1 | /*
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2 | * Copyright (c) 2011 Jiri Zarevucky
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | *
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9 | * - Redistributions of source code must retain the above copyright
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10 | * notice, this list of conditions and the following disclaimer.
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11 | * - Redistributions in binary form must reproduce the above copyright
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12 | * notice, this list of conditions and the following disclaimer in the
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13 | * documentation and/or other materials provided with the distribution.
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14 | * - The name of the author may not be used to endorse or promote products
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15 | * derived from this software without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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27 | */
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28 |
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29 | /** @addtogroup libposix
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30 | * @{
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31 | */
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32 | /** @file
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33 | */
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34 |
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35 | #define LIBPOSIX_INTERNAL
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36 |
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37 | #include "signal.h"
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38 | #include "internal/common.h"
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39 | #include "limits.h"
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40 | #include "stdlib.h"
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41 | #include "string.h"
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42 | #include "errno.h"
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43 |
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44 | #include "libc/fibril_synch.h"
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45 | #include "libc/task.h"
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46 |
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47 | /* Used to serialize signal handling. */
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48 | static FIBRIL_MUTEX_INITIALIZE(_signal_mutex);
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49 |
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50 | static posix_sigset_t _signal_mask = 0;
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51 |
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52 | #define DEFAULT_HANDLER { .sa_handler = SIG_DFL, \
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53 | .sa_mask = 0, .sa_flags = 0, .sa_sigaction = NULL }
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54 |
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55 | static struct posix_sigaction _signal_actions[_TOP_SIGNAL + 1] = {
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56 | DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER,
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57 | DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER,
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58 | DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER,
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59 | DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER,
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60 | DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER,
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61 | DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER,
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62 | DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER, DEFAULT_HANDLER
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63 | };
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64 |
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65 | void __posix_default_signal_handler(int signo)
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66 | {
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67 | switch (signo) {
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68 | case SIGABRT:
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69 | abort();
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70 | case SIGQUIT:
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71 | fprintf(stderr, "Quit signal raised. Exiting.");
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72 | exit(EXIT_FAILURE);
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73 | case SIGINT:
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74 | fprintf(stderr, "Interrupt signal caught. Exiting.");
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75 | exit(EXIT_FAILURE);
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76 | case SIGTERM:
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77 | fprintf(stderr, "Termination signal caught. Exiting.");
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78 | exit(EXIT_FAILURE);
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79 | case SIGSTOP:
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80 | fprintf(stderr, "Stop signal caught, but unsupported. Ignoring.");
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81 | break;
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82 | case SIGKILL:
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83 | /* This will only occur when raise or similar is called. */
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84 | /* Commit suicide. */
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85 | task_kill(task_get_id());
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86 |
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87 | /* Should not be reached. */
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88 | abort();
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89 | case SIGFPE:
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90 | case SIGBUS:
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91 | case SIGILL:
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92 | case SIGSEGV:
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93 | posix_psignal(signo, "Hardware exception raised by user code");
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94 | abort();
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95 | case SIGSYS:
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96 | case SIGXCPU:
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97 | case SIGXFSZ:
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98 | case SIGTRAP:
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99 | case SIGHUP:
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100 | case SIGPIPE:
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101 | case SIGPOLL:
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102 | case SIGURG:
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103 | case SIGTSTP:
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104 | case SIGTTIN:
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105 | case SIGTTOU:
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106 | posix_psignal(signo, "Unsupported signal caught");
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107 | abort();
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108 | case SIGCHLD:
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109 | case SIGUSR1:
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110 | case SIGUSR2:
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111 | case SIGALRM:
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112 | case SIGVTALRM:
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113 | case SIGPROF:
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114 | case SIGCONT:
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115 | /* ignored */
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116 | break;
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117 | }
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118 | }
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119 |
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120 | void __posix_hold_signal_handler(int signo)
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121 | {
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122 | /* Nothing */
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123 | }
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124 |
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125 | void __posix_ignore_signal_handler(int signo)
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126 | {
