Sistemi Operativi - User contributions [en]

ProvaPratica 2013.05.29

2014-05-14T01:22:04Z

Edu san:

[Python 3]

<syntaxhighlight lang="Python">
'''
Prova Pratica di Laboratorio di Sistemi Operativi
29 maggio 2013
Esercizio 3

URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.05.29.pdf

@author: Tommaso Ognibene
'''

import os, sys

def Main(argv):
# Check number of arguments
if len(argv) != 2:
print("The function requires one argument to be passed in.")
return

# Check parameters
topDir = str(sys.argv[1])
if not os.path.isdir(topDir):
print("The parameter should be an existing directory.")
return

# Build a dictionary with key-value pair {file extension - total size}
extensionSize = { }
GetSize(topDir, extensionSize)

# Print results
PrintResults(extensionSize)

def GetSize(topDir, extensionSize):
for dirPath, dirNames, files in os.walk(topDir):
for file in files:
# 'example.mp3' -> ['example', 'mp3']
# 'example.tar.gz' -> ['example', 'tar', 'gz']
parts = file.split('.')
# ['example', 'mp3'] -> ['mp3']
# ['example', 'tar', 'gz'] -> ['tar', 'gz']
parts = parts[1:]
# ['mp3'] -> '.mp3'
# ['tar', 'gz'] -> '.tar.gz'
fileExtension = ".{0}".format(".".join(str(part) for part in parts))

# Compute the size in Bytes and update the dictionary
filePath = os.path.join(dirPath, file)
fileSize = os.path.getsize(filePath)
extensionSize[fileExtension] = extensionSize.get(fileExtension, 0) + fileSize

# Print results
def PrintResults(extensionSize):
for key, value in sorted(extensionSize.items()):
print('{0}: {1} Bytes.'.format(key, value))

if __name__ == "__main__":
sys.exit(Main(sys.argv))
</syntaxhighlight>

----

mia versione
<syntaxhighlight lang="Python">
import os, sys, copy

def dotsubstr(a):#restituisce la sottostringa .suffisso
#fcd = os.listdir('{0}'.format(arg1))
i=0
try:
while a[i]!='.':
i=i+1
return a[i:]
except IndexError:
return -1

def compliarg(li,arg):#restituisce una lista di tutti gli elementi contenenti la sottostringa arg come suffisso
res=[]
while li != []:
a=li.pop()
if a.endswith(arg): res.append(a)
return res

def listremintsect(l2,l1):#restituisce una lista res = l1 - intersezione di l1 ed l2
res=[]
while l1 != []:
a=l1.pop()
if not a in l2: res.append(a)
return res

def createpathlist(c,path):#restituisce una lista di path 'path' relativi ai file contenuti in c.
res = []
while c != []:
res.append('{0}/{1}'.format(path,c.pop()))
return res

def totsizes(d): #data una lista d di path restituisce la somma di tutti i size di d
res = 0
while d != []:
a = d.pop()
if os.path.isfile('{0}'.format(a)):
res = res + os.path.getsize('{0}'.format(a))
return res

def listsubstr(arg): #ritorna un dizionario del tipo diz[str(suffisso)] = int(size relativo al suffisso)
res = {}
fcd = os.listdir('{0}'.format(arg))
while fcd != []:
fcdtmp=copy.deepcopy(fcd) #BUGGONE SENZA COPY!!!!!!
a = fcd.pop()
b = dotsubstr(a)
if b == -1: continue
else: pass
c = compliarg(fcdtmp,b)
s=copy.deepcopy(c) #!!!!!!!!!!!!!!!!!!!!!!!!!
d = createpathlist(c,arg)
res[b] = totsizes(d)

fcd = listremintsect(s,fcd)

return res

try:
res = listsubstr(sys.argv[1])
a=list(res.keys())
while a != []:
b = a.pop()
print('{0}:\t{1}'.format(b,res[b]))
except OSError:
print("Could not solve path")

</syntaxhighlight>
-fede

----

Esercizio 1: Linguaggio C

<syntaxhighlight lang="C">
#include <sys/eventfd.h>
#include <stdio.h>
#include <unistd.h>

#define BUFFSIZE 10

int main(int argc, char *argv[]){
int efd,n,i;
char buf1[BUFFSIZE];
char buf2[BUFFSIZE];

do{
efd = eventfd(0,0);
}while(efd<0);

while(1){
if(fork()){ /*padre*/
read(0,buf1,sizeof(buf1)); /*0 indica lo standard input*/
write(efd, buf1, sizeof(buf1));
}

else{ /*figlio*/
read(efd, buf2, sizeof(buf2));
n=atoi(buf2);
for(i=0; i<n; i++) printf("x\n");
}
}
}
</syntaxhighlight>
GiuliaN. con grande aiuto da parte dei colleghi

Esercizio 1:(visto a lezione , soluzione del Prof. Davoli Pirata_20131203)
<syntaxhighlight lang="C">
#include <sys/eventfd.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>

#define BUFFSIZE 10

int main(int argc, char *argv[]){
int efd , n , i;
uint64_t a , b;
if ( ( efd = eventfd( 0 , EFD_SEMAPHORE ) ) < 0 )
exit( 1 );
if ( fork() > 0 ){
while ( 1 ) {
uint64_t a;
scanf( "%lld" , &a );
write( efd , &a , sizeof( a ) );
}
}
else {
while ( 1 ) {
uint64_t b;
read( efd , &b , sizeof( b ) );
printf( "x\n" );
}
}
}
</syntaxhighlight>

Esercizio 3 in bash(Pirata & Fede):

<syntaxhighlight lang="bash">
#! /bin/bash

for f in "$1"/*.* ; do
somma=0
ext=${f##*.}
for file in *."$ext"
do
somma=$(expr $somma + $(stat -c%s "$file"))
done
echo -n "size of file with extension "$ext" : "
echo "$somma"
done
</syntaxhighlight>
Per (Pirata & Fede) -Bash-: ci siamo quasi...però forse rifate gli stessi calcoli un po' di volte in più del necessario ;-) (am_20131127).

----

[Esercizio 3 in Python (ancora)]

<syntaxhighlight lang="Python">
#!/usr/bin/env python3
#
# Prova Pratica di Lab SO 2013.05.29
# Es. 3
# Eduardo Santarelli
#####################################

import os, sys

# return the suffix of file named fname, if present.
# return boolean value False otherwise
def get_suffix(fname):
if '.' in fname:
separator = fname.find('.')
return fname[separator : ]
else:
return False

# Place a file in a dictionary. Each key corresponds
# to a specific suffix, its value is a list of all the
# file with that suffix
def build_dict(item, suffix):
if suffix in all_files:
all_files[suffix].append(item)
else:
all_files[suffix] = []
all_files[suffix].append(item)

# For each suffix key in the dictionary,
# calculates the total size of the files
# in the corresponding list
def size_of_entry(file_list):
size = 0
for item in file_list:
size += os.path.getsize(item)
return size

# This dictionary will contain a key for each suffix,
# associated with a list of all the files ending with
# that suffix
all_files = dict()

# Go to target directory and build a list containing all filenames
try:
target_dir = sys.argv[1]
except:
target_dir = '.'
os.chdir(target_dir)
dir_list = os.listdir('.')

# For each file call get_suffix and then build_dict
# (unless get_suffix returns False)
for item in dir_list:
suffix = get_suffix(item)
if not suffix:
pass
else:
build_dict(item, suffix)

for key in all_files :
print("{0}: {1} Bytes".format(key, size_of_entry(all_files[key])))
</syntaxhighlight>
-Eduardo
--edit: dir_list = os.listdir(target_dir) non funzionava bene coi path relativi.
Ora os.listdir('.') dovrebbe andare bene.

