getenv.cpp File Reference

#include <corecrt_internal_traits.h>
#include <stdlib.h>
#include <string.h>

Include dependency graph for getenv.cpp:

Go to the source code of this file.

Functions
template<typename Character >
static Character *__cdecl	common_getenv_nolock (Character const *const name) throw ()
template<typename Character >
static Character *__cdecl	common_getenv (Character const *const name) throw ()
char *__cdecl	getenv (char const *const name)
wchar_t *__cdecl	_wgetenv (wchar_t const *const name)
template<typename Character >
	_Success_ (return==0) static errno_t __cdecl common_getenv_s_nolock(size_t *const required_count
	_Out_writes_z_ (buffer_count) Character *const buffer
size_t const Character const *const name	throw ()
errno_t __cdecl	getenv_s (size_t *const required_count, char *const buffer, size_t const buffer_count, char const *const name)
errno_t __cdecl	_wgetenv_s (size_t *const required_count, wchar_t *const buffer, size_t const buffer_count, wchar_t const *const name)
template<typename Character >
static errno_t __cdecl	common_dupenv_s_nolock (_Outptr_result_buffer_maybenull_(*buffer_count) _Outptr_result_maybenull_z_ Character **const buffer_pointer, _Out_opt_ size_t *const buffer_count, Character const *const name, int const block_use, char const *const file_name, int const line_number) throw ()
template<typename Character >
	_Success_ (return !=0) static errno_t __cdecl common_dupenv_s(_Outptr_result_buffer_maybenull_(*buffer_count) _Outptr_result_maybenull_z_ Character **const buffer_pointer
errno_t __cdecl	_dupenv_s (char **const buffer_pointer, size_t *const buffer_count, char const *const name)
errno_t __cdecl	_wdupenv_s (wchar_t **const buffer_pointer, size_t *const buffer_count, wchar_t const *const name)

Variables
size_t const	buffer_count
_Out_opt_ size_t *const Character const *const	name
_Out_opt_ size_t *const Character const *const int const	block_use
_Out_opt_ size_t *const Character const *const int const char const *const	file_name

Function Documentation

_dupenv_s()

errno_t __cdecl _dupenv_s	(	char **const	buffer_pointer,
		size_t *const	buffer_count,
		char const *const	name
	)

Definition at line 285 of file getenv.cpp.

{
    return common_dupenv_s(buffer_pointer, buffer_count, name, _NORMAL_BLOCK, nullptr, 0);
}

_Out_writes_z_()

_Out_writes_z_

(

buffer_count

)

const

_Success_() [1/2]

template<typename Character >

_Success_

(

return !

= 0

)

const

_Success_() [2/2]

template<typename Character >

_Success_

(

return

= = 0

)

const

Definition at line 57 of file chdir.cpp.

{
    typedef __crt_char_traits<Character> traits;
 
    _VALIDATE_CLEAR_OSSERR_RETURN(path != nullptr, EINVAL, -1);
 
    if (!traits::set_current_directory(path))
    {
        __acrt_errno_map_os_error(GetLastError());
        return -1;
    }
 
    // If the new current directory path is not a UNC path, we must update the
    // OS environment variable specifying the current full current directory,
    // build the environment variable string, and call SetEnvironmentVariable().
    // We need to do this because the SetCurrentDirectory() API does not update
    // the environment variables, and other functions (fullpath, spawn, etc.)
    // need them to be set.
    //
    // If associated with a 'drive', the current directory should have the
    // form of the example below:
    //
    //     D:\nt\private\mytests
    //
    // So that the environment variable should be of the form:
    //
    //     =D:=D:\nt\private\mytests
 
    Character buffer_initial_storage[MAX_PATH + 1];
    __crt_internal_win32_buffer<Character> current_directory_buffer(buffer_initial_storage);
 
    errno_t const err = traits::get_current_directory(current_directory_buffer);
 
    if (err != 0) {
        // Appropriate error already set
        return -1;
    }
 
    return set_cwd_environment_variable(current_directory_buffer.data());
}

_wdupenv_s()

errno_t __cdecl _wdupenv_s	(	wchar_t **const	buffer_pointer,
		size_t *const	buffer_count,
		wchar_t const *const	name
	)

Definition at line 294 of file getenv.cpp.

{
    return common_dupenv_s(buffer_pointer, buffer_count, name, _NORMAL_BLOCK, nullptr, 0);
}

_wgetenv()

wchar_t *__cdecl _wgetenv

(

wchar_t const *const

name

)

Definition at line 89 of file getenv.cpp.

{
    return common_getenv(name);
}

_wgetenv_s()

errno_t __cdecl _wgetenv_s	(	size_t *const	required_count,
		wchar_t *const	buffer,
		size_t const	buffer_count,
		wchar_t const *const	name
	)

Definition at line 179 of file getenv.cpp.

{
    return common_getenv_s(required_count, buffer, buffer_count, name);
}

Referenced by get_tz_environment_variable().

common_dupenv_s_nolock()

template<typename Character >

static errno_t __cdecl common_dupenv_s_nolock ( _Outptr_result_buffer_maybenull_ *buffer_count _Outptr_result_maybenull_z_ Character **const  buffer_pointer, _Out_opt_ size_t *const  buffer_count, Character const *const  name, int const  block_use, char const *const  file_name, int const  line_number  ) throw ( )

static

Definition at line 207 of file getenv.cpp.

