If currently two unsigned values are compared via `a - b`, in the case b
is actually bigger than a, the result will not be an negative number (as
-1 is expected) but a huge positive number as the subtraction is an
unsigned subtraction.
Avoid over-/underflow affected operations; use comparisons.
Modern compilers will generate sane code, like:
xor eax, eax
cmp rdi, rsi
seta al
sbb eax, 0
ret
Reasoning:
- implementation was unsound -- broke down when I added a fairly
basic macro definition expanding to a struct initializer in a *.c
file.
- made it way too easy (e.g. via otherwise totally innocuous git
commands) to end up with timestamps such that it always ran
MakeHeader.py but never used its output, leading to overbuild noise
when running what should be a null 'make'.
- but mostly: it's just an awkward way of dealing with C code.
Squashed the following commits:
* Solaris: Get LWP enumeration working
* Solaris: Make showing and hiding of kernel threads behave
* Solaris: remove usage of lwpstatus that is no longer needed
* Solaris: no discrete access to parent proc structure needed
* Solaris: Restore runtime MaxPid detection after LWP changes
* Solaris: Workaround virtual PID signal issue by shadowing kill() with a macro
* Solaris: Fix unintention double-shifting of virtual PID for LWP enumeration
* Solaris: Add LWPID to default display since LWP enumeration is also default
* Solaris: use PAGE_SIZE_KB from Process.h instead of custom definition
* Solaris: stop LWP enumeration at 1023 LWPs per proc since that is all we can handle in the virtual PID
This commit adds support for Solaris, squashed from PR #741:
Summary of additions:
* Initial setup of Solaris platform directory
* Add Solaris platform into autoconf template
* Uptime and load averages
* Add dependency on libkstat
* Basic process listing
* Zone name display
* CPU detection
* Per-process memory and CPU usage parsed correctly
* Uses sysconf to discover number of CPUs, instead of more complex libkstat code
* Simple memory display working
* Reduce repetitive calls to the PAGE_SIZE macro when reading memory info
* Add Project, Contract, Task, and Pool into process properties
* Use system major()/minor() implementations and remove extraneous definition of mkdev()
* Get the STARTTIME column working properly, using the Linux implementation as a guide
Christian Göttsche