text: /*
   * Copyright (c) 2010, 2012-2014 Todd C. Miller <Todd.Miller@courtesan.com>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <config.h>
  
  #include <sys/types.h>
  
  #include <stdio.h>
  #ifdef STDC_HEADERS
  # include <stdlib.h>
  # include <stddef.h>
  #else
  # ifdef HAVE_STDLIB_H
  #  include <stdlib.h>
  # endif
  #endif /* STDC_HEADERS */
  #ifdef HAVE_STRING_H
  # include <string.h>
  #endif /* HAVE_STRING_H */
  #ifdef HAVE_STRINGS_H
  # include <strings.h>
  #endif /* HAVE_STRINGS_H */
  #if defined(HAVE_SHL_LOAD)
  # include <dl.h>
  #elif defined(HAVE_DLOPEN)
  # include <dlfcn.h>
  #endif
  #include <errno.h>
  
  #include "sudo_dso.h"
  #include "missing.h"
  
  /*
   * Pointer for statically compiled symbols.
   */
  static struct sudo_preload_table *preload_table;
  
  void
  sudo_dso_preload_table(struct sudo_preload_table *table)
  {
      preload_table = table;
  }
  
  #if defined(HAVE_SHL_LOAD)
  
  # ifndef DYNAMIC_PATH
  #  define DYNAMIC_PATH	0
  # endif
  
  void *
  sudo_dso_load(const char *path, int mode)
  {
      struct sudo_preload_table *pt;
      int flags = DYNAMIC_PATH | BIND_VERBOSE;
  
      if (mode == 0)
  	mode = SUDO_DSO_LAZY;	/* default behavior */
  
      /* Check prelinked symbols first. */
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->path != NULL && strcmp(path, pt->path) == 0)
  		return pt->handle;
  	}
      }
  
      /* We don't support SUDO_DSO_GLOBAL or SUDO_DSO_LOCAL yet. */
      if (ISSET(mode, SUDO_DSO_LAZY))
  	flags |= BIND_DEFERRED;
      if (ISSET(mode, SUDO_DSO_NOW))
  	flags |= BIND_IMMEDIATE;
  
      return (void *)shl_load(path, flags, 0L);
  }
  
  int
  sudo_dso_unload(void *handle)
  {
      struct sudo_preload_table *pt;
  
      /* Check prelinked symbols first. */
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->handle == handle)
  		return 0;
  	}
      }
  
      return shl_unload((shl_t)handle);
  }
  
  void *
  sudo_dso_findsym(void *vhandle, const char *symbol)
  {
      struct sudo_preload_table *pt;
      shl_t handle = vhandle;
      void *value = NULL;
  
      /* Check prelinked symbols first. */
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->handle == handle) {
  		struct sudo_preload_symbol *sym;
  		for (sym = pt->symbols; sym->name != NULL; sym++) {
  		    if (strcmp(sym->name, symbol) == 0)
  			return sym->addr;
  		}
  		errno = ENOENT;
  		return NULL;
  	    }
  	}
      }
  
      /*
       * Note that the behavior of of SUDO_DSO_NEXT and SUDO_DSO_SELF 
       * differs from most implementations when called from
       * a shared library.
       */
      if (vhandle == SUDO_DSO_NEXT) {
  	/* Iterate over all shared libs looking for symbol. */
  	shl_t myhandle = PROG_HANDLE;
  	struct shl_descriptor *desc;
  	int idx = 0;
  
  	/* Find program's real handle. */
  	if (shl_gethandle(PROG_HANDLE, &desc) == 0)
  	    myhandle = desc->handle;
  	while (shl_get(idx++, &desc) == 0) {
  	    if (desc->handle == myhandle)
  		continue;
  	    if (shl_findsym(&desc->handle, symbol, TYPE_UNDEFINED, &value) == 0)
  		break;
  	}
      } else {
  	if (vhandle == SUDO_DSO_DEFAULT)
  	    handle = NULL;
  	else if (vhandle == SUDO_DSO_SELF)
  	    handle = PROG_HANDLE;
  	(void)shl_findsym(&handle, symbol, TYPE_UNDEFINED, &value);
      }
  
      return value;
  }
  
  char *
  sudo_dso_strerror(void)
  {
      return strerror(errno);
  }
  
  #elif defined(HAVE_DLOPEN)
  
