/*
 * kmp_environment.c -- Handle environment variables OS-independently.
 * $Revision: 42263 $
 * $Date: 2013-04-04 11:03:19 -0500 (Thu, 04 Apr 2013) $
 */


//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.txt for details.
//
//===----------------------------------------------------------------------===//


/*
    ------------------------------------------------------------------------------------------------
    We use GetEnvironmentVariable for Windows* OS instead of getenv because the act of
    loading a DLL on Windows* OS makes any user-set environment variables (i.e. with putenv())
    unavailable.  getenv() apparently gets a clean copy of the env variables as they existed
    at the start of the run.
    JH 12/23/2002
    ------------------------------------------------------------------------------------------------
    On Windows* OS, there are two environments (at least, see below):

        1. Environment maintained by Windows* OS on IA-32 architecture. 
	   Accessible through GetEnvironmentVariable(),
           SetEnvironmentVariable(), and GetEnvironmentStrings().

        2. Environment maintained by C RTL. Accessible through getenv(), putenv().

    putenv() function updates both C and Windows* OS on IA-32 architecture. getenv() function 
    search for variables in C RTL environment only. Windows* OS on IA-32 architecture functions work *only* 
    with Windows* OS on IA-32 architecture.

    Windows* OS on IA-32 architecture maintained by OS, so there is always only one Windows* OS on 
    IA-32 architecture per process. Changes in Windows* OS on IA-32 architecture are process-visible.

    C environment maintained by C RTL. Multiple copies of C RTL may be present in the process, and
    each C RTL maintains its own environment. :-(

    Thus, proper way to work with environment on Windows* OS is:

        1. Set variables with putenv() function -- both C and Windows* OS on
	   IA-32 architecture are being updated. Windows* OS on 
	   IA-32 architecture may be considered as primary target,
	   while updating C RTL environment is a free bonus.

        2. Get variables with GetEnvironmentVariable() -- getenv() does not 
	   search Windows* OS on IA-32 architecture, and can not see variables
	   set with SetEnvironmentVariable().

    2007-04-05 -- lev
    ------------------------------------------------------------------------------------------------
*/

#include "kmp_environment.h"

#include "kmp_os.h"    // KMP_OS_*.
#include "kmp.h"       //
#include "kmp_str.h"   // __kmp_str_*().
#include "kmp_i18n.h"

#if KMP_OS_UNIX
    #include <stdlib.h>    // getenv, setenv, unsetenv.
    #include <string.h>    // strlen, strcpy.
    #if KMP_OS_LINUX || KMP_OS_FREEBSD
        extern char * * environ;
    #elif KMP_OS_DARWIN
        #include <crt_externs.h>
        #define environ (*_NSGetEnviron())
    #else
        #error Unknown or unsupported OS.
    #endif
#elif KMP_OS_WINDOWS
    #include <windows.h>   // GetEnvironmentVariable, SetEnvironmentVariable, GetLastError.
#else
    #error Unknown or unsupported OS.
#endif


// TODO: Eliminate direct memory allocations, use string operations instead.

static inline
void *
allocate(
    size_t size
) {
    void * ptr = KMP_INTERNAL_MALLOC( size );
    if ( ptr == NULL ) {
	KMP_FATAL( MemoryAllocFailed );
    }; // if
    return ptr;
} // allocate


char *
__kmp_env_get( char const * name ) {

    char * result = NULL;

