diff options
Diffstat (limited to 'shlab-handout')
31 files changed, 3112 insertions, 6 deletions
diff --git a/shlab-handout b/shlab-handout deleted file mode 160000 -Subproject 1ffed57168ffaa8bec0dfda56b4b0b8dc957b11 diff --git a/shlab-handout/.gitignore b/shlab-handout/.gitignore new file mode 100644 index 0000000..d448e21 --- /dev/null +++ b/shlab-handout/.gitignore @@ -0,0 +1,77 @@ +# Prerequisites +*.d + +# Compiled Object files +*.slo +*.lo +*.o +*.obj + +# Precompiled Headers +*.gch +*.pch + +# Linker files +*.ilk + +# Debugger Files +*.pdb + +# Compiled Dynamic libraries +*.so +*.dylib +*.dll +*.so.* + + +# Fortran module files +*.mod +*.smod + +# Compiled Static libraries +*.lai +*.la +*.a +*.lib + +# Executables +*.exe +*.out +*.app + +# Build directories +build/ +Build/ +build-*/ + +# CMake generated files +CMakeFiles/ +CMakeCache.txt +cmake_install.cmake +#Makefile +install_manifest.txt +compile_commands.json + +# Temporary files +*.tmp +*.log +*.bak +*.swp + +# vcpkg +vcpkg_installed/ + +# debug information files +*.dwo + +# test output & cache +Testing/ +.cache/ + +.vscode/ +myint +myspin +mysplit +mystop +tsh +output diff --git a/shlab-handout/LICENSE b/shlab-handout/LICENSE new file mode 100644 index 0000000..0ad25db --- /dev/null +++ b/shlab-handout/LICENSE @@ -0,0 +1,661 @@ + GNU AFFERO GENERAL PUBLIC LICENSE + Version 3, 19 November 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/> + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU Affero General Public License is a free, copyleft license for +software and other kinds of works, specifically designed to ensure +cooperation with the community in the case of network server software. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + <one line to give the program's name and a brief idea of what it does.> + Copyright (C) <year> <name of author> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License as published + by the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + +Also add information on how to contact you by electronic and paper mail. + + If your software can interact with users remotely through a computer +network, you should also make sure that it provides a way for users to +get its source. For example, if your program is a web application, its +interface could display a "Source" link that leads users to an archive +of the code. There are many ways you could offer source, and different +solutions will be better for different programs; see section 13 for the +specific requirements. + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU AGPL, see +<https://www.gnu.org/licenses/>. diff --git a/shlab-handout/Makefile b/shlab-handout/Makefile new file mode 100644 index 0000000..051dbaa --- /dev/null +++ b/shlab-handout/Makefile @@ -0,0 +1,103 @@ +# Makefile for the CS:APP Shell Lab + +TEAM = NOBODY +VERSION = 1 +HANDINDIR = /afs/cs/academic/class/15213-f02/L5/handin +DRIVER = ./sdriver.pl +TSH = ./tsh +TSHREF = ./tshref +TSHARGS = "-p" +CXX = g++ +CXXFLAGS = -std=c++17 -Wall -Wno-write-strings -O2 +CC = gcc +CFLAGS = -Wall -O2 +FILES = $(TSH) ./myspin ./mysplit ./mystop ./myint ./output + +all: $(FILES) + +$(TSH): tsh.cc + $(CXX) $(CXXFLAGS) -o $@ $< + +################## +# Handin your work +################## +handin: + cp tsh.cc $(HANDINDIR)/$(TEAM)-$(VERSION)-tsh.cc + + +################## +# Regression tests +################## + +# Run tests using the student's shell program +test01: + $(DRIVER) -t trace01.txt -s $(TSH) -a $(TSHARGS) +test02: + $(DRIVER) -t trace02.txt -s $(TSH) -a $(TSHARGS) +test03: + $(DRIVER) -t trace03.txt -s $(TSH) -a $(TSHARGS) +test04: + $(DRIVER) -t trace04.txt -s $(TSH) -a $(TSHARGS) +test05: + $(DRIVER) -t trace05.txt -s $(TSH) -a $(TSHARGS) +test06: + $(DRIVER) -t trace06.txt -s $(TSH) -a $(TSHARGS) +test07: + $(DRIVER) -t trace07.txt -s $(TSH) -a $(TSHARGS) +test08: + $(DRIVER) -t trace08.txt -s $(TSH) -a $(TSHARGS) +test09: + $(DRIVER) -t trace09.txt -s $(TSH) -a $(TSHARGS) +test10: + $(DRIVER) -t trace10.txt -s $(TSH) -a $(TSHARGS) +test11: + $(DRIVER) -t trace11.txt -s $(TSH) -a $(TSHARGS) +test12: + $(DRIVER) -t trace12.txt -s $(TSH) -a $(TSHARGS) +test13: + $(DRIVER) -t trace13.txt -s $(TSH) -a $(TSHARGS) +test14: + $(DRIVER) -t trace14.txt -s $(TSH) -a $(TSHARGS) +test15: + $(DRIVER) -t trace15.txt -s $(TSH) -a $(TSHARGS) +test16: + $(DRIVER) -t trace16.txt -s $(TSH) -a $(TSHARGS) + +# Run the tests using the reference shell program +rtest01: + $(DRIVER) -t trace01.txt -s $(TSHREF) -a $(TSHARGS) +rtest02: + $(DRIVER) -t trace02.txt -s $(TSHREF) -a $(TSHARGS) +rtest03: + $(DRIVER) -t trace03.txt -s $(TSHREF) -a $(TSHARGS) +rtest04: + $(DRIVER) -t trace04.txt -s $(TSHREF) -a $(TSHARGS) +rtest05: + $(DRIVER) -t trace05.txt -s $(TSHREF) -a $(TSHARGS) +rtest06: + $(DRIVER) -t trace06.txt -s $(TSHREF) -a $(TSHARGS) +rtest07: + $(DRIVER) -t trace07.txt -s $(TSHREF) -a $(TSHARGS) +rtest08: + $(DRIVER) -t trace08.txt -s $(TSHREF) -a $(TSHARGS) +rtest09: + $(DRIVER) -t trace09.txt -s $(TSHREF) -a $(TSHARGS) +rtest10: + $(DRIVER) -t trace10.txt -s $(TSHREF) -a $(TSHARGS) +rtest11: + $(DRIVER) -t trace11.txt -s $(TSHREF) -a $(TSHARGS) +rtest12: + $(DRIVER) -t trace12.txt -s $(TSHREF) -a $(TSHARGS) +rtest13: + $(DRIVER) -t trace13.txt -s $(TSHREF) -a $(TSHARGS) +rtest14: + $(DRIVER) -t trace14.txt -s $(TSHREF) -a $(TSHARGS) +rtest15: + $(DRIVER) -t trace15.txt -s $(TSHREF) -a $(TSHARGS) +rtest16: + $(DRIVER) -t trace16.txt -s $(TSHREF) -a $(TSHARGS) + + +# clean up +clean: + rm -f $(FILES) *.o *~ diff --git a/shlab-handout/README b/shlab-handout/README new file mode 100644 index 0000000..a5add38 --- /dev/null +++ b/shlab-handout/README @@ -0,0 +1,22 @@ +################ +CS:APP Shell Lab +################ + +Files: + +Makefile # Compiles your shell program and runs the tests +README # This file +tsh.c # The shell program that you will write and hand in +tshref # The reference shell binary. + +# The remaining files are used to test your shell +sdriver.pl # The trace-driven shell driver +trace*.txt # The 15 trace files that control the shell driver +tshref.out # Example output of the reference shell on all 15 traces + +# Little C programs that are called by the trace files +myspin.c # Takes argument <n> and spins for <n> seconds +mysplit.c # Forks a child that spins for <n> seconds +mystop.c # Spins for <n> seconds and sends SIGTSTP to itself +myint.c # Spins for <n> seconds and sends SIGINT to itself + diff --git a/shlab-handout/autograder/sdriver.pl b/shlab-handout/autograder/sdriver.pl new file mode 100755 index 0000000..852bf3d --- /dev/null +++ b/shlab-handout/autograder/sdriver.pl @@ -0,0 +1,210 @@ +#!/usr/bin/perl +#!