Pythonで学ぶUnixプロセスの基礎

「なるほどUnixプロセス」をPythonで学ぶ

Transcript

1. 1ZUIPOͰֶͿ
   6OJYϓϩηεͷجૅ
   1Z'VLVPLB
   

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2. ࣗݾ঺հ
   ͭΔͨ
   ʢ!UTVSVCFFʣ
   ΤϯδχΞྺɿ
   ೥ͪΐ͍
   େֶͷઐ߈͸Խֶ
   લ৬͸ফ๷࢜
   झຯ͸ےτϨ
   ʢಛʹϕϯνϓϨεʣ
   

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3. ࠓճͷ໨త
   Θ͔ͬͨΑ͏ͰΘ͔Βͳ͍ʮϓϩηεʯʹ͍ͭͯ
   1ZUIPOΛ༻͍ͯཧղΛਂΊΔ͜ͱɻ
   ͜ͷຊΛࢀߟʹ
   ͠·ͨ͠ɻ
   ௒Φεεϝʂ
   ಈ࡞؀ڥɿ6CVOUV
   ʢ7JSUVBM#PY্ʹߏஙʣ
   ࢀߟจݙ
   

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4. ໨࣍
   l ϓϩηεͱ͸ʁ
   l ϓϩηεͱ͸ʁ
   l ϓϩηεʹ͸*%͕͋Δ
   l ϓϩηεʹ͸਌͕͍Δ
   l ϓϩηεͷϦιʔεΛݟͯΈΑ͏ʂ
   l ϓϩηεΛ࡞Δ
   l ϓϩηε͸ࢠϓϩηεΛ࡞ΕΔ
   l GPSLͷڍಈΛ௥ͬͯΈΑ͏ʂ
   l ϓϩηεؒ௨৴
   l ϓϩηεؒ௨৴ͱ͸ʁ
   l ύΠϓʹΑΔ௨৴
   l ·ͱΊ
   

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5. ϓϩηεͱ͸ʁ
   

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6. ϓϩάϥϜͷ࣮ߦத
   ͷ࢟Ͱ͋Δɻ
   ϓϩηεͱ͸ʁ
   

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7. ϓϩηεʹ͸*%͕͋Δ
   $ ps u
   USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
   ubuntu 2005 0.0 0.5 21392 5392 pts/0 Ss+ 02:21 0:00 –bash
   ubuntu 2212 0.1 0.5 21388 5260 pts/1 Ss 06:18 0:00 –bash
   ubuntu 2228 0.0 0.3 36084 3348 pts/1 R+ 06:18 0:00 ps u
   1ZUIPOͰ͸ɾɾ
   $ python
   >>> import os
   >>> os.getpid()
   1229
   QTίϚϯυ
   04ͷػೳΛར༻͢ΔͨΊͷʮPTʯͱ͍͏ඪ४ϥΠϒϥϦ͕͋Δɻ
   1*%͸୯ʹ࿈൪ʹͳ͍ͬͯΔ਺஋ͷϥϕϧͰ͋Δɻ
   

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8. ϓϩηεʹ͸਌͕͍Δ
   QTUSFFίϚϯυ
   $ pstree
   systemd─┬─VBoxService─┬─{automount}
   │ ├─{control}
   │ ├─{cpuhotplug}
   │ ├─{memballoon}
   │ ├─{timesync}
   │ ├─{vminfo}
   │ └─{vmstats}
   ├─polkitd─┬─{gdbus}
   │ └─{gmain}
   ├─snapd───6*[{snapd}]
   ├─sshd─┬─sshd───sshd───bash
   │ └─sshd───sshd───bash───pstree
   ├─systemd───(sd-pam)
   ├─systemd-journal
   ˞Ұ෦লུ
   ϓϩηεͷ਌ࢠؔ܎ΛπϦʔදࣔͰ͖Δɻ
   QTUSFF͸CBTIͷࢠ
   

