Annotation of prex/usr/lib/libc/stdlib/setenv.c, Revision 1.1
1.1 ! nbrk 1: /*
! 2: * Copyright (c) 1987, 1993
! 3: * The Regents of the University of California. All rights reserved.
! 4: *
! 5: * Redistribution and use in source and binary forms, with or without
! 6: * modification, are permitted provided that the following conditions
! 7: * are met:
! 8: * 1. Redistributions of source code must retain the above copyright
! 9: * notice, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice, this list of conditions and the following disclaimer in the
! 12: * documentation and/or other materials provided with the distribution.
! 13: * 3. Neither the name of the University nor the names of its contributors
! 14: * may be used to endorse or promote products derived from this software
! 15: * without specific prior written permission.
! 16: *
! 17: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 20: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 27: * SUCH DAMAGE.
! 28: */
! 29:
! 30: #include <stddef.h>
! 31: #include <stdlib.h>
! 32: #include <string.h>
! 33:
! 34: extern char **environ;
! 35:
! 36: char *__findenv(const char *, int *);
! 37:
! 38: /*
! 39: * setenv --
! 40: * Set the value of the environmental variable "name" to be
! 41: * "value". If rewrite is set, replace any current value.
! 42: */
! 43: int
! 44: setenv(name, value, rewrite)
! 45: const char *name;
! 46: const char *value;
! 47: int rewrite;
! 48: {
! 49: static int alloced; /* if allocated space before */
! 50: char *c;
! 51: int l_value, offset;
! 52:
! 53: if (*value == '=') /* no `=' in value */
! 54: ++value;
! 55: l_value = strlen(value);
! 56: if ((c = __findenv(name, &offset))) { /* find if already exists */
! 57: if (!rewrite)
! 58: return (0);
! 59: if ((int)strlen(c) >= l_value) { /* old larger; copy over */
! 60: while ( (*c++ = *value++) );
! 61: return (0);
! 62: }
! 63: } else { /* create new slot */
! 64: int cnt;
! 65: char **p;
! 66:
! 67: for (p = environ, cnt = 0; *p; ++p, ++cnt);
! 68: if (alloced) { /* just increase size */
! 69: environ = (char **)realloc((char *)environ,
! 70: (size_t)(sizeof(char *) * (cnt + 2)));
! 71: if (!environ)
! 72: return (-1);
! 73: }
! 74: else { /* get new space */
! 75: alloced = 1; /* copy old entries into it */
! 76: p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
! 77: if (!p)
! 78: return (-1);
! 79: bcopy(environ, p, cnt * sizeof(char *));
! 80: environ = p;
! 81: }
! 82: environ[cnt + 1] = NULL;
! 83: offset = cnt;
! 84: }
! 85: for (c = (char *)name; *c && *c != '='; ++c); /* no `=' in name */
! 86: if (!(environ[offset] = /* name + `=' + value */
! 87: malloc((size_t)((int)(c - name) + l_value + 2))))
! 88: return (-1);
! 89: for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
! 90: for (*c++ = '='; (*c++ = *value++) != 0;);
! 91: return (0);
! 92: }
! 93:
! 94: /*
! 95: * unsetenv(name) --
! 96: * Delete environmental variable "name".
! 97: */
! 98: void
! 99: unsetenv(name)
! 100: const char *name;
! 101: {
! 102: char **p;
! 103: int offset;
! 104:
! 105: while (__findenv(name, &offset)) /* if set multiple times */
! 106: for (p = &environ[offset];; ++p)
! 107: if (!(*p = *(p + 1)))
! 108: break;
! 109: }
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