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CSI 402 – Systems Programming
Programming Assignment I
Date given: Sept. 16, 2016
Total grade for this assignment: 100 points
Due date: Sept. 26, 2016
Weightage: 5%
A. Purpose. A typical question users may have regarding files on the file system is how big they
are. There are a number of programs that can answer this question, such as the ls program that
lists information about files of any type, including directories. Sometimes users might want to find
the size of all files (that match some filename pattern) in all subdirectories. For example, a user
might want to find the size of all C or text files in the current directory and all subdirectories. It
is possible to do this with the find program that searches for files in a directory hierarchy.
Your task is to develop a modified version of the ls command so that it can find the size of
all files that match some filename pattern in all subdirectories. Your program should take as input
filename patterns, and report the size of each file that matches these patterns. Obviously, you are
not allowed to use the find or ls programs. Instead, you are asked to go through the files that
match the given filename pattern, open the files in succession and read through their contents to
determine their size.
The purpose of this assignment is to familiarize yourself with (i) C programming, (ii) splitting a
program into multiple files (including header files), (iii) using make and makefile, (iv) file operations.
The necessary information about splitting a program into multiple files (including header files),
using make and makefile, and file operations have already been presented in class. Information
about Directories and the directory hierarchy will be presented in class next week.
B. Description. The executable version of your program must be named fs. Your makefile
must ensure this. The fs program must support the following usage:
fs [-r] [-d] [-b|-k] ‘‘filepattern’’
If no switches are given, your fs program should report the size (in bytes, as reported by stat)
of all files relative to the current directory that match the file patterns, one per line. You may
assume that any argument that begins with a dash (-) is a command line switch, and all switches
precede any file patterns.
The command line parameter filepatern represents the pattern that files need to match in
order for their size to be reported by the fs program. If no file patterns are given, or if no files match
the given patterns, your program should produce no output. For the purposes of this assignment,
a pattern will be identified by a short text string that complies with the following pattern syntax:
• You can assume that filenames are defined as any sequence of consecutive alphanumeric
characters (a-z, A-Z, 0-9). There is no need to check for illegal characters in your program.
• You can assume that only non-hidden files are considered.
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• For a literal match (i.e., exact match, wrap the name of the file to be matched in brackets.
For example, “[foo.c]” matches the file foo.c.
• If the first character after the opening quotes character (i.e., “) is a star (*), it specifies a
wildcard notation, i.e., a pattern that can start with any character sequence. In other words,
it specifies a suffix pattern. For example, “*.c” matches all C files.
• If the last character before the closing quotes character (i.e., “) is a star (*), it specifies a
pattern that can end with any character sequence. In other words, it specifies a prefix pattern.
For example, “foo.*” matches all files named foo (e.g., “foo.c”, “foo.exe”, “foo.txt” etc.).
• If the user wants to mach a file containing a string, she can specify that by enclosing the
string with star (*) characters. For example, the “*oo*” pattern matches all files named foo
(e.g., “foo.c”), zoo (e.g., “zoo.txt”) etc. as well as files named “oops”, “ooip”, or “oo”.
• The “*.*” pattern matches any filename.
For cases not covered by this specification (such as error handling), you may specify and implement
a reasonable behavior.
If the -r switch is given, your fs program should operate recursively. Normally, a filepattern
should be matched against the entire file name of all files in the current repository. Instead, when
the -r option is provided your fs program should report not only files relative to the current
directory, but also any files relative to any subdirectories, and so on. You can assume that only
non-hidden subdirectories are considered.
If the -d switch is given, your fs program should also report the size of ordinarily directories
in addition to regular files.
If the -b switch is given, the number of blocks (as reported by stat) occupied by each file
should be reported instead of its size. At most one of -b or -k (see below) may be specified.
If the -k switch is provided as an argument to your -k orfs program, sizes should be reported
in kilobytes instead of bytes. Recall that there are 1, 024 bytes in a kilobyte. You may choose and
document a suitable rounding convention.
Your program should report the file (or directory) sizes based on the following format: file size
(or number of blocks), followed by a tab character, followed by the path to the file relative to the
current directory. See the examples below for details.
Your program must detect the following fatal errors. In each case, your program should produce
a suitable error message to stderr and stop.