--------
[es.2 - C]
<syntaxhighlight lang="C">
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/eventfd.h>

#define SIZE 64

int main(int argc, char **argv){
int efd_parent, efd_child;
pid_t pid;

efd_parent = eventfd(0, 0);
efd_child = eventfd(0, 0);

pid = fork();
if(pid < 0){
perror("Fork error. ");
exit(EXIT_FAILURE);
}
/* parent */
if(pid){
int okToWrite = 1;
ssize_t n;
char buf[SIZE];

for(;;){
if(okToWrite){
scanf("%s", buf);

n = write(efd_parent, buf, SIZE);
if(n < 0){
perror("Parent: write error.");
exit(EXIT_FAILURE);
}
okToWrite = 1-okToWrite;
}
else{
n = read(efd_child, buf, SIZE);
if( n < sizeof(uint64_t) ){
printf("Parent: something bad happened");
exit(EXIT_FAILURE);
}

printf("padre: %s\n", buf);
okToWrite = 1-okToWrite;
}
}
close(efd_parent);
}
/* child */
else{
int okToWrite = 0;
char buf[SIZE];
int n;

for(;;){
if(okToWrite){
scanf("%s", buf);

n = write(efd_child, buf, SIZE);
if(n < 0){
perror("child: write error.");
exit(EXIT_FAILURE);
}
okToWrite = 1-okToWrite;
}
else{
n = read(efd_parent, buf, SIZE);
if( n < sizeof(uint64_t) ){
printf("Child: something bad happened");
exit(EXIT_FAILURE);
}
printf("figlio: %s\n", buf);
okToWrite = 1-okToWrite;
}
}
close(efd_child);
}

return EXIT_SUCCESS;
}
</syntaxhighlight>
- Eduardo

ProvaPratica 2012.09.19

2014-04-30T13:29:08Z

Edu san:

URL-> http://www.cs.unibo.it/~renzo/so/pratiche/2012.09.19.pdf
----
[C Esercizio 1]
<syntaxhighlight lang="C">
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>

#define BUFSIZE 1024

long int n = 0;

void handler(int sig_num){

signal(SIGUSR1, handler);
fprintf(stderr, "\n%ld Bytes copied until now\n", n);

}

int main(){

int nread, nwritten,
i = 0;
char buffer[BUFSIZE],
cool_gui[] = "-\\|/";

signal(SIGUSR1, handler);
fprintf(stderr, "Copying ");

while( (nread = read(STDIN_FILENO, buffer, BUFSIZE)) != 0 ){
if(nread < 0){
perror("Read error: ");
exit(EXIT_FAILURE);
}

nwritten = write(STDOUT_FILENO, buffer, nread);
if(nwritten < 0){
perror("Write error: ");
exit(EXIT_FAILURE);
}

n += nwritten
fprintf(stderr, "\b\b%c ",cool_gui[i%4]);
(i == INT_MAX) ? (i=0) : (i++);
}

fprintf(stderr, "\nDone\n");

return EXIT_SUCCESS;

}
</syntaxhighlight>
-Eduardo

----
[Bash Esercizio 3]
In due versioni: 
1. one-liner, per amore di leggibilità
<syntaxhighlight lang="Bash">
IFS=$(echo -ne "\n\b") && file `find $DIRECTORY` | sed -rn "s/(.*):\ +`file -b $FILENAME`/\1/p"
</syntaxhighlight>
Purtroppo se esistono troppi file nell'albero della directory non funziona (Argument list too long) 
2. script
<syntaxhighlight lang="Bash">
#!/bin/bash

SUCCESS=0
FAILURE=1

#Check arguments
if [[ $# -ne 2 ]]
then
echo "Usage: `basename $0` file directory"
exit $FAILURE
fi

IFS=$(echo -e "\n\b") #set newline as separator
file_type=$(file -b $1)
file_list=$(find $2)

for item in $file_list
do
item_type=$(file -b $item)
if [[ $item_type == $file_type ]]
then
echo $item
fi
done

exit $SUCCESS
</syntaxhighlight>
La riga di codice per settare il separatore l'ho trovata qui: http://www.cyberciti.biz/tips/handling-filenames-with-spaces-in-bash.html . Non mi è chiaro perchè il separatore debba essere "\n\b" e non solo "\n", ma ho provato in varie salse, e questo è l'unico modo in cui lo script funziona. 
-Eduardo

ProvaPratica 2012.09.19

2014-04-30T13:27:47Z

Edu san:

URL-> http://www.cs.unibo.it/~renzo/so/pratiche/2012.09.19.pdf
----
[C Esercizio 1]
<syntaxhighlight lang="C">
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>

#define BUFSIZE 1024

long int n = 0;

void handler(int sig_num){

signal(SIGUSR1, handler);
fprintf(stderr, "\n%ld Bytes copied until now\n", n);

}

int main(){

int nread, nwritten,
i = 0;
char buffer[BUFSIZE],
cool_gui[] = "-\\|/";

signal(SIGUSR1, handler);
fprintf(stderr, "Copying ");

while( (nread = read(STDIN_FILENO, buffer, BUFSIZE)) != 0 ){
if(nread < 0){
perror("Read error: ");
exit(EXIT_FAILURE);
}

nwritten = write(STDOUT_FILENO, buffer, nread);

n += nwritten
fprintf(stderr, "\b\b%c ",cool_gui[i%4]);
(i == INT_MAX) ? (i=0) : (i++);
}

fprintf(stderr, "\nDone\n");

return EXIT_SUCCESS;

}
</syntaxhighlight>
-Eduardo

----
[Bash Esercizio 3]
In due versioni: 
1. one-liner, per amore di leggibilità
<syntaxhighlight lang="Bash">
IFS=$(echo -ne "\n\b") && file `find $DIRECTORY` | sed -rn "s/(.*):\ +`file -b $FILENAME`/\1/p"
</syntaxhighlight>
Purtroppo se esistono troppi file nell'albero della directory non funziona (Argument list too long) 
2. script
<syntaxhighlight lang="Bash">
#!/bin/bash

SUCCESS=0
FAILURE=1

#Check arguments
if [[ $# -ne 2 ]]
then
echo "Usage: `basename $0` file directory"
exit $FAILURE
fi

IFS=$(echo -e "\n\b") #set newline as separator
file_type=$(file -b $1)
file_list=$(find $2)

for item in $file_list
do
item_type=$(file -b $item)
if [[ $item_type == $file_type ]]
then
echo $item
fi
done

exit $SUCCESS
</syntaxhighlight>
La riga di codice per settare il separatore l'ho trovata qui: http://www.cyberciti.biz/tips/handling-filenames-with-spaces-in-bash.html . Non mi è chiaro perchè il separatore debba essere "\n\b" e non solo "\n", ma ho provato in varie salse, e questo è l'unico modo in cui lo script funziona. 
-Eduardo

ProvaPratica 2012.09.19

2014-04-30T13:26:52Z

Edu san:

URL-> http://www.cs.unibo.it/~renzo/so/pratiche/2012.09.19.pdf
----
[C Esercizio 1]
<syntaxhighlight lang="C">
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>

#define BUFSIZE 1024

long int n = 0;

void handler(int sig_num){

signal(SIGUSR1, handler);
fprintf(stderr, "\n%ld Bytes copied until now\n", n);

}

int main(){

int nread, nwritten,
i = 0;
char buffer[BUFSIZE],
cool_gui[] = "-\\|/";

signal(SIGUSR1, handler);
fprintf(stderr, "Copying ");

while( (nread = read(STDIN_FILENO, buffer, BUFSIZE)) != 0 ){
if(nread < 0){
perror("Read error: ");
exit(EXIT_FAILURE);
}

nwritten = write(STDOUT_FILENO, buffer, nread);

n += nwritten
fprintf(stderr, "\b\b%c ",cool_gui[i%4]);
(i == INT_MAX) ? (i=0) : (i++);
}

fprintf(stderr, "\nDone\n");

return EXIT_SUCCESS;

