collect2.c

GUN开源阻止下的编译器GCC

  else
    return 0;
}

/* Given the name NAME of a dynamic dependency, find its pathname and add
   it to the list of libraries.  */

static void
locatelib (name)
     char *name;
{
  static char **l;
  static int cnt;
  char buf[MAXPATHLEN];
  char *p, *q;
  char **pp;

  if (l == 0)
    {
      char *ld_rules;
      char *ldr = 0;
      /* counting elements in array, need 1 extra for null */
      cnt = 1;  
      ld_rules = (char *) (ld_2->ld_rules + code);
      if (ld_rules)
	{
	  cnt++;
	  for (; *ld_rules != 0; ld_rules++)
	    if (*ld_rules == ':')
	      cnt++;
	  ld_rules = (char *) (ld_2->ld_rules + code);
	  ldr = (char *) malloc (strlen (ld_rules) + 1);
	  strcpy (ldr, ld_rules);
	}
      p = getenv ("LD_LIBRARY_PATH");
      q = 0;
      if (p)
	{
	  cnt++;
	  for (q = p ; *q != 0; q++)
	    if (*q == ':')
	      cnt++;
	  q = (char *) malloc (strlen (p) + 1);
	  strcpy (q, p);
	}
      l = (char **) malloc ((cnt + 3) * sizeof (char *));
      pp = l;
      if (ldr)
	{
	  *pp++ = ldr;
	  for (; *ldr != 0; ldr++) 
	    if (*ldr == ':')
	      {
		*ldr++ = 0;
		*pp++ = ldr;
	      }
	}
      if (q)
	{
	  *pp++ = q;
	  for (; *q != 0; q++) 
	    if (*q == ':')
	      {
		*q++ = 0;
		*pp++ = q;
	      }
	}
      /* built in directories are /lib, /usr/lib, and /usr/local/lib */
      *pp++ = "/lib";
      *pp++ = "/usr/lib";
      *pp++ = "/usr/local/lib";
      *pp = 0;
    }
  libname = name;
  for (pp = l; *pp != 0 ; pp++)
    {
      struct direct **namelist;
      int entries;
      if ((entries = scandir (*pp, &namelist, libselect, libcompare)) > 0)
	{
	  sprintf (buf, "%s/%s", *pp, namelist[entries - 1]->d_name);
	  add_to_list (&libraries, buf);
	  if (debug)
	    fprintf (stderr, "%s\n", buf);
	  break;
	}
    }
  if (*pp == 0)
    {
      if (debug)
	fprintf (stderr, "not found\n");
      else
	fatal ("dynamic dependency %s not found", name);
    }
}

/* Scan the _DYNAMIC structure of the output file to find shared libraries
   that it depends upon and any constructors or destructors they contain.  */

static void 
scan_libraries (prog_name)
     char *prog_name;
{
  struct exec *header;
  char *base;
  struct link_object *lo;
  char buff[MAXPATHLEN];
  struct id *list;

  mapfile (prog_name);
  header = (struct exec *)object;
  if (N_BADMAG (*header))
    fatal ("bad magic number in file '%s'", prog_name);
  if (header->a_dynamic == 0)
    return;

  code = (char *) (N_TXTOFF (*header) + (long) header);
  data = (char *) (N_DATOFF (*header) + (long) header);
  symtab = (struct nlist *) (N_SYMOFF (*header) + (long) header);

  if (header->a_magic == ZMAGIC && header->a_entry == 0x20)
    {
      /* shared object */
      ld = (struct link_dynamic *) (symtab->n_value + code);
      base = code;
    }
  else
    {
      /* executable */
      ld = (struct link_dynamic *) data;
      base = code-PAGSIZ;
    }

  if (debug)
    fprintf (stderr, "dynamic dependencies.\n");

  ld_2 = (struct link_dynamic_2 *) ((long) ld->ld_un.ld_2 + (long)base);
  for (lo = (struct link_object *) ld_2->ld_need; lo;
       lo = (struct link_object *) lo->lo_next)
    {
      char *name;
      lo = (struct link_object *) ((long) lo + code);
      name = (char *) (code + lo->lo_name);
      if (lo->lo_library)
	{
	  if (debug)
	    fprintf (stderr, "\t-l%s.%d => ", name, lo->lo_major);
	  sprintf (buff, "lib%s.so.%d.%d", name, lo->lo_major, lo->lo_minor);
	  locatelib (buff);
	}
      else
	{
	  if (debug)
	    fprintf (stderr, "\t%s\n", name);
	  add_to_list (&libraries, name);
	}
    }

  if (debug)
    fprintf (stderr, "\n");