• The number of command line arguments is less than two or more than 5.
• A filepattern is not specified.
• A filepattern does not comply to the pattern syntax rules specified above.
• An unknown switch is provided.
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C. Examples.
The following command reports the size of all C files in the current directory.
$>fs “*.c”
162
a.c
938
b.c
The following command reports the size of all C files in all directories including and below the
current directory.
$>fs -r “*.c”
162
a.c
938
b.c
2490
subdir/xyz.c
727
subdir/readn.c
661
subdir/subdir2/writen.c
The following command reports the size of all files starting with s in the current directory.
$>fs “s*”
31424
sol.txt
162
s.c
The following command repeats this, but including the subdir directory because of the -d flag.
$>fs -d “’s*”
31424
512
sol.txt
subdir
The following command reports the number of blocks in all files that contain the characters ’sa’
in their filename.
$>fs -b -r “*sa*”
2
subdir/sail.c
4
subdir/salty.txt
2
subdir/subdir2/asap.txt
4
subdir3/haltsa.c
D. Structural Requirements. Your submission must have at least two C source files, zero or
more header files, and a makefile. Additional requirements on the C source files are as follows.
• One source file must contain just the main function.
• A second source file must contain only the function that reports the size of a file (or directory).
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The C files (i.e., files with extension “.c”), header files (i.e., files with extension “.h”) and
the makefile must be submitted together using the turnin-csi402 command. Instructions for
using the turnin-csi402 command have been provided in Programming Assignment 0, which you
should have already submitted.
E. Hints and Clarifications.
• Try to get the basic functionality working first before adding extra features. For instance, get
the size of files in the current directory working before adding -b or -k functions, and then
make it recursive.
• Explore the man page for stat.
• Generally, you should only need the commands that we have covered in class.
• Do not use find or ls in your solution; instead use recursion and the stat tool.
• For full marks, your makefile should produce an executable named fs when run with the
make command.
• For full marks, your fs program must be well-documented and easily understandable.
CSI 402 – Systems ProgrammingProgramming Assignment IDate given:Sept. 16, 2016Due date:Sept. 26, 2016Total grade for this assignment:100 pointsWeightage:5%A. Purpose.A typical question users may have regarding files on the file system is how big theyare. There are a number of programs that can answer this question, such as thelsprogram thatlists information about files of any type, including directories. Sometimes users might want to findthe size of all files (that match some filename pattern) in all subdirectories. For example, a usermight want to find the size of all C or text files in the current directory and all subdirectories. Itis possible to do this with thefindprogram that searches for files in a directory hierarchy.Your task is to develop a modified version of thelscommand so that it can find the size ofall files that match some filename pattern in all subdirectories. Your program should take as inputfilename patterns, and report the size of each file that matches these patterns. Obviously, you arenot allowed to use thefindorlsprograms. Instead, you are asked to go through the files thatmatch the given filename pattern, open the files in succession and read through their contents todetermine their size.The purpose of this assignment is to familiarize yourself with (i) C programming, (ii) splitting aprogram into multiple files (including header files), (iii) using make and makefile, (iv) file operations.The necessary information about splitting a program into multiple files (including header files),using make and makefile, and file operations have already been presented in class. Informationabout Directories and the directory hierarchy will be presented in class next week.B. Description.The executable version of your program must be namedfs. Yourmakefilemust ensure this. Thefsprogram must support the following usage:fs [-r] [-d] [-b|-k] ‘‘filepattern’’If no switches are given, yourfsprogram should report the size (in bytes, as reported bystat)of all files relative to the current directory that match the file patterns, one per line. You mayassume that any argument that begins with a dash (-) is a command line switch, and all switchesprecede any file patterns.The command line parameterfilepaternrepresents the pattern that files need to match inorder for their size to be reported by the fs program. If no file patterns are given, or if no files matchthe given patterns, your program should produce no output. For the purposes of this assignment,a pattern will be identified by a short text string that complies with the following pattern syntax:•You can assume that filenames are defined as any sequence of consecutive alphanumericcharacters (a-z, A-Z, 0-9). There is no need to check for illegal characters in your program.•You can assume that only non-hidden files are considered.1
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