    #if KMP_OS_UNIX
        char const * value = getenv( name );
        if ( value != NULL ) {
            size_t len = strlen( value ) + 1;
            result = (char *) KMP_INTERNAL_MALLOC( len );
            if ( result == NULL ) {
		KMP_FATAL( MemoryAllocFailed );
            }; // if
            strncpy( result, value, len );
        }; // if
    #elif KMP_OS_WINDOWS
        /*
            We use GetEnvironmentVariable for Windows* OS instead of getenv because the act of
            loading a DLL on Windows* OS makes any user-set environment variables (i.e. with putenv())
            unavailable.  getenv() apparently gets a clean copy of the env variables as they existed
            at the start of the run.
            JH 12/23/2002
        */
        DWORD rc;
        rc = GetEnvironmentVariable( name, NULL, 0 );
        if ( ! rc ) {
            DWORD error = GetLastError();
            if ( error != ERROR_ENVVAR_NOT_FOUND ) {
                __kmp_msg(
                    kmp_ms_fatal,
                    KMP_MSG( CantGetEnvVar, name ),
                    KMP_ERR( error ),
                    __kmp_msg_null
                );
            }; // if
            // Variable is not found, it's ok, just continue.
        } else {
            DWORD len = rc;
            result = (char *) KMP_INTERNAL_MALLOC( len );
            if ( result == NULL ) {
		KMP_FATAL( MemoryAllocFailed );
            }; // if
            rc = GetEnvironmentVariable( name, result, len );
            if ( ! rc ) {
                // GetEnvironmentVariable() may return 0 if variable is empty.
                // In such a case GetLastError() returns ERROR_SUCCESS.
                DWORD error = GetLastError();
                if ( error != ERROR_SUCCESS ) {
                    // Unexpected error. The variable should be in the environment,
                    // and buffer should be large enough.
                    __kmp_msg(
                        kmp_ms_fatal,
                        KMP_MSG( CantGetEnvVar, name ),
                        KMP_ERR( error ),
                        __kmp_msg_null
                    );
                    KMP_INTERNAL_FREE( (void *) result );
                    result = NULL;
                }; // if
            }; // if
        }; // if
    #else
        #error Unknown or unsupported OS.
    #endif

    return result;

} // func __kmp_env_get


// TODO: Find and replace all regular free() with __kmp_env_free().

void
__kmp_env_free( char const * * value ) {

    KMP_DEBUG_ASSERT( value != NULL );
    KMP_INTERNAL_FREE( (void *) * value );
    * value = NULL;

} // func __kmp_env_free



int
__kmp_env_exists( char const * name ) {

    #if KMP_OS_UNIX
        char const * value = getenv( name );
        return ( ( value == NULL ) ? ( 0 ) : ( 1 ) );
    #elif KMP_OS_WINDOWS
        DWORD rc;
        rc = GetEnvironmentVariable( name, NULL, 0 );
        if ( rc == 0 ) {
            DWORD error = GetLastError();
            if ( error != ERROR_ENVVAR_NOT_FOUND ) {
                __kmp_msg(
                    kmp_ms_fatal,
                    KMP_MSG( CantGetEnvVar, name ),
                    KMP_ERR( error ),
                    __kmp_msg_null
                );
            }; // if
            return 0;
        }; // if
        return 1;
    #else
        #error Unknown or unsupported OS.
    #endif

} // func __kmp_env_exists



void
__kmp_env_set( char const * name, char const * value, int overwrite ) {

    #if KMP_OS_UNIX
        int rc = setenv( name, value, overwrite );
        if ( rc != 0 ) {
            // Dead code. I tried to put too many variables into Linux* OS
            // environment on IA-32 architecture. When application consumes
            // more than ~2.5 GB of memory, entire system feels bad. Sometimes
            // application is killed (by OS?), sometimes system stops 
            // responding... But this error message never appears. --ln
            __kmp_msg(
                kmp_ms_fatal,
                KMP_MSG( CantSetEnvVar, name ),
                KMP_HNT( NotEnoughMemory ),
                __kmp_msg_null
            );
        }; // if
    #elif KMP_OS_WINDOWS
        BOOL rc;
        if ( ! overwrite ) {
            rc = GetEnvironmentVariable( name, NULL, 0 );
            if ( rc ) {
                // Variable exists, do not overwrite.
                return;
            }; // if
            DWORD error = GetLastError();
            if ( error != ERROR_ENVVAR_NOT_FOUND ) {
                __kmp_msg(
                    kmp_ms_fatal,
                    KMP_MSG( CantGetEnvVar, name ),
                    KMP_ERR( error ),
                    __kmp_msg_null
                );
            }; // if
        }; // if
        rc = SetEnvironmentVariable( name, value );
        if ( ! rc ) {
            DWORD error = GetLastError();
            __kmp_msg(
                kmp_ms_fatal,
                KMP_MSG( CantSetEnvVar, name ),
                KMP_ERR( error ),
                __kmp_msg_null
            );
        }; // if
    #else
        #error Unknown or unsupported OS.
    #endif

} // func __kmp_env_set



void
__kmp_env_unset( char const * name ) {

    #if KMP_OS_UNIX
        unsetenv( name );
    #elif KMP_OS_WINDOWS
        BOOL rc = SetEnvironmentVariable( name, NULL );
        if ( ! rc ) {
            DWORD error = GetLastError();
            __kmp_msg(
                kmp_ms_fatal,
                KMP_MSG( CantSetEnvVar, name ),
                KMP_ERR( error ),
                __kmp_msg_null
            );
        }; // if
    #else
        #error Unknown or unsupported OS.
    #endif