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127 | /* Nothing */
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128 | }
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129 |
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130 |
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131 | int posix_sigemptyset(posix_sigset_t *set)
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132 | {
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133 | assert(set != NULL);
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134 |
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135 | *set = 0;
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136 | return 0;
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137 | }
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138 |
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139 | int posix_sigfillset(posix_sigset_t *set)
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140 | {
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141 | assert(set != NULL);
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142 |
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143 | *set = UINT32_MAX;
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144 | return 0;
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145 | }
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146 |
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147 | int posix_sigaddset(posix_sigset_t *set, int signo)
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148 | {
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149 | assert(set != NULL);
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150 |
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151 | *set |= (1 << signo);
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152 | return 0;
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153 | }
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154 |
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155 | int posix_sigdelset(posix_sigset_t *set, int signo)
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156 | {
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157 | assert(set != NULL);
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158 |
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159 | *set &= ~(1 << signo);
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160 | return 0;
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161 | }
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162 |
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163 | int posix_sigismember(const posix_sigset_t *set, int signo)
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164 | {
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165 | assert(set != NULL);
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166 |
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167 | return (*set & (1 << signo)) != 0;
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168 | }
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169 |
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170 | static void _sigaction_unsafe(int sig, const struct posix_sigaction *restrict act,
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171 | struct posix_sigaction *restrict oact)
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172 | {
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173 | if (oact != NULL) {
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174 | memcpy(oact, &_signal_actions[sig],
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175 | sizeof(struct posix_sigaction));
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176 | }
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177 |
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178 | if (act != NULL) {
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179 | memcpy(&_signal_actions[sig], act,
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180 | sizeof(struct posix_sigaction));
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181 | }
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182 | }
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183 |
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184 | int posix_sigaction(int sig, const struct posix_sigaction *restrict act,
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185 | struct posix_sigaction *restrict oact)
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186 | {
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187 | if (sig > _TOP_SIGNAL || (act != NULL &&
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188 | (sig == SIGKILL || sig == SIGSTOP))) {
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189 | errno = EINVAL;
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190 | return -1;
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191 | }
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192 |
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193 | if (sig > _TOP_CATCHABLE_SIGNAL) {
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194 | posix_psignal(sig,
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195 | "WARNING: registering handler for a partially"
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196 | " or fully unsupported signal. This handler may only be"
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197 | " invoked by the raise() function, which may not be what"
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198 | " the application developer intended.\nSignal name");
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199 | }
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200 |
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201 | fibril_mutex_lock(&_signal_mutex);
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202 | _sigaction_unsafe(sig, act, oact);
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203 | fibril_mutex_unlock(&_signal_mutex);
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204 |
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205 | return 0;
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206 | }
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207 |
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208 | void (*posix_signal(int sig, void (*func)(int)))(int)
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209 | {
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210 | struct posix_sigaction new = {
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211 | .sa_handler = func,
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212 | .sa_mask = 0,
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213 | .sa_flags = 0,
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214 | .sa_sigaction = NULL
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215 | };
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216 | struct posix_sigaction old;
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217 | if (posix_sigaction(sig, func == NULL ? NULL : &new, &old) == 0) {
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218 | return old.sa_handler;
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219 | } else {
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220 | return SIG_ERR;
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221 | }
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222 | }
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223 |
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224 | static int _raise_sigaction(int signo, posix_siginfo_t *siginfo)
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225 | {
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226 | assert(signo >= 0 && signo <= _TOP_SIGNAL);
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227 | assert(siginfo != NULL);
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228 |
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229 | fibril_mutex_lock(&_signal_mutex);
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230 |
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231 | struct posix_sigaction action = _signal_actions[signo];
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232 |
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233 | if (posix_sigismember(&_signal_mask, signo) ||
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234 | action.sa_handler == SIG_HOLD) {
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235 | // TODO: queue signal
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236 | fibril_mutex_unlock(&_signal_mutex);
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237 | return -1;
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238 | }
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239 |
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240 | /* Modifying signal mask is unnecessary,
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241 | * signal handling is serialized.
