77 lines
1.5 KiB
C
77 lines
1.5 KiB
C
/*
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* (c) copyright 1989 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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#include <stdlib.h>
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#include <string.h>
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#define ENTRY_INC 10
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#define rounded(x) (((x / ENTRY_INC) + 1) * ENTRY_INC)
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extern const char **environ;
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int
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putenv(char *name)
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{
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register const char **v = environ;
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register char *r;
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static int size = 0;
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/* When size != 0, it contains the number of entries in the
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* table (including the final NULL pointer). This means that the
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* last non-null entry is environ[size - 2].
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*/
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if (!name) return 0;
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if (r = strchr(name, '=')) {
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register const char *p, *q;
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*r = '\0';
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if (v != NULL) {
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while ((p = *v) != NULL) {
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q = name;
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while (*q && (*q++ == *p++))
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/* EMPTY */ ;
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if (*q || (*p != '=')) {
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v++;
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} else {
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/* The name was already in the
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* environment.
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*/
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*r = '=';
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*v = name;
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return 0;
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}
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}
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}
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v = environ;
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}
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if (!size) {
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register const char **p;
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register int i = 0;
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if (v)
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do {
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i++;
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} while (*v++);
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if (!(v = malloc(rounded(i) * sizeof(char **))))
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return 1;
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size = i;
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p = environ;
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environ = v;
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while (*v++ = *p++); /* copy the environment */
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v = environ;
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} else if (!(size % ENTRY_INC)) {
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if (!(v = realloc(environ, rounded(size) * sizeof(char **))))
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return 1;
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environ = v;
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}
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v[size - 1] = name;
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v[size] = NULL;
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size++;
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return 0;
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}
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