root / prex-0.9.0 / usr / lib / libc / stdlib / setenv.c @ 03e9c04a
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/*
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* Copyright (c) 1987, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stddef.h> |
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#include <stdlib.h> |
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#include <string.h> |
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extern char **environ; |
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char *__findenv(const char *, int *); |
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/*
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* setenv --
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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
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setenv(name, value, rewrite) |
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const char *name; |
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const char *value; |
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int rewrite;
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{ |
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static int alloced; /* if allocated space before */ |
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char *c;
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int l_value, 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))) { /* find if already exists */ |
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if (!rewrite)
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return (0); |
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if ((int)strlen(c) >= l_value) { /* old larger; copy over */ |
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while ( (*c++ = *value++) );
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return (0); |
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} |
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} else { /* create new slot */ |
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int cnt;
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char **p;
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for (p = environ, cnt = 0; *p; ++p, ++cnt); |
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if (alloced) { /* just increase size */ |
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environ = (char **)realloc((char *)environ, |
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(size_t)(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 { /* get new space */ |
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alloced = 1; /* copy old entries into it */ |
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p = malloc((size_t)(sizeof(char *) * (cnt + 2))); |
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if (!p)
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return (-1); |
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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); /* no `=' in name */ |
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if (!(environ[offset] = /* name + `=' + value */ |
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malloc((size_t)((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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for (*c++ = '='; (*c++ = *value++) != 0;); |
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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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void
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unsetenv(name) |
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const char *name; |
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{ |
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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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} |