/usr/local/bin/perl +use Getopt::Std; +use FileHandle; +use IPC::Open2; + +####################################################################### +# sdriver.pl - Shell driver +# +# Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved. +# May not be used, modified, or copied without permission. +# +# The driver runs a student's shell program as a child, sends +# commands and signals to the child as directed by a trace file, +# and captures and displays the output produced by the child. +# +# Tracefile format: +# +# The tracefile consists of text lines that are either blank lines, +# comment lines, driver commands, or shell commands. Blank lines are +# ignored. Comment lines begin with "#" and are echo'd without change +# to stdout. Driver commands are intepreted by the driver and are not +# passed to the child shell. All other lines are shell commands and +# are passed without modification to the shell, which reads them on +# stdin. Output produced by the child on stdout/stderr is read by +# the parent and printed on its stdout. +# +# Driver commands: +# TSTP Send a SIGTSTP signal to the child +# INT Send a SIGINT signal to the child +# QUIT Send a SIGQUIT signal to the child +# KILL Send a SIGKILL signal to the child +# CLOSE Close Writer (sends EOF signal to child) +# WAIT Wait() for child to terminate +# SLEEP <n> Sleep for <n> seconds +# +###################################################################### + +# +# usage - print help message and terminate +# +sub usage +{ + printf STDERR "$_[0]\n"; + printf STDERR "Usage: $0 [-hv] -t <trace> -s <shellprog> -a <args>\n"; + printf STDERR "Options:\n"; + printf STDERR " -h Print this message\n"; + printf STDERR " -v Be more verbose\n"; + printf STDERR " -t <trace> Trace file\n"; + printf STDERR " -s <shell> Shell program to test\n"; + printf STDERR " -a <args> Shell arguments\n"; + printf STDERR " -g Generate output for autograder\n"; + die "\n" ; +} + +# Parse the command line arguments +getopts('hgvt:s:a:'); +if ($opt_h) { + usage(); +} +if (!$opt_t) { + usage("Missing required -t argument"); +} +if (!$opt_s) { + usage("Missing required -s argument"); +} +$verbose = $opt_v; +$infile = $opt_t; +$shellprog = $opt_s; +$shellargs = $opt_a; +$grade = $opt_g; + +# Make sure the input script exists and is readable +-e $infile + or die "$0: ERROR: $infile not found\n"; +-r $infile + or die "$0: ERROR: $infile is not readable\n"; + +# Make sure the shell program exists and is executable +-e $shellprog + or die "$0: ERROR: $shellprog not found\n"; +-x $shellprog + or die "$0: ERROR: $shellprog is not executable\n"; + + +# Open the input script +open INFILE, $infile + or die "$0: ERROR: Couldn't open input file $infile: $!\n"; + +# +# Fork a child, run the shell in it, and connect the parent +# and child with a pair of unidirectional pipes: +# parent:Writer -> child:stdin +# child:stdout -> parent:Reader +# +$pid = open2(\*Reader, \*Writer, "$shellprog $shellargs"); +Writer->autoflush(); + +# The autograder will want to know the child shell's pid +if ($grade) { + print ("pid=$pid\n"); +} + +# +# Parent reads a trace file, sends commands to the child shell. +# +while (<INFILE>) { + $line = $_; + chomp($line); + + # Comment line + if ($line =~ /^#/) { + print "$line\n"; + } + + # Blank line + elsif ($line =~ /^\s*$/) { + if ($verbose) { + print "$0: Ignoring blank line\n"; + } + } + + # Send SIGTSTP (ctrl-z) + elsif ($line =~ /TSTP/) { + if ($verbose) { + print "$0: Sending SIGTSTP signal to process $pid\n"; + } + kill 'TSTP', $pid; + } + + # Send SIGINT (ctrl-c) + elsif ($line =~ /INT/) { + if ($verbose) { + print "$0: Sending SIGINT signal to process $pid\n"; + } + kill 'INT', $pid; + } + + # Send SIGQUIT (whenever we need graceful termination) + elsif ($line =~ /QUIT/) { + if ($verbose) { + print "$0: Sending SIGQUIT signal to process $pid\n"; + } + kill 'QUIT', $pid; + } + + # Send SIGKILL + elsif ($line =~ /KILL/) { + if ($verbose) { + print "$0: Sending SIGKILL signal to process $pid\n"; + } + kill 'KILL', $pid; + } + + # Close pipe (sends EOF notification to child) + elsif ($line =~ /CLOSE/) { + if ($verbose) { + print "$0: Closing output end of pipe to child $pid\n"; + } + close Writer; + } + + # Wait for child to terminate + elsif ($line =~ /WAIT/) { + if ($verbose) { + print "$0: Waiting for child $pid\n"; + } + wait; + if ($verbose) { + print "$0: Child $pid reaped\n"; + } + } + + # Sleep + elsif ($line =~ /SLEEP (\d+)/) { + if ($verbose) { + print "$0: Sleeping $1 secs\n"; + } + sleep $1; + } + + # Unknown input + else { + if ($verbose) { + print "$0: Sending :$line: to child $pid\n"; + } + print Writer "$line\n"; + } +} + +# +# Parent echoes the output produced by the child. +# +close Writer; +if ($verbose) { + print "$0: Reading data from child $pid\n"; +} +while ($line = <Reader>) { + print $line; +} +close Reader; + +# Finally, parent reaps child +wait; + +if ($verbose) { + print "$0: Shell terminated\n"; +} + +exit; diff --git a/shlab-handout/autograder/trace01.txt b/shlab-handout/autograder/trace01.txt new file mode 100644 index 0000000..9c8561e --- /dev/null +++ b/shlab-handout/autograder/trace01.txt @@ -0,0 +1,5 @@ +# +# trace01.txt - Properly terminate on EOF. +# +CLOSE +WAIT diff --git a/shlab-handout/autograder/trace02.txt b/shlab-handout/autograder/trace02.txt new file mode 100644 index 0000000..e97643b --- /dev/null +++ b/shlab-handout/autograder/trace02.txt @@ -0,0 +1,5 @@ +# +# trace02.txt - Process builtin quit command. +# +quit +WAIT diff --git a/shlab-handout/autograder/trace03.txt b/shlab-handout/autograder/trace03.txt new file mode 100644 index 0000000..be8869c --- /dev/null +++ b/shlab-handout/autograder/trace03.txt @@ -0,0 +1,5 @@ +# +# trace03.txt - Run a foreground job. +# +/bin/echo tsh> quit +quit diff --git a/shlab-handout/autograder/trace04.txt b/shlab-handout/autograder/trace04.txt new file mode 100644 index 0000000..554df0e --- /dev/null +++ b/shlab-handout/autograder/trace04.txt @@ -0,0 +1,5 @@ +# +# trace04.txt - Run a background job. +# +/bin/echo -e tsh> ./myspin 1 \046 +./myspin 1 & diff --git a/shlab-handout/autograder/trace05.txt b/shlab-handout/autograder/trace05.txt new file mode 100644 index 0000000..03c1876 --- /dev/null +++ b/shlab-handout/autograder/trace05.txt @@ -0,0 +1,11 @@ +# +# trace05.txt - Process jobs builtin command. +# +/bin/echo -e tsh> ./myspin 2 \046 +./myspin 2 & + +/bin/echo -e tsh> ./myspin 3 \046 +./myspin 3 & + +/bin/echo tsh> jobs +jobs diff --git a/shlab-handout/autograder/trace06.txt b/shlab-handout/autograder/trace06.txt new file mode 100644 index 0000000..bfa3890 --- /dev/null +++ b/shlab-handout/autograder/trace06.txt @@ -0,0 +1,8 @@ +# +# trace06.txt - Forward SIGINT to foreground job. +# +/bin/echo -e tsh> ./myspin 4 +./myspin 4 + +SLEEP 2 +INT diff --git a/shlab-handout/autograder/trace07.txt b/shlab-handout/autograder/trace07.txt new file mode 100644 index 0000000..259a285 --- /dev/null +++ b/shlab-handout/autograder/trace07.txt @@ -0,0 +1,14 @@ +# +# trace07.txt - Forward SIGINT only to foreground job. +# +/bin/echo -e tsh> ./myspin 4 \046 +./myspin 4 & + +/bin/echo -e tsh> ./myspin 5 +./myspin 5 + +SLEEP 2 +INT + +/bin/echo tsh> jobs +jobs diff --git a/shlab-handout/autograder/trace08.txt b/shlab-handout/autograder/trace08.txt new file mode 100644 index 0000000..49be19f --- /dev/null +++ b/shlab-handout/autograder/trace08.txt @@ -0,0 +1,14 @@ +# +# trace08.txt - Forward SIGTSTP only to foreground job. +# +/bin/echo -e tsh> ./myspin 4 \046 +./myspin 4 & + +/bin/echo -e tsh> ./myspin 5 +./myspin 5 + +SLEEP 2 +TSTP + +/bin/echo tsh> jobs +jobs diff --git a/shlab-handout/autograder/trace09.txt b/shlab-handout/autograder/trace09.txt new file mode 100644 index 0000000..340d998 --- /dev/null +++ b/shlab-handout/autograder/trace09.txt @@ -0,0 +1,20 @@ +# +# trace09.txt - Process bg builtin command +# +/bin/echo -e tsh> ./myspin 4 \046 +./myspin 4 & + +/bin/echo -e tsh> ./myspin 5 +./myspin 5 + +SLEEP 2 +TSTP + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> bg %2 +bg %2 + +/bin/echo tsh> jobs +jobs diff --git a/shlab-handout/autograder/trace10.txt b/shlab-handout/autograder/trace10.txt new file mode 100644 index 0000000..e7de996 --- /dev/null +++ b/shlab-handout/autograder/trace10.txt @@ -0,0 +1,22 @@ +# +# trace10.txt - Process fg builtin command. +# +/bin/echo -e tsh> ./myspin 4 \046 +./myspin 4 & + +SLEEP 1 +/bin/echo tsh> fg %1 +fg %1 + +SLEEP 1 +TSTP + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> fg %1 +fg %1 + +/bin/echo tsh> jobs +jobs + diff --git a/shlab-handout/autograder/trace11.txt b/shlab-handout/autograder/trace11.txt new file mode 100644 index 0000000..d2f8663 --- /dev/null +++ b/shlab-handout/autograder/trace11.txt @@ -0,0 +1,12 @@ +# +# trace11.txt - Forward SIGINT to every process in foreground process group +# +/bin/echo -e tsh> ./mysplit 4 +./mysplit 4 + +SLEEP 2 +INT + +/bin/echo tsh> /bin/ps a +/bin/ps a + diff --git a/shlab-handout/autograder/trace12.txt b/shlab-handout/autograder/trace12.txt new file mode 100644 index 0000000..88455e3 --- /dev/null +++ b/shlab-handout/autograder/trace12.txt @@ -0,0 +1,17 @@ +# +# trace12.txt - Forward SIGTSTP to every process in foreground process group +# +/bin/echo -e tsh> ./mysplit 4 +./mysplit 4 + +SLEEP 2 +TSTP + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> /bin/ps a +/bin/ps a + + + diff --git a/shlab-handout/autograder/trace13.txt b/shlab-handout/autograder/trace13.txt new file mode 100644 index 0000000..d734cbc --- /dev/null +++ b/shlab-handout/autograder/trace13.txt @@ -0,0 +1,23 @@ +# +# trace13.txt - Restart every stopped process in process group +# +/bin/echo -e tsh> ./mysplit 4 +./mysplit 4 + +SLEEP 2 +TSTP + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> /bin/ps a +/bin/ps a + +/bin/echo tsh> fg %1 +fg %1 + +/bin/echo tsh> /bin/ps a +/bin/ps a + + + diff --git a/shlab-handout/autograder/trace14.txt b/shlab-handout/autograder/trace14.txt new file mode 100644 index 0000000..8086580 --- /dev/null +++ b/shlab-handout/autograder/trace14.txt @@ -0,0 +1,47 @@ +# +# trace14.txt - Simple error handling +# +/bin/echo tsh> ./bogus +./bogus + +/bin/echo -e tsh> ./myspin 4 \046 +./myspin 4 & + +/bin/echo tsh> fg +fg + +/bin/echo tsh> bg +bg + +/bin/echo tsh> fg a +fg a + +/bin/echo tsh> bg a +bg a + +/bin/echo tsh> fg 9999999 +fg 9999999 + +/bin/echo tsh> bg 9999999 +bg 9999999 + +/bin/echo tsh> fg %2 +fg %2 + +/bin/echo tsh> fg %1 +fg %1 + +SLEEP 2 +TSTP + +/bin/echo tsh> bg %2 +bg %2 + +/bin/echo tsh> bg %1 +bg %1 + +/bin/echo tsh> jobs +jobs + + + diff --git a/shlab-handout/autograder/trace15.txt b/shlab-handout/autograder/trace15.txt new file mode 100644 index 0000000..2cc780e --- /dev/null +++ b/shlab-handout/autograder/trace15.txt @@ -0,0 +1,46 @@ +# +# trace15.txt - Putting it all together +# + +/bin/echo tsh> ./bogus +./bogus + +/bin/echo tsh> ./myspin 10 +./myspin 10 + +SLEEP 2 +INT + +/bin/echo -e tsh> ./myspin 3 \046 +./myspin 3 & + +/bin/echo -e tsh> ./myspin 4 \046 +./myspin 4 & + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> fg %1 +fg %1 + +SLEEP 2 +TSTP + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> bg %3 +bg %3 + +/bin/echo tsh> bg %1 +bg %1 + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> fg %1 +fg %1 + +/bin/echo tsh> quit +quit + diff --git a/shlab-handout/autograder/trace16.txt b/shlab-handout/autograder/trace16.txt new file mode 100644 index 0000000..822ba14 --- /dev/null +++ b/shlab-handout/autograder/trace16.txt @@ -0,0 +1,16 @@ +# +# trace16.txt - Tests whether the shell can handle SIGTSTP and SIGINT +# signals that come from other processes instead of the terminal. +# + +/bin/echo tsh> ./mystop 2 +./mystop 2 + +SLEEP 3 + +/bin/echo tsh> jobs +jobs + +/bin/echo tsh> ./myint 2 +./myint 2 + diff --git a/shlab-handout/myint.c b/shlab-handout/myint.c new file mode 100644 index 0000000..ea5bee1 --- /dev/null +++ b/shlab-handout/myint.c @@ -0,0 +1,36 @@ +/* + * myint.c - Another handy routine for testing your tiny shell + * + * usage: myint <n> + * Sleeps for <n> seconds and sends SIGINT to itself. + * + */ +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <signal.h> + +int main(int argc, char **argv) +{ + int i, secs; + pid_t pid; + + if (argc != 2) { + fprintf(stderr, "Usage: %s <n>\n", argv[0]); + exit(0); + } + secs = atoi(argv[1]); + + for (i=0; i < secs; i++) + sleep(1); + + pid = getpid(); + + if (kill(pid, SIGINT) < 0) + fprintf(stderr, "kill (int) error"); + + exit(0); + +} diff --git a/shlab-handout/myspin.c b/shlab-handout/myspin.c new file mode 100644 index 0000000..08c3e0c --- /dev/null +++ b/shlab-handout/myspin.c @@ -0,0 +1,24 @@ +/* + * myspin.c - A handy program for testing your tiny shell + * + * usage: myspin <n> + * Sleeps for <n> seconds in 1-second chunks. + * + */ +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> + +int main(int argc, char **argv) +{ + int i, secs; + + if (argc != 2) { + fprintf(stderr, "Usage: %s <n>\n", argv[0]); + exit(0); + } + secs = atoi(argv[1]); + for (i=0; i < secs; i++) + sleep(1); + exit(0); +} diff --git a/shlab-handout/mysplit.c b/shlab-handout/mysplit.c new file mode 100644 index 0000000..9ac016e --- /dev/null +++ b/shlab-handout/mysplit.c @@ -0,0 +1,35 @@ +/* + * mysplit.c - Another handy routine for testing your tiny shell + * + * usage: mysplit <n> + * Fork a child that spins for <n> seconds in 1-second chunks. + */ +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <signal.h> + +int main(int argc, char **argv) +{ + int i, secs; + + if (argc != 2) { + fprintf(stderr, "Usage: %s <n>\n", argv[0]); + exit(0); + } + secs = atoi(argv[1]); + + + if (fork() == 0) { /* child */ + for (i=0; i < secs; i++) + sleep(1); + exit(0); + } + + /* parent waits for child to terminate */ + wait(NULL); + + exit(0); +} diff --git a/shlab-handout/mystop.c b/shlab-handout/mystop.c new file mode 100644 index 0000000..12eee5f --- /dev/null +++ b/shlab-handout/mystop.c @@ -0,0 +1,36 @@ +/* + * mystop.c - Another handy routine for testing your tiny shell + * + * usage: mystop <n> + * Sleeps for <n> seconds and sends SIGTSTP to itself. + * + */ +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <signal.h> + +int main(int argc, char **argv) +{ + int i, secs; + pid_t pid; + + if (argc != 2) { + fprintf(stderr, "Usage: %s <n>\n", argv[0]); + exit(0); + } + secs = atoi(argv[1]); + + for (i=0; i < secs; i++) + sleep(1); + + pid = getpid(); + + if (kill(-pid, SIGTSTP) < 0) + fprintf(stderr, "kill (tstp) error"); + + exit(0); + +} diff --git a/shlab-handout/output.c b/shlab-handout/output.c new file mode 100644 index 0000000..bba2760 --- /dev/null +++ b/shlab-handout/output.c @@ -0,0 +1,21 @@ +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> + +int main(int argc, char **argv) +{ + int i, secs; + + if (argc != 2) { + fprintf(stderr, "Usage: %s <n>\n", argv[0]); + exit(0); + } + secs = atoi(argv[1]); + for (i=0; i < secs; i++) + { + printf("%d\n", i); + fflush(stdout); + sleep(1); + } + exit(0); +} diff --git a/shlab-handout/tsh.cc b/shlab-handout/tsh.cc new file mode 100644 index 0000000..c004564 --- /dev/null +++ b/shlab-handout/tsh.cc @@ -0,0 +1,791 @@ +/* + * tsh - A tiny shell program with job control + * + * <Put your name and login ID here> + */ +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <ctype.h> +#include <signal.