}
</syntaxhighlight>
-Eduardo

----
[Bash Esercizio 3]
In due versioni: 
1. one-liner, per amore di leggibilità
<syntaxhighlight lang="Bash">
IFS=$(echo -ne "\n\b") && file `find $DIRECTORY` | sed -rn "s/(.*):\ +`file -b $FILENAME`/\1/p"
</syntaxhighlight>
Purtroppo se esistono troppi file nell'albero della directory non funziona (Argument list too long) 
2. script
<syntaxhighlight lang="Bash">
#!/bin/bash

SUCCESS=0
FAILURE=1

#Check arguments
if [[ $# -ne 2 ]]
then
echo "Usage: `basename $0` file directory"
exit $FAILURE
fi

IFS=$(echo -e "\n\b") #set newline as separator
file_type=$(file -b $1)
file_list=$(find $2)

for item in $file_list
do
item_type=$(file -b $item)
if [[ $item_type == $file_type ]]
then
echo $item
fi
done

exit $SUCCESS
</syntaxhighlight>
La riga di codice per settare il separatore l'ho trovata qui: http://www.cyberciti.biz/tips/handling-filenames-with-spaces-in-bash.html . Non mi è chiaro perchè il separatore debba essere "\n\b" e non solo "\n", ma ho provato in varie salse, e questo è l'unico modo in cui lo script funziona. 
-Eduardo

ProvaPratica 2012.09.19

2014-04-29T23:20:43Z

Edu san: Created page with " URL-> http://www.cs.unibo.it/~renzo/so/pratiche/2012.09.19.pdf ---- [Bash esercizio 3] In due versioni: 1. one-liner, per amore di leggibilità <syntaxhighlight lang="Bas..."

URL-> http://www.cs.unibo.it/~renzo/so/pratiche/2012.09.19.pdf
----
[Bash esercizio 3]
In due versioni: 
1. one-liner, per amore di leggibilità
<syntaxhighlight lang="Bash">
IFS=$(echo -ne "\n\b") && file `find $DIRECTORY` | sed -rn "s/(.*):\ +`file -b $FILENAME`/\1/p"
</syntaxhighlight>
Purtroppo se esistono troppi file nell'albero della directory non funziona (Argument list too long) 
2. script
<syntaxhighlight lang="Bash">
#!/bin/bash

SUCCESS=0
FAILURE=1

#Check arguments
if [[ $# -ne 2 ]]
then
echo "Usage: `basename $0` file directory"
exit $FAILURE
fi

IFS=$(echo -e "\n\b") #set newline as separator
file_type=$(file -b $1)
file_list=$(find $2)

for item in $file_list
do
item_type=$(file -b $item)
if [[ $item_type == $file_type ]]
then
echo $item
fi
done

exit $SUCCESS
</syntaxhighlight>
La riga di codice per settare il separatore l'ho trovata qui: http://www.cyberciti.biz/tips/handling-filenames-with-spaces-in-bash.html . Non mi è chiaro perchè il separatore debba essere "\n\b" e non solo "\n", ma ho provato in varie salse, e questo è l'unico modo in cui lo script funziona.
Eduardo

Main Page

2014-04-29T22:19:45Z

Edu san:

Questo è il Wiki del Corso di Sistemi Operativi

[[Esercizi a caso del Prof.]]

[[Decalogo di Programmazione Concorrente]]

[[Python Programma tieni punteggio.]]

[[Comandi visti alle lezioni.]]

[[SYS CALL viste a lezione.]]

[[Parametri con getopt().]]

[[Funzione con numero variabile di parametri.]]

[[stampf - implementazione ridotta della printf.]]

[[Producer&Consumer MP.]]

[[ProvaPratica 2014.01.23]]

[[ProvaPratica 2013.09.13]]

[[ProvaPratica 2013.07.18]]

[[ProvaPratica 2013.06.21]]

[[ProvaPratica 2013.05.29]]

[[ProvaPratica 2013.02.15]]

[[ProvaPratica 2013.01.25]]

[[ProvaPratica 2012.09.19]]

[[ProvaPratica 2005.02.10]]

[[ProvaTeoria_2011.07.25]]

[[ProvaTeorica_2012.02.09]]

[[ProvaTeorica_2012.05.24]]

[[ProvaTeorica_2012.06.15]]

[[ProvaTeorica_2012.09.18]]

[[ProvaTeorica_2013.02.15]]

[[ProvaTeorica_2011.02.11]]

[[ProvaTeorica 2013.07.19]]

[[ProvaTeorica 2013.01.24]]

[[ProvaTeorica 2014.01.22]]

[[ProvaTeorica 2012.07.16]]

[[ProvaPratica_2010.07.12]]

[[Prova Teorica 2008.01.16]]

[[Prova Teorica 2013.09.12]]

[[Prova Teorica 2009.09.18]]

[[Prova Teorica 2008.09.17]]

[[Prova Teorica 2007.09.07]]

[[Prova Teorica 2013.06.21]]

[[ProvaPratica 2010.02.03]]

[[ProvaPratica 2011.09.12]]

[[ProvaPratica 2009.02.12]]

[[ProvaPratica 2009.01.15]]
----
Ricordate che per creare un account o quando viene richiesto di risolvere un semplice calcolo occorre ricordare quanto scritto [[qui]]

ProvaPratica 2013.09.13

2014-03-09T18:31:28Z

Edu san:

[C esercizio 1 e 2]
<syntaxhighlight lang="C">

/***********************************************************************
* Prova Pratica di Laboratorio di Sistemi Operativi *
* 13 settembre 2013 *
* Esercizio 1+2 *
* *
* URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.09.13.pdf *
* Autore: Eduardo Santarelli *
************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <unistd.h>

/* An entry in the hash table. */
typedef struct fileEntry{

const char *filename;
struct fileEntry *next;

} fileEntry;

/* Global variables */
fileEntry **table = NULL;
int table_size;

/* Hash function. Calculates XOR of 8-bytes blocks *
* (actually, sizeof(long int)) read from the input file */
unsigned int hash(const char *fname){

FILE *f;
unsigned long int hash_val = 0;
unsigned long int tmp = 0;

f = fopen(fname, "r");
fread(&hash_val, sizeof(unsigned long int), 1, f);

while((fread(&tmp, sizeof(unsigned long int), 1, f) == 1))
hash_val = hash_val^tmp;

fclose(f);
return hash_val;

}

/* Creates a table of struct fileEntry elements, based on the hash values of the files *
* detected by scandir. If a collision is detected, the new entry is pointed by the *
* 'next' field of the current last element*/
void populate_table(struct dirent *dir_list[], int n){

int i;

table_size = 2*n;
table = (fileEntry**)calloc(table_size, sizeof(fileEntry));
if(!table) abort();

for(i=0; i<n; i++){
unsigned int index;
fileEntry *entry = NULL;

entry = (fileEntry*)malloc(sizeof(fileEntry));
if(!entry) abort();

index = hash(dir_list[i]->d_name)%table_size;
if(table[index] == NULL){
entry->filename = dir_list[i]->d_name;
entry->next = NULL;
table[index] = entry;
}
else{
entry->filename = dir_list[i]->d_name;
entry->next = table[index];
table[index] = entry;
}
}

}

/* Compares two files */
int fcompare(const char *f1, const char *f2){

FILE *f, *g;
int file1, file2;

f = fopen(f1, "r");
g = fopen(f2, "r");

while(fread(&file1, sizeof(int), 1, f) && fread(&file2, sizeof(int), 1, g)){
if(file1!=file2){
fclose(f);
fclose(g);
return 0;
}
}
fclose(f);
fclose(g);
return 1;

