible, and sorting them into functions * and data, maintaining symbol table order. */ static iiburst_t * sort_iidescs(Elf *elf, const char *file, tdata_t *td, int fuzzymatch, int dynsym) { iiburst_t *iiburst; Elf_Scn *scn; GElf_Shdr shdr; Elf_Data *data, *strdata; int i, stidx; int nent; iidesc_match_t match; match.iim_fuzzy = fuzzymatch; match.iim_file = NULL; if ((stidx = findelfsecidx(elf, file, dynsym ? ".dynsym" : ".symtab")) < 0) terminate("%s: Can't open symbol table\n", file); scn = elf_getscn(elf, stidx); data = elf_getdata(scn, NULL); gelf_getshdr(scn, &shdr); nent = shdr.sh_size / shdr.sh_entsize; scn = elf_getscn(elf, shdr.sh_link); strdata = elf_getdata(scn, NULL); iiburst = iiburst_new(td, nent); for (i = 0; i < nent; i++) { GElf_Sym sym; char *bname; iidesc_t **tolist; GElf_Sym ssym; iidesc_match_t smatch; int *curr; iidesc_t *iidesc; if (gelf_getsym(data, i, &sym) == NULL) elfterminate(file, "Couldn't read symbol %d", i); match.iim_name = (char *)strdata->d_buf + sym.st_name; match.iim_bind = GELF_ST_BIND(sym.st_info); switch (GELF_ST_TYPE(sym.st_info)) { case STT_FILE: bname = strrchr(match.iim_name, '/'); match.iim_file = bname == NULL ? match.iim_name : bname + 1; continue; case STT_OBJECT: tolist = iiburst->iib_objts; curr = &iiburst->iib_nobjts; break; case STT_FUNC: tolist = iiburst->iib_funcs; curr = &iiburst->iib_nfuncs; break; default: continue; } if (ignore_symbol(&sym, match.iim_name)) continue; iidesc = find_iidesc(td, &match); if (iidesc != NULL) { tolist[*curr] = iidesc; iidesc->ii_flags |= IIDESC_F_USED; (*curr)++; continue; } if (!check_for_weak(&sym, match.iim_file, data, nent, strdata, &ssym, &smatch.iim_file)) { (*curr)++; continue; } smatch.iim_fuzzy = fuzzymatch; smatch.iim_name = (char *)strdata->d_buf + ssym.st_name; smatch.iim_bind = GELF_ST_BIND(ssym.st_info); debug(3, "Weak symbol %s resolved to %s\n", match.iim_name, smatch.iim_name); iidesc = find_iidesc(td, &smatch); if (iidesc != NULL) { tolist[*curr] = copy_from_strong(td, &sym, iidesc, match.iim_name, match.iim_file); tolist[*curr]->ii_flags |= IIDESC_F_USED; } (*curr)++; } /* * Stabs are generated for every function declared in a given C source * file. When converting an object file, we may encounter a stab that * has no symbol table entry because the optimizer has decided to omit * that item (for example, an unreferenced static function). We may * see iidescs that do not have an associated symtab entry, and so * we do not write records for those functions into the CTF data. * All others get marked as a root by this function. */ iiburst_types(iiburst); /* * By not adding some of the functions and/or objects, we may have * caused some types that were referenced solely by those * functions/objects to be suppressed. This could cause a label, * generated prior to the evisceration, to be incorrect. Find the * highest type index, and change the label indicies to be no higher * than this value. */ tdata_label_newmax(td, iiburst->iib_maxtypeid); return (iiburst); } static void write_file(Elf *src, const char *srcname, Elf *dst, const char *dstname, caddr_t ctfdata, size_t ctfsize, int flags) { GElf_Ehdr sehdr, dehdr; Elf_Scn *sscn, *dscn; Elf_Data *sdata, *ddata; GElf_Shdr shdr; GElf_Word symtab_type; int symtab_idx = -1; off_t new_offset = 0; off_t ctfnameoff = 0; int dynsym = (flags & CTF_USE_DYNSYM); int keep_stabs = (flags & CTF_KEEP_STABS); int *secxlate; int srcidx, dstidx; int curnmoff = 0; int changing = 0; int pad; int i; if (gelf_newehdr(dst, gelf_getclass(src)) == NULL) elfterminate(dstname, "Cannot copy ehdr to temp