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nlist.c revision 1.5 
      1 /*	$NetBSD: nlist.c,v 1.5 1995/02/27 04:35:29 cgd Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #if defined(LIBC_SCCS) && !defined(lint)
     37 #if 0
     38 static char sccsid[] = "@(#)nlist.c	8.1 (Berkeley) 6/4/93";
     39 #else
     40 static char rcsid[] = "$NetBSD: nlist.c,v 1.5 1995/02/27 04:35:29 cgd Exp $";
     41 #endif
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include <sys/param.h>
     45 #include <sys/mman.h>
     46 #include <sys/stat.h>
     47 #include <sys/file.h>
     48 
     49 #include <errno.h>
     50 #include <a.out.h>
     51 #include <stdio.h>
     52 #include <string.h>
     53 #include <unistd.h>
     54 
     55 int
     56 nlist(name, list)
     57 	const char *name;
     58 	struct nlist *list;
     59 {
     60 	int fd, n;
     61 
     62 	fd = open(name, O_RDONLY, 0);
     63 	if (fd < 0)
     64 		return (-1);
     65 	n = __fdnlist(fd, list);
     66 	(void)close(fd);
     67 	return (n);
     68 }
     69 
     70 #define	ISLAST(p)	(p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
     71 
     72 int
     73 __fdnlist(fd, list)
     74 	register int fd;
     75 	register struct nlist *list;
     76 {
     77 	register struct nlist *p, *s;
     78 	register caddr_t strtab;
     79 	register off_t stroff, symoff;
     80 	register u_long symsize;
     81 	register int nent, cc;
     82 	size_t strsize;
     83 	struct nlist nbuf[1024];
     84 	struct exec exec;
     85 	struct stat st;
     86 
     87 	if (lseek(fd, (off_t)0, SEEK_SET) == -1 ||
     88 	    read(fd, &exec, sizeof(exec)) != sizeof(exec) ||
     89 	    N_BADMAG(exec) || fstat(fd, &st) < 0)
     90 		return (-1);
     91 
     92 	symoff = N_SYMOFF(exec);
     93 	symsize = exec.a_syms;
     94 	stroff = symoff + symsize;
     95 
     96 	/* Check for files too large to mmap. */
     97 	if (st.st_size - stroff > SIZE_T_MAX) {
     98 		errno = EFBIG;
     99 		return (-1);
    100 	}
    101 	/*
    102 	 * Map string table into our address space.  This gives us
    103 	 * an easy way to randomly access all the strings, without
    104 	 * making the memory allocation permanent as with malloc/free
    105 	 * (i.e., munmap will return it to the system).
    106 	 */
    107 	strsize = st.st_size - stroff;
    108 	strtab = mmap(NULL, (size_t)strsize, PROT_READ, 0, fd, stroff);
    109 	if (strtab == (char *)-1)
    110 		return (-1);
    111 	/*
    112 	 * clean out any left-over information for all valid entries.
    113 	 * Type and value defined to be 0 if not found; historical
    114 	 * versions cleared other and desc as well.  Also figure out
    115 	 * the largest string length so don't read any more of the
    116 	 * string table than we have to.
    117 	 *
    118 	 * XXX clearing anything other than n_type and n_value violates
    119 	 * the semantics given in the man page.
    120 	 */
    121 	nent = 0;
    122 	for (p = list; !ISLAST(p); ++p) {
    123 		p->n_type = 0;
    124 		p->n_other = 0;
    125 		p->n_desc = 0;
    126 		p->n_value = 0;
    127 		++nent;
    128 	}
    129 	if (lseek(fd, symoff, SEEK_SET) == -1)
    130 		return (-1);
    131 
    132 	while (symsize > 0) {
    133 		cc = MIN(symsize, sizeof(nbuf));
    134 		if (read(fd, nbuf, cc) != cc)
    135 			break;
    136 		symsize -= cc;
    137 		for (s = nbuf; cc > 0; ++s, cc -= sizeof(*s)) {
    138 			register int soff = s->n_un.n_strx;
    139 
    140 			if (soff == 0 || (s->n_type & N_STAB) != 0)
    141 				continue;
    142 			for (p = list; !ISLAST(p); p++)
    143 				if (!strcmp(&strtab[soff], p->n_un.n_name)) {
    144 					p->n_value = s->n_value;
    145 					p->n_type = s->n_type;
    146 					p->n_desc = s->n_desc;
    147 					p->n_other = s->n_other;
    148 					if (--nent <= 0)
    149 						break;
    150 				}
    151 		}
    152 	}
    153 	munmap(strtab, strsize);
    154 	return (nent);
    155 }
    156