OpenBSD-4.6/usr.bin/gprof/aout.c

/*-
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

#include <sys/types.h>
#include <a.out.h>

#include "gprof.h"

static void getstrtab(FILE *, const char *);
static void getsymtab(FILE *, const char *);
static void gettextspace(FILE *);
static bool funcsymbol(struct nlist *);

static char	*strtab;		/* string table in core */
static long	ssiz;			/* size of the string table */
static struct	exec xbuf;		/* exec header of a.out */

/* Things which get -E excluded by default. */
static char	*excludes[] = { "mcount", "__mcleanup", NULL };

/*
 * Set up string and symbol tables from a.out.
 *	and optionally the text space.
 * On return symbol table is sorted by value.
 *
 * Returns 0 on success, -1 on failure.
 */
int
getnfile(const char *filename, char ***defaultEs)
{
	FILE	*nfile;

	nfile = fopen( filename ,"r");
	if (nfile == NULL)
		err(1, "fopen: %s", filename);

	fread(&xbuf, 1, sizeof(xbuf), nfile);
	if (N_BADMAG(xbuf)) {
		/* Bail out and let other binary formats try. */
		fclose(nfile);
		return (-1);
	}
	getstrtab(nfile, filename);
	getsymtab(nfile, filename);
	gettextspace(nfile);
	fclose(nfile);
#ifdef DEBUG
	if (debug & AOUTDEBUG) {
		int j;

		for (j = 0; j < nname; j++) {
			printf("[getnfile] 0X%08lx\t%s\n", nl[j].value,
			    nl[j].name);
		}
	}
#endif
    *defaultEs = excludes;
    return (0);
}

static void
getstrtab(FILE *nfile, const char *filename)
{
	fseek(nfile, (long)(N_SYMOFF(xbuf) + xbuf.a_syms), SEEK_SET);
	if (fread(&ssiz, sizeof (ssiz), 1, nfile) == 0)
		errx(1, "%s: no string table (old format?)" , filename );
	strtab = calloc(ssiz, 1);
	if (strtab == NULL)
		errx(1, "%s: no room for %d bytes of string table", filename,
		    ssiz);
	if (fread(strtab + sizeof(ssiz), ssiz - sizeof(ssiz), 1, nfile) != 1)
		errx(1, "%s: error reading string table", filename );
}

/*
 * Read in symbol table
 */
static void
getsymtab(FILE *nfile, const char *filename)
{
	struct nlist nbuf;
	int askfor;
	long i;

	/* pass1 - count symbols */
	fseek(nfile, (long)N_SYMOFF(xbuf), SEEK_SET);
	nname = 0;
	for (i = xbuf.a_syms; i > 0; i -= sizeof(struct nlist)) {
		fread(&nbuf, sizeof(nbuf), 1, nfile);
		if (funcsymbol(&nbuf))
			nname++;
	}
	if (nname == 0)
		errx(1, "%s: no symbols", filename);

	askfor = nname + 1;
	nl = calloc(askfor , sizeof(nltype));
	if (nl == 0)
		errx(1, "No room for %d bytes of symbol table",
		    askfor * sizeof(nltype));

	/* pass2 - read symbols */
	fseek(nfile, (long)N_SYMOFF(xbuf), SEEK_SET);
	npe = nl;
	nname = 0;
	for (i = xbuf.a_syms; i > 0; i -= sizeof(struct nlist)) {
		fread(&nbuf, sizeof(nbuf), 1, nfile);
		if (!funcsymbol(&nbuf)) {
#ifdef DEBUG
			if (debug & AOUTDEBUG) {
				printf("[getsymtab] rejecting: 0x%x %s\n",
				    nbuf.n_type, strtab + nbuf.n_un.n_strx);
			}
#endif
			continue;
		}
		npe->value = nbuf.n_value;
		npe->name = strtab + nbuf.n_un.n_strx;
#ifdef DEBUG
		if (debug & AOUTDEBUG) {
			printf("[getsymtab] %d %s 0x%08lx\n",
			    nname, npe->name, npe->value);
		}
#endif
		npe++;
		nname++;
	}
	npe->value = -1;
}

/*
 * read in the text space of an a.out file
 */
static void
gettextspace(FILE *nfile)
{
	if (cflag == 0)
		return;
	textspace = malloc(xbuf.a_text);
	if (textspace == 0) {
		warnx("ran out room for %d bytes of text space: can't do -c" ,
		  xbuf.a_text);
		return;
	}
	(void)fseek(nfile, N_TXTOFF(xbuf), SEEK_SET);
	if (fread(textspace, 1, xbuf.a_text, nfile) != xbuf.a_text ) {
		warnx("couldn't read text space: can't do -c");
		free(textspace);
		textspace = 0;
		return;
    	}
}

static bool
funcsymbol(struct nlist *nlistp)
{
	char *name, c;

	/*
	 *	must be a text symbol,
	 *	and static text symbols don't qualify if aflag set.
	 */
	if (!((nlistp->n_type == (N_TEXT|N_EXT))
	    || ((nlistp->n_type == N_TEXT) && (aflag == 0))))
		return FALSE;

	/*
	 *	name must start with an underscore if uflag is set.
	 *	can't have any `funny' characters in name,
	 *	where `funny' means `.' (.o file names)
	 *	need to make an exception for sparc .mul & co.
	 *	perhaps we should just drop this code entirely...
	 */
	name = strtab + nlistp -> n_un.n_strx;
#ifdef sparc
	if (nlistp -> n_value & 3)
		return (FALSE);
	if (*name == '.') {
		char *p = name + 1;
		if (*p == 'u')
			p++;
		if (strcmp(p, "mul") == 0 || strcmp(p, "div") == 0 ||
		    strcmp(p, "rem") == 0 )
			return (TRUE);
    	}
#endif
	while (c = *name++) {
		if (c == '.') {
			return (FALSE);
		}
	}

	return (TRUE);
}