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Support symbols in .tbss and .tdata ELF sections

With this change nm(1) prints the expected symbol type ('B' or 'D')
for variables in the .tbss and .tdata sections respectively, instead
of '?'.  This would be what binutils do for non-automatic variables
that are marked as thread-local with the __thread attribute in GCC.

help and ok miod@, guenther@

/*	$OpenBSD: elf.c,v 1.20 2011/09/28 19:58:14 uwe Exp $	*/

/*
 * Copyright (c) 2003 Michael Shalayeff
 * 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.
 *
 * 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 OR HIS RELATIVES 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 MIND, 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.
 */

#include <sys/param.h>
#include <sys/mman.h>
#include <unistd.h>
#include <a.out.h>
#include <elf_abi.h>
#include <errno.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "elfuncs.h"
#include "util.h"

#if ELFSIZE == 32
#define	swap_addr	swap32
#define	swap_off	swap32
#define	swap_sword	swap32
#define	swap_word	swap32
#define	swap_sxword	swap32
#define	swap_xword	swap32
#define	swap_half	swap16
#define	swap_quarter	swap16
#define	elf_fix_header	elf32_fix_header
#define	elf_load_shdrs	elf32_load_shdrs
#define	elf_load_phdrs	elf32_load_phdrs
#define	elf_fix_shdrs	elf32_fix_shdrs
#define	elf_fix_phdrs	elf32_fix_phdrs
#define	elf_fix_sym	elf32_fix_sym
#define	elf_size	elf32_size
#define	elf_symloadx	elf32_symloadx
#define	elf_symload	elf32_symload
#define	elf2nlist	elf32_2nlist
#define	elf_shn2type	elf32_shn2type
#elif ELFSIZE == 64
#define	swap_addr	swap64
#define	swap_off	swap64
#ifdef __alpha__
#define	swap_sword	swap64
#define	swap_word	swap64
#else
#define	swap_sword	swap32
#define	swap_word	swap32
#endif
#define	swap_sxword	swap64
#define	swap_xword	swap64
#define	swap_half	swap64
#define	swap_quarter	swap16
#define	elf_fix_header	elf64_fix_header
#define	elf_load_shdrs	elf64_load_shdrs
#define	elf_load_phdrs	elf64_load_phdrs
#define	elf_fix_shdrs	elf64_fix_shdrs
#define	elf_fix_phdrs	elf64_fix_phdrs
#define	elf_fix_sym	elf64_fix_sym
#define	elf_size	elf64_size
#define	elf_symloadx	elf64_symloadx
#define	elf_symload	elf64_symload
#define	elf2nlist	elf64_2nlist
#define	elf_shn2type	elf64_shn2type
#else
#error "Unsupported ELF class"
#endif

#define	ELF_SDATA	".sdata"
#define	ELF_TDATA	".tdata"
#define	ELF_SBSS	".sbss"
#define	ELF_TBSS	".tbss"
#define	ELF_PLT		".plt"

#ifndef	SHN_MIPS_ACOMMON
#define	SHN_MIPS_ACOMMON	SHN_LOPROC + 0
#endif
#ifndef	SHN_MIPS_TEXT
#define	SHN_MIPS_TEXT		SHN_LOPROC + 1
#endif
#ifndef	SHN_MIPS_DATA
#define	SHN_MIPS_DATA		SHN_LOPROC + 2
#endif
#ifndef	SHN_MIPS_SUNDEFINED
#define	SHN_MIPS_SUNDEFINED	SHN_LOPROC + 4
#endif
#ifndef	SHN_MIPS_SCOMMON
#define	SHN_MIPS_SCOMMON	SHN_LOPROC + 3
#endif

#ifndef	STT_PARISC_MILLI
#define	STT_PARISC_MILLI	STT_LOPROC + 0
#endif

int
elf_fix_header(Elf_Ehdr *eh)
{
	/* nothing to do */
	if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
		return (0);

	eh->e_type = swap16(eh->e_type);
	eh->e_machine = swap16(eh->e_machine);
	eh->e_version = swap32(eh->e_version);
	eh->e_entry = swap_addr(eh->e_entry);
	eh->e_phoff = swap_off(eh->e_phoff);
	eh->e_shoff = swap_off(eh->e_shoff);
	eh->e_flags = swap32(eh->e_flags);
	eh->e_ehsize = swap16(eh->e_ehsize);
	eh->e_phentsize = swap16(eh->e_phentsize);
	eh->e_phnum = swap16(eh->e_phnum);
	eh->e_shentsize = swap16(eh->e_shentsize);
	eh->e_shnum = swap16(eh->e_shnum);
	eh->e_shstrndx = swap16(eh->e_shstrndx);

