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#ifndef LIBC_H
#define LIBC_H
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
struct __locale_map;
struct __locale_struct {
const struct __locale_map *volatile cat[6];
};
struct tls_module {
struct tls_module *next;
void *image;
size_t len, size, align, offset;
};
struct __libc {
always initialize thread pointer at program start this is the first step in an overhaul aimed at greatly simplifying and optimizing everything dealing with thread-local state. previously, the thread pointer was initialized lazily on first access, or at program startup if stack protector was in use, or at certain random places where inconsistent state could be reached if it were not initialized early. while believed to be fully correct, the logic was fragile and non-obvious. in the first phase of the thread pointer overhaul, support is retained (and in some cases improved) for systems/situation where loading the thread pointer fails, e.g. old kernels. some notes on specific changes: - the confusing use of libc.main_thread as an indicator that the thread pointer is initialized is eliminated in favor of an explicit has_thread_pointer predicate. - sigaction no longer needs to ensure that the thread pointer is initialized before installing a signal handler (this was needed to prevent a situation where the signal handler caused the thread pointer to be initialized and the subsequent sigreturn cleared it again) but it still needs to ensure that implementation-internal thread-related signals are not blocked. - pthread tsd initialization for the main thread is deferred in a new manner to minimize bloat in the static-linked __init_tp code. - pthread_setcancelstate no longer needs special handling for the situation before the thread pointer is initialized. it simply fails on systems that cannot support a thread pointer, which are non-conforming anyway. - pthread_cleanup_push/pop now check for missing thread pointer and nop themselves out in this case, so stdio no longer needs to avoid the cancellable path when the thread pointer is not available. a number of cases remain where certain interfaces may crash if the system does not support a thread pointer. at this point, these should be limited to pthread interfaces, and the number of such cases should be fewer than before.
12 years ago
int can_do_threads;
int threaded;
int secure;
volatile int threads_minus_1;
size_t *auxv;
struct tls_module *tls_head;
size_t tls_size, tls_align, tls_cnt;
size_t page_size;
struct __locale_struct global_locale;
};
#ifndef PAGE_SIZE
#define PAGE_SIZE libc.page_size
#endif
extern hidden struct __libc __libc;
#define libc __libc
hidden void __init_libc(char **, char *);
hidden void __init_tls(size_t *);
hidden void __init_ssp(void *);
hidden void __libc_start_init(void);
hidden void __funcs_on_exit(void);
hidden void __funcs_on_quick_exit(void);
hidden void __libc_exit_fini(void);
hidden void __fork_handler(int);
overhaul internally-public declarations using wrapper headers commits leading up to this one have moved the vast majority of libc-internal interface declarations to appropriate internal headers, allowing them to be type-checked and setting the stage to limit their visibility. the ones that have not yet been moved are mostly namespace-protected aliases for standard/public interfaces, which exist to facilitate implementing plain C functions in terms of POSIX functionality, or C or POSIX functionality in terms of extensions that are not standardized. some don't quite fit this description, but are "internally public" interfacs between subsystems of libc. rather than create a number of newly-named headers to declare these functions, and having to add explicit include directives for them to every source file where they're needed, I have introduced a method of wrapping the corresponding public headers. parallel to the public headers in $(srcdir)/include, we now have wrappers in $(srcdir)/src/include that come earlier in the include path order. they include the public header they're wrapping, then add declarations for namespace-protected versions of the same interfaces and any "internally public" interfaces for the subsystem they correspond to. along these lines, the wrapper for features.h is now responsible for the definition of the hidden, weak, and weak_alias macros. this means source files will no longer need to include any special headers to access these features. over time, it is my expectation that the scope of what is "internally public" will expand, reducing the number of source files which need to include *_impl.h and related headers down to those which are actually implementing the corresponding subsystems, not just using them.
8 years ago
extern hidden size_t __hwcap;
extern hidden size_t __sysinfo;
extern char *__progname, *__progname_full;
extern hidden const char __libc_version[];
hidden void __synccall(void (*)(void *), void *);
hidden int __setxid(int, int, int, int);
#endif