file"); gelf_getehdr(src, &sehdr); memcpy(&dehdr, &sehdr, sizeof (GElf_Ehdr)); gelf_update_ehdr(dst, &dehdr); symtab_type = dynsym ? SHT_DYNSYM : SHT_SYMTAB; /* * Neither the existing stab sections nor the SUNW_ctf sections (new or * existing) are SHF_ALLOC'd, so they won't be in areas referenced by * program headers. As such, we can just blindly copy the program * headers from the existing file to the new file. */ if (sehdr.e_phnum != 0) { (void) elf_flagelf(dst, ELF_C_SET, ELF_F_LAYOUT); if (gelf_newphdr(dst, sehdr.e_phnum) == NULL) elfterminate(dstname, "Cannot make phdrs in temp file"); for (i = 0; i < sehdr.e_phnum; i++) { GElf_Phdr phdr; gelf_getphdr(src, i, &phdr); gelf_update_phdr(dst, i, &phdr); } } secxlate = xmalloc(sizeof (int) * sehdr.e_shnum); for (srcidx = dstidx = 0; srcidx < sehdr.e_shnum; srcidx++) { Elf_Scn *scn = elf_getscn(src, srcidx); GElf_Shdr shdr1; char *sname; gelf_getshdr(scn, &shdr1); sname = elf_strptr(src, sehdr.e_shstrndx, shdr1.sh_name); if (sname == NULL) { elfterminate(srcname, "Can't find string at %u", shdr1.sh_name); } if (strcmp(sname, CTF_ELF_SCN_NAME) == 0) { secxlate[srcidx] = -1; } else if (!keep_stabs && (strncmp(sname, ".stab", 5) == 0 || strncmp(sname, ".debug", 6) == 0 || strncmp(sname, ".rel.debug", 10) == 0 || strncmp(sname, ".rela.debug", 11) == 0)) { secxlate[srcidx] = -1; } else if (dynsym && shdr1.sh_type == SHT_SYMTAB) { /* * If we're building CTF against the dynsym, * we'll rip out the symtab so debuggers aren't * confused. */ secxlate[srcidx] = -1; } else { secxlate[srcidx] = dstidx++; curnmoff += strlen(sname) + 1; } new_offset = (off_t)dehdr.e_phoff; } for (srcidx = 1; srcidx < sehdr.e_shnum; srcidx++) { char *sname; sscn = elf_getscn(src, srcidx); gelf_getshdr(sscn, &shdr); if (secxlate[srcidx] == -1) { changing = 1; continue; } dscn = elf_newscn(dst); /* * If this file has program headers, we need to explicitly lay * out sections. If none of the sections prior to this one have * been removed, then we can just use the existing location. If * one or more sections have been changed, then we need to * adjust this one to avoid holes. */ if (changing && sehdr.e_phnum != 0) { pad = new_offset % shdr.sh_addralign; if (pad) new_offset += shdr.sh_addralign - pad; shdr.sh_offset = new_offset; } shdr.sh_link = secxlate[shdr.sh_link]; if (shdr.sh_type == SHT_REL || shdr.sh_type == SHT_RELA) shdr.sh_info = secxlate[shdr.sh_info]; sname = elf_strptr(src, sehdr.e_shstrndx, shdr.sh_name); if (sname == NULL) { elfterminate(srcname, "Can't find string at %u", shdr.sh_name); } #ifndef illumos if (gelf_update_shdr(dscn, &shdr) == 0) elfterminate(dstname, "Cannot update sect %s", sname); #endif if ((sdata = elf_getdata(sscn, NULL)) == NULL) elfterminate(srcname, "Cannot get sect %s data", sname); if ((ddata = elf_newdata(dscn)) == NULL) elfterminate(dstname, "Can't make sect %s data", sname); #ifdef illumos bcopy(sdata, ddata, sizeof (Elf_Data)); #else /* * FreeBSD's Elf_Data has private fields which the * elf_* routines manage. Simply copying the * entire structure corrupts the data. So we need * to copy the public fields explictly. */ ddata->d_align = sdata->d_align; ddata->d_off = sdata->d_off; ddata->d_size = sdata->d_size; ddata->d_type = sdata->d_type; ddata->d_version = sdata->d_version; #endif if (srcidx == sehdr.e_shstrndx) { char seclen = strlen(CTF_ELF_SCN_NAME); ddata->d_buf = xmalloc(ddata->d_size + shdr.sh_size + seclen + 1); bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size); strcpy((caddr_t)ddata->d_buf + shdr.sh_size, CTF_ELF_SCN_NAME); ctfnameoff = (off_t)shdr.sh_size; shdr.sh_size += seclen + 