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add unveil(2) to ctfconv(1)

Once we know what the input file is, usually /bsd.gdb, we can unveil it in read
mode. If we also define as argument an output file we can additionally unveil
that one with write/create permissions.

We don't need to care about calling unveil(NULL, NULL) since we can call
pledge(2) and reduce the permissions down the road depending on the code path.

"reads OK" jasper@, "put it in if works" mpi@
prodded by deraadt@

/*	$OpenBSD: ctfconv.c,v 1.17 2018/08/08 20:15:17 mestre Exp $ */

/*
 * Copyright (c) 2016-2017 Martin Pieuchot
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/queue.h>
#include <sys/tree.h>
#include <sys/ctf.h>

#include <assert.h>
#include <elf.h>
#include <err.h>
#include <fcntl.h>
#include <locale.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "itype.h"
#include "xmalloc.h"

#ifndef nitems
#define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
#endif

#define DEBUG_ABBREV	".debug_abbrev"
#define DEBUG_INFO	".debug_info"
#define DEBUG_LINE	".debug_line"
#define DEBUG_STR	".debug_str"

__dead void	 usage(void);
int		 convert(const char *);
int		 generate(const char *, const char *, int);
int		 elf_convert(char *, size_t);
void		 elf_sort(void);
struct itype	*find_symb(struct itype *, size_t);
void		 dump_type(struct itype *);
void		 dump_func(struct itype *, int *);
void		 dump_obj(struct itype *, int *);

/* elf.c */
int		 iself(const char *, size_t);
int		 elf_getshstab(const char *, size_t, const char **, size_t *);
ssize_t		 elf_getsymtab(const char *, size_t, const char *, size_t,
		     const Elf_Sym **, size_t *, const char **, size_t *);
ssize_t		 elf_getsection(char *, size_t, const char *, const char *,
		     size_t, const char **, size_t *);

/* parse.c */
void		 dwarf_parse(const char *, size_t, const char *, size_t);

const char	*ctf_enc2name(unsigned short);

/* lists of parsed types and functions */
struct itype_queue itypeq = TAILQ_HEAD_INITIALIZER(itypeq);
struct itype_queue ifuncq = TAILQ_HEAD_INITIALIZER(ifuncq);
struct itype_queue iobjq = TAILQ_HEAD_INITIALIZER(iobjq);

__dead void
usage(void)
{
	fprintf(stderr, "usage: %s [-d] -l label -o outfile file\n",
	    getprogname());
	exit(1);
}

int
main(int argc, char *argv[])
{
	const char *filename, *label = NULL, *outfile = NULL;
	int dump = 0;
	int ch, error = 0;
	struct itype *it;

	setlocale(LC_ALL, "");

	while ((ch = getopt(argc, argv, "dl:o:")) != -1) {
		switch (ch) {
		case 'd':
			dump = 1;	/* ctfdump(1)-like SUNW_ctf sections */
			break;
		case 'l':
			if (label != NULL)
				usage();
			label = optarg;
			break;
		case 'o':
			if (outfile != NULL)
				usage();
			outfile = optarg;
			break;
		default:
			usage();
		}
	}

	argc -= optind;
	argv += optind;

	if (argc != 1)
		usage();

	/* Either dump the sections, or write it out. */
	if ((dump && (outfile != NULL || label != NULL)) ||
	    (!dump && (outfile == NULL || label == NULL)))
		usage();

	filename = *argv;

	if (unveil(filename, "r") == -1)
		err(1, "unveil");

	if (outfile != NULL) {
		if (unveil(outfile, "wc") == -1)
			err(1, "unveil");
	}

	if (pledge("stdio rpath wpath cpath", NULL) == -1)
		err(1, "pledge");

	error = convert(filename);
	if (error != 0)
		return error;

	if (outfile != NULL) {
		if (pledge("stdio wpath cpath", NULL) == -1)
			err(1, "pledge");

		error = generate(outfile, label, 1);
		if (error != 0)
			return error;
	}

	if (dump) {
		if (pledge("stdio", NULL) == -1)
			err(1, "pledge");

		int fidx = -1, oidx = -1;

		TAILQ_FOREACH(it, &iobjq, it_symb)
			dump_obj(it, &oidx);
		printf("\n");

		TAILQ_FOREACH(it, &ifuncq, it_symb)
			dump_func(it, &fidx);
		printf("\n");