	return (1);
}

Elf_Shdr *
elf_load_shdrs(const char *name, FILE *fp, off_t foff, Elf_Ehdr *head)
{
	Elf_Shdr *shdr;

	elf_fix_header(head);

	if ((shdr = calloc(head->e_shentsize, head->e_shnum)) == NULL) {
		warn("%s: malloc shdr", name);
		return (NULL);
	}

	if (fseeko(fp, foff + head->e_shoff, SEEK_SET)) {
		warn("%s: fseeko", name);
		free(shdr);
		return (NULL);
	}

	if (fread(shdr, head->e_shentsize, head->e_shnum, fp) != head->e_shnum) {
		warnx("%s: premature EOF", name);
		free(shdr);
		return (NULL);
	}

	elf_fix_shdrs(head, shdr);
	return (shdr);
}

Elf_Phdr *
elf_load_phdrs(const char *name, FILE *fp, off_t foff, Elf_Ehdr *head)
{
	Elf_Phdr *phdr;

	if ((phdr = calloc(head->e_phentsize, head->e_phnum)) == NULL) {
		warn("%s: malloc phdr", name);
		return (NULL);
	}

	if (fseeko(fp, foff + head->e_phoff, SEEK_SET)) {
		warn("%s: fseeko", name);
		free(phdr);
		return (NULL);
	}

	if (fread(phdr, head->e_phentsize, head->e_phnum, fp) != head->e_phnum) {
		warnx("%s: premature EOF", name);
		free(phdr);
		return (NULL);
	}

	elf_fix_phdrs(head, phdr);
	return (phdr);
}

int
elf_fix_shdrs(Elf_Ehdr *eh, Elf_Shdr *shdr)
{
	int i;

	/* nothing to do */
	if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
		return (0);

	for (i = eh->e_shnum; i--; shdr++) {
		shdr->sh_name = swap32(shdr->sh_name);
		shdr->sh_type = swap32(shdr->sh_type);
		shdr->sh_flags = swap_xword(shdr->sh_flags);
		shdr->sh_addr = swap_addr(shdr->sh_addr);
		shdr->sh_offset = swap_off(shdr->sh_offset);
		shdr->sh_size = swap_xword(shdr->sh_size);
		shdr->sh_link = swap32(shdr->sh_link);
		shdr->sh_info = swap32(shdr->sh_info);
		shdr->sh_addralign = swap_xword(shdr->sh_addralign);
		shdr->sh_entsize = swap_xword(shdr->sh_entsize);
	}

	return (1);
}

int
elf_fix_phdrs(Elf_Ehdr *eh, Elf_Phdr *phdr)
{
	int i;

	/* nothing to do */
	if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
		return (0);

	for (i = eh->e_phnum; i--; phdr++) {
		phdr->p_type = swap32(phdr->p_type);
		phdr->p_flags = swap32(phdr->p_flags);
		phdr->p_offset = swap_off(phdr->p_offset);
		phdr->p_vaddr = swap_addr(phdr->p_vaddr);
		phdr->p_paddr = swap_addr(phdr->p_paddr);
		phdr->p_filesz = swap_xword(phdr->p_filesz);
		phdr->p_memsz = swap_xword(phdr->p_memsz);
		phdr->p_align = swap_xword(phdr->p_align);
	}

	return (1);
}

int
elf_fix_sym(Elf_Ehdr *eh, Elf_Sym *sym)
{
	/* nothing to do */
	if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
		return (0);

	sym->st_name = swap32(sym->st_name);
	sym->st_shndx = swap16(sym->st_shndx);
	sym->st_value = swap_addr(sym->st_value);
	sym->st_size = swap_xword(sym->st_size);

	return (1);
}

int
elf_shn2type(Elf_Ehdr *eh, u_int shn, const char *sn)
{
	switch (shn) {
	case SHN_MIPS_SUNDEFINED:
		if (eh->e_machine == EM_MIPS)
			return (N_UNDF | N_EXT);
		break;

	case SHN_UNDEF:
		return (N_UNDF | N_EXT);

	case SHN_ABS:
		return (N_ABS);

	case SHN_MIPS_ACOMMON:
		if (eh->e_machine == EM_MIPS)
			return (N_COMM);
		break;

	case SHN_MIPS_SCOMMON:
		if (eh->e_machine == EM_MIPS)
			return (N_COMM);
		break;