} // func __kmp_env_unset

// -------------------------------------------------------------------------------------------------

/*
    Intel OpenMP RTL string representation of environment: just a string of characters, variables
    are separated with vertical bars, e. g.:

        "KMP_WARNINGS=0|KMP_AFFINITY=compact|"

    Empty variables are allowed and ignored:

        "||KMP_WARNINGS=1||"

*/

static
void
___kmp_env_blk_parse_string(
    kmp_env_blk_t * block,   // M: Env block to fill.
    char const *    env      // I: String to parse.
) {

    char const chr_delimiter   = '|';
    char const str_delimiter[] = { chr_delimiter, 0 };

    char *          bulk       = NULL;
    kmp_env_var_t * vars       = NULL;
    int             count      = 0;  // Number of used elements in vars array.
    int             delimiters = 0;  // Number of delimiters in input string.

    // Copy original string, we will modify the copy.
    bulk = __kmp_str_format( "%s", env );

    // Loop thru all the vars in environment block. Count delimiters (maximum number of variables
    // is number of delimiters plus one).
    {
        char const * ptr = bulk;
        for ( ; ; ) {
            ptr = strchr( ptr, chr_delimiter );
            if ( ptr == NULL ) {
                break;
            }; // if
            ++ delimiters;
            ptr += 1;
        }; // forever
    }

    // Allocate vars array.
    vars = (kmp_env_var_t *) allocate( ( delimiters + 1 ) * sizeof( kmp_env_var_t ) );

    // Loop thru all the variables.
    {
        char * var;     // Pointer to variable (both name and value).
        char * name;    // Pointer to name of variable.
        char * value;   // Pointer to value.
        char * buf;     // Buffer for __kmp_str_token() function.
        var = __kmp_str_token( bulk, str_delimiter, & buf );      // Get the first var.
        while ( var != NULL ) {
            // Save found variable in vars array.
            __kmp_str_split( var, '=', & name, & value );
            KMP_DEBUG_ASSERT( count < delimiters + 1 );
            vars[ count ].name  = name;
            vars[ count ].value = value;
            ++ count;
            // Get the next var.
            var = __kmp_str_token( NULL, str_delimiter, & buf );
        }; // while
    }

    // Fill out result.
    block->bulk  = bulk;
    block->vars  = vars;
    block->count = count;

}; // ___kmp_env_blk_parse_string



/*
    Windows* OS (actually, DOS) environment block is a piece of memory with environment variables. Each
    variable is terminated with zero byte, entire block is terminated with one extra zero byte, so
    we have two zero bytes at the end of environment block, e. g.:

        "HOME=C:\\users\\lev\x00OS=Windows_NT\x00\x00"

    It is not clear how empty environment is represented. "\x00\x00"?
*/

static
void
___kmp_env_blk_parse_windows(
    kmp_env_blk_t * block,   // M: Env block to fill.
    char const *    env      // I: Pointer to Windows* OS (DOS) environment block.
) {

    char *          bulk  = NULL;
    kmp_env_var_t * vars  = NULL;
    int             count = 0;     // Number of used elements in vars array.
    int             size  = 0;     // Size of bulk.

    char * name;    // Pointer to name of variable.
    char * value;   // Pointer to value.

    if ( env != NULL ) {

        // Loop thru all the vars in environment block. Count variables, find size of block.
        {
            char const * var;     // Pointer to beginning of var.
            int          len;     // Length of variable.
            count = 0;
            var = env;            // The first variable starts and beginning of environment block.
            len = strlen( var );
            while ( len != 0 ) {
                ++ count;
                size = size + len + 1;
                var = var + len + 1; // Move pointer to the beginning of the next variable.
                len = strlen( var );
            }; // while
            size = size + 1;         // Total size of env block, including terminating zero byte.
        }

        // Copy original block to bulk, we will modify bulk, not original block.
        bulk = (char *) allocate( size );
        memcpy( bulk, env, size );
        // Allocate vars array.
        vars = (kmp_env_var_t *) allocate( count * sizeof( kmp_env_var_t ) );

        // Loop thru all the vars, now in bulk.
        {
            char * var;     // Pointer to beginning of var.
            int    len;     // Length of variable.
            count = 0;
            var = bulk;
            len = strlen( var );
            while ( len != 0 ) {
                // Save variable in vars array.
                __kmp_str_split( var, '=', & name, & value );
                vars[ count ].name  = name;
                vars[ count ].value = value;
                ++ count;
                // Get the next var.
                var = var + len + 1;
                len = strlen( var );
            }; // while
        }