  /* now iterate through the library list adding their symbols to
     the list.  */
  for (list = libraries.first; list; list = list->next)
    scan_prog_file (list->name, PASS_LIB);
}

#else  /* SUNOS4_SHARED_LIBRARIES */
#ifdef LDD_SUFFIX

/* Use the List Dynamic Dependencies program to find shared libraries that
   the output file depends upon and their initialization/finalization
   routines, if any.  */

static void 
scan_libraries (prog_name)
     char *prog_name;
{
  static struct head libraries;		/* list of shared libraries found */
  struct id *list;
  void (*int_handler) ();
  void (*quit_handler) ();
  char *ldd_argv[4];
  int pid;
  int argc = 0;
  int pipe_fd[2];
  char buf[1024];
  FILE *inf;

  /* If we don't have an `ldd', complain.  */
  if (ldd_file_name == 0)
    {
      error ("cannot find `ldd'");
      return;
    }

  ldd_argv[argc++] = ldd_file_name;
  ldd_argv[argc++] = prog_name;
  ldd_argv[argc++] = (char *) 0;

  if (pipe (pipe_fd) < 0)
    fatal_perror ("pipe");

  inf = fdopen (pipe_fd[0], "r");
  if (inf == (FILE *) 0)
    fatal_perror ("fdopen");

  /* Trace if needed.  */
  if (vflag)
    {
      char **p_argv;
      char *str;

      for (p_argv = &ldd_argv[0]; (str = *p_argv) != (char *) 0; p_argv++)
	fprintf (stderr, " %s", str);

      fprintf (stderr, "\n");
    }

  fflush (stdout);
  fflush (stderr);

  /* Spawn child ldd on pipe */
  pid = vfork ();
  if (pid == -1)
    {
#ifdef vfork
      fatal_perror ("fork");
#else
      fatal_perror ("vfork");
#endif
    }

  if (pid == 0)			/* child context */
    {
      /* setup stdout */
      if (dup2 (pipe_fd[1], 1) < 0)
	fatal_perror ("dup2 (%d, 1)", pipe_fd[1]);

      if (close (pipe_fd[0]) < 0)
	fatal_perror ("close (%d)", pipe_fd[0]);

      if (close (pipe_fd[1]) < 0)
	fatal_perror ("close (%d)", pipe_fd[1]);

      execv (ldd_file_name, ldd_argv);
      fatal_perror ("executing %s", ldd_file_name);
    }

  /* Parent context from here on.  */
  int_handler  = (void (*) ()) signal (SIGINT,  SIG_IGN);
#ifdef SIGQUIT
  quit_handler = (void (*) ()) signal (SIGQUIT, SIG_IGN);
#endif

  if (close (pipe_fd[1]) < 0)
    fatal_perror ("close (%d)", pipe_fd[1]);

  if (debug)
    fprintf (stderr, "\nldd output with constructors/destructors.\n");

  /* Read each line of ldd output.  */
  while (fgets (buf, sizeof buf, inf) != (char *) 0)
    {
      int ch, ch2;
      char *name, *end, *p = buf;

      /* Extract names of libraries and add to list. */
      PARSE_LDD_OUTPUT (p);
      if (p == 0)
	continue;

      name = p;
      if (strncmp (name, "not found", sizeof ("not found") - 1) == 0)
	fatal ("dynamic dependency %s not found", buf);

      /* Find the end of the symbol name. */
      for (end = p; 
	   (ch2 = *end) != '\0' && ch2 != '\n' && !isspace (ch2) && ch2 != '|';
	   end++)
	continue;
      *end = '\0';

      if (access (name, R_OK) == 0)
        add_to_list (&libraries, name);
      else
	fatal ("unable to open dynamic dependency '%s'", buf);

      if (debug)
	fprintf (stderr, "\t%s\n", buf);
    }
  if (debug)
    fprintf (stderr, "\n");

  if (fclose (inf) != 0)
    fatal_perror ("fclose of pipe");

  do_wait (ldd_file_name);

  signal (SIGINT,  int_handler);
#ifdef SIGQUIT
  signal (SIGQUIT, quit_handler);
#endif

