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[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [packages/] [language/] [c/] [libc/] [stdlib/] [v2_0/] [src/] [getenv.cxx] - Rev 27
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//======================================================================== // // getenv.cxx // // Implementation of the ISO C standard getenv() function // //======================================================================== //####ECOSGPLCOPYRIGHTBEGIN#### // ------------------------------------------- // This file is part of eCos, the Embedded Configurable Operating System. // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. // // eCos is free software; you can redistribute it and/or modify it under // the terms of the GNU General Public License as published by the Free // Software Foundation; either version 2 or (at your option) any later version. // // eCos is distributed in the hope that it will be useful, but WITHOUT ANY // WARRANTY; without even the implied warranty of MERCHANTABILITY or // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // // You should have received a copy of the GNU General Public License along // with eCos; if not, write to the Free Software Foundation, Inc., // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. // // As a special exception, if other files instantiate templates or use macros // or inline functions from this file, or you compile this file and link it // with other works to produce a work based on this file, this file does not // by itself cause the resulting work to be covered by the GNU General Public // License. However the source code for this file must still be made available // in accordance with section (3) of the GNU General Public License. // // This exception does not invalidate any other reasons why a work based on // this file might be covered by the GNU General Public License. // // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. // at http://sources.redhat.com/ecos/ecos-license/ // ------------------------------------------- //####ECOSGPLCOPYRIGHTEND#### //======================================================================== //#####DESCRIPTIONBEGIN#### // // Author(s): jlarmour // Contributors: // Date: 2000-04-30 // Purpose: // Description: // Usage: // //####DESCRIPTIONEND#### // //======================================================================== // CONFIGURATION #include <pkgconf/libc_stdlib.h> // Configuration header // INCLUDES #include <cyg/infra/cyg_type.h> // Common type definitions and support #include <cyg/infra/cyg_ass.h> // Tracing support #include <cyg/infra/cyg_trac.h> // Tracing support #include <stdlib.h> // Main header for stdlib functions #include <string.h> // strchr(), strlen() and strncmp() // VARIABLES externC char **environ; // standard definition of environ // FUNCTIONS extern char * getenv( const char *name ) { // This function assumes the POSIX 1003.1 layout of the environment // in the environ variable, i.e. extern char **environ is a pointer // to an array of character pointers to the environment strings // (POSIX 3.1.2.2 and 2.6). // // getenv() searches the environment list for a string of the form // "name=value" (POSIX 4.6.1). The strings must have this form // (POSIX 2.6) CYG_REPORT_FUNCNAMETYPE( "getenv", "returning %08x" ); CYG_PRECONDITION( name != NULL, "getenv() called with NULL string!" ); CYG_REPORT_FUNCARG1( "name=%s", name ); CYG_PRECONDITION( environ != NULL, "environ not set i.e. environ == NULL" ); CYG_CHECK_DATA_PTR( environ, "environ isn't a valid pointer!" ); CYG_CHECK_DATA_PTR( name, "name isn't a valid pointer!" ); // check name doesn't contain '=' CYG_PRECONDITION( strchr(name, '=') == NULL, "name contains '='!" ); char **env_str_p; cyg_ucount32 len = strlen( name ); for (env_str_p = environ; *env_str_p != NULL; ++env_str_p ) { CYG_CHECK_DATA_PTR( env_str_p, "current environment string isn't valid!" ); CYG_CHECK_DATA_PTR( *env_str_p, "current environment string isn't valid!" ); // do we have a match? if ( !strncmp(*env_str_p, name, len) ) { // but it could be just a prefix i.e. we could have // matched MYNAMEFRED when we're looking for just MYNAME, so: if ( (*env_str_p)[len] == '=' ) { // we got a match CYG_REPORT_RETVAL( *env_str_p + len + 1 ); return (*env_str_p + len + 1); } // if } // if // check the next pointer isn't NULL, as we're about to dereference // it CYG_ASSERT( env_str_p+1 != NULL, "environment contains a NULL pointer!" ); } // for CYG_REPORT_RETVAL( NULL ); return NULL; } // getenv() // EOF getenv.cxx
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