		TAILQ_FOREACH(it, &itypeq, it_next) {
			if (it->it_flags & (ITF_FUNC|ITF_OBJ))
				continue;

			dump_type(it);
		}

		return 0;
	}

	return 0;
}

int
convert(const char *path)
{
	struct stat		 st;
	int			 fd, error = 1;
	char			*p;

	fd = open(path, O_RDONLY);
	if (fd == -1) {
		warn("open %s", path);
		return 1;
	}
	if (fstat(fd, &st) == -1) {
		warn("fstat %s", path);
		close(fd);
		return 1;
	}
	if ((uintmax_t)st.st_size > SIZE_MAX) {
		warnx("file too big to fit memory");
		close(fd);
		return 1;
	}

	p = mmap(NULL, st.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
	if (p == MAP_FAILED)
		err(1, "mmap");

	if (iself(p, st.st_size))
		error = elf_convert(p, st.st_size);

	munmap(p, st.st_size);
	close(fd);

	return error;
}

const char		*dstrbuf;
size_t			 dstrlen;
const char		*strtab;
const Elf_Sym		*symtab;
size_t			 strtabsz, nsymb;

int
elf_convert(char *p, size_t filesize)
{
	const char		*shstab;
	const char		*infobuf, *abbuf;
	size_t			 infolen, ablen;
	size_t			 shstabsz;

	/* Find section header string table location and size. */
	if (elf_getshstab(p, filesize, &shstab, &shstabsz))
		return 1;

	/* Find symbol table and associated string table. */
	if (elf_getsymtab(p, filesize, shstab, shstabsz, &symtab, &nsymb,
	    &strtab, &strtabsz) == -1)
		warnx("symbol table not found");

	/* Find abbreviation location and size. */
	if (elf_getsection(p, filesize, DEBUG_ABBREV, shstab, shstabsz, &abbuf,
	    &ablen) == -1) {
		warnx("%s section not found", DEBUG_ABBREV);
		return 1;
	}

	if (elf_getsection(p, filesize, DEBUG_INFO, shstab, shstabsz, &infobuf,
	    &infolen) == -1) {
		warnx("%s section not found", DEBUG_INFO);
		return 1;
	}

	/* Find string table location and size. */
	if (elf_getsection(p, filesize, DEBUG_STR, shstab, shstabsz, &dstrbuf,
	    &dstrlen) == -1)
		warnx("%s section not found", DEBUG_STR);

	dwarf_parse(infobuf, infolen, abbuf, ablen);

	/* Sort functions */
	elf_sort();

	return 0;
}

struct itype *
find_symb(struct itype *tmp, size_t stroff)
{
	struct itype		*it;
	char 			*sname, *p;

	if (strtab == NULL || stroff >= strtabsz)
		return NULL;

	/*
	 * Skip local suffix
	 *
	 * FIXME: only skip local copies.
	 */
	sname = xstrdup(strtab + stroff);
	if ((p = strtok(sname, ".")) == NULL) {
		free(sname);
		return NULL;
	}

	strlcpy(tmp->it_name, p, ITNAME_MAX);
	free(sname);
	it = RB_FIND(isymb_tree, &isymbt, tmp);

	/* Restore original name */
	if (it == NULL)
		strlcpy(tmp->it_name, (strtab + stroff), ITNAME_MAX);

	return it;
}

void
elf_sort(void)
{
	struct itype		*it, tmp;
	size_t			 i;

	memset(&tmp, 0, sizeof(tmp));
	for (i = 0; i < nsymb; i++) {
		const Elf_Sym	*st = &symtab[i];

		if (st->st_shndx == SHN_UNDEF || st->st_shndx == SHN_COMMON)
			continue;

		switch (ELF_ST_TYPE(st->st_info)) {
		case STT_FUNC:
			tmp.it_flags = ITF_FUNC;
			break;
		case STT_OBJECT:
			tmp.it_flags = ITF_OBJ;
			break;
		default:
			continue;
		}

		it = find_symb(&tmp, st->st_name);
		if (it == NULL) {
			/* Insert 'unknown' entry to match symbol order. */
			it = it_dup(&tmp);
			it->it_refp = it;
#ifdef DEBUG
			warnx("symbol not found: %s", it_name(it));
#endif
		}

		if (it->it_flags & ITF_INSERTED) {
#ifdef DEBUG
			warnx("%s: already inserted", it_name(it));
#endif
			it = it_dup(it);
		}

		/* Save symbol index for dump. */
		it->it_ref = i;

		it->it_flags |= ITF_INSERTED;
		if (it->it_flags & ITF_FUNC)
			TAILQ_INSERT_TAIL(&ifuncq, it, it_symb);
		else
			TAILQ_INSERT_TAIL(&iobjq, it, it_symb);
	}
}

const char *
type_name(struct itype *it)
{
	const char *name;

	name = it_name(it);
	if (name == NULL)
		return "(anon)";

	return name;
}

/* Display parsed types a la ctfdump(1) */
void
dump_type(struct itype *it)
{
	struct imember *im;