  /* now iterate through the library list adding their symbols to
     the list.  */
  for (list = libraries.first; list; list = list->next)
    scan_prog_file (list->name, PASS_LIB);
}

#endif /* LDD_SUFFIX */
#endif /* SUNOS4_SHARED_LIBRARIES */

#endif /* OBJECT_FORMAT_NONE */


/*
 * COFF specific stuff.
 */

#ifdef OBJECT_FORMAT_COFF

#if defined(EXTENDED_COFF)
#   define GCC_SYMBOLS(X)	(SYMHEADER(X).isymMax + SYMHEADER(X).iextMax)
#   define GCC_SYMENT		SYMR
#   define GCC_OK_SYMBOL(X)	((X).st == stProc && (X).sc == scText)
#   define GCC_SYMINC(X)	(1)
#   define GCC_SYMZERO(X)	(SYMHEADER(X).isymMax)
#   define GCC_CHECK_HDR(X)	(PSYMTAB(X) != 0)
#else
#   define GCC_SYMBOLS(X)	(HEADER(ldptr).f_nsyms)
#   define GCC_SYMENT		SYMENT
#   define GCC_OK_SYMBOL(X) \
     (((X).n_sclass == C_EXT) && \
        (((X).n_type & N_TMASK) == (DT_NON << N_BTSHFT) || \
         ((X).n_type & N_TMASK) == (DT_FCN << N_BTSHFT)))
#   define GCC_SYMINC(X)	((X).n_numaux+1)
#   define GCC_SYMZERO(X)	0
#   define GCC_CHECK_HDR(X)	(1)
#endif

extern char *ldgetname ();

/* COFF version to scan the name list of the loaded program for
   the symbols g++ uses for static constructors and destructors.

   The constructor table begins at __CTOR_LIST__ and contains a count
   of the number of pointers (or -1 if the constructors are built in a
   separate section by the linker), followed by the pointers to the
   constructor functions, terminated with a null pointer.  The
   destructor table has the same format, and begins at __DTOR_LIST__.  */

static void
scan_prog_file (prog_name, which_pass)
     char *prog_name;
     enum pass which_pass;
{
  LDFILE *ldptr = NULL;
  int sym_index, sym_count;

  if (which_pass != PASS_FIRST && which_pass != PASS_OBJ)
    return;

  if ((ldptr = ldopen (prog_name, ldptr)) == NULL)
    fatal ("%s: can't open as COFF file", prog_name);
      
  if (!MY_ISCOFF (HEADER (ldptr).f_magic))
    fatal ("%s: not a COFF file", prog_name);

  if (GCC_CHECK_HDR (ldptr))
    {
      sym_count = GCC_SYMBOLS (ldptr);
      sym_index = GCC_SYMZERO (ldptr);
      while (sym_index < sym_count)
	{
	  GCC_SYMENT symbol;

	  if (ldtbread (ldptr, sym_index, &symbol) <= 0)
	    break;
	  sym_index += GCC_SYMINC (symbol);

	  if (GCC_OK_SYMBOL (symbol))
	    {
	      char *name;

	      if ((name = ldgetname (ldptr, &symbol)) == NULL)
		continue;		/* should never happen */

#ifdef XCOFF_DEBUGGING_INFO
	      /* All AIX function names have a duplicate entry beginning
		 with a dot. */
	      if (*name == '.')
		++name;
#endif

	      switch (is_ctor_dtor (name))
		{
		case 1:
		  add_to_list (&constructors, name);
		  if (which_pass == PASS_OBJ)
		    add_to_list (&exports, name);
		  break;

		case 2:
		  add_to_list (&destructors, name);
		  if (which_pass == PASS_OBJ)
		    add_to_list (&exports, name);
		  break;

		default:		/* not a constructor or destructor */
		  continue;
		}

#if !defined(EXTENDED_COFF)
	      if (debug)
		fprintf (stderr, "\tsec=%d class=%d type=%s%o %s\n",
			 symbol.n_scnum, symbol.n_sclass,
			 (symbol.n_type ? "0" : ""), symbol.n_type,
			 name);
#else
	      if (debug)
		fprintf (stderr, "\tiss = %5d, value = %5d, index = %5d, name = %s\n",
			 symbol.iss, symbol.value, symbol.index, name);
#endif
	    }
	}
    }