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9. ϓϩηεʹ͸਌͕͍Δ
   ਌ϓϩηεͷ*%Λऔಘ͢Δ
   ͍͍ͨͯͷ৔߹ɺ਌ϓϩηε͸ͦͷϓϩηεΛىಈͨ͠
   ϓϩηεͱͳΔɻ
   $ python
   >>> import os
   >>> os.getppid()
   1165
   USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
   root 1 0.9 0.5 37916 5976 ? Ss 06:43 0:08 /sbin/init
   ͢΂ͯͷى఺͸1*%͕ͷJOJUϓϩηε
   ʢγεςϜىಈ࣌ʹ࠷ॳʹ্ཱ͕ͪΔϓϩηεʣ
   ਌ΛͨͲ͍ͬͯ͘ͱɾɾ
   

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10. ϓϩηεͷϦιʔεΛݟͯΈΑ͏ʂ
    l TUBUVT
    l DXE
    l FOWJSPO
    l FYF
    l UBTL
    l NBQT ͳͲ
    QSPDϓϩηε*%
    

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11. ϓϩηεΛ࡞Δ
    

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12. ϓϩηε͸ࢠϓϩηεΛ࡞ΕΔ
    l GPSL
    γεςϜίʔϧʹΑͬͯɺ࣮ߦதͷϓϩηε͔Β
    ৽͍͠ϓϩηεΛੜ੒Ͱ͖Δɻ
    l GPSL
    ΛݺͿଆͷϓϩηε͸ʮ਌ϓϩηεʯɺੜ੒͞Ε
    Δϓϩηε͸ʮࢠϓϩηεʯͱͳΔɻ
    l ࢠϓϩηε͸ɺ਌ϓϩηεͰ࢖ΘΕ͍ͯΔ͢΂ͯͷϝϞ
    Ϧͷίϐʔͱɺ਌ϓϩηε͕։͍͍ͯΔϑΝΠϧσΟε
    ΫϦϓλΛҾ͖ܧ͙ɻ
    

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13. GPSLͷڍಈΛ௥ͬͯΈΑ͏
    import os
    if os.fork():
    print("Here in the if block.")
    else:
    print("Here in the else block.")
    $ python fork.py
    Here in the if block.
    Here in the else block.
    ࣮ߦ
    JG۟΋FMTF۟΋࣮ߦ͞Ε͍ͯΔɻͳʹ͕ى͖ͯΔʁ
    GPSL͢ΔͱԿ͕ى͖Δͷ͔ʁ
    fork.py
    

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14. GPSLͷڍಈΛ௥ͬͯΈΑ͏
    import os
    print("---- before fork ----")
    print("pid: {0}".format(os.getpid()))
    if os.fork():
    print("----- if block ------")
    print("pid: {0}".format(os.getpid()))
    else:
    print("---- else block -----")
    print("pid: {0}".format(os.getpid()))
    $ python fork.py
    ---- before fork ----
    pid: 1547
    ----- if block ------
    pid: 1547
    ---- else block -----
    pid: 1548
    ࣮ߦ
    JG͕۟਌ϓϩηεɺ
    FMTF͕۟ࢠϓϩηε
    ʹΑ࣮ͬͯߦ͞Ε͍ͯΔɻ
    ϓϩηε*%͕Ͳ͏ͳ͍ͬͯΔ͔ௐ΂Δ
    fork.py
    

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15. GPSLͷڍಈΛ௥ͬͯΈΑ͏
    import os
    ret = os.fork()
    if ret:
    print("----- if block ------")
    print("return value: {0}".format(ret))
    else:
    print("---- else block -----")
    print("return value: {0}".format(ret))
    $ python fork.py
    ----- if block ------
    return value: 1548
    ---- else block -----
    return value: 0
    ࣮ߦ
    ਌ϓϩηεଆʹ͸ʮੜ੒ͨ͠ࢠϓϩηεͷ1*%ʯΛฦ͠ɺ
    ࢠϓϩηεଆʹ͸ʮʯΛฦ͢ɻ
    GPSLͷฦΓ஋͕Ͳ͏ͳ͍ͬͯΔ͔ௐ΂Δ
    fork.py
    

