text: /* Auxiliary vector support for GDB, the GNU debugger.
  
     Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
  
     This file is part of GDB.
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  #include "defs.h"
  #include "target.h"
  #include "gdbtypes.h"
  #include "command.h"
  #include "inferior.h"
  #include "valprint.h"
  #include "gdb_assert.h"
  
  #include "auxv.h"
  #include "elf/common.h"
  
  #include <unistd.h>
  #include <fcntl.h>
  
  
  /* This function is called like a to_xfer_partial hook,
     but must be called with TARGET_OBJECT_AUXV.
     It handles access via /proc/PID/auxv, which is the common method.
     This function is appropriate for doing:
  	   #define NATIVE_XFER_AUXV	procfs_xfer_auxv
     for a native target that uses inftarg.c's child_xfer_partial hook.  */
  
  LONGEST
  procfs_xfer_auxv (struct target_ops *ops,
  		  int /* enum target_object */ object,
  		  const char *annex,
  		  gdb_byte *readbuf,
  		  const gdb_byte *writebuf,
  		  ULONGEST offset,
  		  LONGEST len)
  {
    char *pathname;
    int fd;
    LONGEST n;
  
    gdb_assert (object == TARGET_OBJECT_AUXV);
    gdb_assert (readbuf || writebuf);
  
    pathname = xstrprintf ("/proc/%d/auxv", PIDGET (inferior_ptid));
    fd = open (pathname, writebuf != NULL ? O_WRONLY : O_RDONLY);
    xfree (pathname);
    if (fd < 0)
      return -1;
  
    if (offset != (ULONGEST) 0
        && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
      n = -1;
    else if (readbuf != NULL)
      n = read (fd, readbuf, len);
    else
      n = write (fd, writebuf, len);
  
    (void) close (fd);
  
    return n;
  }
  
  /* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
     Return 0 if *READPTR is already at the end of the buffer.
     Return -1 if there is insufficient buffer for a whole entry.
     Return 1 if an entry was read into *TYPEP and *VALP.  */
  int
  target_auxv_parse (struct target_ops *ops, gdb_byte **readptr,
  		   gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp)
  {
    const int sizeof_auxv_field = TYPE_LENGTH (builtin_type_void_data_ptr);
    gdb_byte *ptr = *readptr;
  
    if (endptr == ptr)
      return 0;
  
    if (endptr - ptr < sizeof_auxv_field * 2)
      return -1;
  
    *typep = extract_unsigned_integer (ptr, sizeof_auxv_field);
    ptr += sizeof_auxv_field;
    *valp = extract_unsigned_integer (ptr, sizeof_auxv_field);
    ptr += sizeof_auxv_field;
  
    *readptr = ptr;
    return 1;
  }
  
  /* Extract the auxiliary vector entry with a_type matching MATCH.
     Return zero if no such entry was found, or -1 if there was
     an error getting the information.  On success, return 1 after
     storing the entry's value field in *VALP.  */
  int
  target_auxv_search (struct target_ops *ops, CORE_ADDR match, CORE_ADDR *valp)
  {
    CORE_ADDR type, val;
    gdb_byte *data;
    LONGEST n = target_read_alloc (ops, TARGET_OBJECT_AUXV, NULL, &data);
    gdb_byte *ptr = data;
    int ents = 0;
  
    if (n <= 0)
      return n;
  
    while (1)
      switch (target_auxv_parse (ops, &ptr, data + n, &type, &val))
        {
        case 1:			/* Here's an entry, check it.  */
  	if (type == match)
  	  {
  	    xfree (data);
  	    *valp = val;
  	    return 1;
  	  }
  	break;
        case 0:			/* End of the vector.  */
  	xfree (data);
  	return 0;
        default:			/* Bogosity.  */
  	xfree (data);
  	return -1;
        }
  
    /*NOTREACHED*/
  }
  
  
  /* Print the contents of the target's AUXV on the specified file. */
  int
  fprint_target_auxv (struct ui_file *file, struct target_ops *ops)
  {
    CORE_ADDR type, val;
    gdb_byte *data;
    LONGEST len = target_read_alloc (ops, TARGET_OBJECT_AUXV, NULL,
  				   &data);
    gdb_byte *ptr = data;
    int ents = 0;
  
    if (len <= 0)
      return len;
  
    while (target_auxv_parse (ops, &ptr, data + len, &type, &val) > 0)
      {
        extern int addressprint;
        const char *name = "???";
        const char *description = "";
        enum { dec, hex, str } flavor = hex;
  
