95 lines
2.1 KiB
C
95 lines
2.1 KiB
C
/*
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* (c) copyright 1987 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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/* $Id$ */
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#include <stdlib.h>
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#include <string.h>
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extern char* _findenv(const char* name, int* offset);
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extern char** environ;
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/*
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* setenv(name,value,rewrite)
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* Set the value of the environmental variable "name" to be
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* "value". If rewrite is set, replace any current value.
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*/
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int setenv(register const char* name, register const char* value, int rewrite)
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{
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static int alloced = 0; /* if allocated space before */
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register char* C;
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int l_value,
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offset;
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if (*value == '=') /* no `=' in value */
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++value;
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l_value = strlen(value);
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if ((C = _findenv(name, &offset)))
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{ /* find if already exists */
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if (!rewrite)
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return (0);
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if (strlen(C) >= l_value)
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{ /* old larger; copy over */
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while (*C++ = *value++)
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;
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return (0);
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}
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}
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else
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{ /* create new slot */
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register int cnt = 0;
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register char** P;
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if (environ)
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for (P = environ; *P; ++P, ++cnt)
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;
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if (alloced)
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{ /* just increase size */
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environ = (char**)realloc((char*)environ,
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(unsigned)(sizeof(char*) * (cnt + 2)));
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if (!environ)
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return (-1);
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}
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else
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{ /* get new space */
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alloced = 1; /* copy old entries into it */
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P = (char**)malloc((unsigned)(sizeof(char*) * (cnt + 2)));
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if (!P)
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return (-1);
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if (environ)
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bcopy(environ, P, cnt * sizeof(char*));
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environ = P;
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}
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environ[cnt + 1] = NULL;
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offset = cnt;
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}
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for (C = (char*) name; *C && *C != '='; ++C)
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; /* no `=' in name */
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if (!(environ[offset] = /* name + `=' + value */
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malloc((unsigned)((int)(C - name) + l_value + 2))))
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return (-1);
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for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
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;
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for (*C++ = '='; *C++ = *value++;)
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;
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return (0);
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}
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/*
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* unsetenv(name) --
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* Delete environmental variable "name".
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*/
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int unsetenv(const char* name)
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{
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register char** P;
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int offset;
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while (_findenv(name, &offset)) /* if set multiple times */
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for (P = &environ[offset];; ++P)
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if (!(*P = *(P + 1)))
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break;
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return 0;
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}
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