ltdl.c

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  /* No BEFORE address indicates ENTRY should be inserted after the
     current last element.  */
  if (!before)
    return argz_append (pargz, pargz_len, entry, 1+ LT_STRLEN (entry));

  /* This probably indicates a programmer error, but to preserve
     semantics, scan back to the start of an entry if BEFORE points
     into the middle of it.  */
  while ((before >= *pargz) && (before[-1] != LT_EOS_CHAR))
    --before;

  {
    size_t entry_len    = 1+ LT_STRLEN (entry);
    size_t argz_len     = *pargz_len + entry_len;
    size_t offset       = before - *pargz;
    char   *argz        = LT_DLREALLOC (char, *pargz, argz_len);

    if (!argz)
      return ENOMEM;

    /* Make BEFORE point to the equivalent offset in ARGZ that it
       used to have in *PARGZ incase realloc() moved the block.  */
    before = argz + offset;

    /* Move the ARGZ entries starting at BEFORE up into the new
       space at the end -- making room to copy ENTRY into the
       resulting gap.  */
    memmove (before + entry_len, before, *pargz_len - offset);
    memcpy  (before, entry, entry_len);

    /* Assign new values.  */
    *pargz = argz;
    *pargz_len = argz_len;
  }

  return 0;
}
#endif /* !HAVE_ARGZ_INSERT */


#if ! HAVE_ARGZ_NEXT
#  define argz_next rpl_argz_next

static char *argz_next LT_PARAMS((char *argz, size_t argz_len,
                                    const char *entry));

static char *
argz_next (argz, argz_len, entry)
     char *argz;
     size_t argz_len;
     const char *entry;
{
  assert ((argz && argz_len) || (!argz && !argz_len));

  if (entry)
    {
      /* Either ARGZ/ARGZ_LEN is empty, or ENTRY points into an address
         within the ARGZ vector.  */
      assert ((!argz && !argz_len)
              || ((argz <= entry) && (entry < (argz + argz_len))));

      /* Move to the char immediately after the terminating
         '\0' of ENTRY.  */
      entry = 1+ strchr (entry, LT_EOS_CHAR);

      /* Return either the new ENTRY, or else NULL if ARGZ is
         exhausted.  */
      return (entry >= argz + argz_len) ? 0 : (char *) entry;
    }
  else
    {
      /* This should probably be flagged as a programmer error,
         since starting an argz_next loop with the iterator set
         to ARGZ is safer.  To preserve semantics, handle the NULL
         case by returning the start of ARGZ (if any).  */
      if (argz_len > 0)
        return argz;
      else
        return 0;
    }
}
#endif /* !HAVE_ARGZ_NEXT */



#if ! HAVE_ARGZ_STRINGIFY
#  define argz_stringify rpl_argz_stringify

static void argz_stringify LT_PARAMS((char *argz, size_t argz_len,
                                       int sep));

static void
argz_stringify (argz, argz_len, sep)
     char *argz;
     size_t argz_len;
     int sep;
{
  assert ((argz && argz_len) || (!argz && !argz_len));

  if (sep)
    {
      --argz_len;               /* don't stringify the terminating EOS */
      while (--argz_len > 0)
        {
          if (argz[argz_len] == LT_EOS_CHAR)
            argz[argz_len] = sep;
        }
    }
}
#endif /* !HAVE_ARGZ_STRINGIFY */




/* --- TYPE DEFINITIONS -- */


/* This type is used for the array of caller data sets in each handler. */
typedef struct {
  lt_dlcaller_id        key;
  lt_ptr                data;
} lt_caller_data;




/* --- OPAQUE STRUCTURES DECLARED IN LTDL.H --- */


/* Extract the diagnostic strings from the error table macro in the same
   order as the enumerated indices in ltdl.h. */

static const char *lt_dlerror_strings[] =
  {
#define LT_ERROR(name, diagnostic)      (diagnostic),
    lt_dlerror_table
#undef LT_ERROR

    0
  };