    }; // if

    // Fill out result.
    block->bulk  = bulk;
    block->vars  = vars;
    block->count = count;

}; // ___kmp_env_blk_parse_windows



/*
    Unix environment block is a array of pointers to variables, last pointer in array is NULL:

        { "HOME=/home/lev", "TERM=xterm", NULL }
*/

static
void
___kmp_env_blk_parse_unix(
    kmp_env_blk_t * block,   // M: Env block to fill.
    char * *        env      // I: Unix environment to parse.
) {

    char *          bulk  = NULL;
    kmp_env_var_t * vars  = NULL;
    int             count = 0;
    int             size  = 0;    // Size of bulk.

    // Count number of variables and length of required bulk.
    {
        count = 0;
        size  = 0;
        while ( env[ count ] != NULL ) {
            size += strlen( env[ count ] ) + 1;
            ++ count;
        }; // while
    }

    // Allocate memory.
    bulk = (char *) allocate( size );
    vars = (kmp_env_var_t *) allocate( count * sizeof( kmp_env_var_t ) );

    // Loop thru all the vars.
    {
        char * var;     // Pointer to beginning of var.
        char * name;    // Pointer to name of variable.
        char * value;   // Pointer to value.
        int    len;     // Length of variable.
        int    i;
        var = bulk;
        for ( i = 0; i < count; ++ i ) {
            // Copy variable to bulk.
            len = strlen( env[ i ] );
            memcpy( var, env[ i ], len + 1 );
            // Save found variable in vars array.
            __kmp_str_split( var, '=', & name, & value );
            vars[ i ].name  = name;
            vars[ i ].value = value;
            // Move pointer.
            var += len + 1;
        }; // for
    }

    // Fill out result.
    block->bulk  = bulk;
    block->vars  = vars;
    block->count = count;

}; // ___kmp_env_blk_parse_unix



void
__kmp_env_blk_init(
    kmp_env_blk_t * block,  // M: Block to initialize.
    char const *    bulk    // I: Initialization string, or NULL.
) {

    if ( bulk != NULL ) {
        ___kmp_env_blk_parse_string( block, bulk );
    } else {
        #if KMP_OS_UNIX
            ___kmp_env_blk_parse_unix( block, environ );
        #elif KMP_OS_WINDOWS
            {
                char * mem = GetEnvironmentStrings();
                if ( mem == NULL ) {
                    DWORD error = GetLastError();
                    __kmp_msg(
                        kmp_ms_fatal,
                        KMP_MSG( CantGetEnvironment ),
                        KMP_ERR( error ),
                        __kmp_msg_null
                    );
                }; // if
                ___kmp_env_blk_parse_windows( block, mem );
                FreeEnvironmentStrings( mem );
            }
        #else
            #error Unknown or unsupported OS.
        #endif
    }; // if

} // __kmp_env_blk_init



static
int
___kmp_env_var_cmp(                              // Comparison function for qsort().
    kmp_env_var_t const * lhs,
    kmp_env_var_t const * rhs
) {
    return strcmp( lhs->name, rhs->name );
}

void
__kmp_env_blk_sort(
    kmp_env_blk_t * block  // M: Block of environment variables to sort.
) {

    qsort(
        (void *) block->vars,
        block->count,
        sizeof( kmp_env_var_t ),
        ( int ( * )( void const *, void const * ) ) & ___kmp_env_var_cmp
    );

} // __kmp_env_block_sort



void
__kmp_env_blk_free(
    kmp_env_blk_t * block  // M: Block of environment variables to free.
) {

    KMP_INTERNAL_FREE( (void *) block->vars );
    KMP_INTERNAL_FREE( (void *) block->bulk );

    block->count = 0;
    block->vars  = NULL;
    block->bulk  = NULL;

} // __kmp_env_blk_free



char const *               // R: Value of variable or NULL if variable does not exist.
__kmp_env_blk_var(
    kmp_env_blk_t * block, // I: Block of environment variables.
    char const *    name   // I: Name of variable to find.
) {

    int i;
    for ( i = 0; i < block->count; ++ i ) {
        if ( strcmp( block->vars[ i ].name, name ) == 0 ) {
            return block->vars[ i ].value;
        }; // if
    }; // for
    return NULL;

} // __kmp_env_block_var


// end of file //
