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/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/file.h>
#include <nlist.h>
#include <libelf.h>
/*
* EDSYM -- Edit the symbol table of a process or object module which uses
* the IRAF shared library. (Sun Solaris version July94).
*
* Usage: edsym file shimage [flags]
*
* -d debug: show symbol table being edited
* -k keep: do not omit "uninteresting" symbols
* -n noact: do not modify any files
* -t delete symbols pointing into transfer vector
* -T delete all shared image symbols, keeping only client symbols
*/
#define VHDRSIZE 0x1c
#define v_end vec[4]
#define IS_TVECT(a) ((a)>=(vshlib+VHDRSIZE)&&(a)<vshend)
#define max(a,b) (((a)>=(b))?(a):(b))
static int debug = 0; /* print symbol table */
static int noact = 0; /* do not modify any files */
static int omit_tv = 0; /* omit transfer vector symbols */
static int omit_shsym = 0; /* omit all shlib symbols */
static int keep_sym = 0; /* do not omit uninteresting symbols */
extern char *malloc();
/* EDSYM -- Edit the symbol table of a process which uses the IRAF shared
* library. For each symbol found which points to a location in the shared
* library transfer vector, add a V prefix to the symbol name, and add a
* symbol with the old name pointing to the actual function in the shared
* image. This is desirable before runtime debugging of processes linked
* with the shared library.
*/
main (argc, argv)
int argc;
char *argv[];
{
register Elf32_Phdr *phdr;
register Elf32_Ehdr *ehdr;
register Elf32_Shdr *shdr;
register Elf32_Sym *sym;
unsigned vshlib, vshend, vsize;
char *fname, *shlib, *buf, *ip, *op;
int version, fd, fd_sh, nsyms, arg;
char *out, shpath[256];
int offset, nbytes;
struct nlist nl[3];
unsigned ushlib[8];
unsigned *vec, *epa;
Elf *elf, *elf_sh;
Elf_Scn *scn;
/* Process arguments. This version of edsym does not support all of
* the following arguments.
*/
if (argc < 3) {
fprintf (stderr, "Usage: edsym <file> <shlib> [-dkntT]\n");
exit (0);
} else {
fname = argv[1];
shlib = argv[2];
for (arg=3; arg < argc; arg++) {
if (argv[arg][0] != '-')
continue;
for (ip=argv[arg]+1; *ip; ip++) {
switch (*ip) {
case 'd': /* print symbols */
debug++;
break;
case 'k': /* do not omit uninteresting symbols */
keep_sym++;
break;
case 'n': /* do not edit object file */
noact++;
break;
case 't': /* omit transfer vector symbols */
omit_tv++;
break;
case 'T': /* omit all shlib symbols */
omit_shsym++;
break;
default:
fprintf (stderr, "edsym: unknown switch -%c\n", *ip);
}
}
}
}
/* Open the file to be edited. */
if ((fd = open (fname, 2)) < 0) {
fprintf (stderr, "edsym: cannot open file %s\n", fname);
exit (1);
}
elf_version (EV_CURRENT);
elf = elf_begin (fd, ELF_C_READ, NULL);
if (!elf) {
fprintf (stderr, "edsym: not an ELF format executable\n");
exit (2);
}
/* Read file header. */
ehdr = elf32_getehdr (elf);
if (!ehdr) {
fprintf (stderr, "edsym: cannot read file header\n");
exit (3);
}
/* Read program header for text segment, which we assume to be the
* first loadable program segment.
*/
phdr = elf32_getphdr (elf);
if (ehdr->e_phnum <= 0 || !phdr) {
printf ("cannot read program header\n");
exit (4);
}
/* Get the ushlib vector from the file being edited.
