bsdi.c 2.13 KB
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/*-------------------------------------------------------------------------
 *
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 * dynloader.c
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 *	  Dynamic Loader for Postgres for Linux, generated from those for
 *	  Ultrix.
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 *
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 *	  You need to install the dld library on your Linux system!
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 *
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 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
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 * Portions Copyright (c) 1994, Regents of the University of California
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 *
 *
 * IDENTIFICATION
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 *	  /usr/local/devel/pglite/cvs/src/backend/port/linux/dynloader.c,v 1.1.1.1 1994/11/07 05:19:37 andrew Exp
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 *
 *-------------------------------------------------------------------------
 */
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#ifndef HAVE_DLOPEN
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#include "postgres.h"

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extern char pg_pathname[];
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void *
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pg_dlopen(char *filename)
{
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	static int	dl_initialized = 0;
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	/*
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	 * initializes the dynamic loader with the executable's pathname.
	 * (only needs to do this the first time pg_dlopen is called.)
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	 */
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	if (!dl_initialized)
	{
		if (dld_init(dld_find_executable(pg_pathname)))
			return NULL;
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		/*
		 * if there are undefined symbols, we want dl to search from the
		 * following libraries also.
		 */
		dl_initialized = 1;
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	}
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	/*
	 * link the file, then check for undefined symbols!
	 */
	if (dld_link(filename))
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		return NULL;

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	/*
	 * If undefined symbols: try to link with the C and math libraries!
	 * This could be smarter, if the dynamic linker was able to handle
	 * shared libs!
	 */
	if (dld_undefined_sym_count > 0)
	{
		if (dld_link("/usr/lib/libc.a"))
		{
			elog(NOTICE, "dld: Cannot link C library!");
			return NULL;
		}
		if (dld_undefined_sym_count > 0)
		{
			if (dld_link("/usr/lib/libm.a"))
			{
				elog(NOTICE, "dld: Cannot link math library!");
				return NULL;
			}
			if (dld_undefined_sym_count > 0)
			{
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				int			count = dld_undefined_sym_count;
				char	  **list = dld_list_undefined_sym();
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				/* list the undefined symbols, if any */
				elog(NOTICE, "dld: Undefined:");
				do
				{
					elog(NOTICE, "  %s", *list);
					list++;
					count--;
				} while (count > 0);

				dld_unlink_by_file(filename, 1);
				return NULL;
			}
		}
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	}

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	return (void *) strdup(filename);
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}

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char *
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pg_dlerror()
{
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	return dld_strerror(dld_errno);
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}
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#endif /* not HAVE_DLOPEN */