1; ddata->d_size += seclen + 1; if (sehdr.e_phnum != 0) changing = 1; } if (shdr.sh_type == symtab_type && shdr.sh_entsize != 0) { int nsym = shdr.sh_size / shdr.sh_entsize; symtab_idx = secxlate[srcidx]; ddata->d_buf = xmalloc(shdr.sh_size); bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size); for (i = 0; i < nsym; i++) { GElf_Sym sym; short newscn; if (gelf_getsym(ddata, i, &sym) == NULL) printf("Could not get symbol %d\n",i); if (sym.st_shndx >= SHN_LORESERVE) continue; if ((newscn = secxlate[sym.st_shndx]) != sym.st_shndx) { sym.st_shndx = (newscn == -1 ? 1 : newscn); gelf_update_sym(ddata, i, &sym); } } } #ifndef illumos if (ddata->d_buf == NULL && sdata->d_buf != NULL) { ddata->d_buf = xmalloc(shdr.sh_size); bcopy(sdata->d_buf, ddata->d_buf, shdr.sh_size); } #endif if (gelf_update_shdr(dscn, &shdr) == 0) elfterminate(dstname, "Cannot update sect %s", sname); new_offset = (off_t)shdr.sh_offset; if (shdr.sh_type != SHT_NOBITS) new_offset += shdr.sh_size; } if (symtab_idx == -1) { terminate("%s: Cannot find %s section\n", srcname, dynsym ? "SHT_DYNSYM" : "SHT_SYMTAB"); } /* Add the ctf section */ dscn = elf_newscn(dst); gelf_getshdr(dscn, &shdr); shdr.sh_name = ctfnameoff; shdr.sh_type = SHT_PROGBITS; shdr.sh_size = ctfsize; shdr.sh_link = symtab_idx; shdr.sh_addralign = 4; if (changing && sehdr.e_phnum != 0) { pad = new_offset % shdr.sh_addralign; if (pad) new_offset += shdr.sh_addralign - pad; shdr.sh_offset = new_offset; new_offset += shdr.sh_size; } ddata = elf_newdata(dscn); ddata->d_buf = ctfdata; ddata->d_size = ctfsize; ddata->d_align = shdr.sh_addralign; ddata->d_off = 0; gelf_update_shdr(dscn, &shdr); /* update the section header location */ if (sehdr.e_phnum != 0) { size_t align = gelf_fsize(dst, ELF_T_ADDR, 1, EV_CURRENT); size_t r = new_offset % align; if (r) new_offset += align - r; dehdr.e_shoff = new_offset; } /* commit to disk */ dehdr.e_shstrndx = secxlate[sehdr.e_shstrndx]; gelf_update_ehdr(dst, &dehdr); if (elf_update(dst, ELF_C_WRITE) < 0) elfterminate(dstname, "Cannot finalize temp file"); free(secxlate); } static caddr_t make_ctf_data(tdata_t *td, Elf *elf, const char *file, size_t *lenp, int flags) { iiburst_t *iiburst; caddr_t data; iiburst = sort_iidescs(elf, file, td, flags & CTF_FUZZY_MATCH, flags & CTF_USE_DYNSYM); data = ctf_gen(iiburst, lenp, flags & (CTF_COMPRESS | CTF_SWAP_BYTES)); iiburst_free(iiburst); return (data); } void write_ctf(tdata_t *td, const char *curname, const char *newname, int flags) { struct stat st; Elf *elf = NULL; Elf *telf = NULL; GElf_Ehdr ehdr; caddr_t data; size_t len; int fd = -1; int tfd = -1; int byteorder; (void) elf_version(EV_CURRENT); if ((fd = open(curname, O_RDONLY)) < 0 || fstat(fd, &st) < 0) terminate("%s: Cannot open for re-reading", curname); if ((elf = elf_begin(fd, ELF_C_READ, NULL)) == NULL) elfterminate(curname, "Cannot re-read"); if ((tfd = open(newname, O_RDWR | O_CREAT | O_TRUNC, st.st_mode)) < 0) terminate("Cannot open temp file %s for writing", newname); if ((telf = elf_begin(tfd, ELF_C_WRITE, NULL)) == NULL) elfterminate(curname, "Cannot write"); if (gelf_getehdr(elf, &ehdr)) { #if BYTE_ORDER == _BIG_ENDIAN byteorder = ELFDATA2MSB; #else byteorder = ELFDATA2LSB; #endif /* * If target and host has the same byte order * clear byte swapping request */ if (ehdr.e_ident[EI_DATA] == byteorder) flags &= ~CTF_SWAP_BYTES; } else elfterminate(curname, "Failed to get EHDR"); data = make_ctf_data(td, elf, curname, &len, flags); write_file(elf, curname, telf, newname, data, len, flags); free(data); elf_end(telf); elf_end(elf); (void) close(fd); (void) close(tfd); }