postgresql/src/port/win32env.c

164 line
3.9 KiB
C

/*-------------------------------------------------------------------------
*
* win32env.c
* putenv(), setenv(), and unsetenv() for win32.
*
* These functions update both the process environment and caches in
* (potentially multiple) C run-time library (CRT) versions.
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/port/win32env.c
*
*-------------------------------------------------------------------------
*/
#include "c.h"
/*
* Note that unlike POSIX putenv(), this doesn't use the passed-in string
* as permanent storage.
*/
int
pgwin32_putenv(const char *envval)
{
char *envcpy;
char *cp;
typedef int (_cdecl * PUTENVPROC) (const char *);
static const char *const modulenames[] = {
"msvcrt", /* Visual Studio 6.0 / MinGW */
"msvcrtd",
"msvcr70", /* Visual Studio 2002 */
"msvcr70d",
"msvcr71", /* Visual Studio 2003 */
"msvcr71d",
"msvcr80", /* Visual Studio 2005 */
"msvcr80d",
"msvcr90", /* Visual Studio 2008 */
"msvcr90d",
"msvcr100", /* Visual Studio 2010 */
"msvcr100d",
"msvcr110", /* Visual Studio 2012 */
"msvcr110d",
"msvcr120", /* Visual Studio 2013 */
"msvcr120d",
"ucrtbase", /* Visual Studio 2015 and later */
"ucrtbased",
NULL
};
int i;
/*
* Update process environment, making this change visible to child
* processes and to CRTs initializing in the future. Do this before the
* _putenv() loop, for the benefit of any CRT that initializes during this
* pgwin32_putenv() execution, after the loop checks that CRT.
*
* Need a copy of the string so we can modify it.
*/
envcpy = strdup(envval);
if (!envcpy)
return -1;
cp = strchr(envcpy, '=');
if (cp == NULL)
{
free(envcpy);
return -1;
}
*cp = '\0';
cp++;
if (*cp)
{
/*
* Only call SetEnvironmentVariable() when we are adding a variable,
* not when removing it. Calling it on both crashes on at least
* certain versions of MinGW.
*/
if (!SetEnvironmentVariable(envcpy, cp))
{
free(envcpy);
return -1;
}
}
free(envcpy);
/*
* Each CRT has its own _putenv() symbol and copy of the environment.
* Update the environment in each CRT module currently loaded, so every
* third-party library sees this change regardless of the CRT it links
* against. Addresses within these modules may become invalid the moment
* we call FreeLibrary(), so don't cache them.
*/
for (i = 0; modulenames[i]; i++)
{
HMODULE hmodule = NULL;
BOOL res = GetModuleHandleEx(0, modulenames[i], &hmodule);
if (res != 0 && hmodule != NULL)
{
PUTENVPROC putenvFunc;
putenvFunc = (PUTENVPROC) (pg_funcptr_t) GetProcAddress(hmodule, "_putenv");
if (putenvFunc)
putenvFunc(envval);
FreeLibrary(hmodule);
}
}
/*
* Finally, update our "own" cache. This is redundant with the loop
* above, except when PostgreSQL itself links to a CRT not listed above.
* Ideally, the loop does visit all possible CRTs, making this redundant.
*/
return _putenv(envval);
}
int
pgwin32_setenv(const char *name, const char *value, int overwrite)
{
int res;
char *envstr;
/* Error conditions, per POSIX */
if (name == NULL || name[0] == '\0' || strchr(name, '=') != NULL ||
value == NULL)
{
errno = EINVAL;
return -1;
}
/* No work if variable exists and we're not to replace it */
if (overwrite == 0 && getenv(name) != NULL)
return 0;
envstr = (char *) malloc(strlen(name) + strlen(value) + 2);
if (!envstr) /* not much we can do if no memory */
return -1;
sprintf(envstr, "%s=%s", name, value);
res = pgwin32_putenv(envstr);
free(envstr);
return res;
}
int
pgwin32_unsetenv(const char *name)
{
int res;
char *envbuf;
envbuf = (char *) malloc(strlen(name) + 2);
if (!envbuf)
return -1;
sprintf(envbuf, "%s=", name);
res = pgwin32_putenv(envbuf);
free(envbuf);
return res;
}