}

/* This function scans the file table. If an entry contains more than one file, *
* it compares all them. If a duplicate is found, the first file is removed, *
* and a hard link is created with the deleted file's name, pointing to the *
* second, identical, file. */
void deduplicate(){

int i;

for(i=0; i<table_size; i++){
while(table[i] != NULL && table[i]->next != NULL){

fileEntry *file1, *file2;
file1 = table[i];
file2 = table[i]->next;
while(file2 != NULL){
if(fcompare(file1->filename, file2->filename)){
unlink(file1->filename);
link(file2->filename, file1->filename);
printf("%s -> %s\n", file1->filename, file2->filename);
break;
}
file2 = file2->next;
}
table[i] = table[i]->next;
}
}
}

/*selector function for scandir() */
int exclude(const struct dirent *dir){

if(dir->d_type != DT_REG)
return 0;
else
return 1;

}

int main(int argc, char *argv[]){

struct dirent **entries = NULL;
int num_files;

num_files = scandir(".", &entries, exclude, alphasort);

populate_table(entries, num_files);
deduplicate();

return EXIT_SUCCESS;

}
</syntaxhighlight>

------

[Python esercizio 3]
<syntaxhighlight lang="Python">
#!/usr/bin/env python3

# Prova Pratica di Laboratorio di Sistemi Operativi
# 13 settembre 2013
# Esercizio 3
#
# URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.09.13.pdf *
# Autore: Eduardo Santarelli

class LineCounter:

def __init__(self, fileList):
# A list containing the char-per-line
# count for the specified files.
# Value for line 1 is in result[0] and so on.
self.result = []
self.files = fileList # List of files to elaborate.
self.getLinesCount()

# Count the chars for each lines of specified file,
# add the result to the relevant field in self.result,
# if already present, append the value to the
# end of the list if not.
def countLines(self, file):
i = 0
fd = open(file)
for line in fd:
lineLength = len(line)
# If an entry for the current line does
# not exist, append the value to the end of the list
try:
self.result[i] += lineLength
except IndexError:
self.result.append(lineLength)
i = i+1
fd.close()

# Call self.countLines() for each file in self.files
# in order to build the self.result list
def getLinesCount(self):
for entry in self.files:
self.countLines(entry)

# Print the items in self.result, each preceded by the
# corresponding line number.
def printLines(self):
i = 1
for value in self.result:
print("{:d}: {:d}".format(i, value))
i = i+1

import os

lc = LineCounter(os.listdir(os.getcwd()))
lc.printLines()
</syntaxhighlight>

ProvaPratica 2013.09.13

2014-03-04T23:58:31Z

Edu san: Created page with "[C esercizio 1 e 2] <syntaxhighlight lang="C"> /*********************************************************************** * Prova Pratica di Laboratorio di Sistemi Operativi ..."

Main Page

2014-03-04T23:50:21Z

Edu san:

ProvaPratica 2013.02.15

2013-12-16T01:08:22Z

Edu san:

Esercizio 1 del 2013.02.15
<syntaxhighlight lang="C">
/*
* Prova Pratica di Lab SO 2013.02.15
* http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf
* Es.1
* Eduardo Santarelli
*/
#include <dirent.h>
#include <string.h>
#include <unistd.h>

/* Selector function, called by scandir. Only selects
* palindrome file names. Discards implied directories.
*/
int dir_is_pal(const struct dirent* dir){
int i,j;

//discard implied dirs
if(dir->d_name[0]=='.' && strlen(dir->d_name)<3)
return 0;

for(i=0, j=strlen(dir->d_name)-1; i<j; i++, j--)
if(dir->d_name[i]!=dir->d_name[j])
return 0;

return 1;
}

int main(int argc, char** argv){
struct dirent** entry;
int i, items;
pid_t pid;

items=scandir("./", &entry, dir_is_pal, alphasort);

for(i=0; i<items; i++){
if(access(entry[i]->d_name, X_OK)==0){ //Check execution rights
if((pid=fork())) ; //do nothing
else
execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
}
}

return 0;
}
</syntaxhighlight>
-Eduardo 
edit: avevo dimenticato un pezzo.

----
Seconda parte dell'esercizio
<syntaxhighlight lang="C">
/*
* Prova Pratica di Lab SO 2013.02.15
* http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf
* Es.2
* Eduardo Santarelli
*/
#include <dirent.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/wait.h>
#include <libgen.h>
#include <sys/stat.h>
#include <fcntl.h>

/* Global variables
* declaration
*/
const char *PROGRAM_NAME, *WORKING_DIR;
int b_flag, c_flag, p_flag; //option flags

/* Function
* prototypes
*/
int selector(const struct dirent *file);
int checkbang(char *file_name);
void init(int argc, char **argv);

/* Main function
*/
int main(int argc, char **argv){
struct dirent **entry;
int i, items, count=0;
pid_t pid;

init(argc, argv);

items=scandir(WORKING_DIR, &entry, selector, alphasort);

for(i=0; i<items; i++){
if((pid=fork())){
if(!c_flag)
count++;
else{
int status;
waitpid(pid, &status, 0);
}
}
else{
execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
exit(EXIT_FAILURE);
}
}

if(c_flag){
for(i=0; i<count; i++){
int status;
wait(&status);
}
}

return EXIT_SUCCESS;
}

/* Check first two bytes of file for #!
*/
int checkbang(char *file_name){
int fd;
char bang[2];

fd=open(file_name, O_RDONLY);
read(fd, bang, 2);

if((strncmp(bang, "#!", 2)) == 0)
return 1;
else
return 0;
}

/* Initialize variables: program name(global const),
* current directory, option flags
*/
void init(int argc, char **argv){
int options;

while((options=getopt(argc, argv, "bcp")) != -1 )
switch(options){
case 'b':
b_flag=1;
break;
case 'c':
c_flag=1;
break;
case 'p':
p_flag=1;
break;
case '?':
printf("Invalid option: '%c'\n", optopt);
break;
default:
abort();
}
PROGRAM_NAME=basename(strdup(argv[0]));

//accept a target directory as an argument from command line
if(optind==argc)
WORKING_DIR=getcwd(NULL,0);
else
WORKING_DIR=argv[optind];

}

/* Selector function, called by scandir. Selects files
* depending on command line options.
* Discards implied directories.
*/
int selector(const struct dirent *file){
int i,j;
char *filename;

filename=strdup(file->d_name);
//discard implied files
if(strcmp(filename, ".")==0 || strcmp(filename, "..")==0)
return 0;

//Check if file is executable
if(!access(filename, X_OK)==0)
return 0;

//prevent the program from running itself
if(strcmp(filename, PROGRAM_NAME)==0)
return 0;

//if flag is set check if program is a script
if(b_flag && !(checkbang(filename)))
return 0;

//if flag is set, check if prog. name is palindrome
if(p_flag){
for(i=0, j=strlen(filename)-1; i<j; i++, j--)
if(filename[i]!=filename[j])
return 0;
}

return 1;
}

</syntaxhighlight>
-Eduardo

ProvaPratica 2013.02.15

2013-12-12T03:31:18Z

Edu san:

ProvaPratica 2013.02.15

2013-12-12T03:28:05Z

Edu san:

ProvaPratica 2013.02.15

2013-12-12T02:24:24Z

Edu san:

ProvaPratica 2013.02.15

2013-12-12T02:21:17Z

Edu san:

Esercizio 1 del 2013.02.15
<syntaxhighlight lang="C">
/*
* Prova Pratica di Lab SO 2013.02.15
* http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf
* Es.1
* Eduardo Santarelli
*/
#include <stdio.h>
#include <errno.h>
#include <dirent.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

/* Selector function, called by scandir. Only selects
* palindrome file names. Discards implied directories.
*/
int dir_is_pal(const struct dirent* dir){
int i,j;