  (void) ldclose(ldptr);
}

#ifdef XCOFF_SCAN_LIBS
/* Scan imported AIX libraries for GCC static ctors and dtors.
   FIXME: it is possible to link an executable without the actual import
	  library by using an "import file" - a text file listing symbols
	  exported by a library.  To support this, we would have to scan
	  import files as well as actual shared binaries to find GCC ctors.
   TODO: use memory mapping instead of 'ld' routines, files are already
	 memory mapped, but we could eliminate the extra in-memory copies.
	 Is it worth the effort?  */

static void
scan_libraries (prog_name)
     char *prog_name;
{
  LDFILE *ldptr;
  SCNHDR ldsh;
  static struct path_prefix libpath; /* we should only do this once */

  if ((ldptr = ldopen (prog_name, ldptr)) == NULL)
    fatal ("%s: can't open as COFF file", prog_name);
      
  if (!MY_ISCOFF (HEADER (ldptr).f_magic))
    fatal ("%s: not a COFF file", prog_name);

  /* find and read loader section */
  if (ldnshread (ldptr, _LOADER, &ldsh))
    {
      LDHDR ldh;
      char *impbuf;
      int entry;

      FSEEK (ldptr, ldsh.s_scnptr, BEGINNING);
      FREAD (&ldh, sizeof (ldh), 1, ldptr);
      /* read import library list */
      impbuf = alloca (ldh.l_istlen);
      FSEEK (ldptr, ldh.l_impoff + ldsh.s_scnptr, BEGINNING);
      FREAD (impbuf, ldh.l_istlen, 1, ldptr);

      if (debug)
	fprintf (stderr, "LIBPATH=%s\n", impbuf);
      prefix_from_string (impbuf, &libpath);

      /* skip LIBPATH and empty base and member fields */
      impbuf += strlen (impbuf) + 3;
      for (entry = 1; entry < ldh.l_nimpid; ++entry)
	{
	  char *impath = impbuf;
	  char *implib = impath + strlen (impath) + 1;
	  char *impmem = implib + strlen (implib) + 1;
	  char *soname = NULL;
	  char *trial;
	  int pathlen;
	  LDFILE *libptr = NULL;
	  struct prefix_list *pl;
	  ARCHDR ah;

	  impbuf = impmem + strlen (impmem) + 1;
	  if (debug)
	    fprintf (stderr, "PATH+BASE=%s%s\n", impath, implib);
	  /* Skip AIX kernel exports */
	  if (*impath == '/' && *(impath+1) == '\0'
	      && strcmp (implib, "unix") == 0)
	    continue;
	  pathlen = strlen (impath);
          trial = alloca (MAX (pathlen + 1, libpath.max_len)
			  + strlen (implib) + 1);
	  if (*impath)
	    {
	      strcpy (trial, impath);
	      if (impath[pathlen - 1] != '/')
		trial[pathlen++] = '/';
	      strcpy (trial + pathlen, implib);
	      if (access (trial, R_OK) == 0)
		soname = trial;
	    }
	  else
	    for (pl = libpath.plist; pl; pl = pl->next)
	      {
		strcpy (trial, pl->prefix);
		strcat (trial, implib);
		if (access (trial, R_OK) == 0)
		  {
		    soname = trial;
		    break;
		  }
	      }

	  if (! soname)
	    fatal ("%s: library not found", implib);
	  if (debug)
	    if (*impmem)
	      fprintf (stderr, "%s (%s)\n", soname, impmem);
	    else
	      fprintf (stderr, "%s\n", soname);

	  do
	    {
	      /* scan imported shared objects for GCC GLOBAL ctors */
	      short type;
	      if ((libptr = ldopen (soname, libptr)) == NULL)
		fatal ("%s: can't open import library", soname)