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/*********************************************************
* Copyright (C) 2008-2015 VMware, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation version 2.1 and no later version.
*
* This program 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 Lesser GNU General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
*********************************************************/
/*
* posixInt.h --
*
* Internal definitions for the Posix wrapper module.
*/
#ifndef _POSIXINT_H_
#define _POSIXINT_H_
#define INCLUDE_ALLOW_USERLEVEL
#include "includeCheck.h"
#include "posix.h"
#include "unicode.h"
#include "hashTable.h"
#include "vm_atomic.h"
#include "util.h"
#include "str.h"
#ifndef _WIN32 // {
/*
*----------------------------------------------------------------------
*
* PosixConvertToCurrent --
*
* Utility function to convert a Unicode string
* to the current encoding.
*
* Results:
* TRUE on success.
* Conversion result in *out or NULL on failure.
* errno is untouched on success, set to UNICODE_CONVERSION_ERRNO
* on failure.
*
* Side effects:
* As described.
*
*----------------------------------------------------------------------
*/
static INLINE Bool
PosixConvertToCurrent(ConstUnicode in, // IN: string to convert
char **out) // OUT: conversion result
{
int e = errno;
char *p = Unicode_GetAllocBytes(in, STRING_ENCODING_DEFAULT);
Bool success = p != NULL || in == NULL;
if (success) {
errno = e;
*out = p;
} else {
errno = UNICODE_CONVERSION_ERRNO;
*out = NULL;
}
return success;
}
/*
*----------------------------------------------------------------------
*
* PosixConvertToCurrentList --
*
* Utility function to convert a list of Unicode strings
* to the current encoding.
* Return NULL if list is NULL.
*
* Results:
* TRUE on success.
* Conversion result in *out or NULL on failure.
* errno is untouched on success, set to UNICODE_CONVERSION_ERRNO
* on failure.
*
* Side effects:
* As described.
*
*----------------------------------------------------------------------
*/
static INLINE Bool
PosixConvertToCurrentList(Unicode const *in, // IN: list to convert
char ***out) // OUT: conversion result
{
int e = errno;
char **p;
Bool success;
if (in == NULL) {
p = NULL;
success = TRUE;
} else {
p = Unicode_GetAllocList(in, -1, STRING_ENCODING_DEFAULT);
success = p != NULL;
}
if (!success) {
e = UNICODE_CONVERSION_ERRNO;
}
*out = p;
errno = e;
return success;
}
#endif // }
/*
* Hash table for Posix_Getenv
*/
typedef struct PosixEnvEntry {
Atomic_Ptr value;
Atomic_Ptr lastValue;
} PosixEnvEntry;
static INLINE void
PosixEnvFree(void *v)
{
// never called
NOT_REACHED();
}
/*
*-----------------------------------------------------------------------------
*
* PosixGetenvHash --
*
* Save away Unicode result for Posix_Getenv() to make
* it persistent.
*
* Results:
* The value.
*
* Side effects:
* The passed-in value string may be saved in a hash table,
* or it may be freed.
*
*-----------------------------------------------------------------------------
*/
static INLINE_SINGLE_CALLER Unicode
PosixGetenvHash(ConstUnicode name, // IN
Unicode value) // IN/OUT: may be freed
{
static Atomic_Ptr htPtr;
HashTable *ht;
Unicode oldValue;
PosixEnvEntry *e;
/*
* Don't need to save NULL.
*/
if (value == NULL) {
return value;
}
ht = HashTable_AllocOnce(&htPtr, 128,
HASH_FLAG_ATOMIC | HASH_FLAG_COPYKEY |
HASH_STRING_KEY,
PosixEnvFree);
/*
* We have to allow any number of concurrent getenv()'s.
* So if the saved value is the same, don't change it,
* and if it must change, all the threads together must
* establish a single new value.
*
* On the other hand, we don't have to support concurrent
* getenv() and setenv().
*/
for (;;) {
/*
* If not in hash table, then insert and return.
*/
if (!HashTable_Lookup(ht, name, (void **) &e)) {
e = Util_SafeMalloc(sizeof *e);
Atomic_WritePtr(&e->value, value);
Atomic_WritePtr(&e->lastValue, NULL);
if (!HashTable_Insert(ht, name, e)) {
free(e);
continue;
}
break;
}
/*
* If old value is the same, then use it.
*/
oldValue = Atomic_ReadPtr(&e->value);
if (Str_Strcmp(oldValue, value) == 0) {
Unicode_Free(value);
value = oldValue;
break;
}
/*
* If value has changed, use new value, but don't free old
* value yet because somebody else may be going through this
* same code and still using it. Because we don't need
* to care about concurrent setenv(), a single lastValue
* slot is sufficient.
*/
if (Atomic_ReadIfEqualWritePtr(&e->value, oldValue, value) == oldValue) {
oldValue = Atomic_ReadWritePtr(&e->lastValue, oldValue);
Unicode_Free(oldValue);
break;
}
}
return value;
}
#endif // ifndef _POSIXINT_H_
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