mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-30 16:28:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Implement support for POSIX thread cancellations

Browse source 
This change makes some miracle modifications to the System Five system
call support, which lets us have safe, correct, and atomic handling of
thread cancellations. It all turned out to be cheaper than anticipated
because it wasn't necessary to modify the system call veneers. We were
able to encode the cancellability of each system call into the magnums
found in libc/sysv/syscalls.sh. Since cancellations are so waq, we are
also supporting a lovely Musl Libc mask feature for raising ECANCELED.
This commit is contained in:
Justine Tunney 2022-11-04 01:04:43 -07:00
parent 37d40e087f
commit 2278327eba
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
145 changed files with 715 additions and 265 deletions
Download patch file Download diff file Expand all files Collapse all files

20
libc/thread/posixthread.internal.h
View file

@ -8,14 +8,13 @@
#define PT_OWNSTACK 1
#define PT_MAINTHREAD 2
#define PT_ASYNC 4
#define PT_NOCANCEL 8
#define PT_MASKED 16
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
/**
* @fileoverview Cosmopolitan POSIX Thread Internals
*/
// LEGAL TRANSITIONS ┌──> TERMINATED
// pthread_create ─┬─> JOINABLE ─┴┬─> DETACHED ──> ZOMBIE
// └──────────────┘
@ -60,15 +59,13 @@ enum PosixThreadStatus {
};
struct PosixThread {
int flags; // 0x00: see PT_* constants
_Atomic(int) cancelled; // 0x04: thread has bad beliefs
_Atomic(enum PosixThreadStatus) status;
void *(*start_routine)(void *);
void *arg; // start_routine's parameter
void *rc; // start_routine's return value
int tid; // clone parent tid
int flags; // see PT_* constants
_Atomic(int) cancelled; // thread has bad beliefs
char cancelasync; // PTHREAD_CANCEL_DEFERRED/ASYNCHRONOUS
char canceldisable; // PTHREAD_CANCEL_ENABLE/DISABLE
void *(*start)(void *); // creation callback
void *arg; // start's parameter
void *rc; // start's return value
char *altstack; // thread sigaltstack
char *tls; // bottom of tls allocation
struct CosmoTib *tib; // middle of tls allocation
@ -98,6 +95,7 @@ void _pthread_key_destruct(void) hidden;
void _pthread_onfork_prepare(void) hidden;
void _pthread_onfork_parent(void) hidden;
void _pthread_onfork_child(void) hidden;
int _pthread_cancel_sys(void) hidden;
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */