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Implement _set_user_dir_suffix
Please, please, *please* take a look at my comments in _libcoreservices_fork_child! If there are ever any issues with threading and forking, remember to take a look at this code
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src/libsystem_coreservices/dirhelper.c
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src/libsystem_coreservices/dirhelper.c
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <pthread.h>
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#include "dirhelper_priv.h"
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static const char* dir_suffix = NULL;
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static pthread_mutex_t dir_suffix_lock = PTHREAD_MUTEX_INITIALIZER;
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void _dirhelper_fork_child(void)
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{
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void _libcoreservices_fork_child(void)
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{
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/**
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* my god, threading is *incredibly* tricky when mixed with `fork()`!
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* and the POSIX spec is so unclear about the behavior of mutexes when `fork()`ing
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* and the macOS docs are no help
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*
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* the *only* viable resources i found was this commit in jemalloc:
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* https://github.com/jemalloc/jemalloc/commit/0a4f5a7eea5e42292cea95fd30a88201c8d4a1ca
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*
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* basically, it *seems* that it's fine to reinitialize mutexes in the child---on macOS at least
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* but i really wish the POSIX spec or macOS docs mentioned this kind of stuff!
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*
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* undefined behavior is really the **worst** behavior
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*/
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dir_suffix_lock = (pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER;
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/**
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* i checked on a real macOS system and confirmed this behavior:
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* `fork()` does NOT reset the directory suffix
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*/
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//dir_suffix = NULL;
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}
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enum {
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DIRHELPER_USER_LOCAL = 0,
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DIRHELPER_USER_LOCAL_TEMP,
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DIRHELPER_USER_LOCAL_CACHE
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};
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char* _dirhelper(int which, char* p, size_t limit)
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{
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pthread_mutex_lock(&dir_suffix_lock);
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switch (which)
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{
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case DIRHELPER_USER_LOCAL:
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home = getenv("HOME");
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if (home == NULL)
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home = "/";
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home = "";
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strlcpy(p, home, limit);
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snprintf(p, limit, "%s/%s%s", home, dir_suffix ? dir_suffix : "", dir_suffix ? "/" : "");
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return p;
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}
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case DIRHELPER_USER_LOCAL_TEMP:
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if (tmp == NULL)
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tmp = "/tmp";
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strlcpy(p, tmp, limit);
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snprintf(p, limit, "%s/%s%s", tmp, dir_suffix ? dir_suffix : "", dir_suffix ? "/" : "");
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return p;
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}
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case DIRHELPER_USER_LOCAL_CACHE:
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home = getenv("HOME");
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if (home != NULL)
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snprintf(p, limit, "%s/.cache", home);
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snprintf(p, limit, "%s/.cache/%s%s", home, dir_suffix ? dir_suffix : "", dir_suffix ? "/" : "");
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else
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strlcpy(p, "/tmp", limit);
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snprintf(p, limit, "/tmp/%s%s", dir_suffix ? dir_suffix : "", dir_suffix ? "/" : "");
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return p;
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}
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default:
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return NULL;
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p = NULL;
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}
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pthread_mutex_unlock(&dir_suffix_lock);
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return p;
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}
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int _set_user_dir_suffix(const char* suffix) {
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pthread_mutex_lock(&dir_suffix_lock);
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dir_suffix = suffix;
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pthread_mutex_unlock(&dir_suffix_lock);
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return 0;
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};
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+63
src/libsystem_coreservices/dirhelper_priv.h
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src/libsystem_coreservices/dirhelper_priv.h
···
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/*
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* Copyright (c) 2006, 2007, 2010 Apple Inc. All rights reserved.
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*
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* @APPLE_LICENSE_HEADER_START@
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*
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* This file contains Original Code and/or Modifications of Original Code
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* as defined in and that are subject to the Apple Public Source License
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* Version 2.0 (the 'License'). You may not use this file except in
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* compliance with the License. Please obtain a copy of the License at
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* http://www.opensource.apple.com/apsl/ and read it before using this
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* file.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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* Please see the License for the specific language governing rights and
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* limitations under the License.
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*
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* @APPLE_LICENSE_HEADER_END@
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*/
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/**
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*
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* Modified for Darling
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*
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*/
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#ifndef _DIRHELPER_PRIV_H_
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#define _DIRHELPER_PRIV_H_
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#define VAR_FOLDERS_PATH "/var/folders/"
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#define DIRHELPER_BOOTSTRAP_NAME "com.apple.bsd.dirhelper"
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#define DIRHELPER_CACHE_STR "C/"
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#define DIRHELPER_TEMP_STR "T/"
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#define DIRHELPER_TOP_STR "0/"
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#define DIRHELPER_ENV_USER_DIR_SUFFIX "DIRHELPER_USER_DIR_SUFFIX"
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typedef enum {
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DIRHELPER_USER_LOCAL = 0,
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DIRHELPER_USER_LOCAL_TEMP,
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DIRHELPER_USER_LOCAL_CACHE,
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DIRHELPER_USER_LOCAL_LAST = DIRHELPER_USER_LOCAL_CACHE
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} dirhelper_which_t;
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__BEGIN_DECLS
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char *__user_local_dirname(uid_t uid, dirhelper_which_t which, char *path,
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size_t pathlen);
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char *__user_local_mkdir_p(char *path);
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__attribute__((visibility("hidden"), __format__(__printf__,1,2)))
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void _setcrashlogmessage(const char *fmt, ...);
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#define setcrashlogmessage(fmt, ...) _setcrashlogmessage("%s: %u: " fmt, __func__, __LINE__, ##__VA_ARGS__)
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int _set_user_dir_suffix(const char* suffix);
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__END_DECLS
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#endif /* _DIRHELPER_PRIV_H_ */