Mercurial > hg > nginx
view src/os/unix/ngx_atomic.h @ 9270:3d455e37abf8
Core: PID file writing synchronization.
Now, ngx_daemon() does not call exit() in the parent process immediately,
but instead waits for the child process to signal it actually started (and
wrote the PID file if configured to). This ensures that the PID file
already exists when the parent process exits.
To make sure that signal handlers won't cause unexpected logging in the
parent process if the child process dies (for example, due to errors when
writing the PID file), ngx_init_signals() is moved to the child process.
This resolves "PID file ... not readable (yet?) after start" and "Failed
to parse PID from file..." errors as observed with systemd.
Note that the errors observed are considered to be a bug in systemd, which
isn't able to work properly with traditional Unix daemons. Still, the
workaround is implemented to make sure there will be no OS vendor patches
trying to address this.
| author | Maxim Dounin <mdounin@mdounin.ru> |
|---|---|
| date | Mon, 13 May 2024 06:13:22 +0300 |
| parents | 09d15a2dbc6b |
| children | d286426eab1a |
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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_ */