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242 | */
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243 |
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244 | if ((action.sa_flags & SA_RESETHAND) && signo != SIGILL && signo != SIGTRAP) {
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245 | _signal_actions[signo] = (struct posix_sigaction) DEFAULT_HANDLER;
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246 | };
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247 |
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248 | if (action.sa_flags & SA_SIGINFO) {
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249 | assert(action.sa_sigaction != NULL);
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250 | action.sa_sigaction(signo, siginfo, NULL);
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251 | } else {
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252 | assert(action.sa_handler != NULL);
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253 | action.sa_handler(signo);
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254 | }
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255 |
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256 | fibril_mutex_unlock(&_signal_mutex);
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257 |
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258 | return 0;
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259 | }
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260 |
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261 | int posix_raise(int sig)
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262 | {
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263 | if (sig >= 0 && sig <= _TOP_SIGNAL) {
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264 | posix_siginfo_t siginfo = {
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265 | .si_signo = sig,
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266 | .si_code = SI_USER
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267 | };
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268 | return _raise_sigaction(sig, &siginfo);
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269 | } else {
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270 | errno = EINVAL;
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271 | return -1;
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272 | }
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273 | }
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274 |
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275 | int posix_kill(posix_pid_t pid, int signo)
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276 | {
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277 | if (pid < 1) {
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278 | // TODO
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279 | errno = ENOTSUP;
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280 | return -1;
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281 | }
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282 |
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283 | if (pid == (posix_pid_t) task_get_id()) {
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284 | return posix_raise(signo);
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285 | }
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286 |
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287 | if (pid > _TOP_SIGNAL) {
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288 | errno = EINVAL;
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289 | return -1;
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290 | }
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291 |
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292 | switch (signo) {
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293 | case SIGKILL:
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294 | task_kill(pid);
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295 | break;
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296 | default:
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297 | /* Nothing else supported yet. */
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298 | errno = ENOTSUP;
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299 | return -1;
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300 | }
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301 |
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302 | return 0;
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303 | }
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304 |
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305 | int posix_killpg(posix_pid_t pid, int sig)
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306 | {
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307 | assert(pid > 1);
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308 | return posix_kill(-pid, sig);
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309 | }
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310 |
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311 | void posix_psiginfo(const posix_siginfo_t *pinfo, const char *message)
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312 | {
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313 | assert(pinfo != NULL);
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314 | posix_psignal(pinfo->si_signo, message);
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315 | // TODO: print si_code
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316 | }
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317 |
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318 | void posix_psignal(int signum, const char *message)
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319 | {
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320 | char *sigmsg = posix_strsignal(signum);
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321 | if (message == NULL || *message == '\0') {
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322 | fprintf(stderr, "%s\n", sigmsg);
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323 | } else {
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324 | fprintf(stderr, "%s: %s\n", message, sigmsg);
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325 | }
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326 | }
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327 |
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328 | int posix_thread_sigmask(int how, const posix_sigset_t *restrict set,
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329 | posix_sigset_t *restrict oset)
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330 | {
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331 | fibril_mutex_lock(&_signal_mutex);
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332 |
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333 | if (oset != NULL) {
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334 | *oset = _signal_mask;
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335 | }
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336 | if (set != NULL) {
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337 | switch (how) {
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338 | case SIG_BLOCK:
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339 | _signal_mask |= *set;
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340 | break;
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341 | case SIG_UNBLOCK:
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342 | _signal_mask &= ~*set;
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343 | break;
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344 | case SIG_SETMASK:
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345 | _signal_mask = *set;
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346 | break;
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347 | default:
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348 | fibril_mutex_unlock(&_signal_mutex);
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349 | return EINVAL;
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350 | }
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351 | }
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352 |
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353 | // TODO: queued signal handling
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354 |
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355 | fibril_mutex_unlock(&_signal_mutex);
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356 |
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357 | return 0;
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358 | }
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359 |
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360 | int posix_sigprocmask(int how, const posix_sigset_t *restrict set,
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361 | posix_sigset_t *restrict oset)
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362 | {
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363 | int result = posix_thread_sigmask(how, set, oset);
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364 | if (result != 0) {
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365 | errno = result;
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366 | return -1;
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367 | }
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368 | return 0;
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369 | }
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370 |
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371 | /** @}
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372 | */
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373 |
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