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <errno.h> +#include <iostream> +#include <vector> +#include <string> +#include "util.h" + +using namespace std; +using ov4::atomic_print; +using ov4::atomic_debug; +using ov4::isnum; + +/* Misc manifest constants */ +#define MAXLINE 1024 /* max line size */ +#define MAXARGS 128 /* max args on a command line */ +#define MAXJOBS 16 /* max jobs at any point in time */ +#define MAXJID 1<<16 /* max job ID */ + +/* Job states */ +#define UNDEF 0 /* undefined */ +#define FG 1 /* running in foreground */ +#define BG 2 /* running in background */ +#define ST 3 /* stopped */ + +/* + * Jobs states: FG (foreground), BG (background), ST (stopped) + * Job state transitions and enabling actions: + * FG -> ST : ctrl-z + * ST -> FG : fg command + * ST -> BG : bg command + * BG -> FG : fg command + * At most 1 job can be in the FG state. + */ + +/* Global variables */ +extern char **environ; /* defined in libc */ +char prompt[] = "tsh> "; /* command line prompt (DO NOT CHANGE) */ +int verbose = 0; /* if true, print additional output */ +int nextjid = 1; /* next job ID to allocate */ +char sbuf[MAXLINE]; /* for composing sprintf messages */ + +struct job_t { /* The job struct */ + pid_t pid; /* job PID */ + int jid; /* job ID [1, 2, ...] */ + int state; /* UNDEF, BG, FG, or ST */ + char cmdline[MAXLINE]; /* command line */ +}; +struct job_t jobs[MAXJOBS]; /* The job list */ + +vector<string> builtin_cmd_list = {"quit", "fg", "bg", "jobs"}; +sigset_t BLOCK_HANDLER; +/* End global variables */ + + +/* Function prototypes */ + +/* Here are the functions that you will implement */ +void eval(char *cmdline); +int builtin_cmd(char *c_str); +void do_bgfg(char **argv); +void waitfg(pid_t pid); + +void sigchld_handler(int sig); +void sigtstp_handler(int sig); +void sigint_handler(int sig); + +/* Here are helper routines that we've provided for you */ +int parseline(const char *cmdline, char **argv); +void sigquit_handler(int sig); + +void clearjob(struct job_t *job); +void initjobs(struct job_t *jobs); +int maxjid(struct job_t *jobs); +int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline); +int deletejob(struct job_t *jobs, pid_t pid); +pid_t fgpid(struct job_t *jobs); +struct job_t *getjobpid(struct job_t *jobs, pid_t pid); +struct job_t *getjobjid(struct job_t *jobs, int jid); +int pid2jid(pid_t pid); +void listjobs(struct job_t *jobs); +bool job_suspend(struct job_t *jobs, pid_t pid); + +void usage(void); +void unix_error(char *msg); +void app_error(char *msg); +typedef void handler_t(int); +handler_t *Signal(int signum, handler_t *handler); + +// built-in commands +void builtin_command_quit(); + +inline int block_all(sigset_t*); +inline int block_handler(sigset_t*); + +void init(); + +/* + * main - The shell's main routine + */ +int main(int argc, char **argv) +{ + init(); + char c; + char cmdline[MAXLINE]; + int emit_prompt = 1; /* emit prompt (default) */ + + /* Redirect stderr to stdout (so that driver will get all output + * on the pipe connected to stdout) */ + dup2(1, 2); + + /* Parse the command line */ + while ((c = getopt(argc, argv, "hvp")) != EOF) { + switch (c) { + case 'h': /* print help message */ + usage(); + break; + case 'v': /* emit additional diagnostic info */ + ov4::DEBUG = true; + verbose = 1; + break; + case 'p': /* don't print a prompt */ + emit_prompt = 0; /* handy for automatic testing */ + break; + default: + usage(); + } + } + + /* Install the signal handlers */ + + /* These are the ones you will need to implement */ + Signal(SIGINT, sigint_handler); /* ctrl-c */ + Signal(SIGTSTP, sigtstp_handler); /* ctrl-z */ + Signal(SIGCHLD, sigchld_handler); /* Terminated or stopped child */ + + /* This one provides a clean way to kill the shell */ + Signal(SIGQUIT, sigquit_handler); + + /* Initialize the job list */ + initjobs(jobs); + + /* Execute the shell's read/eval loop */ + while (1) { + + /* Read command line */ + if (emit_prompt) { + printf("%s", prompt); + fflush(stdout); + } + if ((fgets(cmdline, MAXLINE, stdin) == NULL) && ferror(stdin)) + app_error("fgets error"); + if (feof(stdin)) { /* End of file (ctrl-d) */ + fflush(stdout); + exit(0); + } + + /* Evaluate the command line */ + eval(cmdline); + fflush(stdout); + fflush(stdout); + } + + exit(0); /* control never reaches here */ +} + +/* + * eval - Evaluate the command line that the user has just typed in + * + * If the user has requested a built-in command (quit, jobs, bg or fg) + * then execute it immediately. Otherwise, fork a child process and + * run the job in the context of the child. If the job is running in + * the foreground, wait for it to terminate and then return. Note: + * each child process must have a unique process group ID so that our + * background children don't receive SIGINT (SIGTSTP) from the kernel + * when we type ctrl-c (ctrl-z) at the keyboard. +*/ +void eval(char *cmdline) +{ + char arg[MAXARGS][MAXLINE]; + char *argv[MAXARGS]; + for (int i = 0 ; i < MAXARGS; i++) + { + argv[i] = &arg[i][0]; + } + int ground = parseline(cmdline, argv); + + if (argv[0] == nullptr) return; + + if (builtin_cmd(argv[0])) + { + LOG << "built-in" << endl; + if (strcmp(argv[0], "quit") == 0) builtin_command_quit(); + else if (strcmp(argv[0], "jobs") == 0) listjobs(jobs); + else if (strcmp(argv[0], "fg") == 0) do_bgfg(argv); + else if (strcmp(argv[0], "bg") == 0) do_bgfg(argv); + else cerr << "built-in but not supported" << endl; + return; + } + + sigset_t prev; + block_all(&prev); + + pid_t pid = fork(); + if (pid == 0) // child + { + sigprocmask(SIG_SETMASK, &prev, nullptr); + setpgid(0, 0); + + execve(argv[0], argv, environ); + + atomic_print(cmdline, true); + atomic_print(": Command not found\n"); + exit(-1); // if no command is found + } + + // parent + + if (!ground) // foreground + { + addjob(jobs, pid, FG, cmdline); + sigset_t prev_with_sigchld_blocked = prev; + sigaddset(&prev_with_sigchld_blocked, SIGCHLD); + sigprocmask(SIG_SETMASK, &prev_with_sigchld_blocked, NULL); + waitfg(pid); + sigprocmask(SIG_SETMASK, &prev, NULL); + } + else // background + { + addjob(jobs, pid, BG, cmdline); + sigprocmask(SIG_SETMASK, &prev, NULL); + cout << "[" << pid2jid(pid) << "] (" << pid << ") " << cmdline; + } + + + + return; +} + +/* + * parseline - Parse the command line and build the argv array. + * + * Characters enclosed in single quotes are treated as a single + * argument. Return true if the user has requested a BG job, false if + * the user has requested a FG job. + */ +int parseline(const char *cmdline, char **argv) +{ + static char array[MAXLINE]; /* holds local copy of command line */ + char *buf = array; /* ptr that traverses command line */ + char *delim; /* points to first space delimiter */ + int argc; /* number of args */ + int bg; /* background job? */ + + strcpy(buf, cmdline); + buf[strlen(buf)-1] = ' '; /* replace trailing '\n' with space */ + while (*buf && (*buf == ' ')) /* ignore leading spaces */ + buf++; + + /* Build the argv list */ + argc = 0; + if (*buf == '\'') { + buf++; + delim = strchr(buf, '\''); + } + else { + delim = strchr(buf, ' '); + } + + while (delim) { + argv[argc++] = buf; + *delim = '\0'; + buf = delim + 1; + while (*buf && (*buf == ' ')) /* ignore spaces */ + buf++; + + if (*buf == '\'') { + buf++; + delim = strchr(buf, '\''); + } + else { + delim = strchr(buf, ' '); + } + } + argv[argc] = NULL; + + if (argc == 0) /* ignore blank line */ + return 1; + + /* should the job run in the background? */ + if ((bg = (*argv[argc-1] == '&')) != 0) { + argv[--argc] = NULL; + } + return bg; +} + +/* + * builtin_cmd - If the user has typed a built-in command then execute + * it immediately. + */ +int builtin_cmd(char *c_str) +{ + string s(c_str); + for (auto c : builtin_cmd_list) + if (c == s) + return 1; + return 0; /* not a builtin command */ +} + +/* + * do_bgfg - Execute the builtin bg and fg commands + */ +void do_bgfg(char **argv) +{ + if ((strcmp(argv[0], "fg") == 0) || (strcmp(argv[0], "bg") == 0)) + { + int x; + job_t *j = nullptr; + sigset_t prev; + if (argv[1] == nullptr) + { + cerr << ((strcmp(argv[0], "fg") == 0) ? "fg" : "bg") << " command requires PID or %jobid argument" << endl; + return; + } + if (argv[1][0] == '%') // jid provided + { + if (!isnum(&argv[1][1])) + { + cerr << ((strcmp(argv[0], "fg") == 0) ? "fg" : "bg") << ": argument must be a PID or %jobid" << endl; + return; + } + x = atoi(&argv[1][1]); // eat % + j = getjobjid(jobs, x); + if (j == nullptr) + { + cerr << argv[1] << ": No such job" << endl; + return; + } + } else { // pid + if (!isnum(&argv[1][0])) + { + cerr << ((strcmp(argv[0], "fg") == 0) ? "fg" : "bg") << ": argument must be a PID or %jobid" << endl; + return; + } + x = atoi(&argv[1][0]); + j = getjobpid(jobs, x); + if (j == nullptr) + { + cerr << "(" << argv[1] << "): No such process" << endl; + return; + } + } + + + block_all(&prev); + if (strcmp(argv[0], "fg") == 0) // fg + { + LOG << "fg" << endl; + j->state = FG; + + sigset_t prev_with_sigchld_blocked = prev; + sigaddset(&prev_with_sigchld_blocked, SIGCHLD); + sigprocmask(SIG_SETMASK, &prev_with_sigchld_blocked, NULL); + if (kill(-(j->pid), SIGCONT) < 0) + { + cerr << "Cannot continue process " << j->pid; + sigprocmask(SIG_SETMASK, &prev, NULL); + return; + } + + waitfg(j->pid); + + sigprocmask(SIG_SETMASK, &prev, NULL); + } else // bg + { + LOG << "bg" << endl; + j->state = BG; + kill(-(j->pid), SIGCONT); + sigprocmask(SIG_SETMASK, &prev, NULL); + // cmdline has nerd '\n' at the end + // so just flush + cout << "[" << j->jid << "] (" << j->pid << ") " << j->cmdline << flush; + } + } + else + cerr << "not fg/bg" << endl; +} + +/* + * waitfg - Block until process pid is no longer the foreground process + */ +void waitfg(pid_t pid) +{ + sigset_t prev_with_sigchld_unblocked; + // get current blocked signals + sigprocmask(0, nullptr, &prev_with_sigchld_unblocked); + sigdelset(&prev_with_sigchld_unblocked, SIGCHLD); + LOG << "waiting for pid "<< fgpid(jobs) << endl; + while (fgpid(jobs) != 0) + sigsuspend(&prev_with_sigchld_unblocked); + LOG << "finished fg " << endl; + return; +} + +/***************** + * Signal handlers + *****************/ + +/* + * sigchld_handler - The kernel sends a SIGCHLD to the shell whenever + * a child job terminates (becomes a zombie), or stops because it + * received a SIGSTOP or SIGTSTP signal. The handler reaps all + * available zombie children, but doesn't wait for any other + * currently running children to terminate. + */ +void sigchld_handler(int sig) +{ + int errno_backup = errno; + + sigset_t prev; + block_handler(&prev); + + int status, pid; + atomic_debug("SIGCHLD\n"); + + while ((pid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) + { + if (WIFSIGNALED(status) || WIFSTOPPED(status)) + { + int jid = pid2jid(pid); + atomic_print("Job ["); + atomic_print(jid); + atomic_print("] ("); + atomic_print(pid); + atomic_print(") "); + if (!WIFSTOPPED(status) && WTERMSIG(status) == SIGINT) + atomic_print("terminated"); + else if (WIFSTOPPED(status)) + atomic_print("stopped"); + else + atomic_print("idk"); + atomic_print(" by signal "); + if (WIFSTOPPED(status)) + atomic_print(WSTOPSIG(status)); + else + atomic_print(WTERMSIG(status)); + atomic_print("\n"); + } + + if (WIFSTOPPED(status)) + { + atomic_debug("suspended pid: "); + atomic_debug(pid); + atomic_debug("\n"); + sigset_t prev_inner; + block_all(&prev_inner); + job_suspend(jobs, pid); + sigprocmask(SIG_SETMASK, &prev_inner, nullptr); + } + else { + atomic_debug("terminated pid: "); + atomic_debug(pid); + sigset_t prev_inner; + block_all(&prev_inner); + deletejob(jobs, pid); + sigprocmask(SIG_SETMASK, &prev_inner, nullptr); + } + } + + sigprocmask(SIG_SETMASK, &prev, nullptr); + + errno = errno_backup; + return; +} + +/* + * sigint_handler - The kernel sends a SIGINT to the shell whenver the + * user types ctrl-c at the keyboard. Catch it and send it along + * to the foreground job. + */ +void sigint_handler(int sig) +{ + int errno_backup = errno; + + sigset_t prev; + block_handler(&prev); + + int pid = fgpid(jobs); + if (pid != 0) + { + kill(-pid, SIGINT); + } + + sigprocmask(SIG_SETMASK, &prev, nullptr); + + errno = errno_backup; + return; +} + +/* + * sigtstp_handler - The kernel sends a SIGTSTP to the shell whenever + * the user types ctrl-z at the keyboard. Catch it and suspend the + * foreground job by sending it a SIGTSTP. + */ +void sigtstp_handler(int sig) +{ + int errno_backup = errno; + + sigset_t prev; + block_handler(&prev); + + int pid = fgpid(jobs); + if (pid != 0) + { + kill(-pid, SIGTSTP); + } + + sigprocmask(SIG_SETMASK, &prev, nullptr); + + errno = errno_backup; + return; +} + +/********************* + * End signal handlers + *********************/ + +/*********************************************** + * Helper routines that manipulate the job list + **********************************************/ + +/* clearjob - Clear the entries in a job struct */ +void clearjob(struct job_t *job) { + job->pid = 0; + job->jid = 0; + job->state = UNDEF; + job->cmdline[0] = '\0'; +} + +/* initjobs - Initialize the job list */ +void initjobs(struct job_t *jobs) { + int i; + + for (i = 0; i < MAXJOBS; i++) + clearjob(&jobs[i]); +} + +/* maxjid - Returns largest allocated job ID */ +int maxjid(struct job_t *jobs) +{ + int i, max=0; + + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].jid > max) + max = jobs[i].jid; + return max; +} + +/* addjob - Add a job to the job list */ +int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline) +{ + int i; + + if (pid < 1) + return 0; + + for (i = 0; i < MAXJOBS; i++) { + if (jobs[i].pid == 0) { + jobs[i].pid = pid; + jobs[i].state = state; + jobs[i].jid = nextjid++; + if (nextjid > MAXJOBS) + nextjid = 1; + strcpy(jobs[i].cmdline, cmdline); + if(verbose){ + printf("Added job [%d] %d %s\n", jobs[i].jid, jobs[i].pid, jobs[i].cmdline); + } + return 1; + } + } + printf("Tried to create too many jobs\n"); + return 0; +} + +/* deletejob - Delete a job whose PID=pid from the job list */ +int deletejob(struct job_t *jobs, pid_t pid) +{ + int i; + + if (pid < 1) + return 0; + + for (i = 0; i < MAXJOBS; i++) { + if (jobs[i].pid == pid) { + clearjob(&jobs[i]); + nextjid = maxjid(jobs)+1; + return 1; + } + } + return 0; +} + +/* fgpid - Return PID of current foreground job, 0 if no such job */ +pid_t fgpid(struct job_t *jobs) { + int i; + + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].state == FG) + return jobs[i].pid; + return 0; +} + +/* getjobpid - Find a job (by PID) on the job list */ +struct job_t *getjobpid(struct job_t *jobs, pid_t pid) { + int i; + + if (pid < 1) + return NULL; + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].pid == pid) + return &jobs[i]; + return NULL; +} + +/* getjobjid - Find a job (by JID) on the job list */ +struct job_t *getjobjid(struct job_t *jobs, int jid) +{ + int i; + + if (jid < 1) + return NULL; + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].jid == jid) + return &jobs[i]; + return NULL; +} + +/* pid2jid - Map process ID to job ID */ +int pid2jid(pid_t pid) +{ + int i; + + if (pid < 1) + return 0; + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].pid == pid) { + return jobs[i].jid; + } + return 0; +} + +/* listjobs - Print the job list */ +void listjobs(struct job_t *jobs) +{ + int i; + + for (i = 0; i < MAXJOBS; i++) { + if (jobs[i].pid != 0) { + printf("[%d] (%d) ", jobs[i].jid, jobs[i].pid); + switch (jobs[i].state) { + case BG: + printf("Running "); + break; + case FG: + printf("Foreground "); + break; + case ST: + printf("Stopped "); + break; + default: + printf("listjobs: Internal error: job[%d].state=%d ", + i, jobs[i].state); + } + printf("%s", jobs[i].cmdline); + } + } +} +/****************************** + * end job list helper routines + ******************************/ + + +/*********************** + * Other helper routines + ***********************/ + +/* + * usage - print a help message + */ +void usage(void) +{ + printf("Usage: shell [-hvp]\n"); + printf(" -h print this message\n"); + printf(" -v print additional diagnostic information\n"); + printf(" -p do not emit a command prompt\n"); + exit(1); +} + +/* + * unix_error - unix-style error routine + */ +void unix_error(char *msg) +{ + fprintf(stdout, "%s: %s\n", msg, strerror(errno)); + exit(1); +} + +/* + * app_error - application-style error routine + */ +void app_error(char *msg) +{ + fprintf(stdout, "%s\n", msg); + exit(1); +} + +/* + * Signal - wrapper for the sigaction function + */ +handler_t *Signal(int signum, handler_t *handler) +{ + struct sigaction action, old_action; + + action.sa_handler = handler; + sigemptyset(&action.sa_mask); /* block sigs of type being handled */ + action.sa_flags = SA_RESTART; /* restart syscalls if possible */ + + if (sigaction(signum, &action, &old_action) < 0) + unix_error("Signal error"); + return (old_action.sa_handler); +} + +/* + * sigquit_handler - The driver program can gracefully terminate the + * child shell by sending it a SIGQUIT signal. + */ +void sigquit_handler(int sig) +{ + printf("Terminating after receipt of SIGQUIT signal\n"); + exit(1); +} + + +void builtin_command_quit() +{ + exit(0); +} + +// return true if suspended, otherwise false +bool job_suspend(struct job_t *jobs, pid_t pid) { + int i; + + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].pid == pid) + { + jobs[i].state = ST; + return true; + } + return false; +} + +inline int block_all(sigset_t *prev) +{ + sigset_t set; + sigfillset(&set); + return sigprocmask(SIG_SETMASK, &set, prev); +} + +inline int block_handler(sigset_t *prev) +{ + return sigprocmask(SIG_BLOCK, &BLOCK_HANDLER, prev); +} + +void init() +{ + sigemptyset(&BLOCK_HANDLER); + sigaddset(&BLOCK_HANDLER, SIGINT); + sigaddset(&BLOCK_HANDLER, SIGTSTP); + sigaddset(&BLOCK_HANDLER, SIGCHLD); +} diff --git a/shlab-handout/tshref b/shlab-handout/tshref Binary files differnew file mode 100755 index 0000000..d7e2108 --- /dev/null +++ b/shlab-handout/tshref diff --git a/shlab-handout/tshref.c b/shlab-handout/tshref.c new file mode 100644 index 0000000..e0d15bd --- /dev/null +++ b/shlab-handout/tshref.c @@ -0,0 +1,700 @@ +// reverse engineering of tshref +// ft. CSAPP 3e + +/* + * tsh - A tiny shell program with job control + * + * <Put your name and login ID here> + */ +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <ctype.h> +#include <signal.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <errno.h> + +/* Misc manifest constants */ +#define MAXLINE 1024 /* max line size */ +#define MAXARGS 128 /* max args on a command line */ +#define MAXJOBS 16 /* max jobs at any point in time */ +#define MAXJID 1<<16 /* max job ID */ + +/* Job states */ +#define UNDEF 0 /* undefined */ +#define FG 1 /* running in foreground */ +#define BG 2 /* running in background */ +#define ST 3 /* stopped */ + +/* + * Jobs states: FG (foreground), BG (background), ST (stopped) + * Job state transitions and enabling actions: + * FG -> ST : ctrl-z + * ST -> FG : fg command + * ST -> BG : bg command + * BG -> FG : fg command + * At most 1 job can be in the FG state. + */ + +/* Global variables */ +extern char **environ; /* defined in libc */ +char prompt[] = "tsh> "; /* command line prompt (DO NOT CHANGE) */ +int verbose = 0; /* if true, print additional output */ +int nextjid = 1; /* next job ID to allocate */ +char sbuf[MAXLINE]; /* for composing sprintf messages */ + +struct job_t { /* The job struct */ + pid_t pid; /* job PID */ + int jid; /* job ID [1, 2, ...] */ + int state; /* UNDEF, BG, FG, or ST */ + char cmdline[MAXLINE]; /* command line */ +}; +struct job_t jobs[MAXJOBS]; /* The job list */ +/* End global variables */ + + +/* Function prototypes */ + +/* Here are the functions that you will implement */ +void eval(char *cmdline); +int builtin_cmd(char **argv); +void do_bgfg(char **argv); +void waitfg(pid_t pid); + +void sigchld_handler(int sig); +void sigtstp_handler(int sig); +void sigint_handler(int sig); + +/* Here are helper routines that we've provided for you */ +int parseline(const char *cmdline, char **argv); +void sigquit_handler(int sig); + +void clearjob(struct job_t *job); +void initjobs(struct job_t *jobs); +int maxjid(struct job_t *jobs); +int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline); +int deletejob(struct job_t *jobs, pid_t pid); +pid_t fgpid(struct job_t *jobs); +struct job_t *getjobpid(struct job_t *jobs, pid_t pid); +struct job_t *getjobjid(struct job_t *jobs, int jid); +int pid2jid(pid_t pid); +void listjobs(struct job_t *jobs); + +void usage(void); +void unix_error(char *msg); +void app_error(char *msg); +typedef void handler_t(int); +handler_t *Signal(int signum, handler_t *handler); + +/* + * main - The shell's main routine + */ +int main(int argc, char **argv) +{ + char c; + char cmdline[MAXLINE]; + int emit_prompt = 1; /* emit prompt (default) */ + + /* Redirect stderr to stdout (so that driver will get all output + * on the pipe connected to stdout) */ + dup2(1, 2); + + /* Parse the command line */ + while ((c = getopt(argc, argv, "hvp")) != EOF) { + switch (c) { + case 'h': /* print help message */ + usage(); + break; + case 'v': /* emit additional diagnostic info */ + verbose = 1; + break; + case 'p': /* don't print a prompt */ + emit_prompt = 0; /* handy for automatic testing */ + break; + default: + usage(); + } + } + + /* Install the signal handlers */ + + /* These are the ones you will need to implement */ + Signal(SIGINT, sigint_handler); /* ctrl-c */ + Signal(SIGTSTP, sigtstp_handler); /* ctrl-z */ + Signal(SIGCHLD, sigchld_handler); /* Terminated or stopped child */ + + /* This one provides a clean way to kill the shell */ + Signal(SIGQUIT, sigquit_handler); + + /* Initialize the job list */ + initjobs(jobs); + + /* Execute the shell's read/eval loop */ + while (1) { + + /* Read command line */ + if (emit_prompt) { + printf("%s", prompt); + fflush(stdout); + } + if ((fgets(cmdline, MAXLINE, stdin) == NULL) && ferror(stdin)) + app_error("fgets error"); + if (feof(stdin)) { /* End of file (ctrl-d) */ + fflush(stdout); + exit(0); + } + + /* Evaluate the command line */ + eval(cmdline); + fflush(stdout); + fflush(stdout); + } + + exit(0); /* control never reaches here */ +} + +/* + * eval - Evaluate the command line that the user has just typed in + * + * If the user has requested a built-in command (quit, jobs, bg or fg) + * then execute it immediately. Otherwise, fork a child process and + * run the job in the context of the child. If the job is running in + * the foreground, wait for it to terminate and then return. Note: + * each child process must have a unique process group ID so that our + * background children don't receive SIGINT (SIGTSTP) from the kernel + * when we type ctrl-c (ctrl-z) at the keyboard. +*/ +void eval(char *cmdline) +{ + char *argv[MAXARGS]; + int bg; + pid_t pid; + sigset_t mask; + + bg = parseline(cmdline, argv); + if (argv[0] == NULL) + return; + + if (builtin_cmd(argv)) + return; + + if (sigemptyset(&mask) < 0) + unix_error("sigemptyset error"); + if (sigaddset(&mask, SIGCHLD) != 0) + unix_error("sigaddset error"); + if (sigaddset(&mask, SIGINT) != 0) + unix_error("sigaddset error"); + if (sigaddset(&mask, SIGTSTP) != 0) + unix_error("sigaddset error"); + if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0) + unix_error("sigprocmask error"); + + if ((pid = fork()) < 0) + unix_error("fork error"); + + if (pid == 0) { + sigprocmask(SIG_UNBLOCK, &mask, NULL); + if (setpgid(0, 0) < 0) + unix_error("setpgid error"); + if (execve(argv[0], argv, environ) < 0) { + printf("%s: Command not found\n", argv[0]); + exit(0); + } + } + + if (bg) + addjob(jobs, pid, BG, cmdline); + else + addjob(jobs, pid, FG, cmdline); + + sigprocmask(SIG_UNBLOCK, &mask, NULL); + + if (bg) + printf("[%d] (%d) %s", pid2jid(pid), pid, cmdline); + else + waitfg(pid); +} + +/* + * parseline - Parse the command line and build the argv array. + * + * Characters enclosed in single quotes are treated as a single + * argument. Return true if the user has requested a BG job, false if + * the user has requested a FG job. + */ +int parseline(const char *cmdline, char **argv) +{ + static char array[MAXLINE]; /* holds local copy of command line */ + char *buf = array; /* ptr that traverses command line */ + char *delim; /* points to first space delimiter */ + int argc; /* number of args */ + int bg; /* background job? */ + + strcpy(buf, cmdline); + buf[strlen(buf)-1] = ' '; /* replace trailing '\n' with space */ + while (*buf && (*buf == ' ')) /* ignore leading spaces */ + buf++; + + /* Build the argv list */ + argc = 0; + if (*buf == '\'') { + buf++; + delim = strchr(buf, '\''); + } + else { + delim = strchr(buf, ' '); + } + + while (delim) { + argv[argc++] = buf; + *delim = '\0'; + buf = delim + 1; + while (*buf && (*buf == ' ')) /* ignore spaces */ + buf++; + + if (*buf == '\'') { + buf++; + delim = strchr(buf, '\''); + } + else { + delim = strchr(buf, ' '); + } + } + argv[argc] = NULL; + + if (argc == 0) /* ignore blank line */ + return 1; + + /* should the job run in the background? */ + if ((bg = (*argv[argc-1] == '&')) != 0) { + argv[--argc] = NULL; + } + return bg; +} + +/* + * builtin_cmd - If the user has typed a built-in command then execute + * it immediately. + */ +int builtin_cmd(char **argv) +{ + if (!strcmp(argv[0], "quit")) + exit(0); + + if (!strcmp(argv[0], "jobs")) { + listjobs(jobs); + return 1; + } + + if (!strcmp(argv[0], "bg") || !strcmp(argv[0], "fg")) { + do_bgfg(argv); + return 1; + } + + if (!strcmp(argv[0], "&")) + return 1; + + return 0; /* not a builtin command */ +} + +/* + * do_bgfg - Execute the builtin bg and fg commands + */ +void do_bgfg(char **argv) +{ + struct job_t *job; + int id; + + if (argv[1] == NULL) { + printf("%s command requires PID or %%jobid argument\n", argv[0]); + return; + } + + if (isdigit(argv[1][0])) { + id = strtol(argv[1], NULL, 10); + if (id <= 0 || (job = getjobpid(jobs, id)) == NULL) { + printf("(%d): No such process\n", id); + return; + } + } + else if (argv[1][0] == '%') { + id = strtol(&argv[1][1], NULL, 10); + if (id <= 0 || (job = getjobjid(jobs, id)) == NULL) { + printf("%s: No such job\n", argv[1]); + return; + } + } + else { + printf("%s: argument must be a PID or %%jobid\n", argv[0]); + return; + } + + if (!strcmp(argv[0], "bg")) { + if (kill(-job->pid, SIGCONT) < 0) + unix_error("kill (bg) error"); + job->state = BG; + printf("[%d] (%d) %s", job->jid, job->pid, job->cmdline); + } + else if (!strcmp(argv[0], "fg")) { + if (kill(-job->pid, SIGCONT) < 0) + unix_error("kill (fg) error"); + job->state = FG; + waitfg(job->pid); + } + else { + printf("do_bgfg: Internal error\n"); + exit(0); + } +} + +/* + * waitfg - Block until process pid is no longer the foreground process + */ +void waitfg(pid_t pid) +{ + struct job_t *job; + + if (pid <= 0) + return; + + job = getjobpid(jobs, pid); + if (job == NULL) + return; + + while (job->pid == pid && job->state == FG) + sleep(1); + + if (verbose) + printf("waitfg: Process (%d) no longer the fg process\n", pid); +} + +/***************** + * Signal handlers + *****************/ + +/* + * sigchld_handler - The kernel sends a SIGCHLD to the shell whenever + * a child job terminates (becomes a zombie), or stops because it + * received a SIGSTOP or SIGTSTP signal. The handler reaps all + * available zombie children, but doesn't wait for any other + * currently running children to terminate. + */ +void sigchld_handler(int sig) +{ + int status; + pid_t pid; + int jid; + struct job_t *job; + + if (verbose) + printf("sigchld_handler: entering\n"); + + while ((pid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) { + if (WIFSTOPPED(status)) { + job = getjobpid(jobs, pid); + if (job == NULL) { + printf("Lost track of (%d)\n", pid); + return; + } + job->state = ST; + fprintf(stdout, "Job [%d] (%d) stopped by signal %d\n", + pid2jid(pid), pid, WSTOPSIG(status)); + } + else if (WIFSIGNALED(status)) { + jid = pid2jid(pid); + if (deletejob(jobs, pid) && verbose) + printf("sigchld_handler: Job [%d] (%d) deleted\n", jid, pid); + fprintf(stdout, "Job [%d] (%d) terminated by signal %d\n", + jid, pid, WTERMSIG(status)); + } + else if (WIFEXITED(status)) { + jid = pid2jid(pid); + if (deletejob(jobs, pid) && verbose) + printf("sigchld_handler: Job [%d] (%d) deleted\n", jid, pid); + if (verbose) + printf("sigchld_handler: Job [%d] (%d) terminates OK (status %d)\n", + jid, pid, WEXITSTATUS(status)); + } + else { + unix_error("waitpid error"); + } + } + + if (pid != 0) { + if (pid != -1 || errno != ECHILD) + unix_error("sigchld_handler wait error"); + } + + if (verbose) + printf("sigchld_handler: exiting\n"); +} + +/* + * sigint_handler - The kernel sends a SIGINT to the shell whenver the + * user types ctrl-c at the keyboard. Catch it and send it along + * to the foreground job. + */ +void sigint_handler(int sig) +{ + pid_t pid; + + if (verbose) + printf("sigint_handler: entering\n"); + + if ((pid = fgpid(jobs)) > 0) { + if (kill(-pid, SIGINT) < 0) + unix_error("kill (sigint) error"); + if (verbose) + printf("sigint_handler: Job (%d) killed\n", pid); + } + + if (verbose) + printf("sigint_handler: exiting\n"); +} + +/* + * sigtstp_handler - The kernel sends a SIGTSTP to the shell whenever + * the user types ctrl-z at the keyboard. Catch it and suspend the + * foreground job by sending it a SIGTSTP. + */ +void sigtstp_handler(int sig) +{ + pid_t pid; + + if (verbose) + printf("sigtstp_handler: entering\n"); + + if ((pid = fgpid(jobs)) > 0) { + if (kill(-pid, SIGTSTP) < 0) + unix_error("kill (tstp) error"); + if (verbose) + printf("sigtstp_handler: Job [%d] (%d) stopped\n", pid2jid(pid), pid); + } + + if (verbose) + printf("sigtstp_handler: exiting\n"); +} + +/********************* + * End signal handlers + *********************/ + +/*********************************************** + * Helper routines that manipulate the job list + **********************************************/ + +/* clearjob - Clear the entries in a job struct */ +void clearjob(struct job_t *job) { + job->pid = 0; + job->jid = 0; + job->state = UNDEF; + job->cmdline[0] = '\0'; +} + +/* initjobs - Initialize the job list */ +void initjobs(struct job_t *jobs) { + int i; + + for (i = 0; i < MAXJOBS; i++) + clearjob(&jobs[i]); +} + +/* maxjid - Returns largest allocated job ID */ +int maxjid(struct job_t *jobs) +{ + int i, max=0; + + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].jid > max) + max = jobs[i].jid; + return max; +} + +/* addjob - Add a job to the job list */ +int addjob(struct job_t *jobs, pid_t pid, int state, char *cmdline) +{ + int i; + + if (pid < 1) + return 0; + + for (i = 0; i < MAXJOBS; i++) { + if (jobs[i].pid == 0) { + jobs[i].pid = pid; + jobs[i].state = state; + jobs[i].jid = nextjid++; + if (nextjid > MAXJOBS) + nextjid = 1; + strcpy(jobs[i].cmdline, cmdline); + if(verbose){ + printf("Added job [%d] %d %s\n", jobs[i].jid, jobs[i].pid, jobs[i].cmdline); + } + return 1; + } + } + printf("Tried to create too many jobs\n"); + return 0; +} + +/* deletejob - Delete a job whose PID=pid from the job list */ +int deletejob(struct job_t *jobs, pid_t pid) +{ + int i; + + if (pid < 1) + return 0; + + for (i = 0; i < MAXJOBS; i++) { + if (jobs[i].pid == pid) { + clearjob(&jobs[i]); + nextjid = maxjid(jobs)+1; + return 1; + } + } + return 0; +} + +/* fgpid - Return PID of current foreground job, 0 if no such job */ +pid_t fgpid(struct job_t *jobs) { + int i; + + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].state == FG) + return jobs[i].pid; + return 0; +} + +/* getjobpid - Find a job (by PID) on the job list */ +struct job_t *getjobpid(struct job_t *jobs, pid_t pid) { + int i; + + if (pid < 1) + return NULL; + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].pid == pid) + return &jobs[i]; + return NULL; +} + +/* getjobjid - Find a job (by JID) on the job list */ +struct job_t *getjobjid(struct job_t *jobs, int jid) +{ + int i; + + if (jid < 1) + return NULL; + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].jid == jid) + return &jobs[i]; + return NULL; +} + +/* pid2jid - Map process ID to job ID */ +int pid2jid(pid_t pid) +{ + int i; + + if (pid < 1) + return 0; + for (i = 0; i < MAXJOBS; i++) + if (jobs[i].pid == pid) { + return jobs[i].jid; + } + return 0; +} + +/* listjobs - Print the job list */ +void listjobs(struct job_t *jobs) +{ + int i; + + for (i = 0; i < MAXJOBS; i++) { + if (jobs[i].pid != 0) { + printf("[%d] (%d) ", jobs[i].jid, jobs[i].pid); + switch (jobs[i].state) { + case BG: + printf("Running "); + break; + case FG: + printf("Foreground "); + break; + case ST: + printf("Stopped "); + break; + default: + printf("listjobs: Internal error: job[%d].state=%d ", + i, jobs[i].state); + } + printf("%s", jobs[i].cmdline); + } + } +} +/****************************** + * end job list helper routines + ******************************/ + + +/*********************** + * Other helper routines + ***********************/ + +/* + * usage - print a help message + */ +void usage(void) +{ + printf("Usage: shell [-hvp]\n"); + printf(" -h print this message\n"); + printf(" -v print additional diagnostic information\n"); + printf(" -p do not emit a command prompt\n"); + exit(1); +} + +/* + * unix_error - unix-style error routine + */ +void unix_error(char *msg) +{ + fprintf(stdout, "%s: %s\n", msg, strerror(errno)); + exit(1); +} + +/* + * app_error - application-style error routine + */ +void app_error(char *msg) +{ + fprintf(stdout, "%s\n", msg); + exit(1); +} + +/* + * Signal - wrapper for the sigaction function + */ +handler_t *Signal(int signum, handler_t *handler) +{ + struct sigaction action, old_action; + + action.sa_handler = handler; + sigemptyset(&action.sa_mask); /* block sigs of type being handled */ + action.sa_flags = SA_RESTART; /* restart syscalls if possible */ + + if (sigaction(signum, &action, &old_action) < 0) + unix_error("Signal error"); + return (old_action.sa_handler); +} + +/* + * sigquit_handler - The driver program can gracefully terminate the + * child shell by sending it a SIGQUIT signal. + */ +void sigquit_handler(int sig) +{ + printf("Terminating after receipt of SIGQUIT signal\n"); + exit(1); +} + + + diff --git a/shlab-handout/util.h b/shlab-handout/util.h new file mode 100644 index 0000000..26dab12 --- /dev/null +++ b/shlab-handout/util.h @@ -0,0 +1,126 @@ +#pragma once + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <ctype.h> +#include <signal.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <errno.h> +#include <iostream> +#include <vector> +#include <string> + +#define LOG !(ov4::GLOBAL_DEBUG && ov4::DEBUG) ? (void)0 : ov4::LogVoidify() & std::clog + +namespace ov4 { + +void atomic_print(char*, bool); +void atomic_print(int x); +void atomic_debug(char*, bool); +void atomic_debug(int); +bool isnum(char*); +void reverse(char[], int); +char *itoa(int, char*, int); + +constexpr bool GLOBAL_DEBUG = true; +bool DEBUG = false; // verbose mode, can be enabled on demand using something like -v +struct LogVoidify { void operator&(std::ostream&) const {} }; + +const int DECIMAL = 10; +const int LENGTH = 25; + +void atomic_print(char *s, bool ignore_wrap = false) +{ + if (ignore_wrap) + for (int i = 0; s[i] != 0; i++) + if (s[i] == '\n') + { + write(STDOUT_FILENO, s, i); + return; + } + write(STDOUT_FILENO, s, strlen(s)); +} + +void atomic_print(int x) +{ + char msg[LENGTH]; + itoa(x, msg, DECIMAL); + atomic_print(msg); +} + +void reverse(char str[], int length) +{ + int start = 0; + int end = length - 1; + while (start < end) { + char temp = str[start]; + str[start] = str[end]; + str[end] = temp; + end--; + start++; + } +} + +void atomic_debug(char *s, bool ignore_wrap = false) +{ + if (DEBUG && GLOBAL_DEBUG) atomic_print(s, ignore_wrap); +} + +void atomic_debug(int x) +{ + if (DEBUG && GLOBAL_DEBUG) atomic_print(x); +} + +bool isnum(char *s) +{ + for (int i = 0; s[i] != 0; i++) + if (!isdigit(s[i])) + return false; + return true; +} + + +char *itoa(int num, char* str, int base) +{ + int i = 0; + bool isNegative = false; + + /* Handle 0 explicitly, otherwise empty string is + * printed for 0 */ + if (num == 0) { + str[i++] = '0'; + str[i] = '\0'; + return str; + } + + // In standard itoa(), negative numbers are handled + // only with base 10. Otherwise numbers are + // considered unsigned. + if (num < 0 && base == 10) { + isNegative = true; + num = -num; + } + + // Process individual digits + while (num != 0) { + int rem = num % base; + str[i++] = (rem > 9) ? (rem - 10) + 'a' : rem + '0'; + num = num / base; + } + + // If number is negative, append '-' + if (isNegative) + str[i++] = '-'; + + str[i] = '\0'; // Append string terminator + + // Reverse the string + reverse(str, i); + + return str; +} + +} |