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Remove a.out support from nlist()
Some libc libraries do not have an <a.out.h> header. And a.out as an executable format is very much obsolete on pretty much all currently supported systems, even if they might still support loading such objects. Remove the a.out support to increase portability.
This commit is contained in:
Guillem Jover
parent
7aede6a999
commit
e8d340de9e
@ -29,11 +29,64 @@
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#include <sys/cdefs.h>
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#if __has_include(<a.out.h>)
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#include <a.out.h>
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#elif __has_include(<linux/a.out.h>)
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#include <linux/a.out.h>
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#endif
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struct nlist {
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union {
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char *n_name;
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struct n_list *n_next;
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long n_strx;
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} n_un;
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unsigned char n_type;
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char n_other;
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short n_desc;
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unsigned long n_value;
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};
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#define n_hash n_desc /* used internally by ld(1); XXX */
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/*
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* Defines for n_type.
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*/
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#define N_UNDF 0x00 /* Undefined */
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#define N_ABS 0x02 /* Absolute address */
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#define N_TEXT 0x04 /* Text segment */
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#define N_DATA 0x06 /* Data segment */
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#define N_BSS 0x08 /* Bss segment */
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#define N_INDR 0x0a /* Alias definition */
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#define N_SIZE 0x0c /* Pseudo type, defines a symbol's size */
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#define N_COMM 0x12 /* Common reference */
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/* GNU extensions */
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#define N_SETA 0x14 /* Absolute set element symbol */
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#define N_SETT 0x16 /* Text set element symbol */
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#define N_SETD 0x18 /* Data set element symbol */
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#define N_SETB 0x1a /* Bss set element symbol */
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#define N_SETV 0x1c /* Set vector symbol */
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/* end GNU extensions */
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#define N_FN 0x1e /* File name (N_EXT on) */
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#define N_WARN 0x1e /* Warning message (N_EXT off) */
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#define N_EXT 0x01 /* External (global) bit, OR'ed in */
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#define N_TYPE 0x1e /* Mask for all the type bits */
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#define N_STAB 0xe0 /* Mask for debugger symbols -- stab(5) */
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#define N_NAME(p) ((p)->n_un.n_name)
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/*
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* Defines for n_other. It contains the ".type" (AUX) field in the least
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* significant 4 bits, and the binding (for weak symbols) in the most
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* significant 4 bits.
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*/
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#define N_AUX(p) ((p)->n_other & 0xf)
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#define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf)
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#define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf))
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#define AUX_OBJECT 1 /* Data object */
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#define AUX_FUNC 2 /* Function */
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/*#define BIND_LOCAL 0 Not used */
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/*#define BIND_GLOBAL 1 Not used */
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#define BIND_WEAK 2 /* Weak binding */
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#define N_FORMAT "%08x" /* namelist value format; XXX */
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__BEGIN_DECLS
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extern int nlist(const char *filename, struct nlist *list);
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247
src/nlist.c
247
src/nlist.c
@ -10,7 +10,7 @@
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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@ -27,186 +27,29 @@
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)nlist.c 8.1 (Berkeley) 6/4/93";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/file.h>
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#include <arpa/inet.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <a.out.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <nlist.h>
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#if !defined(__NO_A_OUT_SUPPORT)
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#define _NLIST_DO_AOUT
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#endif
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#define _NLIST_DO_ELF
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#ifdef _NLIST_DO_ELF
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#include "local-elf.h"
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#endif
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#define SIZE_T_MAX 0xffffffffU
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#ifdef _NLIST_DO_AOUT
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static int __aout_fdnlist(int, struct nlist *);
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#ifndef N_SYMSIZE
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#define N_SYMSIZE(a) ((a).a_syms)
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#endif
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#endif
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#ifdef _NLIST_DO_ELF
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static int __elf_fdnlist(int, struct nlist *);
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#endif
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/* FIXME: This function is used by libkvm0, so we need to export it.
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It is not declared in the include files though. */
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/* Note: This function is used by libkvm0, so we need to export it.
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* It is not declared in the include files though. */
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int __fdnlist(int, struct nlist *);
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int
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nlist(const char *name, struct nlist *list)
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{
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int fd, n;
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fd = open(name, O_RDONLY, 0);
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if (fd < 0)
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return (-1);
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n = __fdnlist(fd, list);
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(void)close(fd);
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return (n);
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}
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static struct nlist_handlers {
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int (*fn)(int fd, struct nlist *list);
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} nlist_fn[] = {
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#ifdef _NLIST_DO_AOUT
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{ __aout_fdnlist },
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#endif
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#ifdef _NLIST_DO_ELF
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{ __elf_fdnlist },
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#endif
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};
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int
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__fdnlist(int fd, struct nlist *list)
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{
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size_t i;
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int n = -1;
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for (i = 0; i < sizeof(nlist_fn) / sizeof(nlist_fn[0]); i++) {
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n = (nlist_fn[i].fn)(fd, list);
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if (n != -1)
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break;
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}
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return (n);
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}
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#define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
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#ifdef _NLIST_DO_AOUT
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static int
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__aout_fdnlist(int fd, struct nlist *list)
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{
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struct nlist *p, *symtab;
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caddr_t strtab, a_out_mmap;
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off_t stroff, symoff;
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unsigned long symsize;
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int nent;
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struct exec * exec;
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struct stat st;
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/* check that file is at least as large as struct exec! */
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if ((fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec)))
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return (-1);
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/* Check for files too large to mmap. */
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if (st.st_size > SIZE_T_MAX) {
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errno = EFBIG;
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return (-1);
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}
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/*
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* Map the whole a.out file into our address space.