//discard implied dirs
if(dir->d_name[0]=='.' && strlen(dir->d_name)<3)
return 0;

for(i=0, j=strlen(dir->d_name)-1; i<j; i++, j--)
if(dir->d_name[i]!=dir->d_name[j])
return 0;

return 1;
}

int main(int argc, char** argv){
struct dirent** entry;
int i, items;
pid_t pid;

items=scandir("./", &entry, dir_is_pal, alphasort);

for(i=0; i<items; i++){
if((pid=fork())) ; //do nothing
else
execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
}

return EXIT_SUCCESS;
}
</syntaxhighlight>
-Eduardo

ProvaPratica 2013.02.15

2013-12-12T02:20:25Z

Edu san:

Esercizio 1 del 2013.02.15
<syntaxhighlight lang="C">
/*
* Prova Pratica di Lab SO 2013.02.15
* http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf
* Es.1
* Eduardo Santarelli
*/
#include <stdio.h>
#include <errno.h>
#include <dirent.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

/* Selector function, called by scandir. Only selects
* palindrome file names. Discards implied directories.
*/
int dir_is_pal(const struct dirent* dir){
int i,j;

//discard implied dirs
if(dir->d_name[0]=='.' && strlen(dir->d_name)<3)
return 0;

for(i=0, j=strlen(dir->d_name)-1; i<j; i++, j--)
if(dir->d_name[i]!=dir->d_name[j])
return 0;

return 1;
}

int main(int argc, char** argv){
struct dirent** entry;
int i, items;
pid_t pid;

items=scandir("./", &entry, dir_is_pal, alphasort);

for(i=0; i<items; i++){
int status;
if((pid=fork())) ; //do nothing
else
execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
}

return EXIT_SUCCESS;
}
</syntaxhighlight>
-Eduardo

ProvaPratica 2013.02.15

2013-12-12T02:17:17Z

Edu san: Created page with "Esercizio 1 del 2013.02.15 <syntaxhighlight lang="C"> /* * Prova Pratica di Lab SO 2013.02.15 * http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf * Es.1 * Eduardo S..."

Esercizio 1 del 2013.02.15
<syntaxhighlight lang="C">
/*
* Prova Pratica di Lab SO 2013.02.15
* http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf
* Es.1
* Eduardo Santarelli
*/
#include <stdio.h>
#include <errno.h>
#include <dirent.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

/* Selector function, called by scandir. Only selects
* palindrome file names. Discards implied directories.
*/
int dir_is_pal(const struct dirent* dir){
int i,j;

//discard implied dirs
if(dir->d_name[0]=='.' && strlen(dir->d_name)<3)
return 0;

for(i=0, j=strlen(dir->d_name)-1; i<j; i++, j--)
if(dir->d_name[i]!=dir->d_name[j])
return 0;

return 1;
}

int main(int argc, char** argv){
struct dirent** entry;
int i, items;
pid_t pid;

items=scandir("./", &entry, dir_is_pal, alphasort);

for(i=0; i<items; i++){
int status;
if((pid=fork())) ; //do nothing
else
execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
}

return 0;
}
</syntaxhighlight>
-Eduardo

Main Page

2013-12-12T02:08:29Z

Edu san:

Questo è il Wiki del Corso di Sistemi Operativi

[[Esercizi a caso del Prof.]]

[[Python Programma tieni punteggio.]]

[[Comandi visti alle lezioni.]]

[[SYS CALL viste a lezione.]]

[[Parametri con getopt().]]

[[Funzione con numero variabile di parametri.]]

[[stampf - implementazione ridotta della printf.]]

[[ProvaPratica 2013.07.18]]

[[ProvaPratica 2013.06.21]]

[[ProvaPratica 2013.05.29]]

[[ProvaPratica 2013.02.15]]

----
Ricordate che per creare un account o quando viene richiesto di risolvere un semplice calcolo occorre ricordare quanto scritto [[qui]]

ProvaPratica 2013.05.29

2013-11-28T01:37:47Z

Edu san:

[Python 3]

<syntaxhighlight lang="Python">
'''
Prova Pratica di Laboratorio di Sistemi Operativi
29 maggio 2013
Esercizio 3

URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.05.29.pdf

@author: Tommaso Ognibene
'''

import os, sys

def Main(argv):
# Check number of arguments
if len(argv) != 2:
print("The function requires one argument to be passed in.")
return

# Check parameters
topDir = str(sys.argv[1])
if not os.path.isdir(topDir):
print("The parameter should be an existing directory.")
return

# Build a dictionary with key-value pair {file extension - total size}
extensionSize = { }
GetSize(topDir, extensionSize)

# Print results
PrintResults(extensionSize)

def GetSize(topDir, extensionSize):
for dirPath, dirNames, files in os.walk(topDir):
for file in files:
# 'example.mp3' -> ['example', 'mp3']
# 'example.tar.gz' -> ['example', 'tar', 'gz']
parts = file.split('.')
# ['example', 'mp3'] -> ['mp3']
# ['example', 'tar', 'gz'] -> ['tar', 'gz']
parts = parts[1:]
# ['mp3'] -> '.mp3'
# ['tar', 'gz'] -> '.tar.gz'
fileExtension = ".{0}".format(".".join(str(part) for part in parts))

# Compute the size in Bytes and update the dictionary
filePath = os.path.join(dirPath, file)
fileSize = os.path.getsize(filePath)
extensionSize[fileExtension] = extensionSize.get(fileExtension, 0) + fileSize

# Print results
def PrintResults(extensionSize):
for key, value in sorted(extensionSize.items()):
print('{0}: {1} Bytes.'.format(key, value))

if __name__ == "__main__":
sys.exit(Main(sys.argv))
</syntaxhighlight>

----

mia versione
<syntaxhighlight lang="Python">
import os, sys, copy

def dotsubstr(a):#restituisce la sottostringa .suffisso
#fcd = os.listdir('{0}'.format(arg1))
i=0
try:
while a[i]!='.':
i=i+1
return a[i:]
except IndexError:
return -1

def compliarg(li,arg):#restituisce una lista di tutti gli elementi contenenti la sottostringa arg come suffisso
res=[]
while li != []:
a=li.pop()
if a.endswith(arg): res.append(a)
return res

def listremintsect(l2,l1):#restituisce una lista res = l1 - intersezione di l1 ed l2
res=[]
while l1 != []:
a=l1.pop()
if not a in l2: res.append(a)
return res

def createpathlist(c,path):#restituisce una lista di path 'path' relativi ai file contenuti in c.
res = []
while c != []:
res.append('{0}/{1}'.format(path,c.pop()))
return res

def totsizes(d): #data una lista d di path restituisce la somma di tutti i size di d
res = 0
while d != []:
a = d.pop()
if os.path.isfile('{0}'.format(a)):
res = res + os.path.getsize('{0}'.format(a))
return res

def listsubstr(arg): #ritorna un dizionario del tipo diz[str(suffisso)] = int(size relativo al suffisso)
res = {}
fcd = os.listdir('{0}'.format(arg))
while fcd != []:
fcdtmp=copy.deepcopy(fcd) #BUGGONE SENZA COPY!!!!!!
a = fcd.pop()
b = dotsubstr(a)
if b == -1: continue
else: pass
c = compliarg(fcdtmp,b)
s=copy.deepcopy(c) #!!!!!!!!!!!!!!!!!!!!!!!!!
d = createpathlist(c,arg)
res[b] = totsizes(d)

fcd = listremintsect(s,fcd)

return res

try:
res = listsubstr(sys.argv[1])
a=list(res.keys())
while a != []:
b = a.pop()
print('{0}:\t{1}'.format(b,res[b]))
except OSError:
print("Could not solve path")

</syntaxhighlight>
-fede

----

Esercizio 1: Linguaggio C

<syntaxhighlight lang="C">
#include <sys/eventfd.h>
#include <stdio.h>
#include <unistd.h>

