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https://github.com/jart/cosmopolitan.git
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af7bd80430
This change introduces a new deadlock detector for Cosmo's POSIX threads implementation. Error check mutexes will now track a DAG of nested locks and report EDEADLK when a deadlock is theoretically possible. These will occur rarely, but it's important for production hardening your code. You don't even need to change your mutexes to use the POSIX error check mode because `cosmocc -mdbg` will enable error checking on mutexes by default globally. When cycles are found, an error message showing your demangled symbols describing the strongly connected component are printed and then the SIGTRAP is raised, which means you'll also get a backtrace if you're using ShowCrashReports() too. This new error checker is so low-level and so pure that it's able to verify the relationships of every libc runtime lock, including those locks upon which the mutex implementation depends.
94 lines
2.7 KiB
C
94 lines
2.7 KiB
C
#ifndef COSMOPOLITAN_LIBC_THREAD_TLS_H_
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#define COSMOPOLITAN_LIBC_THREAD_TLS_H_
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#define TLS_ALIGNMENT 64
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#define TIB_FLAG_VFORKED 1
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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COSMOPOLITAN_C_START_
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struct CosmoFtrace { /* 16 */
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char ft_once; /* 0 */
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char ft_noreentry; /* 1 */
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int ft_skew; /* 4 */
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int64_t ft_lastaddr; /* 8 */
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};
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/* cosmopolitan thread information block (1024 bytes) */
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/* NOTE: update aarch64 libc/errno.h if sizeof changes */
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/* NOTE: update aarch64 libc/proc/vfork.S if sizeof changes */
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/* NOTE: update aarch64 libc/nexgen32e/gc.S if sizeof changes */
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struct CosmoTib {
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struct CosmoTib *tib_self; /* 0x00 */
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struct CosmoFtrace tib_ftracer; /* 0x08 */
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void *tib_garbages; /* 0x18 */
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intptr_t __unused; /* 0x20 */
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intptr_t tib_pthread; /* 0x28 */
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struct CosmoTib *tib_self2; /* 0x30 */
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_Atomic(int32_t) tib_tid; /* 0x38 transitions -1 → tid → 0 */
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int32_t tib_errno; /* 0x3c */
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uint64_t tib_flags; /* 0x40 */
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int tib_ftrace; /* inherited */
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int tib_strace; /* inherited */
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_Atomic(uint64_t) tib_sigmask; /* inherited */
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_Atomic(uint64_t) tib_sigpending;
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_Atomic(uint64_t) tib_syshand; /* win32=kThread, xnusilicon=pthread_t */
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char *tib_sigstack_addr;
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uint32_t tib_sigstack_size;
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uint32_t tib_sigstack_flags;
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void *tib_nsync;
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void *tib_atexit;
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_Atomic(void *) tib_keys[46];
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void *tib_locks[64];
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} __attribute__((__aligned__(64)));
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extern char __tls_morphed;
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extern unsigned __tls_index;
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char *_mktls(struct CosmoTib **) libcesque;
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void __bootstrap_tls(struct CosmoTib *, char *) libcesque;
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#ifdef __x86_64__
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extern char __tls_enabled;
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#define __tls_enabled_set(x) __tls_enabled = x
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#elif defined(__aarch64__)
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#define __tls_enabled true
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#define __tls_enabled_set(x) (void)0
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#else
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#error "unsupported architecture"
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#endif
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void __set_tls(struct CosmoTib *) libcesque;
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/**
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* Returns location of thread information block.
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*
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* This can't be used in privileged functions.
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*/
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forceinline pureconst struct CosmoTib *__get_tls(void) {
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#ifdef __chibicc__
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return 0;
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#elif __x86_64__
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struct CosmoTib *__tib;
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__asm__("mov\t%%gs:0x30,%0" : "=r"(__tib));
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return __tib;
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#elif defined(__aarch64__)
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register struct CosmoTib *__tls __asm__("x28");
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return __tls - 1;
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#endif
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}
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struct CosmoTib *__get_tls_privileged(void) dontthrow pureconst;
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struct CosmoTib *__get_tls_win32(void) dontthrow;
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void __set_tls_win32(void *) libcesque;
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#ifdef __x86_64__
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#define __adj_tls(tib) (tib)
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#elif defined(__aarch64__)
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#define __adj_tls(tib) ((struct CosmoTib *)(tib) + 1)
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#endif
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COSMOPOLITAN_C_END_
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_THREAD_TLS_H_ */
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