        switch (type)
  	{
  #define TAG(tag, text, kind) \
  	case tag: name = #tag; description = text; flavor = kind; break
  	  TAG (AT_NULL, _("End of vector"), hex);
  	  TAG (AT_IGNORE, _("Entry should be ignored"), hex);
  	  TAG (AT_EXECFD, _("File descriptor of program"), dec);
  	  TAG (AT_PHDR, _("Program headers for program"), hex);
  	  TAG (AT_PHENT, _("Size of program header entry"), dec);
  	  TAG (AT_PHNUM, _("Number of program headers"), dec);
  	  TAG (AT_PAGESZ, _("System page size"), dec);
  	  TAG (AT_BASE, _("Base address of interpreter"), hex);
  	  TAG (AT_FLAGS, _("Flags"), hex);
  	  TAG (AT_ENTRY, _("Entry point of program"), hex);
  	  TAG (AT_NOTELF, _("Program is not ELF"), dec);
  	  TAG (AT_UID, _("Real user ID"), dec);
  	  TAG (AT_EUID, _("Effective user ID"), dec);
  	  TAG (AT_GID, _("Real group ID"), dec);
  	  TAG (AT_EGID, _("Effective group ID"), dec);
  	  TAG (AT_CLKTCK, _("Frequency of times()"), dec);
  	  TAG (AT_PLATFORM, _("String identifying platform"), str);
  	  TAG (AT_HWCAP, _("Machine-dependent CPU capability hints"), hex);
  	  TAG (AT_FPUCW, _("Used FPU control word"), dec);
  	  TAG (AT_DCACHEBSIZE, _("Data cache block size"), dec);
  	  TAG (AT_ICACHEBSIZE, _("Instruction cache block size"), dec);
  	  TAG (AT_UCACHEBSIZE, _("Unified cache block size"), dec);
  	  TAG (AT_IGNOREPPC, _("Entry should be ignored"), dec);
  	  TAG (AT_SYSINFO, _("Special system info/entry points"), hex);
  	  TAG (AT_SYSINFO_EHDR, _("System-supplied DSO's ELF header"), hex);
  	  TAG (AT_SECURE, _("Boolean, was exec setuid-like?"), dec);
  	  TAG (AT_SUN_UID, _("Effective user ID"), dec);
  	  TAG (AT_SUN_RUID, _("Real user ID"), dec);
  	  TAG (AT_SUN_GID, _("Effective group ID"), dec);
  	  TAG (AT_SUN_RGID, _("Real group ID"), dec);
  	  TAG (AT_SUN_LDELF, _("Dynamic linker's ELF header"), hex);
  	  TAG (AT_SUN_LDSHDR, _("Dynamic linker's section headers"), hex);
  	  TAG (AT_SUN_LDNAME, _("String giving name of dynamic linker"), str);
  	  TAG (AT_SUN_LPAGESZ, _("Large pagesize"), dec);
  	  TAG (AT_SUN_PLATFORM, _("Platform name string"), str);
  	  TAG (AT_SUN_HWCAP, _("Machine-dependent CPU capability hints"), hex);
  	  TAG (AT_SUN_IFLUSH, _("Should flush icache?"), dec);
  	  TAG (AT_SUN_CPU, _("CPU name string"), str);
  	  TAG (AT_SUN_EMUL_ENTRY, _("COFF entry point address"), hex);
  	  TAG (AT_SUN_EMUL_EXECFD, _("COFF executable file descriptor"), dec);
  	  TAG (AT_SUN_EXECNAME,
  	       _("Canonicalized file name given to execve"), str);
  	  TAG (AT_SUN_MMU, _("String for name of MMU module"), str);
  	  TAG (AT_SUN_LDDATA, _("Dynamic linker's data segment address"), hex);
  	  TAG (AT_SUN_AUXFLAGS,
  	       _("AF_SUN_ flags passed from the kernel"), hex);
  	}
  
        fprintf_filtered (file, "%-4s %-20s %-30s ",
  			paddr_d (type), name, description);
        switch (flavor)
  	{
  	case dec:
  	  fprintf_filtered (file, "%s\n", paddr_d (val));
  	  break;
  	case hex:
  	  fprintf_filtered (file, "0x%s\n", paddr_nz (val));
  	  break;
  	case str:
  	  if (addressprint)
  	    fprintf_filtered (file, "0x%s", paddr_nz (val));
  	  val_print_string (val, -1, 1, file);
  	  fprintf_filtered (file, "\n");
  	  break;
  	}
        ++ents;
      }
  
    xfree (data);
  
    return ents;
  }
  
  static void
  info_auxv_command (char *cmd, int from_tty)
  {
    if (! target_has_stack)
      error (_("The program has no auxiliary information now."));
    else
      {
        int ents = fprint_target_auxv (gdb_stdout, &current_target);
        if (ents < 0)
  	error (_("No auxiliary vector found, or failed reading it."));
        else if (ents == 0)
  	error (_("Auxiliary vector is empty."));
      }
  }
  
  
  extern initialize_file_ftype _initialize_auxv; /* -Wmissing-prototypes; */
  
  void
  _initialize_auxv (void)
  {
    add_info ("auxv", info_auxv_command,
  	    _("Display the inferior's auxiliary vector.\n\
  This is information provided by the operating system at program startup."));
  }
  