Mercurial > hg > nginx
view src/os/unix/ngx_atomic.h @ 8018:5119c8150478
Fixed runtime handling of systems without EPOLLRDHUP support.
In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the
ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP
support in the kernel (but with EPOLLRDHUP in headers) was broken.
Before the change, rev->available was never set to 0 unless
ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP
introduced in 6536:f7849bfb6d21 succeeded). After the change,
rev->available might reach 0 on systems without runtime EPOLLRDHUP
support, stopping further reading in ngx_readv_chain() and ngx_unix_recv().
And, if EOF happened to be already reported along with the last event,
it is not reported again by epoll_wait(), leading to connection hangs
and timeouts on such systems.
This affects Linux kernels before 2.6.17 if nginx was compiled
with newer headers, and, more importantly, emulation layers, such as
DigitalOcean's App Platform's / gVisor's epoll emulation layer.
Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding
rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author | Marcus Ball <marcus.ball@live.com> |
---|---|
date | Mon, 30 May 2022 02:38:07 +0300 |
parents | 09d15a2dbc6b |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_ATOMIC_H_INCLUDED_ #define _NGX_ATOMIC_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #if (NGX_HAVE_LIBATOMIC) #define AO_REQUIRE_CAS #include <atomic_ops.h> #define NGX_HAVE_ATOMIC_OPS 1 typedef long ngx_atomic_int_t; typedef AO_t ngx_atomic_uint_t; typedef volatile ngx_atomic_uint_t ngx_atomic_t; #if (NGX_PTR_SIZE == 8) #define NGX_ATOMIC_T_LEN (sizeof("-9223372036854775808") - 1) #else #define NGX_ATOMIC_T_LEN (sizeof("-2147483648") - 1) #endif #define ngx_atomic_cmp_set(lock, old, new) \ AO_compare_and_swap(lock, old, new) #define ngx_atomic_fetch_add(value, add) \ AO_fetch_and_add(value, add) #define ngx_memory_barrier() AO_nop() #define ngx_cpu_pause() #elif (NGX_HAVE_GCC_ATOMIC) /* GCC 4.1 builtin atomic operations */ #define NGX_HAVE_ATOMIC_OPS 1 typedef long ngx_atomic_int_t; typedef unsigned long ngx_atomic_uint_t; #if (NGX_PTR_SIZE == 8) #define NGX_ATOMIC_T_LEN (sizeof("-9223372036854775808") - 1) #else #define NGX_ATOMIC_T_LEN (sizeof("-2147483648") - 1) #endif typedef volatile ngx_atomic_uint_t ngx_atomic_t; #define ngx_atomic_cmp_set(lock, old, set) \ __sync_bool_compare_and_swap(lock, old, set) #define ngx_atomic_fetch_add(value, add) \ __sync_fetch_and_add(value, add) #define ngx_memory_barrier() __sync_synchronize() #if ( __i386__ || __i386 || __amd64__ || __amd64 ) #define ngx_cpu_pause() __asm__ ("pause") #else #define ngx_cpu_pause() #endif #elif (NGX_DARWIN_ATOMIC) /* * use Darwin 8 atomic(3) and barrier(3) operations * optimized at run-time for UP and SMP */ #include <libkern/OSAtomic.h> /* "bool" conflicts with perl's CORE/handy.h */ #if 0 #undef bool #endif #define NGX_HAVE_ATOMIC_OPS 1 #if (NGX_PTR_SIZE == 8) typedef int64_t ngx_atomic_int_t; typedef uint64_t ngx_atomic_uint_t; #define NGX_ATOMIC_T_LEN (sizeof("-9223372036854775808") - 1) #define ngx_atomic_cmp_set(lock, old, new) \ OSAtomicCompareAndSwap64Barrier(old, new, (int64_t *) lock) #define ngx_atomic_fetch_add(value, add) \ (OSAtomicAdd64(add, (int64_t *) value) - add) #else typedef int32_t ngx_atomic_int_t; typedef uint32_t ngx_atomic_uint_t; #define NGX_ATOMIC_T_LEN (sizeof("-2147483648") - 1) #define ngx_atomic_cmp_set(lock, old, new) \ OSAtomicCompareAndSwap32Barrier(old, new, (int32_t *) lock) #define ngx_atomic_fetch_add(value, add) \ (OSAtomicAdd32(add, (int32_t *) value) - add) #endif #define ngx_memory_barrier() OSMemoryBarrier() #define ngx_cpu_pause() typedef volatile ngx_atomic_uint_t ngx_atomic_t; #elif ( __i386__ || __i386 ) typedef int32_t ngx_atomic_int_t; typedef uint32_t ngx_atomic_uint_t; typedef volatile ngx_atomic_uint_t ngx_atomic_t; #define NGX_ATOMIC_T_LEN (sizeof("-2147483648") - 1) #if ( __SUNPRO_C ) #define NGX_HAVE_ATOMIC_OPS 1 ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, ngx_atomic_uint_t set); ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add); /* * Sun Studio 12 exits with segmentation fault on '__asm ("pause")', * so ngx_cpu_pause is declared in src/os/unix/ngx_sunpro_x86.il */ void ngx_cpu_pause(void); /* the code in src/os/unix/ngx_sunpro_x86.il */ #define ngx_memory_barrier() __asm (".volatile"); __asm (".nonvolatile") #else /* ( __GNUC__ || __INTEL_COMPILER ) */ #define NGX_HAVE_ATOMIC_OPS 1 #include "ngx_gcc_atomic_x86.h" #endif #elif ( __amd64__ || __amd64 ) typedef int64_t ngx_atomic_int_t; typedef uint64_t ngx_atomic_uint_t; typedef volatile ngx_atomic_uint_t ngx_atomic_t; #define NGX_ATOMIC_T_LEN (sizeof("-9223372036854775808") - 1) #if ( __SUNPRO_C ) #define NGX_HAVE_ATOMIC_OPS 1 ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, ngx_atomic_uint_t set); ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add); /* * Sun Studio 12 exits with segmentation fault on '__asm ("pause")', * so ngx_cpu_pause is declared in src/os/unix/ngx_sunpro_amd64.il */ void ngx_cpu_pause(void); /* the code in src/os/unix/ngx_sunpro_amd64.il */ #define ngx_memory_barrier() __asm (".volatile"); __asm (".nonvolatile") #else /* ( __GNUC__ || __INTEL_COMPILER ) */ #define NGX_HAVE_ATOMIC_OPS 1 #include "ngx_gcc_atomic_amd64.h" #endif #elif ( __sparc__ || __sparc || __sparcv9 ) #if (NGX_PTR_SIZE == 8) typedef int64_t ngx_atomic_int_t; typedef uint64_t ngx_atomic_uint_t; #define NGX_ATOMIC_T_LEN (sizeof("-9223372036854775808") - 1) #else typedef int32_t ngx_atomic_int_t; typedef uint32_t ngx_atomic_uint_t; #define NGX_ATOMIC_T_LEN (sizeof("-2147483648") - 1) #endif typedef volatile ngx_atomic_uint_t ngx_atomic_t; #if ( __SUNPRO_C ) #define NGX_HAVE_ATOMIC_OPS 1 #include "ngx_sunpro_atomic_sparc64.h" #else /* ( __GNUC__ || __INTEL_COMPILER ) */ #define NGX_HAVE_ATOMIC_OPS 1 #include "ngx_gcc_atomic_sparc64.h" #endif #elif ( __powerpc__ || __POWERPC__ ) #define NGX_HAVE_ATOMIC_OPS 1 #if (NGX_PTR_SIZE == 8) typedef int64_t ngx_atomic_int_t; typedef uint64_t ngx_atomic_uint_t; #define NGX_ATOMIC_T_LEN (sizeof("-9223372036854775808") - 1) #else typedef int32_t ngx_atomic_int_t; typedef uint32_t ngx_atomic_uint_t; #define NGX_ATOMIC_T_LEN (sizeof("-2147483648") - 1) #endif typedef volatile ngx_atomic_uint_t ngx_atomic_t; #include "ngx_gcc_atomic_ppc.h" #endif #if !(NGX_HAVE_ATOMIC_OPS) #define NGX_HAVE_ATOMIC_OPS 0 typedef int32_t ngx_atomic_int_t; typedef uint32_t ngx_atomic_uint_t; typedef volatile ngx_atomic_uint_t ngx_atomic_t; #define NGX_ATOMIC_T_LEN (sizeof("-2147483648") - 1) static ngx_inline ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, ngx_atomic_uint_t set) { if (*lock == old) { *lock = set; return 1; } return 0; } static ngx_inline ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) { ngx_atomic_int_t old; old = *value; *value += add; return old; } #define ngx_memory_barrier() #define ngx_cpu_pause() #endif void ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin); #define ngx_trylock(lock) (*(lock) == 0 && ngx_atomic_cmp_set(lock, 0, 1)) #define ngx_unlock(lock) *(lock) = 0 #endif /* _NGX_ATOMIC_H_INCLUDED_ */