/* This structure is used for the list of registered loaders. */
struct lt_dlloader {
  struct lt_dlloader   *next;
  const char           *loader_name;    /* identifying name for each loader */
  const char           *sym_prefix;     /* prefix for symbols */
  lt_module_open       *module_open;
  lt_module_close      *module_close;
  lt_find_sym          *find_sym;
  lt_dlloader_exit     *dlloader_exit;
  lt_user_data          dlloader_data;
};

struct lt_dlhandle_struct {
  struct lt_dlhandle_struct   *next;
  lt_dlloader          *loader;         /* dlopening interface */
  lt_dlinfo             info;
  int                   depcount;       /* number of dependencies */
  lt_dlhandle          *deplibs;        /* dependencies */
  lt_module             module;         /* system module handle */
  lt_ptr                system;         /* system specific data */
  lt_caller_data       *caller_data;    /* per caller associated data */
  int                   flags;          /* various boolean stats */
};

/* Various boolean flags can be stored in the flags field of an
   lt_dlhandle_struct... */
#define LT_DLGET_FLAG(handle, flag) (((handle)->flags & (flag)) == (flag))
#define LT_DLSET_FLAG(handle, flag) ((handle)->flags |= (flag))

#define LT_DLRESIDENT_FLAG          (0x01 << 0)
/* ...add more flags here... */

#define LT_DLIS_RESIDENT(handle)    LT_DLGET_FLAG(handle, LT_DLRESIDENT_FLAG)


#define LT_DLSTRERROR(name)     lt_dlerror_strings[LT_CONC(LT_ERROR_,name)]

static  const char      objdir[]                = LTDL_OBJDIR;
static  const char      archive_ext[]           = LTDL_ARCHIVE_EXT;
#ifdef  LTDL_SHLIB_EXT
static  const char      shlib_ext[]             = LTDL_SHLIB_EXT;
#endif
#ifdef  LTDL_SYSSEARCHPATH
static  const char      sys_search_path[]       = LTDL_SYSSEARCHPATH;
#endif




/* --- MUTEX LOCKING --- */


/* Macros to make it easier to run the lock functions only if they have
   been registered.  The reason for the complicated lock macro is to
   ensure that the stored error message from the last error is not
   accidentally erased if the current function doesn't generate an
   error of its own.  */
#define LT_DLMUTEX_LOCK()                       LT_STMT_START { \
        if (lt_dlmutex_lock_func) (*lt_dlmutex_lock_func)();    \
                                                } LT_STMT_END
#define LT_DLMUTEX_UNLOCK()                     LT_STMT_START { \
        if (lt_dlmutex_unlock_func) (*lt_dlmutex_unlock_func)();\
                                                } LT_STMT_END
#define LT_DLMUTEX_SETERROR(errormsg)           LT_STMT_START { \
        if (lt_dlmutex_seterror_func)                           \
                (*lt_dlmutex_seterror_func) (errormsg);         \
        else    lt_dllast_error = (errormsg);   } LT_STMT_END
#define LT_DLMUTEX_GETERROR(errormsg)           LT_STMT_START { \
        if (lt_dlmutex_seterror_func)                           \
                (errormsg) = (*lt_dlmutex_geterror_func) ();    \
        else    (errormsg) = lt_dllast_error;   } LT_STMT_END

/* The mutex functions stored here are global, and are necessarily the
   same for all threads that wish to share access to libltdl.  */
static  lt_dlmutex_lock     *lt_dlmutex_lock_func     = 0;
static  lt_dlmutex_unlock   *lt_dlmutex_unlock_func   = 0;
static  lt_dlmutex_seterror *lt_dlmutex_seterror_func = 0;
static  lt_dlmutex_geterror *lt_dlmutex_geterror_func = 0;
static  const char          *lt_dllast_error          = 0;


/* Either set or reset the mutex functions.  Either all the arguments must
   be valid functions, or else all can be NULL to turn off locking entirely.
   The registered functions should be manipulating a static global lock
   from the lock() and unlock() callbacks, which needs to be reentrant.  */
int
lt_dlmutex_register (lock, unlock, seterror, geterror)
     lt_dlmutex_lock *lock;
     lt_dlmutex_unlock *unlock;
     lt_dlmutex_seterror *seterror;
     lt_dlmutex_geterror *geterror;
{
  lt_dlmutex_unlock *old_unlock = unlock;
  int                errors     = 0;

  /* Lock using the old lock() callback, if any.  */
  LT_DLMUTEX_LOCK ();

  if ((lock && unlock && seterror && geterror)
      || !(lock || unlock || seterror || geterror))
    {
      lt_dlmutex_lock_func     = lock;
      lt_dlmutex_unlock_func   = unlock;
      lt_dlmutex_geterror_func = geterror;
    }
  else
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (INVALID_MUTEX_ARGS));
      ++errors;
    }