	case SHN_COMMON:
		return (N_COMM);

	case SHN_MIPS_TEXT:
		if (eh->e_machine == EM_MIPS)
			return (N_TEXT);
		break;

	case SHN_MIPS_DATA:
		if (eh->e_machine == EM_MIPS)
			return (N_DATA);
		break;

	default:
		/* TODO: beyond 8 a table-driven binsearch should be used */
		if (sn == NULL)
			return (-1);
		else if (!strcmp(sn, ELF_TEXT))
			return (N_TEXT);
		else if (!strcmp(sn, ELF_RODATA))
			return (N_SIZE);
		else if (!strcmp(sn, ELF_DATA))
			return (N_DATA);
		else if (!strcmp(sn, ELF_SDATA))
			return (N_DATA);
		else if (!strcmp(sn, ELF_TDATA))
			return (N_DATA);
		else if (!strcmp(sn, ELF_BSS))
			return (N_BSS);
		else if (!strcmp(sn, ELF_SBSS))
			return (N_BSS);
		else if (!strcmp(sn, ELF_TBSS))
			return (N_BSS);
		else if (!strncmp(sn, ELF_GOT, sizeof(ELF_GOT) - 1))
			return (N_DATA);
		else if (!strncmp(sn, ELF_PLT, sizeof(ELF_PLT) - 1))
			return (N_DATA);
	}

	return (-1);
}

/*
 * Devise nlist's type from Elf_Sym.
 * XXX this task is done as well in libc and kvm_mkdb.
 */
int
elf2nlist(Elf_Sym *sym, Elf_Ehdr *eh, Elf_Shdr *shdr, char *shstr, struct nlist *np)
{
	u_char stt;
	const char *sn;
	int type;

	if (sym->st_shndx < eh->e_shnum)
		sn = shstr + shdr[sym->st_shndx].sh_name;
	else
		sn = NULL;
#if 0
	{
		extern char *stab;
		printf("%d:%s %d %s\n", sym->st_shndx, sn? sn : "",
		    ELF_ST_TYPE(sym->st_info), stab + sym->st_name);
	}
#endif

	switch (stt = ELF_ST_TYPE(sym->st_info)) {
	case STT_NOTYPE:
	case STT_OBJECT:
	case STT_TLS:
		type = elf_shn2type(eh, sym->st_shndx, sn);
		if (type < 0) {
			if (sn == NULL)
				np->n_other = '?';
			else
				np->n_type = stt == STT_NOTYPE? N_COMM : N_DATA;
		} else {
			/* a hack for .rodata check (; */
			if (type == N_SIZE) {
				np->n_type = N_DATA;
				np->n_other = 'r';
			} else
				np->n_type = type;
		}
		break;

	case STT_FUNC:
		type = elf_shn2type(eh, sym->st_shndx, NULL);
		np->n_type = type < 0? N_TEXT : type;
		if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
			np->n_type = N_INDR;
			np->n_other = 'W';
		} else if (sn != NULL && *sn != 0 &&
		    strcmp(sn, ELF_INIT) &&
		    strcmp(sn, ELF_TEXT) &&
		    strcmp(sn, ELF_FINI))	/* XXX GNU compat */
			np->n_other = '?';
		break;

	case STT_SECTION:
		type = elf_shn2type(eh, sym->st_shndx, NULL);
		if (type < 0)
			np->n_other = '?';
		else
			np->n_type = type;
		break;

	case STT_FILE:
		np->n_type = N_FN | N_EXT;
		break;

	case STT_PARISC_MILLI:
		if (eh->e_machine == EM_PARISC)
			np->n_type = N_TEXT;
		else
			np->n_other = '?';
		break;

	default:
		np->n_other = '?';
		break;
	}
	if (np->n_type != N_UNDF && ELF_ST_BIND(sym->st_info) != STB_LOCAL) {
		np->n_type |= N_EXT;
		if (np->n_other)
			np->n_other = toupper(np->n_other);
	}

	return (0);
}

int
elf_size(Elf_Ehdr *head, Elf_Shdr *shdr,
    u_long *ptext, u_long *pdata, u_long *pbss)
{
	int i;