#define BUFFSIZE 10

int main(int argc, char *argv[]){
int efd,n,i;
char buf1[BUFFSIZE];
char buf2[BUFFSIZE];

do{
efd = eventfd(0,0);
}while(efd<0);

while(1){
if(fork()){ /*padre*/
read(0,buf1,sizeof(buf1)); /*0 indica lo standard input*/
write(efd, buf1, sizeof(buf1));
}

else{ /*figlio*/
read(efd, buf2, sizeof(buf2));
n=atoi(buf2);
for(i=0; i<n; i++) printf("x\n");
}
}
}
</syntaxhighlight>
GiuliaN. con grande aiuto da parte dei colleghi

Esercizio 3 in bash(Pirata & Fede):

<syntaxhighlight lang="bash">
#! /bin/bash

for f in "$1"/*.* ; do
somma=0
ext=${f##*.}
for file in *."$ext"
do
somma=$(expr $somma + $(stat -c%s "$file"))
done
echo -n "size of file with extension "$ext" : "
echo "$somma"
done
</syntaxhighlight>
Per (Pirata & Fede) -Bash-: ci siamo quasi...però forse rifate gli stessi calcoli un po' di volte in più del necessario ;-) (am_20131127).

----

[Esercizio 3 in Python (ancora)]

<syntaxhighlight lang="Python">
#!/usr/bin/env python3
#
# Prova Pratica di Lab SO 2013.05.29
# Es. 3
# Eduardo Santarelli
#####################################

import os, sys

# return the suffix of file named fname, if present.
# return boolean value False otherwise
def get_suffix(fname):
if '.' in fname:
separator = fname.find('.')
return fname[separator : ]
else:
return False

# Place a file in a dictionary. Each key corresponds
# to a specific suffix, its value is a list of all the
# file with that suffix
def build_dict(item, suffix):
if suffix in all_files:
all_files[suffix].append(item)
else:
all_files[suffix] = []
all_files[suffix].append(item)

# For each suffix key in the dictionary,
# calculates the total size of the files
# in the corresponding list
def size_of_entry(file_list):
size = 0
for item in file_list:
size += os.path.getsize(item)
return size

# This dictionary will contain a key for each suffix,
# associated with a list of all the files ending with
# that suffix
all_files = dict()

# Go to target directory and build a list containing all filenames
try:
target_dir = sys.argv[1]
except:
target_dir = '.'
os.chdir(target_dir)
dir_list = os.listdir('.')

# For each file call get_suffix and then build_dict
# (unless get_suffix returns False)
for item in dir_list:
suffix = get_suffix(item)
if not suffix:
pass
else:
build_dict(item, suffix)

for key in all_files :
print("{0}: {1} Bytes".format(key, size_of_entry(all_files[key])))
</syntaxhighlight>
-Eduardo
--edit: dir_list = os.listdir(target_dir) non funzionava bene coi path relativi.
Ora os.listdir('.') dovrebbe andare bene.

ProvaPratica 2013.05.29

2013-11-28T01:37:22Z

Edu san:

[Python 3]

<syntaxhighlight lang="Python">
'''
Prova Pratica di Laboratorio di Sistemi Operativi
29 maggio 2013
Esercizio 3

URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.05.29.pdf

@author: Tommaso Ognibene
'''

import os, sys

def Main(argv):
# Check number of arguments
if len(argv) != 2:
print("The function requires one argument to be passed in.")
return

# Check parameters
topDir = str(sys.argv[1])
if not os.path.isdir(topDir):
print("The parameter should be an existing directory.")
return

# Build a dictionary with key-value pair {file extension - total size}
extensionSize = { }
GetSize(topDir, extensionSize)

# Print results
PrintResults(extensionSize)

def GetSize(topDir, extensionSize):
for dirPath, dirNames, files in os.walk(topDir):
for file in files:
# 'example.mp3' -> ['example', 'mp3']
# 'example.tar.gz' -> ['example', 'tar', 'gz']
parts = file.split('.')
# ['example', 'mp3'] -> ['mp3']
# ['example', 'tar', 'gz'] -> ['tar', 'gz']
parts = parts[1:]
# ['mp3'] -> '.mp3'
# ['tar', 'gz'] -> '.tar.gz'
fileExtension = ".{0}".format(".".join(str(part) for part in parts))

# Compute the size in Bytes and update the dictionary
filePath = os.path.join(dirPath, file)
fileSize = os.path.getsize(filePath)
extensionSize[fileExtension] = extensionSize.get(fileExtension, 0) + fileSize

# Print results
def PrintResults(extensionSize):
for key, value in sorted(extensionSize.items()):
print('{0}: {1} Bytes.'.format(key, value))

if __name__ == "__main__":
sys.exit(Main(sys.argv))
</syntaxhighlight>

----

mia versione
<syntaxhighlight lang="Python">
import os, sys, copy

def dotsubstr(a):#restituisce la sottostringa .suffisso
#fcd = os.listdir('{0}'.format(arg1))
i=0
try:
while a[i]!='.':
i=i+1
return a[i:]
except IndexError:
return -1

def compliarg(li,arg):#restituisce una lista di tutti gli elementi contenenti la sottostringa arg come suffisso
res=[]
while li != []:
a=li.pop()
if a.endswith(arg): res.append(a)
return res

def listremintsect(l2,l1):#restituisce una lista res = l1 - intersezione di l1 ed l2
res=[]
while l1 != []:
a=l1.pop()
if not a in l2: res.append(a)
return res

def createpathlist(c,path):#restituisce una lista di path 'path' relativi ai file contenuti in c.
res = []
while c != []:
res.append('{0}/{1}'.format(path,c.pop()))
return res

def totsizes(d): #data una lista d di path restituisce la somma di tutti i size di d
res = 0
while d != []:
a = d.pop()
if os.path.isfile('{0}'.format(a)):
res = res + os.path.getsize('{0}'.format(a))
return res

def listsubstr(arg): #ritorna un dizionario del tipo diz[str(suffisso)] = int(size relativo al suffisso)
res = {}
fcd = os.listdir('{0}'.format(arg))
while fcd != []:
fcdtmp=copy.deepcopy(fcd) #BUGGONE SENZA COPY!!!!!!
a = fcd.pop()
b = dotsubstr(a)
if b == -1: continue
else: pass
c = compliarg(fcdtmp,b)
s=copy.deepcopy(c) #!!!!!!!!!!!!!!!!!!!!!!!!!
d = createpathlist(c,arg)
res[b] = totsizes(d)

fcd = listremintsect(s,fcd)

return res

try:
res = listsubstr(sys.argv[1])
a=list(res.keys())
while a != []:
b = a.pop()
print('{0}:\t{1}'.format(b,res[b]))
except OSError:
print("Could not solve path")

</syntaxhighlight>
-fede

----

Esercizio 1: Linguaggio C

<syntaxhighlight lang="C">
#include <sys/eventfd.h>
#include <stdio.h>
#include <unistd.h>

#define BUFFSIZE 10

int main(int argc, char *argv[]){
int efd,n,i;
char buf1[BUFFSIZE];
char buf2[BUFFSIZE];

do{
efd = eventfd(0,0);
}while(efd<0);

while(1){
if(fork()){ /*padre*/
read(0,buf1,sizeof(buf1)); /*0 indica lo standard input*/
write(efd, buf1, sizeof(buf1));
}

else{ /*figlio*/
read(efd, buf2, sizeof(buf2));
n=atoi(buf2);
for(i=0; i<n; i++) printf("x\n");
}
}
}
</syntaxhighlight>
GiuliaN. con grande aiuto da parte dei colleghi

Esercizio 3 in bash(Pirata & Fede):

<syntaxhighlight lang="bash">
#! /bin/bash

for f in "$1"/*.* ; do
somma=0
ext=${f##*.}
for file in *."$ext"
do
somma=$(expr $somma + $(stat -c%s "$file"))
done
echo -n "size of file with extension "$ext" : "
echo "$somma"
done
</syntaxhighlight>
Per (Pirata & Fede) -Bash-: ci siamo quasi...però forse rifate gli stessi calcoli un po' di volte in più del necessario ;-) (am_20131127).