  /* Use the old unlock() callback we saved earlier, if any.  Otherwise
     record any errors using internal storage.  */
  if (old_unlock)
    (*old_unlock) ();

  /* Return the number of errors encountered during the execution of
     this function.  */
  return errors;
}




/* --- ERROR HANDLING --- */


static  const char    **user_error_strings      = 0;
static  int             errorcount              = LT_ERROR_MAX;

int
lt_dladderror (diagnostic)
     const char *diagnostic;
{
  int           errindex = 0;
  int           result   = -1;
  const char  **temp     = (const char **) 0;

  assert (diagnostic);

  LT_DLMUTEX_LOCK ();

  errindex = errorcount - LT_ERROR_MAX;
  temp = LT_EREALLOC (const char *, user_error_strings, 1 + errindex);
  if (temp)
    {
      user_error_strings                = temp;
      user_error_strings[errindex]      = diagnostic;
      result                            = errorcount++;
    }

  LT_DLMUTEX_UNLOCK ();

  return result;
}

int
lt_dlseterror (errindex)
     int errindex;
{
  int           errors   = 0;

  LT_DLMUTEX_LOCK ();

  if (errindex >= errorcount || errindex < 0)
    {
      /* Ack!  Error setting the error message! */
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (INVALID_ERRORCODE));
      ++errors;
    }
  else if (errindex < LT_ERROR_MAX)
    {
      /* No error setting the error message! */
      LT_DLMUTEX_SETERROR (lt_dlerror_strings[errindex]);
    }
  else
    {
      /* No error setting the error message! */
      LT_DLMUTEX_SETERROR (user_error_strings[errindex - LT_ERROR_MAX]);
    }

  LT_DLMUTEX_UNLOCK ();

  return errors;
}

static lt_ptr
lt_emalloc (size)
     size_t size;
{
  lt_ptr mem = lt_dlmalloc (size);
  if (size && !mem)
    LT_DLMUTEX_SETERROR (LT_DLSTRERROR (NO_MEMORY));
  return mem;
}

static lt_ptr
lt_erealloc (addr, size)
     lt_ptr addr;
     size_t size;
{
  lt_ptr mem = realloc (addr, size);
  if (size && !mem)
    LT_DLMUTEX_SETERROR (LT_DLSTRERROR (NO_MEMORY));
  return mem;
}

static char *
lt_estrdup (str)
     const char *str;
{
  char *copy = strdup (str);
  if (LT_STRLEN (str) && !copy)
    LT_DLMUTEX_SETERROR (LT_DLSTRERROR (NO_MEMORY));
  return copy;
}




/* --- DLOPEN() INTERFACE LOADER --- */


/* The Cygwin dlopen implementation prints a spurious error message to
   stderr if its call to LoadLibrary() fails for any reason.  We can
   mitigate this by not using the Cygwin implementation, and falling
   back to our own LoadLibrary() wrapper. */
#if HAVE_LIBDL && !defined(__CYGWIN__)

/* dynamic linking with dlopen/dlsym */

#if HAVE_DLFCN_H
#  include <dlfcn.h>
#endif

#if HAVE_SYS_DL_H
#  include <sys/dl.h>
#endif

#ifdef RTLD_GLOBAL
#  define LT_GLOBAL             RTLD_GLOBAL
#else
#  ifdef DL_GLOBAL
#    define LT_GLOBAL           DL_GLOBAL
#  endif
#endif /* !RTLD_GLOBAL */
#ifndef LT_GLOBAL
#  define LT_GLOBAL             0
#endif /* !LT_GLOBAL */

/* We may have to define LT_LAZY_OR_NOW in the command line if we
   find out it does not work in some platform. */
#ifndef LT_LAZY_OR_NOW
#  ifdef RTLD_LAZY
#    define LT_LAZY_OR_NOW      RTLD_LAZY
#  else
#    ifdef DL_LAZY
#      define LT_LAZY_OR_NOW    DL_LAZY
#    endif
#  endif /* !RTLD_LAZY */
#endif
#ifndef LT_LAZY_OR_NOW
#  ifdef RTLD_NOW
#    define LT_LAZY_OR_NOW      RTLD_NOW
#  else
#    ifdef DL_NOW
#      define LT_LAZY_OR_NOW    DL_NOW
#    endif
#  endif /* !RTLD_NOW */
#endif
#ifndef LT_LAZY_OR_NOW
#  define LT_LAZY_OR_NOW        0
#endif /* !LT_LAZY_OR_NOW */

