Source code of Windows XP (NT5)
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/***
*stdenvp.c - standard _setenvp routine** Copyright (c) 1989-2001, Microsoft Corporation. All rights reserved.**Purpose:* This module is called by the C start-up routine to set up "_environ".* Its sets up an array of pointers to strings in the environment.* The global symbol "_environ" is set to point to this array.**Revision History:* 11-07-84 GFW initial version* 01-08-86 SKS Modified for OS/2* 05-21-86 SKS Call _stdalloc to get memory for strings* 09-04-86 SKS Added check to skip the "*C_FILE_INFO" string* 10-21-86 SKS Improved check for "*C_FILE_INFO"/"_C_FILE_INFO"* 02-19-88 SKS Handle case where environment starts with a single null* 05-10-88 JCR Modified code to accept far pointer from _stdalloc* 06-01-88 PHG Merged DLL and normal versions* 07-12-88 JCR Largely re-written: (1) split mem allocation into two* seperate malloc() calls to help simplify putenv(),* (2) stdalloc() no longer robs from stack, (3) cProc/cEnd* sequence, (4) misc cleanup* 09-20-88 WAJ Initial 386 version* 12-13-88 JCR Use rterr.inc parameters for runtime errors* 04-09-90 GJF Added #include <cruntime.h>. Made the calling type* _CALLTYPE1. Also, fixed the copyright and cleaned up* up the formatting a bit.* 06-05-90 GJF Changed error message interface.* 10-08-90 GJF New-style function declarator.* 10-31-90 GJF Fixed statement appending the final NULL (Stevewo* found the bug).* 12-11-90 SRW Changed to include <oscalls.h> and setup _environ* correctly for Win32* 01-21-91 GJF ANSI naming.* 02-07-91 SRW Change _WIN32_ specific code to allocate static copy* 02-18-91 SRW Change _WIN32_ specific code to allocate copy of* variable strings as well [_WIN32_]* 07-25-91 GJF Changed strupr to _strupr.* 03-31-92 DJM POSIX support.* 04-20-92 GJF Removed conversion to upper-case code for Win32.* 04-06-93 SKS Replace _CRTAPI* with __cdecl* 11-24-93 CFW Rip out Cruiser and filter out "=c:\foo" type.* 11-29-93 CFW Remove unused POSIX stuff, wide char enable.* 12-07-93 CFW Change _TCHAR to _TSCHAR.* 01-10-95 CFW Debug CRT allocs.* 04-07-95 CFW Free environment block on demand.* 07-03-95 GJF Always free environment block.* 02-20-96 SKS Set _aenvptr/_wenvptr to NULL after freeing what it* points to (a copy of environment strings).* 06-30-97 GJF Added explicit, conditional init. of the mbctype table.* Set __env_initialized flag. Also detab-ed.* 01-04-99 GJF Changes for 64-bit size_t.* 03-05-01 PML Don't AV if _aenvptr is NULL (vs7#174755).* 03-27-01 PML Return error instead of calling amsg_exit (vs7#231220)********************************************************************************/
#include <cruntime.h>
#include <string.h>
#include <stdlib.h>
#include <internal.h>
#include <rterr.h>
#include <oscalls.h>
#include <tchar.h>
#include <dbgint.h>
#ifndef CRTDLL
#ifdef _MBCS
/*
* Flag to ensure multibyte ctype table is only initialized once */extern int __mbctype_initialized;
#endif
/*
* Flag checked by getenv() and _putenv() to determine if the environment has * been initialized. */extern int __env_initialized;
#endif
/***
*_setenvp - set up "envp" for C programs**Purpose:* Reads the environment and build the envp array for C programs.**Entry:* The environment strings occur at _aenvptr.* The list of environment strings is terminated by an extra null* byte. Thus two null bytes in a row indicate the end of the* last environment string and the end of the environment, resp.**Exit:* "environ" points to a null-terminated list of pointers to ASCIZ* strings, each of which is of the form "VAR=VALUE". The strings* are copied from the environment area. This array of pointers will* be malloc'ed. The block pointed to by _aenvptr is deallocated.**Uses:* Allocates space on the heap for the environment pointers.**Exceptions:* If space cannot be allocated, program is terminated.********************************************************************************/
#ifdef WPRFLAG
int __cdecl _wsetenvp (#else
int __cdecl _setenvp (#endif
void ){ _TSCHAR *p; _TSCHAR **env; /* _environ ptr traversal pointer */ int numstrings; /* number of environment strings */ int cchars;
#if !defined(CRTDLL) && defined(_MBCS)
/* If necessary, initialize the multibyte ctype table. */ if ( __mbctype_initialized == 0 ) __initmbctable();#endif
numstrings = 0;
#ifdef WPRFLAG
p = _wenvptr;#else
p = _aenvptr;#endif
/*
* We called __crtGetEnvironmentStrings[AW] just before this, * so if _[aw]envptr is NULL, we failed to get the environment. * Return an error. */ if (p == NULL) return -1;
/*
* NOTE: starting with single null indicates no environ. * Count the number of strings. Skip drive letter settings * ("=C:=C:\foo" type) by skipping all environment variables * that begin with '=' character. */
while (*p != _T('\0')) { /* don't count "=..." type */ if (*p != _T('=')) ++numstrings; p += _tcslen(p) + 1; }
/* need pointer for each string, plus one null ptr at end */ if ( (_tenviron = env = (_TSCHAR **) _malloc_crt((numstrings+1) * sizeof(_TSCHAR *))) == NULL ) return -1;
/* copy strings to malloc'd memory and save pointers in _environ */#ifdef WPRFLAG
for ( p = _wenvptr ; *p != L'\0' ; p += cchars )#else
for ( p = _aenvptr ; *p != '\0' ; p += cchars )#endif
{ cchars = (int)_tcslen(p) + 1; /* don't copy "=..." type */ if (*p != _T('=')) { if ( (*env = (_TSCHAR *)_malloc_crt(cchars * sizeof(_TSCHAR))) == NULL ) { _free_crt(_tenviron); _tenviron = NULL; return -1; } _tcscpy(*env, p); env++; } }
#ifdef WPRFLAG
_free_crt(_wenvptr); _wenvptr = NULL;#else
_free_crt(_aenvptr); _aenvptr = NULL;#endif
/* and a final NULL pointer */ *env = NULL;
#ifndef CRTDLL
/*
* Set flag for getenv() and _putenv() to know the environment * has been set up. */ __env_initialized = 1;#endif
return 0;}
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