#ifdef DEBUG
	switch (it->it_type) {
	case CTF_K_POINTER:
	case CTF_K_TYPEDEF:
	case CTF_K_VOLATILE:
	case CTF_K_CONST:
	case CTF_K_RESTRICT:
	case CTF_K_ARRAY:
	case CTF_K_FUNCTION:
		if (it->it_refp == NULL) {
			printf("unresolved: %s type=%d\n", it_name(it),
			    it->it_type);
			return;
		}
	default:
		break;
	}
#endif

	switch (it->it_type) {
	case CTF_K_FLOAT:
	case CTF_K_INTEGER:
		printf("  [%u] %s %s encoding=%s offset=0 bits=%u\n",
		    it->it_idx,
		    (it->it_type == CTF_K_INTEGER) ? "INTEGER" : "FLOAT",
		    it_name(it), ctf_enc2name(it->it_enc), it->it_size);
		break;
	case CTF_K_POINTER:
		printf("  <%u> POINTER %s refers to %u\n", it->it_idx,
		    type_name(it), it->it_refp->it_idx);
		break;
	case CTF_K_TYPEDEF:
		printf("  <%u> TYPEDEF %s refers to %u\n",
		    it->it_idx, it_name(it), it->it_refp->it_idx);
		break;
	case CTF_K_VOLATILE:
		printf("  <%u> VOLATILE %s refers to %u\n", it->it_idx,
		    type_name(it), it->it_refp->it_idx);
		break;
	case CTF_K_CONST:
		printf("  <%u> CONST %s refers to %u\n", it->it_idx,
		    type_name(it), it->it_refp->it_idx);
		break;
	case CTF_K_RESTRICT:
		printf("  <%u> RESTRICT %s refers to %u\n", it->it_idx,
		    it_name(it), it->it_refp->it_idx);
		break;
	case CTF_K_ARRAY:
		printf("  [%u] ARRAY %s content: %u index: %u nelems: %u\n",
		    it->it_idx, type_name(it), it->it_refp->it_idx, long_tidx,
		    it->it_nelems);
		printf("\n");
		break;
	case CTF_K_STRUCT:
	case CTF_K_UNION:
		printf("  [%u] %s %s (%u bytes)\n", it->it_idx,
		    (it->it_type == CTF_K_STRUCT) ? "STRUCT" : "UNION",
		    type_name(it), it->it_size);
		TAILQ_FOREACH(im, &it->it_members, im_next) {
			printf("\t%s type=%u off=%zu\n",
			    (im_name(im) == NULL) ? "unknown" : im_name(im),
			    im->im_refp ? im->im_refp->it_idx : 0, im->im_off);
		}
		printf("\n");
		break;
	case CTF_K_ENUM:
		printf("  [%u] ENUM %s\n", it->it_idx, type_name(it));
		TAILQ_FOREACH(im, &it->it_members, im_next) {
			printf("\t%s = %zu\n", im_name(im), im->im_ref);
		}
		printf("\n");
		break;
	case CTF_K_FUNCTION:
		printf("  [%u] FUNCTION (%s) returns: %u args: (",
		    it->it_idx, (it_name(it) != NULL) ? it_name(it) : "anon",
		    it->it_refp->it_idx);
		TAILQ_FOREACH(im, &it->it_members, im_next) {
			printf("%u%s", im->im_refp->it_idx,
			    TAILQ_NEXT(im, im_next) ? ", " : "");
		}
		printf(")\n");
		break;
	default:
		assert(0 == 1);
	}
}

void
dump_func(struct itype *it, int *idx)
{
	struct imember *im;

	(*idx)++;

	if (it->it_type == CTF_K_UNKNOWN && it->it_nelems == 0)
		return;

	printf("  [%u] FUNC (%s) returns: %u args: (", (*idx),
	    (it_name(it) != NULL) ? it_name(it) : "unknown",
	    it->it_refp->it_idx);
	TAILQ_FOREACH(im, &it->it_members, im_next) {
		printf("%u%s", im->im_refp->it_idx,
		    TAILQ_NEXT(im, im_next) ? ", " : "");
	}
	printf(")\n");
}

void
dump_obj(struct itype *it, int *idx)
{
	int l;

	(*idx)++;

	l = printf("  [%u] %u", (*idx), it->it_refp->it_idx);
	printf("%*s %s (%llu)\n", 14 - l, "", it_name(it), it->it_ref);
}

const char *
ctf_enc2name(unsigned short enc)
{
	static const char *enc_name[] = { "SIGNED", "CHAR", "SIGNED CHAR",
	    "BOOL", "SIGNED BOOL" };
	static char invalid[7];

	if (enc == CTF_INT_VARARGS)
		return "VARARGS";

	if (enc > 0 && enc < nitems(enc_name))
		return enc_name[enc - 1];

	snprintf(invalid, sizeof(invalid), "0x%x", enc);
	return invalid;
}