47 lines
2.1 KiB
Plaintext
47 lines
2.1 KiB
Plaintext
Warning:
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This code must corrctly handle lots of picky little details to meet
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the Unix98 standard while simultaneously being as compatible as
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possible with the original Linux ps. Don't "fix" something without
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considering the impact on all the special-case code. For example,
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the "tty" format _must_ use "TT" as the header, even though the SysV
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output formats _must_ use "TTY".
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File overview:
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display.c main(), debug code, iterates over processes
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escape.c Does stuff like \202 and < to command and environment.
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global.c Data + code to init it.
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help.c Help message.
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output.c Giant tables and lots of output functions.
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parser.c Initial command parsing.
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select.c want_this_proc() checks a process against flags & lists
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sortformat.c Parses sort & format specifier lists. Picks output format.
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stacktrace.c Debug code, not normally used.
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../proc/* Library used to gather data.
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regression Regression tests that ought to be run.
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common.h Lots of interesting stuff.
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Makefile Makefile
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p Script used to test ps when the library is not installed.
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utf Empty file used to test "ps ut?" unmangling behavior.
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ps.1 Man page.
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Operation:
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Unless the personality forces BSD parsing, parser.c tries to parse the
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command line as a mixed BSD+SysV+Gnu mess. On failure, BSD parsing is
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attempted. If BSD parsing fails _after_ SysV parsing has been attempted,
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the error message comes from the original SysV parse.
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Control goes to sortformat.c, which must pick apart ambiguous options
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like "O". Failure can reset the whole program and set PER_FORCE_BSD,
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which means a second trip through parser.c and sortformat.c.
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The choice of output format happens in sortformat.c. There is a switch()
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with all the valid format_flags combinations. The SysV and default
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options are NULL (unless overridden by personality), which causes a
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trip through SysV output format generation hackery. Note that the
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default format always goes through there, even if it is for BSD.
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Formats that came from the switch() (generally BSD, plus overrides)
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get mangled a bit to support various SysV output modifiers.
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