1 | #!/usr/bin/env bash
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2 | #
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3 | # See what system calls shells make for various constructs. Similar to
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4 | # test/syscall.sh.
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5 | #
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6 | # Usage:
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7 | # demo/compare-strace.sh <function name>
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8 |
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9 | set -o nounset
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10 | set -o pipefail
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11 | set -o errexit
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12 |
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13 | readonly BASE_DIR=_tmp/survey-strace
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14 |
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15 | OSH=${OSH:-bin/osh}
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16 |
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17 | banner() {
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18 | echo
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19 | echo
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20 | echo -e -n "\t"; echo "$@"
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21 | echo
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22 | echo
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23 | }
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24 |
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25 | redir-strace() {
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26 | ### trace relevant calls
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27 |
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28 | strace -e open,fcntl,dup2,close -- "$@"
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29 | }
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30 |
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31 | redir() {
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32 | #for sh in dash bash mksh bin/osh; do
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33 |
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34 | # hm bin/osh and zsh have too many close() calls. I think this is the Python
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35 | # interpreter
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36 | for sh in dash bash mksh; do
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37 |
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38 | banner "$sh"
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39 |
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40 | #local code='exec 3>_tmp/3.txt; echo hello >&3; exec 3>&-; cat _tmp/3.txt'
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41 |
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42 | #local code='exec 4>_tmp/4.txt; echo hello >&4; exec 4>&-; cat _tmp/4.txt'
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43 | #local code='true 2>&1'
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44 |
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45 | local code='true > _tmp/out.txt'
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46 | redir-strace $sh -c "$code"
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47 | done
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48 | }
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49 |
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50 | here-strace() {
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51 | local sh=$1
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52 | local dir
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53 | dir=$BASE_DIR/$(basename $sh)
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54 | # Not shifting
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55 |
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56 | mkdir -v -p $dir
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57 |
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58 | # -ff because it's a pipeline
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59 | strace -ff -o $dir/here -e 'open,close,fcntl,read,write,fork,execve' -- "$@"
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60 | }
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61 |
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62 | here() {
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63 | mkdir -v -p $BASE_DIR
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64 |
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65 | if false; then
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66 | # osh-cpp doesn't have $(dirname) in wrapper script
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67 | OSH=_bin/cxx-dbg/osh
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68 | ninja $OSH
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69 | fi
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70 |
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71 | for sh in dash bash mksh $OSH; do
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72 |
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73 | banner "$sh"
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74 |
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75 | #local code='exec 3>_tmp/3.txt; echo hello >&3; exec 3>&-; cat _tmp/3.txt'
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76 |
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77 | #local code='exec 4>_tmp/4.txt; echo hello >&4; exec 4>&-; cat _tmp/4.txt'
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78 | #local code='true 2>&1'
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79 |
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80 | cat > $BASE_DIR/here.sh <<SHELL
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81 | tac <<EOF
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82 | one
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83 | two
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84 | three
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85 | EOF
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86 | SHELL
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87 |
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88 | here-strace $sh $BASE_DIR/here.sh
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89 | done
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90 |
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91 | if command -v tree; then
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92 | tree $BASE_DIR
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93 | fi
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94 | }
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95 |
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96 | io-strace() {
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97 | ### trace relevant calls
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98 |
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99 | # -ff because it's a pipeline
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100 | strace -ff -e 'open,close,fcntl,read,write' -- "$@"
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101 | }
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102 |
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103 | readonly OSH_NATIVE=_bin/cxx-dbg/osh
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104 |
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105 | readonly READ_SH='
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106 | { echo "0123456789"; echo "ABCDEFGHIJ"; } |
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107 | while read -r line; do echo $line; done
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108 | '
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109 |
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110 | read-builtin() {
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111 | # RESULTS
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112 | #
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113 | # All shells read 1 byte at a time
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114 |
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115 | for sh in dash bash $OSH_NATIVE; do
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116 | banner "$sh"
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117 |
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118 | io-strace $sh -c "$READ_SH"
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119 | done
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120 | }
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121 |
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122 | read-lines-from-disk-file() {
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123 | # dash can't read this script
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124 |
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125 | # RESULTS:
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126 | # mksh: reads 512 bytes at a time
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127 | # bash: 80 and then 2620?
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128 | # osh_native: using libc readline, it's 832 bytes at a time.
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129 |
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130 | # I think we can have a "regular file reader", which is different than a pipe
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131 | # reader?
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132 |
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133 | for sh in mksh bash $OSH_NATIVE; do
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134 | banner "$sh"
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135 |
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136 | # Run without args
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137 | io-strace $sh $0
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138 | done
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139 | }
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140 |
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141 | read-lines-from-pipe() {
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142 | # RESULTS:
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143 | # - dash does read(8192), hm
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144 | # - mksh reads 1 byte at a time
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145 | # - bash reads 1 byte at a time
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146 | # - zsh reads 1 byte at a time
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147 | # - osh_native with libc does 832 bytes at time.
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148 |
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149 | for sh in dash mksh bash zsh $OSH_NATIVE; do
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150 | banner "$sh"
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151 |
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152 | # Run without args
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153 | io-strace sh -c "cat testdata/osh-runtime/hello_world.sh | $sh"
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154 | done
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155 | }
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156 |
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157 | job-control-trace() {
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158 | ### trace relevant calls
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159 |
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160 | # why isn't tcsetpgrp valid?
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161 | strace -ff -e fork,execve,setpgid -- "$@"
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162 | }
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163 |
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164 | job-control() {
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165 | #for sh in dash bash mksh bin/osh; do
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166 |
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167 | # hm bin/osh and zsh have too many close() calls. I think this is the Python
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168 | # interpreter
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169 | for sh in dash bash mksh zsh; do
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170 |
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171 | echo
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172 | echo "--- $sh ---"
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173 | echo
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174 |
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175 | local code='ls | wc -l'
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176 | job-control-trace $sh -i -c "$code"
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177 | done
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178 | }
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179 |
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180 | interactive() {
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181 | local sh=dash
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182 | local code='ls | wc -l'
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183 |
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184 | # is tcsetpgrp() an ioctl? It takes a file descriptor. I see setpgid() but
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185 | # not tcsetpgrp().
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186 |
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187 | strace -c $sh -c "$code"
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188 | echo -----
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189 | strace -c $sh -i -c "$code"
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190 | }
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191 |
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192 | #
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193 | # Translation tests
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194 | #
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195 |
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196 | _compare-native() {
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197 | local code=$1
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198 |
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199 | rm -r -f -v $BASE_DIR
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200 | mkdir -p $BASE_DIR
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201 |
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202 | ninja $OSH_NATIVE
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203 |
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204 | strace -ff -o $BASE_DIR/py -- bin/osh -c "$code"
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205 | strace -ff -o $BASE_DIR/cpp -- $OSH_NATIVE -c "$code"
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206 |
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207 | wc -l $BASE_DIR/*
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208 | }
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209 |
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210 | native-command-sub() {
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211 | _compare-native 'echo $(echo hi)'
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212 | }
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213 |
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214 | native-redirect() {
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215 | _compare-native 'echo hi > _tmp/redir'
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216 | }
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217 |
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218 | native-read-builtin() {
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219 | _compare-native "$READ_SH"
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220 | }
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221 |
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222 | if test $# -eq 0; then
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223 | echo "$0: expected arguments"
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224 | else
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225 | "$@"
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226 | fi
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