  # ifndef RTLD_GLOBAL
  #  define RTLD_GLOBAL	0
  # endif
  
  void *
  sudo_dso_load(const char *path, int mode)
  {
      struct sudo_preload_table *pt;
      int flags = 0;
  
      /* Check prelinked symbols first. */
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->path != NULL && strcmp(path, pt->path) == 0)
  		return pt->handle;
  	}
      }
  
      /* Map SUDO_DSO_* -> RTLD_* */
      if (ISSET(mode, SUDO_DSO_LAZY))
  	flags |= RTLD_LAZY;
      if (ISSET(mode, SUDO_DSO_NOW))
  	flags |= RTLD_NOW;
      if (ISSET(mode, SUDO_DSO_GLOBAL))
  	flags |= RTLD_GLOBAL;
      if (ISSET(mode, SUDO_DSO_LOCAL))
  	flags |= RTLD_LOCAL;
  
      return dlopen(path, flags);
  }
  
  int
  sudo_dso_unload(void *handle)
  {
      struct sudo_preload_table *pt;
  
      /* Check prelinked symbols first. */
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->handle == handle)
  		return 0;
  	}
      }
  
      return dlclose(handle);
  }
  
  void *
  sudo_dso_findsym(void *handle, const char *symbol)
  {
      struct sudo_preload_table *pt;
  
      /* Check prelinked symbols first. */
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->handle == handle) {
  		struct sudo_preload_symbol *sym;
  		for (sym = pt->symbols; sym->name != NULL; sym++) {
  		    if (strcmp(sym->name, symbol) == 0)
  			return sym->addr;
  		}
  		errno = ENOENT;
  		return NULL;
  	    }
  	}
      }
  
      /*
       * Not all implementations support the special handles.
       */
      if (handle == SUDO_DSO_NEXT) {
  # ifdef RTLD_NEXT
  	handle = RTLD_NEXT;
  # else
  	errno = ENOENT;
  	return NULL;
  # endif
      } else if (handle == SUDO_DSO_DEFAULT) {
  # ifdef RTLD_DEFAULT
  	handle = RTLD_DEFAULT;
  # else
  	errno = ENOENT;
  	return NULL;
  # endif
      } else if (handle == SUDO_DSO_SELF) {
  # ifdef RTLD_SELF
  	handle = RTLD_SELF;
  # else
  	errno = ENOENT;
  	return NULL;
  # endif
      }
  
      return dlsym(handle, symbol);
  }
  
  char *
  sudo_dso_strerror(void)
  {
      return dlerror();
  }
  
  #else /* !HAVE_SHL_LOAD && !HAVE_DLOPEN */
  
  /*
   * Emulate dlopen() using a static list of symbols compiled into sudo.
   */
  void *
  sudo_dso_load(const char *path, int mode)
  {
      struct sudo_preload_table *pt;
  
      /* Check prelinked symbols first. */
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->path != NULL && strcmp(path, pt->path) == 0)
  		return pt->handle;
  	}
      }
      return NULL;
  }
  
  int
  sudo_dso_unload(void *handle)
  {
      struct sudo_preload_table *pt;
  
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->handle == handle)
  		return 0;
  	}
      }
      return -1;
  }
  
  void *
  sudo_dso_findsym(void *handle, const char *symbol)
  {
      struct sudo_preload_table *pt;
  
      if (preload_table != NULL) {
  	for (pt = preload_table; pt->handle != NULL; pt++) {
  	    if (pt->handle == handle) {
  		struct sudo_preload_symbol *sym;
  		for (sym = pt->symbols; sym->name != NULL; sym++) {
  		    if (strcmp(sym->name, symbol) == 0)
  			return sym->addr;
  		}
  	    }
  	}
      }
      errno = ENOENT;
      return NULL;
  }
  
  char *
  sudo_dso_strerror(void)
  {
      return strerror(errno);
  }
  #endif /* !HAVE_SHL_LOAD && !HAVE_DLOPEN */
  