#if HAVE_DLERROR
#  define DLERROR(arg)  dlerror ()
#else
#  define DLERROR(arg)  LT_DLSTRERROR (arg)
#endif

static lt_module
sys_dl_open (loader_data, filename)
     lt_user_data loader_data;
     const char *filename;
{
  lt_module   module   = dlopen (filename, LT_GLOBAL | LT_LAZY_OR_NOW);

  if (!module)
    {
      LT_DLMUTEX_SETERROR (DLERROR (CANNOT_OPEN));
    }

  return module;
}

static int
sys_dl_close (loader_data, module)
     lt_user_data loader_data;
     lt_module module;
{
  int errors = 0;

  if (dlclose (module) != 0)
    {
      LT_DLMUTEX_SETERROR (DLERROR (CANNOT_CLOSE));
      ++errors;
    }

  return errors;
}

static lt_ptr
sys_dl_sym (loader_data, module, symbol)
     lt_user_data loader_data;
     lt_module module;
     const char *symbol;
{
  lt_ptr address = dlsym (module, symbol);

  if (!address)
    {
      LT_DLMUTEX_SETERROR (DLERROR (SYMBOL_NOT_FOUND));
    }

  return address;
}

static struct lt_user_dlloader sys_dl =
  {
#  ifdef NEED_USCORE
    "_",
#  else
    0,
#  endif
    sys_dl_open, sys_dl_close, sys_dl_sym, 0, 0 };


#endif /* HAVE_LIBDL */



/* --- SHL_LOAD() INTERFACE LOADER --- */

#if HAVE_SHL_LOAD

/* dynamic linking with shl_load (HP-UX) (comments from gmodule) */

#ifdef HAVE_DL_H
#  include <dl.h>
#endif

/* some flags are missing on some systems, so we provide
 * harmless defaults.
 *
 * Mandatory:
 * BIND_IMMEDIATE  - Resolve symbol references when the library is loaded.
 * BIND_DEFERRED   - Delay code symbol resolution until actual reference.
 *
 * Optionally:
 * BIND_FIRST      - Place the library at the head of the symbol search
 *                   order.
 * BIND_NONFATAL   - The default BIND_IMMEDIATE behavior is to treat all
 *                   unsatisfied symbols as fatal.  This flag allows
 *                   binding of unsatisfied code symbols to be deferred
 *                   until use.
 *                   [Perl: For certain libraries, like DCE, deferred
 *                   binding often causes run time problems. Adding
 *                   BIND_NONFATAL to BIND_IMMEDIATE still allows
 *                   unresolved references in situations like this.]
 * BIND_NOSTART    - Do not call the initializer for the shared library
 *                   when the library is loaded, nor on a future call to
 *                   shl_unload().
 * BIND_VERBOSE    - Print verbose messages concerning possible
 *                   unsatisfied symbols.
 *
 * hp9000s700/hp9000s800:
 * BIND_RESTRICTED - Restrict symbols visible by the library to those
 *                   present at library load time.
 * DYNAMIC_PATH    - Allow the loader to dynamically search for the
 *                   library specified by the path argument.
 */

#ifndef DYNAMIC_PATH
#  define DYNAMIC_PATH          0
#endif
#ifndef BIND_RESTRICTED
#  define BIND_RESTRICTED       0
#endif

#define LT_BIND_FLAGS   (BIND_IMMEDIATE | BIND_NONFATAL | DYNAMIC_PATH)

static lt_module
sys_shl_open (loader_data, filename)
     lt_user_data loader_data;
     const char *filename;
{
  static shl_t self = (shl_t) 0;
  lt_module module = shl_load (filename, LT_BIND_FLAGS, 0L);

  /* Since searching for a symbol against a NULL module handle will also
     look in everything else that was already loaded and exported with
     the -E compiler flag, we always cache a handle saved before any
     modules are loaded.  */
  if (!self)
    {
      lt_ptr address;
      shl_findsym (&self, "main", TYPE_UNDEFINED, &address);
    }