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16. ϓϩηεؒ௨৴
    

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17. ϓϩηεؒ௨৴ͱ͸ʁ
    ϓϩηεؒ௨৴ʢ*1$*OUFS1SPDFTT$PNNVOJDBUJPOʣͱ͸ɺ
    ෳ਺ͷϓϩηεؒͰσʔλΛ΍ΓͱΓ͢ΔͨΊͷ࢓૊ΈͰ͋Δɻ
    *1$ͷख๏͸༷ʑ
    ɾڞ༗ϝϞϦ
    ɾγάφϧ
    ɾύΠϓ
    ɾιέοτ
    ɾηϚϑΥ
    ɾϝοηʔδύογϯά ͳͲ
    

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18. ϓϩηεؒ௨৴ͱ͸ʁ
    ϓϩηεؒ௨৴ʢ*1$*OUFS1SPDFTT$PNNVOJDBUJPOʣͱ͸ɺ
    ෳ਺ͷϓϩηεؒͰσʔλΛ΍ΓͱΓ͢ΔͨΊͷ࢓૊ΈͰ͋Δɻ
    *1$ͷख๏͸༷ʑ
    ɾڞ༗ϝϞϦ
    ɾγάφϧ
    ɾύΠϓ
    ɾιέοτ
    ɾηϚϑΥ
    ɾϝοηʔδύογϯά ͳͲ
    ࠓ೔͸ίϨʂ
    

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19. ύΠϓʹΑΔ௨৴
    ύΠϓ͸਌ࢠؔ܎ʹ͋Δϓϩηεؒͷ୯ํ޲ͷ௨৴
    Ϣʔβۭؒ
    Χʔωϧۭؒ
    ϑΝΠϧσΟεΫϦϓλ ϑΝΠϧσΟεΫϦϓλ
    
    
    
    
    
    
    
    
    
    
    ਌ϓϩηε ࢠϓϩηε
    σΟεϓϨΠ
    ΩʔϘʔυ
    ύΠϓ
    ୺຤
    ࢀߟɿIUUQXXXDPJOTUTVLVCBBDKQdZBTDPJOTTZTQSP
    GPSL
    
    

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20. ύΠϓʹΑΔ௨৴
    import os
    reader, writer = os.pipe()
    if os.fork():
    os.close(reader)
    write_pipe = os.fdopen(writer, 'w')
    write_pipe.write('Hello child!')
    write_pipe.close()
    else:
    os.close(writer)
    read_pipe = os.fdopen(reader, 'r')
    message= read_pipe.readline()
    read_pipe.close()
    print(message)
    pipe.py
    $ python pipe.py
    Hello child!
    ࣮ߦ
    ਌ϓϩηε
    ࢠϓϩηε
    

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21. ·ͱΊ
    ϓϩηε͸ɺ*%͕͋ͬͯɺ਌͕͍ͯɺࢠΛ࡞Εͯɺ
    ௨৴͕Ͱ͖Δɻ
    ͦͯ͠ɺͦͷ༷ࢠΛ1ZUIPO͔Β֬ೝͰ͖Δɻ
    ࠓճ࿩ͨ͜͠ͱҎ֎ʹ΋͍Ζ͍Ζಛ௃͕͋ΔͷͰɺ
    ͦΕ͸·ͨ࣍ճʂ
    ʻྫʼ
    ɾݽࣇϓϩηε
    ɾκϯϏϓϩηε
    ɾσʔϞϯϓϩηε
    ɾιέοτ௨৴
    ɾϚϧνϓϩηεॲཧ
    

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22. ͝ਗ਼ௌ͋Γ͕ͱ͏
    ͍͟͝·ͨ͠ʂ
    

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