TomOgn at 11:15, 14 May 2014

2014-05-14T11:15:15Z

TomOgn at 08:47, 14 May 2014

2014-05-14T08:47:07Z

TomOgn: Created page with "=[http://www.cs.unibo.it/~renzo/so/pratiche/2011.01.19.pdf TESTO COMPITO]= =Esercizio 1= // Dependencies #include "../const.h" #include #i..."

2014-05-14T08:46:18Z

Created page with "=[http://www.cs.unibo.it/~renzo/so/pratiche/2011.01.19.pdf TESTO COMPITO]= =Esercizio 1= <syntaxhighlight lang="C"> // Dependencies #include "../const.h" #include <stdio.h> #i..."

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=[http://www.cs.unibo.it/~renzo/so/pratiche/2011.01.19.pdf TESTO COMPITO]=
=Esercizio 1=
<syntaxhighlight lang="C">
// Dependencies
#include "../const.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <getopt.h>

// Function declarations
static inline void printAndDie(const char *msg);
static inline void errorAndDie(const char *msg);
static void redirectAndRun(char *outFile, char *inFile, char *path, char *command[]);
static void parseArguments(int argc, char **argv);

// Entry point
extern void run(int argc, char *argv[])
{
parseArguments(argc, argv);
}

/*
* Parse arguments accordingly to a given set of options.
* Input: argc, the argument counter
* argv, the argument vector
*/
static void parseArguments(int argc, char **argv)
{
int i, j, result;
char **command;
char *fileName, *outFile, *inFile;

// Short-named options
const char *shortOptions = "o:i:h";
// Long-named options
static struct option longOptions[] =
{
{"in", required_argument, 0, 'i' },
{"out", required_argument, 0, 'o' },
{"help", no_argument, 0, 'h' },
{0, 0, 0, 0 }
};

result = True;
outFile = inFile = NULL;

// Disable default error message
opterr = 0;

// Parse options
result = getopt_long(argc, argv, shortOptions, longOptions, NULL);
if (result < 0)
printAndDie("Wrong input. Run 'redir -h' for help.");

j = 1;
while (result != -1 && result != '?')
{
// Get the option value
switch (result)
{
case 'i':
inFile = optarg;
j = optind;
break;
case 'o':
outFile = optarg;
j = optind;
break;
case 'h':
printf("Usage: [options] command\n");
printf(" options:\n");
printf(" -i --in required_argument Redirect input.\n");
printf(" -o --out required_argument Redirect output.\n");
printf(" -h --help no_argument Show this help.\n");
exit(EXIT_SUCCESS);
}
result = getopt_long(argc, argv, shortOptions, longOptions, NULL);
}

// Parse command
command = (char **) malloc((argc - optind + 1) * sizeof (char *));
fileName = argv[j];
i = 0;
while (j < argc)
command[i++] = argv[j++];
command[i] = NULL;

redirectAndRun(outFile, inFile, fileName, command);
}

/*
* Re-direct [input, output] and run a command
* Input: outFile, output file
* inFile, input file
* command, command
* args, command arguments
*/
static void redirectAndRun(char *outFile, char *inFile, char *command, char *args[])
{
int pid, outFD, inFD;

outFD = inFD = 0;
if (inFile)
{
inFD = open(inFile, O_RDONLY);
if (inFD < 0)
errorAndDie("open");
}
if (outFile)
{
outFD = open(outFile, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IRGRP | S_IWGRP | S_IWUSR);
if (outFD < 0)
errorAndDie("open");
}

if ((pid = fork()) < 0)
errorAndDie("fork");

// Child process
if (pid == 0)
{
if (inFile)
{
if (dup2(inFD, STDIN_FILENO) < 0)
errorAndDie("dup2");

if (close(inFD) < 0)
errorAndDie("close");
}
if (outFile)
{
if (dup2(outFD, STDOUT_FILENO) < 0)
errorAndDie("dup2");
if (close(outFD) < 0)
errorAndDie("close");
}
execvp(command, args);
errorAndDie("execvp");
}

// Parent process
if (inFile)
if (close(inFD) < 0)
errorAndDie("close");
if (outFile)
if (close(outFD) < 0)
errorAndDie("close");
}

/*
* Print error message and exit
* Input: msg, the error message
*/
static inline void errorAndDie(const char *msg)
{
perror(msg);
exit(EXIT_FAILURE);
}

/*
* Print message and exit
* Input: msg, the message
*/
static inline void printAndDie(const char *msg)
{
printf("%s\n", msg);
exit(EXIT_FAILURE);
}
</syntaxhighlight>
=Esercizio 3=
<syntaxhighlight lang="Python">
def ssend2(m, d1, d2):
msg = ( SND, getpid(), d1, d2, m )
asend(msg, server)
return arecv(server)

def sreceive():
msg = ( RCV, getpid(), None, None, None )
asend(msg, server)
return arecv(server)

def server():
while True:
flag, src, d1, d2, msg = arecv(*)
if flag == RCV:
msg, sender, _, _ = dbSnd.retrieve(query = '(?, ?, src, ?) or (?, ?, ?, src)')
if msg:
asend(msg, src)
asend(src, sender)
else:
dbRcv.insert(src)
else:
if dbRcv.retrieve(d1):
asend(msg, d1)
asend(d1, src)
elif dbRcv.retrieve(d2):
asend(msg, d2)
asend(d2, src)
else:
dbSnd.insert((msg, src, d1, d2))
</syntaxhighlight>
==Esercizio 3==
<syntaxhighlight lang="Python">
import os, sys

'''
@summary: Walk through a directory tree.
Populate a dictionary with key-value pair
{ file name - (last modification - directory) }.
Create soft links of the last modified files in a destination directory.
@param sources: list of source directories
@param n: number of source directories
@param destination: the destination directory
'''
def MergeDirectories(sources, n, destination):
# Populate the dictionary
fileLastMod = {}

for i in range(0, n):
for fileName in os.listdir(sources[i]):
filePath = os.path.join(sources[i], fileName)
lastMod = os.path.getmtime(filePath)
if fileLastMod.get(fileName, None) == None:
fileLastMod[fileName] = (lastMod, sources[i])
elif fileLastMod[fileName][0] < lastMod:
fileLastMod[fileName] = (lastMod, sources[i])

# Generate the soft links
for key, value in fileLastMod.items():
srcPath = os.path.join(value[1], key)
dstPath = os.path.join(destination, key)
if not os.path.lexists(dstPath):
os.symlink(srcPath, dstPath)

# Entry point
def Main(argv, argc):

# Perform a sanity check and parse the parameters
if argc < 4:
sys.exit("The function requires at least three parameters to be passed in.")

last = argc - 1
source = []
for i in range(1, last):
if not os.path.isabs(argv[i]):
source.append(os.path.abspath(argv[i]))
else:
source.append(argv[i])

if not os.path.isdir(source[i - 1]):
sys.exit("The parameters should be existing directories.")

destination = argv[last]

MergeDirectories(source, last - 1, destination)

print("Done!")

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

@@ Line 170: / Line 170: @@
 	exit(EXIT_FAILURE);
+}
 </syntaxhighlight>
 ==Esercizio 3==

ProvaPratica 2011.01.19 - Revision history

TomOgn at 11:15, 14 May 2014

TomOgn at 08:47, 14 May 2014

TomOgn: Created page with "=[http://www.cs.unibo.it/~renzo/so/pratiche/2011.01.19.pdf TESTO COMPITO]= =Esercizio 1= // Dependencies #include "../const.h" #include #i..."