proyuvos is our submission for the Sistemas Operativos course project of 2019-2 in Univalle. It's a modification on the xv6 operative system, that includes three new user commands: trace, uptime and date.
trace prints how many times system calls have been used since boot.
trace will print each availible system call followed by its number of uses.
You can also specify which system call info should be printed by putting its
corresponding number as the argument. So trace 1 will print a single line like
exit 5 meaning that the exit system call has been used 5 times since
xv6 booted up, for example. The use count is stored in an array defined in
trap.c but is modified when the syscall function defined in the syscall.c
file is executed. Then the array is accessed through the newly defined trace
system call.
uptime will print how many ticks have passed since boot. It does so by calling the already built-in uptime system call.
date will print the date pretty-printing the output of the date system call.
xv6 is a re-implementation of Dennis Ritchie's and Ken Thompson's Unix Version 6 (v6). xv6 loosely follows the structure and style of v6, but is implemented for a modern x86-based multiprocessor using ANSI C.
xv6 is inspired by John Lions's Commentary on UNIX 6th Edition (Peer to Peer Communications; ISBN: 1-57398-013-7; 1st edition (June 14, 2000)). See also https://pdos.csail.mit.edu/6.828/, which provides pointers to on-line resources for v6.
xv6 borrows code from the following sources: JOS (asm.h, elf.h, mmu.h, bootasm.S, ide.c, console.c, and others) Plan 9 (entryother.S, mp.h, mp.c, lapic.c) FreeBSD (ioapic.c) NetBSD (console.c)
The following people have made contributions: Russ Cox (context switching, locking), Cliff Frey (MP), Xiao Yu (MP), Nickolai Zeldovich, and Austin Clements.
We are also grateful for the bug reports and patches contributed by Silas Boyd-Wickizer, Anton Burtsev, Cody Cutler, Mike CAT, Tej Chajed, eyalz800, Nelson Elhage, Saar Ettinger, Alice Ferrazzi, Nathaniel Filardo, Peter Froehlich, Yakir Goaron,Shivam Handa, Bryan Henry, Jim Huang, Alexander Kapshuk, Anders Kaseorg, kehao95, Wolfgang Keller, Eddie Kohler, Austin Liew, Imbar Marinescu, Yandong Mao, Matan Shabtay, Hitoshi Mitake, Carmi Merimovich, Mark Morrissey, mtasm, Joel Nider, Greg Price, Ayan Shafqat, Eldar Sehayek, Yongming Shen, Cam Tenny, tyfkda, Rafael Ubal, Warren Toomey, Stephen Tu, Pablo Ventura, Xi Wang, Keiichi Watanabe, Nicolas Wolovick, wxdao, Grant Wu, Jindong Zhang, Icenowy Zheng, and Zou Chang Wei.
The code in the files that constitute xv6 is Copyright 2006-2018 Frans Kaashoek, Robert Morris, and Russ Cox.