freebsd-skq/lib/libc/gen/nlist.c
csgr a22e08d763 Rewrite nlist to mmap the whole a.out file (at Davidg's suggestion).
This means that we don't have to do rounding calculations for page
boundaries.  (We do all our accesses via the mmapped area now.)
Reviewed by:
1994-07-22 12:22:51 +00:00

161 lines
4.8 KiB
C

/*
* Copyright (c) 1989, 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)nlist.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <errno.h>
#include <a.out.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
int
nlist(name, list)
const char *name;
struct nlist *list;
{
int fd, n;
fd = open(name, O_RDONLY, 0);
if (fd < 0)
return (-1);
n = __fdnlist(fd, list);
(void)close(fd);
return (n);
}
#define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
int
__fdnlist(fd, list)
register int fd;
register struct nlist *list;
{
register struct nlist *p, *symtab;
register caddr_t strtab, a_out_mmap;
register off_t stroff, symoff;
register u_long symsize;
register int nent;
size_t strsize;
struct nlist nbuf[1024];
struct exec * exec;
struct stat st;
/* check that file is at least as large as struct exec! */
if ((fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec)))
return (-1);
/* Check for files too large to mmap. */
if (st.st_size > SIZE_T_MAX) {
errno = EFBIG;
return (-1);
}
/*
* Map the whole a.out file into our address space.
* We then find the string table withing this area.
* We do not just mmap the string table, as it probably
* does not start at a page boundary - we save ourselves a
* lot of nastiness by mmapping the whole file.
*
* This gives us an easy way to randomly access all the strings,
* without making the memory allocation permanent as with
* malloc/free (i.e., munmap will return it to the system).
*/
a_out_mmap = mmap(NULL, (size_t)st.st_size, PROT_READ, 0, fd, (off_t)0);
if (a_out_mmap == (char *)-1)
return (-1);
exec = (struct exec *)a_out_mmap;
if (N_BADMAG(*exec)) {
munmap(a_out_mmap, (size_t)st.st_size);
return (-1);
}
symoff = N_SYMOFF(*exec);
symsize = exec->a_syms;
stroff = symoff + symsize;
/* find the string table in our mmapped area */
strtab = a_out_mmap + stroff;
symtab = (struct nlist *)(a_out_mmap + symoff);
/*
* clean out any left-over information for all valid entries.
* Type and value defined to be 0 if not found; historical
* versions cleared other and desc as well. Also figure out
* the largest string length so don't read any more of the
* string table than we have to.
*
* XXX clearing anything other than n_type and n_value violates
* the semantics given in the man page.
*/
nent = 0;
for (p = list; !ISLAST(p); ++p) {
p->n_type = 0;
p->n_other = 0;
p->n_desc = 0;
p->n_value = 0;
++nent;
}
while (symsize > 0) {
register int soff;
symsize-= sizeof(struct nlist);
soff = symtab->n_un.n_strx;
if (soff != 0 && (symtab->n_type & N_STAB) == 0)
for (p = list; !ISLAST(p); p++)
if (!strcmp(&strtab[soff], p->n_un.n_name)) {
p->n_value = symtab->n_value;
p->n_type = symtab->n_type;
p->n_desc = symtab->n_desc;
p->n_other = symtab->n_other;
if (--nent <= 0)
break;
}
symtab++;
}
munmap(a_out_mmap, (size_t)st.st_size);
return (nent);
}