102 lines
3.9 KiB
C
102 lines
3.9 KiB
C
/* Provide relocatable packages.
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Copyright (C) 2003, 2005, 2008-2017 Free Software Foundation, Inc.
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Written by Bruno Haible <bruno@clisp.org>, 2003.
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, see <https://www.gnu.org/licenses/>. */
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#ifndef _RELOCATABLE_H
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#define _RELOCATABLE_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* This can be enabled through the configure --enable-relocatable option. */
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#if ENABLE_RELOCATABLE
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/* When building a DLL, we must export some functions. Note that because
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this is a private .h file, we don't need to use __declspec(dllimport)
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in any case. */
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#if HAVE_VISIBILITY && BUILDING_DLL
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# define RELOCATABLE_DLL_EXPORTED __attribute__((__visibility__("default")))
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#elif defined _MSC_VER && BUILDING_DLL
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# define RELOCATABLE_DLL_EXPORTED __declspec(dllexport)
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#else
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# define RELOCATABLE_DLL_EXPORTED
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#endif
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/* Sets the original and the current installation prefix of the package.
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Relocation simply replaces a pathname starting with the original prefix
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by the corresponding pathname with the current prefix instead. Both
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prefixes should be directory names without trailing slash (i.e. use ""
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instead of "/"). */
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extern RELOCATABLE_DLL_EXPORTED void
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set_relocation_prefix (const char *orig_prefix,
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const char *curr_prefix);
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/* Returns the pathname, relocated according to the current installation
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directory.
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The returned string is either PATHNAME unmodified or a freshly allocated
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string that you can free with free() after casting it to 'char *'. */
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extern const char * relocate (const char *pathname);
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/* Returns the pathname, relocated according to the current installation
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directory.
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This function sets *ALLOCATEDP to the allocated memory, or to NULL if
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no memory allocation occurs. So that, after you're done with the return
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value, to reclaim allocated memory, you can do: free (*ALLOCATEDP). */
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extern const char * relocate2 (const char *pathname, char **allocatedp);
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/* Memory management: relocate() potentially allocates memory, because it has
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to construct a fresh pathname. If this is a problem because your program
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calls relocate() frequently or because you want to fix all potential memory
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leaks anyway, you have three options:
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1) Use this idiom:
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const char *pathname = ...;
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const char *rel_pathname = relocate (pathname);
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...
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if (rel_pathname != pathname)
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free ((char *) rel_pathname);
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2) Use this idiom:
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char *allocated;
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const char *rel_pathname = relocate2 (..., &allocated);
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...
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free (allocated);
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3) Think about caching the result. */
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/* Convenience function:
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Computes the current installation prefix, based on the original
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installation prefix, the original installation directory of a particular
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file, and the current pathname of this file.
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Returns it, freshly allocated. Returns NULL upon failure. */
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extern char * compute_curr_prefix (const char *orig_installprefix,
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const char *orig_installdir,
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const char *curr_pathname);
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#else
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/* By default, we use the hardwired pathnames. */
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#define relocate(pathname) (pathname)
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#define relocate2(pathname,allocatedp) (*(allocatedp) = NULL, (pathname))
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* _RELOCATABLE_H */
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