ebf82447be
the goal is to be able to use pthread_setcancelstate internally in the implementation, whenever a function might want to use functions which are cancellation points but avoid becoming a cancellation point itself. i could have just used a separate internal function for temporarily inhibiting cancellation, but the solution in this commit is better because (1) it's one less implementation-specific detail in functions that need to use it, and (2) application code can also get the same benefit. previously, pthread_setcancelstate dependend on pthread_self, which would pull in unwanted thread setup overhead for non-threaded programs. now, it temporarily stores the state in the global libc struct if threads have not been initialized, and later moves it if needed. this way we can instead use __pthread_self, which has no dependencies and assumes that the thread register is already valid.
61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
#ifndef LIBC_H
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#define LIBC_H
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#include <stdlib.h>
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#include <stdio.h>
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struct __libc {
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int *(*errno_location)(void);
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void (*testcancel)(void);
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void (*lock)(volatile int *);
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void (*lockfile)(FILE *);
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void (*fork_handler)(int);
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int (*atexit)(void (*)(void));
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void (*fini)(void);
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void (*ldso_fini)(void);
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volatile int threads_minus_1;
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int ofl_lock;
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FILE *ofl_head;
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int canceldisable;
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};
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#if 100*__GNUC__+__GNUC_MINOR__ >= 303 || defined(__PCC__) || defined(__TINYC__)
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extern struct __libc __libc __attribute__((visibility("hidden")));
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#define libc __libc
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#elif !defined(__PIC__)
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extern struct __libc __libc;
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#define libc __libc
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#else
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#define USE_LIBC_ACCESSOR
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extern struct __libc *__libc_loc(void) __attribute__((const));
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#define libc (*__libc_loc())
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#endif
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/* Designed to avoid any overhead in non-threaded processes */
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void __lock(volatile int *);
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void __lockfile(FILE *);
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#define LOCK(x) (libc.threads_minus_1 ? (__lock(x),1) : ((void)(x),1))
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#define UNLOCK(x) (*(x)=0)
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int __rsyscall(int, long, long, long, long, long, long);
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extern char **__environ;
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#define environ __environ
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#undef weak_alias
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#define weak_alias(old, new) \
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extern __typeof(old) new __attribute__((weak, alias(#old)))
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#undef LFS64_2
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//#define LFS64_2(x, y) weak_alias(x, y)
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#define LFS64_2(x, y) extern __typeof(x) y
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#undef LFS64
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#define LFS64(x) LFS64_2(x, x##64)
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#endif
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