----

[Esercizio 3 in Python (ancora)]

<syntaxhighlight lang="Python">
#!/usr/bin/env python3
#
# Prova Pratica di Lab SO 2013.05.29
# Es. 3
# Eduardo Santarelli
#####################################

import os, sys

# return the suffix of file named fname, if present.
# return boolean value False otherwise
def get_suffix(fname):
if '.' in fname:
separator = fname.find('.')
return fname[separator : ]
else:
return False

# Place a file in a dictionary. Each key corresponds
# to a specific suffix, its value is a list of all the
# file with that suffix
def build_dict(item, suffix):
if suffix in all_files:
all_files[suffix].append(item)
else:
all_files[suffix] = []
all_files[suffix].append(item)

# For each suffix key in the dictionary,
# calculates the total size of the files
# in the corresponding list
def size_of_entry(file_list):
size = 0
for item in file_list:
size += os.path.getsize(item)
return size

# This dictionary will contain a key for each suffix,
# associated with a list of all the files ending with
# that suffix
all_files = dict()

# Go to target directory and build a list containing all filenames
try:
target_dir = sys.argv[1]
except:
target_dir = '.'
os.chdir(target_dir)
dir_list = os.listdir('.')

# For each file call get_suffix and then build_dict
# (unless get_suffix returns False)
for item in dir_list:
suffix = get_suffix(item)
if not suffix:
pass
else:
build_dict(item, suffix)

for key in all_files :
print("{0}: {1} Bytes".format(key, size_of_entry(all_files[key])))
</syntaxhighlight>
-Eduardo
edit: dir_list = os.listdir(target_dir) non funzionava bene coi path relativi.
Ora os.listdir('.') dovrebbe andare bene.

ProvaPratica 2013.05.29

2013-11-28T01:29:49Z

Edu san:

[Python 3]

<syntaxhighlight lang="Python">
'''
Prova Pratica di Laboratorio di Sistemi Operativi
29 maggio 2013
Esercizio 3

URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.05.29.pdf

@author: Tommaso Ognibene
'''

import os, sys

def Main(argv):
# Check number of arguments
if len(argv) != 2:
print("The function requires one argument to be passed in.")
return

# Check parameters
topDir = str(sys.argv[1])
if not os.path.isdir(topDir):
print("The parameter should be an existing directory.")
return

# Build a dictionary with key-value pair {file extension - total size}
extensionSize = { }
GetSize(topDir, extensionSize)

# Print results
PrintResults(extensionSize)

def GetSize(topDir, extensionSize):
for dirPath, dirNames, files in os.walk(topDir):
for file in files:
# 'example.mp3' -> ['example', 'mp3']
# 'example.tar.gz' -> ['example', 'tar', 'gz']
parts = file.split('.')
# ['example', 'mp3'] -> ['mp3']
# ['example', 'tar', 'gz'] -> ['tar', 'gz']
parts = parts[1:]
# ['mp3'] -> '.mp3'
# ['tar', 'gz'] -> '.tar.gz'
fileExtension = ".{0}".format(".".join(str(part) for part in parts))

# Compute the size in Bytes and update the dictionary
filePath = os.path.join(dirPath, file)
fileSize = os.path.getsize(filePath)
extensionSize[fileExtension] = extensionSize.get(fileExtension, 0) + fileSize

# Print results
def PrintResults(extensionSize):
for key, value in sorted(extensionSize.items()):
print('{0}: {1} Bytes.'.format(key, value))

if __name__ == "__main__":
sys.exit(Main(sys.argv))
</syntaxhighlight>

----

mia versione
<syntaxhighlight lang="Python">
import os, sys, copy

def dotsubstr(a):#restituisce la sottostringa .suffisso
#fcd = os.listdir('{0}'.format(arg1))
i=0
try:
while a[i]!='.':
i=i+1
return a[i:]
except IndexError:
return -1

def compliarg(li,arg):#restituisce una lista di tutti gli elementi contenenti la sottostringa arg come suffisso
res=[]
while li != []:
a=li.pop()
if a.endswith(arg): res.append(a)
return res

def listremintsect(l2,l1):#restituisce una lista res = l1 - intersezione di l1 ed l2
res=[]
while l1 != []:
a=l1.pop()
if not a in l2: res.append(a)
return res

def createpathlist(c,path):#restituisce una lista di path 'path' relativi ai file contenuti in c.
res = []
while c != []:
res.append('{0}/{1}'.format(path,c.pop()))
return res

def totsizes(d): #data una lista d di path restituisce la somma di tutti i size di d
res = 0
while d != []:
a = d.pop()
if os.path.isfile('{0}'.format(a)):
res = res + os.path.getsize('{0}'.format(a))
return res

def listsubstr(arg): #ritorna un dizionario del tipo diz[str(suffisso)] = int(size relativo al suffisso)
res = {}
fcd = os.listdir('{0}'.format(arg))
while fcd != []:
fcdtmp=copy.deepcopy(fcd) #BUGGONE SENZA COPY!!!!!!
a = fcd.pop()
b = dotsubstr(a)
if b == -1: continue
else: pass
c = compliarg(fcdtmp,b)
s=copy.deepcopy(c) #!!!!!!!!!!!!!!!!!!!!!!!!!
d = createpathlist(c,arg)
res[b] = totsizes(d)

fcd = listremintsect(s,fcd)

return res

try:
res = listsubstr(sys.argv[1])
a=list(res.keys())
while a != []:
b = a.pop()
print('{0}:\t{1}'.format(b,res[b]))
except OSError:
print("Could not solve path")

</syntaxhighlight>
-fede

----

Esercizio 1: Linguaggio C

<syntaxhighlight lang="C">
#include <sys/eventfd.h>
#include <stdio.h>
#include <unistd.h>

#define BUFFSIZE 10

int main(int argc, char *argv[]){
int efd,n,i;
char buf1[BUFFSIZE];
char buf2[BUFFSIZE];

do{
efd = eventfd(0,0);
}while(efd<0);

while(1){
if(fork()){ /*padre*/
read(0,buf1,sizeof(buf1)); /*0 indica lo standard input*/
write(efd, buf1, sizeof(buf1));
}

else{ /*figlio*/
read(efd, buf2, sizeof(buf2));
n=atoi(buf2);
for(i=0; i<n; i++) printf("x\n");
}
}
}
</syntaxhighlight>
GiuliaN. con grande aiuto da parte dei colleghi

Esercizio 3 in bash(Pirata & Fede):

<syntaxhighlight lang="bash">
#! /bin/bash

for f in "$1"/*.* ; do
somma=0
ext=${f##*.}
for file in *."$ext"
do
somma=$(expr $somma + $(stat -c%s "$file"))
done
echo -n "size of file with extension "$ext" : "
echo "$somma"
done
</syntaxhighlight>
Per (Pirata & Fede) -Bash-: ci siamo quasi...però forse rifate gli stessi calcoli un po' di volte in più del necessario ;-) (am_20131127).