*/
nl[0].n_name = "ushlib_";
nl[1].n_name = NULL;
if (nlist (fname, nl) != 0) {
fprintf (stderr, "cannot read name list from %s\n", fname);
exit (4);
}
offset = (unsigned)nl[0].n_value - phdr->p_vaddr + phdr->p_offset;
lseek (fd, offset, L_SET);
if (read (fd, (char *)ushlib, sizeof(ushlib)) != sizeof(ushlib)) {
fprintf (stderr, "cannot read shared image %s\n", fname);
exit (9);
}
version = ushlib[0];
vshlib = ushlib[2];
vshend = ushlib[3];
vsize = vshend - vshlib;
/* Read transfer vector from shared image.
*/
/* Use the correct version of the shared image. */
for (ip=shlib, out=op=shpath; *op = *ip++; op++)
if (*op == '/')
out = op + 1;
if (strcmp (out, "S.e") == 0) {
sprintf (out, "S%d.e", version);
shlib = shpath;
}
/* Open the file to be edited. */
if ((fd_sh = open (shlib, 0)) < 0) {
fprintf (stderr, "edsym: cannot open file %s\n", shlib);
exit (1);
}
elf_sh = elf_begin (fd_sh, ELF_C_READ, NULL);
if (!elf_sh) {
fprintf (stderr, "edsym: not an ELF format executable\n");
exit (2);
}
/* Read file header. */
ehdr = elf32_getehdr (elf_sh);
if (!ehdr) {
fprintf (stderr, "edsym: cannot read file header\n");
exit (3);
}
/* Read program header for text segment, which we assume to be the
* first loadable program segment.
*/
phdr = elf32_getphdr (elf_sh);
if (ehdr->e_phnum <= 0 || !phdr) {
printf ("cannot read program header\n");
exit (4);
}
if (!(vec = (unsigned *) malloc (vsize))) {
fprintf (stderr, "out of memory\n");
exit (10);
}
offset = vshlib - phdr->p_vaddr + phdr->p_offset;
lseek (fd_sh, offset, L_SET);
if (read (fd_sh, vec, vsize) != vsize) {
fprintf (stderr,
"cannot read transfer vector from %s\n", shlib);
exit (11);
}
/* Locate symbol table section in file to be edited. */
scn = NULL;
while (scn = elf_nextscn(elf,scn)) {
shdr = elf32_getshdr (scn);
if (shdr->sh_type == SHT_SYMTAB)
break;
}
if (!scn) {
fprintf (stderr, "edsym: file %s has no symbol table\n", fname);
exit (12);
}
/* Read symbol table into memory. */
nbytes = shdr->sh_size;
nsyms = nbytes / sizeof(Elf32_Sym);
if (!(buf = (char *) malloc (nbytes))) {
fprintf (stderr, "edsym: out of memory\n");
exit (13);
}
lseek (fd, shdr->sh_offset, 0);
if (read (fd, buf, nbytes) != nbytes) {
fprintf (stderr, "edsym: cannot read symbol table\n");
exit (14);
}
/* Now edit the symbol table of the object file.
*/
for (sym = (Elf32_Sym *)buf; --nsyms >= 0; sym++) {
Elf32_Addr v = sym->st_value;
if (debug) {
printf ("name=%d value=0x%x size=0x%x info=%o shndx=%d",
sym->st_name, sym->st_value, sym->st_size,
sym->st_info, sym->st_shndx);
}
if (sym->st_size == 0 &&
ELF32_ST_BIND(sym->st_info) == STB_GLOBAL && IS_TVECT(v)) {
epa = (unsigned *)((char *)vec + (v - vshlib));
v = (((*epa & 0x3fffff) << 10) | (*(epa+1) & 0x3ff));
if (debug)
printf ("\t%x -> %x", sym->st_value, v);
sym->st_value = (Elf32_Addr) v;
}
if (debug)
printf ("\n");
}
/* Write out the edited symbol table. */
lseek (fd, shdr->sh_offset, 0);
if (write (fd, buf, nbytes) != nbytes) {
fprintf (stderr, "edsym: cannot update symbol table\n");
exit (7);
}
/* All done. */
free (buf);
free ((char *)vec);
elf_end (elf_sh);
close (fd_sh);
elf_end (elf);
close (fd);
exit (0);
}
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