{
    // These are referenced only in the Debug CRT build
    UNREFERENCED_PARAMETER(block_use);
    UNREFERENCED_PARAMETER(file_name);
    UNREFERENCED_PARAMETER(line_number);
 
    typedef __crt_char_traits<Character> traits;
 
     _VALIDATE_RETURN_ERRCODE(buffer_pointer != nullptr, EINVAL);
    *buffer_pointer = nullptr;
 
    if (buffer_count != nullptr)
        *buffer_count = 0;
 
    _VALIDATE_RETURN_ERRCODE(name != nullptr, EINVAL);
 
    Character const* const value = common_getenv_nolock(name);
    if (value == nullptr)
        return 0;
 
    size_t const value_count = traits::tcslen(value) + 1;
 
    *buffer_pointer = static_cast<Character*>(_calloc_dbg(
        value_count,
        sizeof(Character),
        block_use,
        file_name,
        line_number));
    _VALIDATE_RETURN_ERRCODE_NOEXC(*buffer_pointer != nullptr, ENOMEM);
 
    _ERRCHECK(traits::tcscpy_s(*buffer_pointer, value_count, value));
    if (buffer_count != nullptr)
        *buffer_count = value_count;
 
    return 0;
}

common_getenv()

template<typename Character >

static Character *__cdecl common_getenv ( Character const *const  name ) throw ( )

static

Definition at line 61 of file getenv.cpp.

{
    typedef __crt_char_traits<Character> traits;
 
    _VALIDATE_RETURN(name != nullptr,                            EINVAL, nullptr);
    _VALIDATE_RETURN(traits::tcsnlen(name, _MAX_ENV) < _MAX_ENV, EINVAL, nullptr);
 
    Character* result = 0;
 
    __acrt_lock(__acrt_environment_lock);
    __try
    {
        result = common_getenv_nolock(name);
    }
    __finally
    {
        __acrt_unlock(__acrt_environment_lock);
    }
    __endtry
    
    return result;
}

Referenced by _wgetenv(), and getenv().

common_getenv_nolock()

template<typename Character >

static Character *__cdecl common_getenv_nolock ( Character const *const  name ) throw ( )

static

Definition at line 26 of file getenv.cpp.

{
    typedef __crt_char_traits<Character> traits;
    
    Character** const environment = traits::get_or_create_environment_nolock();
    if (environment == nullptr || name == nullptr)
        return nullptr;
 
    size_t const name_length = traits::tcslen(name);
 
    for (Character** current = environment; *current; ++current)
    {
        if (traits::tcslen(*current) <= name_length)
            continue;
 
        if (*(*current + name_length) != '=')
            continue;
 
        if (traits::tcsnicoll(*current, name, name_length) != 0)
            continue;
 
        // Internal consistency check:  The environment string should never use
        // a bigger buffer than _MAX_ENV.  See also the SetEnvironmentVariable
        // SDK function.
        _ASSERTE(traits::tcsnlen(*current + name_length + 1, _MAX_ENV) < _MAX_ENV);
 
        return *current + name_length + 1;
    }
 
    return nullptr;
}

Referenced by common_dupenv_s_nolock(), common_getenv(), and throw().

getenv()

char *__cdecl getenv

(

char const *const

name

)

Definition at line 84 of file getenv.cpp.

{
    return common_getenv(name);
}

getenv_s()

errno_t __cdecl getenv_s	(	size_t *const	required_count,
		char *const	buffer,
		size_t const	buffer_count,
		char const *const	name
	)

Definition at line 169 of file getenv.cpp.

{
    return common_getenv_s(required_count, buffer, buffer_count, name);
}

throw()

size_t const Character const *const name throw

(

)

Definition at line 113 of file getenv.cpp.

{
    typedef __crt_char_traits<Character> traits;
 
    _VALIDATE_RETURN_ERRCODE(required_count != nullptr, EINVAL);
    *required_count = 0;
 
    _VALIDATE_RETURN_ERRCODE(
        (buffer != nullptr && buffer_count >  0) ||
        (buffer == nullptr && buffer_count == 0), EINVAL);
 
    if (buffer)
        buffer[0] = '\0';
 
    Character const* const value = common_getenv_nolock(name);
    if (!value)
        return 0;
 
    *required_count = traits::tcslen(value) + 1;
    if (buffer_count == 0)
        return 0;
 
    // The buffer is too small; we return an error code and the caller can have
    // the opportunity to try again with a larger buffer:
    if (*required_count > buffer_count)
        return ERANGE;
 
    _ERRCHECK(traits::tcscpy_s(buffer, buffer_count, value));
    return 0;
}

Variable Documentation

block_use

__endtry int const block_use

Initial value:

{
    __acrt_lock(__acrt_heap_lock)

Definition at line 258 of file getenv.cpp.

Referenced by _CrtDefaultAllocHook(), _strdup(), _wcsdup(), and common_dupenv_s_nolock().

buffer_count

_Out_opt_ size_t* const buffer_count

Definition at line 111 of file getenv.cpp.

Referenced by _dupenv_s(), _wdupenv_s(), _wgetenv_s(), common_dupenv_s_nolock(), getenv_s(), and throw().

file_name

size_t const int const char const *const file_name

Definition at line 259 of file getenv.cpp.

Referenced by common_dupenv_s_nolock().

name

_Out_opt_ size_t* const Character const* const name

Definition at line 257 of file getenv.cpp.