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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [stdlib/] [getenv_r.c] - Rev 283
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/* FUNCTION <<_getenv_r>>---look up environment variable INDEX _getenv_r INDEX environ ANSI_SYNOPSIS #include <stdlib.h> char *_getenv_r(struct _reent *<[reent_ptr]>, const char *<[name]>); TRAD_SYNOPSIS #include <stdlib.h> char *_getenv_r(<[reent_ptr]>, <[name]>) struct _reent *<[reent_ptr]>; char *<[name]>; DESCRIPTION <<_getenv_r>> searches the list of environment variable names and values (using the global pointer ``<<char **environ>>'') for a variable whose name matches the string at <[name]>. If a variable name matches, <<_getenv_r>> returns a pointer to the associated value. RETURNS A pointer to the (string) value of the environment variable, or <<NULL>> if there is no such environment variable. PORTABILITY <<_getenv_r>> is not ANSI; the rules for properly forming names of environment variables vary from one system to another. This implementation does not permit '=' to be in identifiers. <<_getenv_r>> requires a global pointer <<environ>>. */ /* This file may have been modified by DJ Delorie (Jan 1991). If so, ** these modifications are Copyright (C) 1991 DJ Delorie. */ /* * Copyright (c) 1987 Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms are permitted * provided that: (1) source distributions retain this entire copyright * notice and comment, and (2) distributions including binaries display * the following acknowledgement: ``This product includes software * developed by the University of California, Berkeley and its contributors'' * in the documentation or other materials provided with the distribution * and in all advertising materials mentioning features or use of this * software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #include <stdlib.h> #include <stddef.h> #include <string.h> #include "envlock.h" extern char **environ; /* Only deal with a pointer to environ, to work around subtle bugs with shared libraries and/or small data systems where the user declares his own 'environ'. */ static char ***p_environ = &environ; /* * _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). * * This routine *should* be a static; don't use it. */ char * _DEFUN (_findenv_r, (reent_ptr, name, offset), struct _reent *reent_ptr _AND register _CONST char *name _AND int *offset) { register int len; register char **p; _CONST char *c; ENV_LOCK; /* In some embedded systems, this does not get set. This protects newlib from dereferencing a bad pointer. */ if (!*p_environ) { ENV_UNLOCK; return NULL; } c = name; while (*c && *c != '=') c++; /* Identifiers may not contain an '=', so cannot match if does */ if(*c != '=') { len = c - name; for (p = *p_environ; *p; ++p) if (!strncmp (*p, name, len)) if (*(c = *p + len) == '=') { *offset = p - *p_environ; ENV_UNLOCK; return (char *) (++c); } } ENV_UNLOCK; return NULL; } /* * _getenv_r -- * Returns ptr to value associated with name, if any, else NULL. */ char * _DEFUN (_getenv_r, (reent_ptr, name), struct _reent *reent_ptr _AND _CONST char *name) { int offset; char *_findenv_r (); return _findenv_r (reent_ptr, name, &offset); }
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