60 lines
1.5 KiB
C
60 lines
1.5 KiB
C
/*************************************************************************\
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* Copyright (c) 2003 The University of Chicago, as Operator of Argonne
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* National Laboratory.
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* EPICS BASE Versions 3.13.7
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* and higher are distributed subject to a Software License Agreement found
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* in file LICENSE that is included with this distribution.
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\*************************************************************************/
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/* $Id$
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*
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* Macro expansion of environment variables
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define epicsExportSharedSymbols
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#include <epicsAssert.h>
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#include <epicsString.h>
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#include "macLib.h"
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char * epicsShareAPI
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macEnvExpand(const char *str)
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{
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MAC_HANDLE *handle;
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static char *pairs[] = { "", "environ", NULL, NULL };
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long status;
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int destCapacity = 128;
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char *dest = NULL;
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int n;
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status = macCreateHandle(&handle, pairs);
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assert(status == 0);
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do {
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destCapacity *= 2;
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/*
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* Use free/malloc rather than realloc since there's no need to
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* bother copying the contents if realloc needs to move the buffer
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*/
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free(dest);
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dest = malloc(destCapacity);
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assert(dest != 0);
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n = macExpandString(handle, str, dest, destCapacity);
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} while (n >= (destCapacity - 1));
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if (n < 0) {
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free(dest);
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dest = NULL;
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} else {
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int unused = destCapacity - ++n;
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if (unused >= 20)
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dest = realloc(dest, n);
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}
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status = macDeleteHandle(handle);
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assert(status == 0);
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return dest;
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}
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