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* We then find the string table within this area.
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* We do not just mmap the string table, as it probably
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* does not start at a page boundary - we save ourselves a
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* lot of nastiness by mmapping the whole file.
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*
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* This gives us an easy way to randomly access all the strings,
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* without making the memory allocation permanent as with
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* malloc/free (i.e., munmap will return it to the system).
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*/
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a_out_mmap = mmap(NULL, (size_t)st.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0);
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if (a_out_mmap == MAP_FAILED)
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return (-1);
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exec = (struct exec *)a_out_mmap;
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if (N_BADMAG(*exec)) {
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munmap(a_out_mmap, (size_t)st.st_size);
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return (-1);
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}
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symoff = N_SYMOFF(*exec);
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symsize = N_SYMSIZE(*exec);
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stroff = symoff + symsize;
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/* find the string table in our mmapped area */
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strtab = a_out_mmap + stroff;
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symtab = (struct nlist *)(a_out_mmap + symoff);
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/*
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* clean out any left-over information for all valid entries.
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* Type and value defined to be 0 if not found; historical
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* versions cleared other and desc as well. Also figure out
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* the largest string length so don't read any more of the
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* string table than we have to.
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*
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* XXX clearing anything other than n_type and n_value violates
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* the semantics given in the man page.
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*/
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nent = 0;
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for (p = list; !ISLAST(p); ++p) {
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p->n_type = 0;
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p->n_other = 0;
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p->n_desc = 0;
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p->n_value = 0;
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++nent;
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}
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while (symsize > 0) {
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int soff;
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symsize-= sizeof(struct nlist);
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soff = symtab->n_un.n_strx;
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if (soff != 0 && (symtab->n_type & N_STAB) == 0)
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for (p = list; !ISLAST(p); p++)
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if (!strcmp(&strtab[soff], p->n_un.n_name)) {
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p->n_value = symtab->n_value;
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p->n_type = symtab->n_type;
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p->n_desc = symtab->n_desc;
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p->n_other = symtab->n_other;
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if (--nent <= 0)
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break;
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}
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symtab++;
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}
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munmap(a_out_mmap, (size_t)st.st_size);
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return (nent);
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}
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#endif
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#ifdef _NLIST_DO_ELF
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static void elf_sym_to_nlist(struct nlist *, Elf_Sym *, Elf_Shdr *, int);
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/*
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* __elf_is_okay__ - Determine if ehdr really
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* is ELF and valid for the target platform.
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@ -237,8 +80,44 @@ __elf_is_okay__(Elf_Ehdr *ehdr)
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return retval;
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}
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static int
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__elf_fdnlist(int fd, struct nlist *list)
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/*
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* Convert an Elf_Sym into an nlist structure. This fills in only the
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* n_value and n_type members.
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*/
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static void
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elf_sym_to_nlist(struct nlist *nl, Elf_Sym *s, Elf_Shdr *shdr, int shnum)
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{
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nl->n_value = s->st_value;
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switch (s->st_shndx) {
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case SHN_UNDEF:
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case SHN_COMMON:
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nl->n_type = N_UNDF;
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break;
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case SHN_ABS:
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nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ?
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N_FN : N_ABS;
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break;
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default:
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if (s->st_shndx >= shnum)
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nl->n_type = N_UNDF;
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else {
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Elf_Shdr *sh = shdr + s->st_shndx;
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nl->n_type = sh->sh_type == SHT_PROGBITS ?
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(sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) :
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(sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF);
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}
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break;
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}
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if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
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ELF_ST_BIND(s->st_info) == STB_WEAK)
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nl->n_type |= N_EXT;
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}
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int
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__fdnlist(int fd, struct nlist *list)
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{
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struct nlist *p;
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Elf_Off symoff = 0, symstroff = 0;
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@ -373,39 +252,15 @@ __elf_fdnlist(int fd, struct nlist *list)
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return (nent);
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}
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/*
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* Convert an Elf_Sym into an nlist structure. This fills in only the
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* n_value and n_type members.
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*/
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static void
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elf_sym_to_nlist(struct nlist *nl, Elf_Sym *s, Elf_Shdr *shdr, int shnum)
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int
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nlist(const char *name, struct nlist *list)
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{
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nl->n_value = s->st_value;
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int fd, n;
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switch (s->st_shndx) {
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case SHN_UNDEF:
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case SHN_COMMON:
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nl->n_type = N_UNDF;
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break;
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case SHN_ABS:
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nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ?
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N_FN : N_ABS;
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break;
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default:
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if (s->st_shndx >= shnum)
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nl->n_type = N_UNDF;
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else {
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Elf_Shdr *sh = shdr + s->st_shndx;
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nl->n_type = sh->sh_type == SHT_PROGBITS ?
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(sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) :
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(sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF);
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}
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break;
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}
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if (ELF_ST_BIND(s->st_info) == STB_GLOBAL ||
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ELF_ST_BIND(s->st_info) == STB_WEAK)
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nl->n_type |= N_EXT;
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fd = open(name, O_RDONLY, 0);
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if (fd < 0)
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return (-1);
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n = __fdnlist(fd, list);
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(void)close(fd);
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return (n);
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}
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#endif /* _NLIST_DO_ELF */
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