----

[Esercizio 3 in Python (ancora)]

<syntaxhighlight lang="Python">
#!/usr/bin/env python3
#
# Prova Pratica di Lab SO 2013.05.29
# Es. 3
# Eduardo Santarelli
#####################################

import os, sys

# return the suffix of file named fname, if present.
# return boolean value False otherwise
def get_suffix(fname):
if '.' in fname:
separator = fname.find('.')
return fname[separator : ]
else:
return False

# Place a file in a dictionary. Each key corresponds
# to a specific suffix, its value is a list of all the
# file with that suffix
def build_dict(item, suffix):
if suffix in all_files:
all_files[suffix].append(item)
else:
all_files[suffix] = []
all_files[suffix].append(item)

# For each suffix key in the dictionary,
# calculates the total size of the files
# in the corresponding list
def size_of_entry(file_list):
size = 0
for item in file_list:
size += os.path.getsize(item)
return size

# This dictionary will contain a key for each suffix,
# associated with a list of all the files ending with
# that suffix
all_files = dict()

# Go to target directory and build a list containing all filenames
try:
target_dir = sys.argv[1]
except:
target_dir = '.'
os.chdir(target_dir)
dir_list = os.listdir(target_dir)

# For each file call get_suffix and then build_dict
# (unless get_suffix returns False)
for item in dir_list:
suffix = get_suffix(item)
if not suffix:
pass
else:
build_dict(item, suffix)

for key in all_files :
print("{0}: {1} Bytes".format(key, size_of_entry(all_files[key])))
</syntaxhighlight>
-Eduardo

ProvaPratica 2013.05.29

2013-11-28T01:14:06Z

Edu san:

[Python 3]

<syntaxhighlight lang="Python">
'''
Prova Pratica di Laboratorio di Sistemi Operativi
29 maggio 2013
Esercizio 3

URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.05.29.pdf

@author: Tommaso Ognibene
'''

import os, sys

def Main(argv):
# Check number of arguments
if len(argv) != 2:
print("The function requires one argument to be passed in.")
return

# Check parameters
topDir = str(sys.argv[1])
if not os.path.isdir(topDir):
print("The parameter should be an existing directory.")
return

# Build a dictionary with key-value pair {file extension - total size}
extensionSize = { }
GetSize(topDir, extensionSize)

# Print results
PrintResults(extensionSize)

def GetSize(topDir, extensionSize):
for dirPath, dirNames, files in os.walk(topDir):
for file in files:
# 'example.mp3' -> ['example', 'mp3']
# 'example.tar.gz' -> ['example', 'tar', 'gz']
parts = file.split('.')
# ['example', 'mp3'] -> ['mp3']
# ['example', 'tar', 'gz'] -> ['tar', 'gz']
parts = parts[1:]
# ['mp3'] -> '.mp3'
# ['tar', 'gz'] -> '.tar.gz'
fileExtension = ".{0}".format(".".join(str(part) for part in parts))

# Compute the size in Bytes and update the dictionary
filePath = os.path.join(dirPath, file)
fileSize = os.path.getsize(filePath)
extensionSize[fileExtension] = extensionSize.get(fileExtension, 0) + fileSize

# Print results
def PrintResults(extensionSize):
for key, value in sorted(extensionSize.items()):
print('{0}: {1} Bytes.'.format(key, value))

if __name__ == "__main__":
sys.exit(Main(sys.argv))
</syntaxhighlight>

----

mia versione
<syntaxhighlight lang="Python">
import os, sys, copy

def dotsubstr(a):#restituisce la sottostringa .suffisso
#fcd = os.listdir('{0}'.format(arg1))
i=0
try:
while a[i]!='.':
i=i+1
return a[i:]
except IndexError:
return -1

def compliarg(li,arg):#restituisce una lista di tutti gli elementi contenenti la sottostringa arg come suffisso
res=[]
while li != []:
a=li.pop()
if a.endswith(arg): res.append(a)
return res

def listremintsect(l2,l1):#restituisce una lista res = l1 - intersezione di l1 ed l2
res=[]
while l1 != []:
a=l1.pop()
if not a in l2: res.append(a)
return res

def createpathlist(c,path):#restituisce una lista di path 'path' relativi ai file contenuti in c.
res = []
while c != []:
res.append('{0}/{1}'.format(path,c.pop()))
return res

def totsizes(d): #data una lista d di path restituisce la somma di tutti i size di d
res = 0
while d != []:
a = d.pop()
if os.path.isfile('{0}'.format(a)):
res = res + os.path.getsize('{0}'.format(a))
return res

def listsubstr(arg): #ritorna un dizionario del tipo diz[str(suffisso)] = int(size relativo al suffisso)
res = {}
fcd = os.listdir('{0}'.format(arg))
while fcd != []:
fcdtmp=copy.deepcopy(fcd) #BUGGONE SENZA COPY!!!!!!
a = fcd.pop()
b = dotsubstr(a)
if b == -1: continue
else: pass
c = compliarg(fcdtmp,b)
s=copy.deepcopy(c) #!!!!!!!!!!!!!!!!!!!!!!!!!
d = createpathlist(c,arg)
res[b] = totsizes(d)

fcd = listremintsect(s,fcd)

return res

try:
res = listsubstr(sys.argv[1])
a=list(res.keys())
while a != []:
b = a.pop()
print('{0}:\t{1}'.format(b,res[b]))
except OSError:
print("Could not solve path")

</syntaxhighlight>
-fede

----

Esercizio 1: Linguaggio C

<syntaxhighlight lang="C">
#include <sys/eventfd.h>
#include <stdio.h>
#include <unistd.h>

#define BUFFSIZE 10

int main(int argc, char *argv[]){
int efd,n,i;
char buf1[BUFFSIZE];
char buf2[BUFFSIZE];

do{
efd = eventfd(0,0);
}while(efd<0);

while(1){
if(fork()){ /*padre*/
read(0,buf1,sizeof(buf1)); /*0 indica lo standard input*/
write(efd, buf1, sizeof(buf1));
}

else{ /*figlio*/
read(efd, buf2, sizeof(buf2));
n=atoi(buf2);
for(i=0; i<n; i++) printf("x\n");
}
}
}
</syntaxhighlight>
GiuliaN. con grande aiuto da parte dei colleghi

Esercizio 3 in bash(Pirata & Fede):

<syntaxhighlight lang="bash">
#! /bin/bash

for f in "$1"/*.* ; do
somma=0
ext=${f##*.}
for file in *."$ext"
do
somma=$(expr $somma + $(stat -c%s "$file"))
done
echo -n "size of file with extension "$ext" : "
echo "$somma"
done
</syntaxhighlight>
Per (Pirata & Fede) -Bash-: ci siamo quasi...però forse rifate gli stessi calcoli un po' di volte in più del necessario ;-) (am_20131127).

[Esercizio 3 in Python (ancora)]

<syntaxhighlight lang="Python">
#!/usr/bin/env python3
#
# Prova Pratica di Lab SO 2013.05.29
# Es. 3
# Eduardo Santarelli
#####################################

import os, sys

# return the suffix of file named fname, if present.
# return boolean value False otherwise
def get_suffix(fname):
if '.' in fname:
separator = fname.find('.')
return fname[separator : ]
else:
return False

# Place a file in a dictionary. Each key corresponds
# to a specific suffix, its value is a list of all the
# file with that suffix
def build_dict(item, suffix):
if suffix in all_files:
all_files[suffix].append(item)
else:
all_files[suffix] = []
all_files[suffix].append(item)

# For each suffix key in the dictionary,
# calculates the total size of the files
# in the corresponding list
def size_of_entry(file_list):
size = 0
for item in file_list:
size += os.path.getsize(item)
return size

# This dictionary will contain a key for each suffix,
# associated with a list of all the files ending with
# that suffix
all_files = dict()

# Go to target directory and build a list containing all filenames
try:
target_dir = sys.argv[1]
except:
target_dir = '.'
os.chdir(target_dir)
dir_list = os.listdir(target_dir)

# For each file call get_suffix and then build_dict
# (unless get_suffix returns False)
for item in dir_list:
suffix = get_suffix(item)
if not suffix:
pass
else:
build_dict(item, suffix)

for key in all_files :
print("{0}: {1} Bytes".format(key, size_of_entry(all_files[key])))
</syntaxhighlight>
-Eduardo