	*ptext = *pdata = *pbss = 0;

	for (i = 0; i < head->e_shnum; i++) {
		if (!(shdr[i].sh_flags & SHF_ALLOC))
			;
		else if (shdr[i].sh_flags & SHF_EXECINSTR ||
		    !(shdr[i].sh_flags & SHF_WRITE))
			*ptext += shdr[i].sh_size;
		else if (shdr[i].sh_type == SHT_NOBITS)
			*pbss += shdr[i].sh_size;
		else
			*pdata += shdr[i].sh_size;
	}

	return (0);
}

int
elf_symloadx(const char *name, FILE *fp, off_t foff, Elf_Ehdr *eh,
    Elf_Shdr *shdr, char *shstr, struct nlist **pnames,
    struct nlist ***psnames, size_t *pstabsize, int *pnrawnames,
    const char *strtab, const char *symtab)
{
	long symsize;
	struct nlist *np;
	Elf_Sym sbuf;
	int i;

	for (i = 0; i < eh->e_shnum; i++) {
		if (!strcmp(shstr + shdr[i].sh_name, strtab)) {
			*pstabsize = shdr[i].sh_size;
			if (*pstabsize > SIZE_T_MAX) {
				warnx("%s: corrupt file", name);
				return (1);
			}

			MMAP(stab, *pstabsize, PROT_READ, MAP_PRIVATE|MAP_FILE,
			    fileno(fp), foff + shdr[i].sh_offset);
			if (stab == MAP_FAILED)
				return (1);
		}
	}
	for (i = 0; i < eh->e_shnum; i++) {
		if (!strcmp(shstr + shdr[i].sh_name, symtab)) {
			symsize = shdr[i].sh_size;
			if (fseeko(fp, foff + shdr[i].sh_offset, SEEK_SET)) {
				warn("%s: fseeko", name);
				if (stab)
					MUNMAP(stab, *pstabsize);
				return (1);
			}

			*pnrawnames = symsize / sizeof(sbuf);
			if ((*pnames = calloc(*pnrawnames, sizeof(*np))) == NULL) {
				warn("%s: malloc names", name);
				if (stab)
					MUNMAP(stab, *pstabsize);
				return (1);
			}
			if ((*psnames = calloc(*pnrawnames, sizeof(np))) == NULL) {
				warn("%s: malloc snames", name);
				if (stab)
					MUNMAP(stab, *pstabsize);
				free(*pnames);
				return (1);
			}

			for (np = *pnames; symsize > 0; symsize -= sizeof(sbuf)) {
				if (fread(&sbuf, 1, sizeof(sbuf),
				    fp) != sizeof(sbuf)) {
					warn("%s: read symbol", name);
					if (stab)
						MUNMAP(stab, *pstabsize);
					free(*pnames);
					free(*psnames);
					return (1);
				}

				elf_fix_sym(eh, &sbuf);

				if (!sbuf.st_name ||
				    sbuf.st_name > *pstabsize)
					continue;

				elf2nlist(&sbuf, eh, shdr, shstr, np);
				np->n_value = sbuf.st_value;
				np->n_un.n_strx = sbuf.st_name;
				np++;
			}
			*pnrawnames = np - *pnames;
		}
	}

}

int
elf_symload(const char *name, FILE *fp, off_t foff, Elf_Ehdr *eh,
    Elf_Shdr *shdr, struct nlist **pnames, struct nlist ***psnames,
    size_t *pstabsize, int *pnrawnames)
{
	long shstrsize;
	char *shstr;

	shstrsize = shdr[eh->e_shstrndx].sh_size;
	if (shstrsize == 0) {
		warnx("%s: no name list", name);
		return (1);
	}

	if ((shstr = malloc(shstrsize)) == NULL) {
		warn("%s: malloc shsrt", name);
		return (1);
	}

	if (fseeko(fp, foff + shdr[eh->e_shstrndx].sh_offset, SEEK_SET)) {
		warn("%s: fseeko", name);
		free(shstr);
		return (1);
	}

	if (fread(shstr, 1, shstrsize, fp) != shstrsize) {
		warnx("%s: premature EOF", name);
		free(shstr);
		return(1);
	}

	stab = NULL;
	*pnames = NULL; *psnames = NULL;
	elf_symloadx(name, fp, foff, eh, shdr, shstr, pnames,
	    psnames, pstabsize, pnrawnames, ELF_STRTAB, ELF_SYMTAB);
	if (stab == NULL) {
		elf_symloadx(name, fp, foff, eh, shdr, shstr, pnames,
		    psnames, pstabsize, pnrawnames, ELF_DYNSTR, ELF_DYNSYM);
	}

	free(shstr);
	if (stab == NULL) {
		warnx("%s: no name list", name);
		if (*pnames)
			free(*pnames);
		if (*psnames)
			free(*psnames);
		return (1);
	}

	return (0);
}