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Diffstat (limited to '20120831/setenv.c')
| -rw-r--r-- | 20120831/setenv.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/20120831/setenv.c b/20120831/setenv.c new file mode 100644 index 0000000..efd0f74 --- /dev/null +++ b/20120831/setenv.c @@ -0,0 +1,154 @@ +/* + * Copyright (c) 1987 Regents of the University of California. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif +#ifndef HAVE_SETENV + +#if defined(LIBC_SCCS) && !defined(lint) +/*static char *sccsid = "from: @(#)setenv.c 5.6 (Berkeley) 6/4/91";*/ +static char *rcsid = "$Id: setenv.c,v 1.5 1996/09/04 22:10:42 sjg Exp $"; +#endif /* LIBC_SCCS and not lint */ + +#include <stddef.h> +#include <stdlib.h> +#include <string.h> + +/* + * __findenv -- + * Returns pointer to value associated with name, if any, else NULL. + * Sets offset to be the offset of the name/value combination in the + * environmental array, for use by setenv(3) and unsetenv(3). + * Explicitly removes '=' in argument name. + * + * This routine *should* be a static; don't use it. + */ +static char * +__findenv(name, offset) + register char *name; + int *offset; +{ + extern char **environ; + register int len; + register char **P, *C; + + for (C = name, len = 0; *C && *C != '='; ++C, ++len); + for (P = environ; *P; ++P) + if (!strncmp(*P, name, len)) + if (*(C = *P + len) == '=') { + *offset = P - environ; + return(++C); + } + return(NULL); +} + +/* + * setenv -- + * Set the value of the environmental variable "name" to be + * "value". If rewrite is set, replace any current value. + */ +setenv(name, value, rewrite) + register const char *name; + register const char *value; + int rewrite; +{ + extern char **environ; + static int alloced; /* if allocated space before */ + register char *C; + int l_value, offset; + char *__findenv(); + + if (*value == '=') /* no `=' in value */ + ++value; + l_value = strlen(value); + if ((C = __findenv(name, &offset))) { /* find if already exists */ + if (!rewrite) + return (0); + if (strlen(C) >= l_value) { /* old larger; copy over */ + while (*C++ = *value++); + return (0); + } + } else { /* create new slot */ + register int cnt; + register char **P; + + for (P = environ, cnt = 0; *P; ++P, ++cnt); + if (alloced) { /* just increase size */ + environ = (char **)realloc((char *)environ, + (size_t)(sizeof(char *) * (cnt + 2))); + if (!environ) + return (-1); + } + else { /* get new space */ + alloced = 1; /* copy old entries into it */ + P = (char **)malloc((size_t)(sizeof(char *) * + (cnt + 2))); + if (!P) + return (-1); + bcopy(environ, P, cnt * sizeof(char *)); + environ = P; + } + environ[cnt + 1] = NULL; + offset = cnt; + } + for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */ + if (!(environ[offset] = /* name + `=' + value */ + malloc((size_t)((int)(C - name) + l_value + 2)))) + return (-1); + for (C = environ[offset]; (*C = *name++) && *C != '='; ++C) + ; + for (*C++ = '='; *C++ = *value++; ) + ; + return (0); +} + +/* + * unsetenv(name) -- + * Delete environmental variable "name". + */ +void +unsetenv(name) + const char *name; +{ + extern char **environ; + register char **P; + int offset; + char *__findenv(); + + while (__findenv(name, &offset)) /* if set multiple times */ + for (P = &environ[offset];; ++P) + if (!(*P = *(P + 1))) + break; +} +#endif |
