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160
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1
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2 /*
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3 * Copyright (C) Igor Sysoev
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4 */
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5
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6
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7 #include <ngx_config.h>
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8 #include <ngx_core.h>
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9
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10
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11 #if (NGX_HAVE_ATOMIC_OPS)
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12
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13
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14 ngx_int_t
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258
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15 ngx_shmtx_create(ngx_shmtx_t *mtx, void *addr, u_char *name)
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160
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16 {
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17 mtx->lock = addr;
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18
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624
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19 if (mtx->spin == (ngx_uint_t) -1) {
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20 return NGX_OK;
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21 }
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22
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23 mtx->spin = 2048;
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24
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25 #if (NGX_HAVE_POSIX_SEM)
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26
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27 if (sem_init(&mtx->sem, 1, 0) == -1) {
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28 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
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29 "sem_init() failed");
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30 } else {
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31 mtx->semaphore = 1;
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32 }
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33
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34 #endif
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35
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160
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36 return NGX_OK;
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37 }
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38
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624
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39
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40 void
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41 ngx_shmtx_destory(ngx_shmtx_t *mtx)
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42 {
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43 #if (NGX_HAVE_POSIX_SEM)
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44
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45 if (mtx->semaphore) {
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46 if (sem_destroy(&mtx->sem) == -1) {
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47 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
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48 "sem_destroy() failed");
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49 }
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50 }
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51
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52 #endif
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53 }
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54
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55
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56 ngx_uint_t
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57 ngx_shmtx_trylock(ngx_shmtx_t *mtx)
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58 {
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59 ngx_atomic_uint_t val;
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60
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61 val = *mtx->lock;
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62
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63 return ((val & 0x80000000) == 0
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64 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000));
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65 }
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66
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67
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68 void
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69 ngx_shmtx_lock(ngx_shmtx_t *mtx)
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70 {
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71 ngx_uint_t i, n;
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72 ngx_atomic_uint_t val;
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73
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74 ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx lock");
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75
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76 for ( ;; ) {
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77
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78 val = *mtx->lock;
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79
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80 if ((val & 0x80000000) == 0
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81 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000))
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82 {
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83 return;
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84 }
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85
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86 if (ngx_ncpu > 1) {
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87
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88 for (n = 1; n < mtx->spin; n <<= 1) {
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89
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90 for (i = 0; i < n; i++) {
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91 ngx_cpu_pause();
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92 }
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93
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94 val = *mtx->lock;
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95
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96 if ((val & 0x80000000) == 0
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97 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000))
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98 {
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99 return;
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100 }
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101 }
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102 }
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103
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104 #if (NGX_HAVE_POSIX_SEM)
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105
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106 if (mtx->semaphore) {
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107 val = *mtx->lock;
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108
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109 if ((val & 0x80000000)
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110 && ngx_atomic_cmp_set(mtx->lock, val, val + 1))
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111 {
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112 ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
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113 "shmtx wait %XA", val);
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114
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115 while (sem_wait(&mtx->sem) == -1) {
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116 ngx_err_t err;
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117
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118 err = ngx_errno;
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119
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120 if (err != NGX_EINTR) {
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121 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, err,
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122 "sem_wait() failed while waiting on shmtx");
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123 break;
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124 }
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125 }
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126
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127 ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
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128 "shmtx awoke");
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129 }
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130
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131 continue;
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132 }
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133
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134 #endif
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135
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136 ngx_sched_yield();
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137 }
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138 }
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139
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140
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141 void
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142 ngx_shmtx_unlock(ngx_shmtx_t *mtx)
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143 {
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144 ngx_atomic_uint_t val, old, wait;
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145
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146 if (mtx->spin != (ngx_uint_t) -1) {
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147 ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx unlock");
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148 }
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149
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150 for ( ;; ) {
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151
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152 old = *mtx->lock;
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153 wait = old & 0x7fffffff;
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154 val = wait ? wait - 1 : 0;
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155
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156 if (ngx_atomic_cmp_set(mtx->lock, old, val)) {
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157 break;
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158 }
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159 }
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160
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161 #if (NGX_HAVE_POSIX_SEM)
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162
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163 if (wait == 0 || !mtx->semaphore) {
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164 return;
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165 }
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166
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167 ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
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168 "shmtx wake %XA", old);
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169
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170 if (sem_post(&mtx->sem) == -1) {
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171 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
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172 "sem_post() failed while wake shmtx");
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173 }
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174
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175 #endif
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176 }
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177
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178
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160
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179 #else
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180
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181
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182 ngx_int_t
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258
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183 ngx_shmtx_create(ngx_shmtx_t *mtx, void *addr, u_char *name)
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160
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184 {
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185 if (mtx->name) {
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186
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187 if (ngx_strcmp(name, mtx->name) == 0) {
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188 mtx->name = name;
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189 return NGX_OK;
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190 }
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191
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192 ngx_shmtx_destory(mtx);
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193 }
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194
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284
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195 mtx->fd = ngx_open_file(name, NGX_FILE_RDWR, NGX_FILE_CREATE_OR_OPEN,
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196 NGX_FILE_DEFAULT_ACCESS);
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160
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197
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198 if (mtx->fd == NGX_INVALID_FILE) {
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258
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199 ngx_log_error(NGX_LOG_EMERG, ngx_cycle->log, ngx_errno,
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160
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200 ngx_open_file_n " \"%s\" failed", name);
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201 return NGX_ERROR;
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202 }
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203
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204 if (ngx_delete_file(name) == NGX_FILE_ERROR) {
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258
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205 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
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160
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206 ngx_delete_file_n " \"%s\" failed", name);
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207 }
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208
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209 mtx->name = name;
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210
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211 return NGX_OK;
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212 }
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213
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214
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215 void
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216 ngx_shmtx_destory(ngx_shmtx_t *mtx)
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217 {
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218 if (ngx_close_file(mtx->fd) == NGX_FILE_ERROR) {
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258
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219 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno,
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160
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220 ngx_close_file_n " \"%s\" failed", mtx->name);
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221 }
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222 }
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223
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224
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624
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225 ngx_uint_t
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226 ngx_shmtx_trylock(ngx_shmtx_t *mtx)
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227 {
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228 ngx_err_t err;
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229
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230 err = ngx_trylock_fd(mtx->fd);
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231
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232 if (err == 0) {
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233 return 1;
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234 }
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235
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236 if (err == NGX_EAGAIN) {
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237 return 0;
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238 }
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239
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240 #if __osf__ /* Tru64 UNIX */
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241
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242 if (err == NGX_EACCESS) {
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243 return 0;
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244 }
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245
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160
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246 #endif
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624
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247
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248 ngx_log_abort(err, ngx_trylock_fd_n " %s failed", mtx->name);
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249
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250 return 0;
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251 }
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252
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253
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254 void
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255 ngx_shmtx_lock(ngx_shmtx_t *mtx)
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256 {
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257 ngx_err_t err;
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258
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259 err = ngx_lock_fd(mtx->fd);
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260
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261 if (err == 0) {
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262 return;
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263 }
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264
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265 ngx_log_abort(err, ngx_lock_fd_n " %s failed", mtx->name);
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266 }
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267
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268
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269 void
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270 ngx_shmtx_unlock(ngx_shmtx_t *mtx)
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271 {
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272 ngx_err_t err;
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273
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274 err = ngx_unlock_fd(mtx->fd);
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275
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276 if (err == 0) {
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277 return;
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278 }
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279
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280 ngx_log_abort(err, ngx_unlock_fd_n " %s failed", mtx->name);
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281 }
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282
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283 #endif
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