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Diffstat (limited to 'lisp/env.c')
| -rw-r--r-- | lisp/env.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/lisp/env.c b/lisp/env.c new file mode 100644 index 0000000..a5da90c --- /dev/null +++ b/lisp/env.c @@ -0,0 +1,151 @@ +/* + * Provide setenv() and unsetenv() on platforms that don't have them. + * From FreeBSD's libc. + */ + +/* + * Copyright (c) 1987, 1993 + * The 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. + */ + +/* $XFree86: xc/programs/xedit/lisp/env.c,v 1.1 2002/03/05 03:52:34 dawes Exp $ */ + + +#include <stdlib.h> +#include <stddef.h> +#include <string.h> + +extern char **environ; + +extern int setenv(const char *name, const char *value, int overwrite); +extern void unsetenv(const char *name); + +static char * +findenv(const char *name, int *offset) +{ + int len, i; + const char *np; + char **p, *cp; + + if (name == NULL || environ == NULL) + return NULL; + + for (np = name; *np && *np != '='; ++np) + continue; + len = np - name; + for (p = environ; (cp = *p) != NULL; ++p) { + for (np = name, i = len; i && *cp; i--) + if (*cp++ != *np++) + break; + if (i == 0 && *cp++ == '=') { + *offset = p - environ; + return cp; + } + } + return NULL; +} + +/* + * setenv -- + * Set the value of the environmental variable "name" to be + * "value". If overwrite is set, replace any current value. + */ + +int +setenv(const char *name, const char *value, int overwrite) +{ + static char **alloced; /* if allocated space before */ + char *c; + int l_value, offset; + + if (*value == '=') /* no '=' in value */ + ++value; + l_value = strlen(value); + if ((c = findenv(name, &offset))) { /* find if already exists */ + if (!overwrite) + return 0; + if (strlen(c) >= l_value) { /* old larger; copy over */ + while ((*c++ = *value++)) + ; + return 0; + } + } else { /* create new slot */ + int cnt; + char **p; + + for (p = environ, cnt = 0; *p; ++p, ++cnt) + ; + if (alloced == environ) { /* just increase size */ + p = (char **)realloc((char *)environ, + sizeof(char *) * (cnt + 2)); + if (!p) + return -1; + alloced = environ = p; + } else { /* get new space */ + /* copy old entries into it */ + p = malloc(sizeof(char *) * (cnt + 2)); + if (!p) + return -1; + memcpy(p, environ, cnt * sizeof(char *)); + alloced = environ = p; + } + environ[cnt + 1] = NULL; + offset = cnt; + } + for (c = (char *)name; *c && *c != '='; ++c) /* no '=' in name */ + ; + if (!(environ[offset] = /* name + '=' + value */ + malloc((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(const char *name) +{ + char **p; + int offset; + + while (findenv(name, &offset)) /* if set multiple times */ + for (p = &environ[offset];; ++p) + if (!(*p = *(p + 1))) + break; +} + |