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more clarity

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Remzi Arpaci-Dusseau
2022-09-19 10:12:41 -05:00
parent c363697dba
commit bbb5693c67
1 changed files with 7 additions and 2 deletions
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9
initial-xv6-tracer/README.md
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@@ -41,11 +41,16 @@ int getcount(void)
The first, `trace()`, simply records the pathname specified by the parameter `pathname`, into
some known location (e.g., an array of characters called `trace_pathname`).
It should also reset the trace counter to 0, and enable tracing (i.e., set some kernel
internal integer, such as `trace_enabled`, to 1).
internal integer, such as `trace_enabled`, to 1).
It should return 0 upon success, and -1 upon failure (e.g., if someone passes in a null pointer).
Note: assume for simplicity that the max pathname is 256 bytes. Also, it is ok to trace
a file that does not yet exist, so no need to check that.
The second, `getcount()`, returns the value of a counter (perhaps called `trace_counter`
or something like that). This counter should be incremented every time any process calls the
`open()` system call if the pathname passed to open matches the pathname being traced.
`open()` system call if the pathname passed to open matches the pathname being traced.
If tracing has not yet been enabled, it should simply return 0.
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