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67 lines
2.7 KiB
67 lines
2.7 KiB
Demonstrations of shmsnoop, the Linux eBPF/bcc version.
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shmsnoop traces shm*() syscalls, for example:
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# ./shmsnoop.py
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PID COMM SYS RET ARGs
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19813 server SHMGET 10000 key: 0x78020001, size: 20, shmflg: 0x3b6 (IPC_CREAT|0666)
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19813 server SHMAT 7f1cf8b1f000 shmid: 0x10000, shmaddr: 0x0, shmflg: 0x0
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19816 client SHMGET 10000 key: 0x78020001, size: 20, shmflg: 0x1b6 (0666)
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19816 client SHMAT 7f4fd8ee7000 shmid: 0x10000, shmaddr: 0x0, shmflg: 0x0
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19816 client SHMDT 0 shmaddr: 0x7f4fd8ee7000
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19813 server SHMDT 0 shmaddr: 0x7f1cf8b1f000
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19813 server SHMCTL 0 shmid: 0x10000, cmd: 0, buf: 0x0
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Every call the shm* syscall (SHM column) is displayed
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on separate line together with process info (PID/COMM
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columns) and argument details: return value (RET column)
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and syscall arguments (ARGs column).
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The ARGs column contains 'arg: value' couples that represent
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given syscall arguments as described in their manpage.
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This works by tracing shm* system calls and sending
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argument details to the python script.
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A -T option can be used to include a timestamp column,
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and a -n option to match on a command name. Regular
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expressions are allowed. For example, matching commands
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containing "server" with timestamps:
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# ./shmsnoop.py -T -n server
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TIME(s) PID COMM SYS RET ARGs
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0.563194000 19825 server SHMDT 0 shmaddr: 0x7f74362e4000
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0.563237000 19825 server SHMCTL 0 shmid: 0x18000, cmd: 0, buf: 0x0
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A -p option can be used to trace only selected process:
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# ./shmsnoop.py -p 19855
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PID COMM SYS RET ARGs
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19855 server SHMDT 0 shmaddr: 0x7f4329ff8000
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19855 server SHMCTL 0 shmid: 0x20000, cmd: 0, buf: 0x0
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USAGE message:
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# ./shmsnoop.py -h
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usage: shmsnoop.py [-h] [-T] [-p PID] [-t TID] [-d DURATION] [-n NAME]
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Trace shm*() syscalls
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optional arguments:
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-h, --help show this help message and exit
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-T, --timestamp include timestamp on output
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-p PID, --pid PID trace this PID only
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-t TID, --tid TID trace this TID only
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-d DURATION, --duration DURATION
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total duration of trace in seconds
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-n NAME, --name NAME only print process names containing this name
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examples:
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./shmsnoop # trace all shm*() syscalls
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./shmsnoop -T # include timestamps
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./shmsnoop -p 181 # only trace PID 181
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./shmsnoop -t 123 # only trace TID 123
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./shmsnoop -d 10 # trace for 10 seconds only
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./shmsnoop -n main # only print process names containing "main"
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