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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 Free Software Foundation, 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.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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 v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public 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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