ProvaPratica 2013.02.15 - Revision history

Edu san at 01:08, 16 December 2013

2013-12-16T01:08:22Z

Edu san at 03:31, 12 December 2013

2013-12-12T03:31:18Z

Edu san at 03:28, 12 December 2013

2013-12-12T03:28:05Z

Edu san at 02:24, 12 December 2013

2013-12-12T02:24:24Z

Edu san at 02:21, 12 December 2013

2013-12-12T02:21:17Z

Edu san at 02:20, 12 December 2013

2013-12-12T02:20:25Z

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

2013-12-12T02:17:17Z

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..."

New page

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

← Older revision		Revision as of 01:08, 16 December 2013
Line 48:		Line 48:
	-Eduardo<br>		-Eduardo<br>
	edit: avevo dimenticato un pezzo.		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

@@ Line 46: / Line 46: @@
+}
 </syntaxhighlight>
--Eduardo
+-Eduardo<br>
 edit: avevo dimenticato un pezzo.

@@ Line 36: / Line 36: @@
    for(i=0; i<items; i++){
-    if((pid=fork())) ; //do nothing
+   if(access(entry[i]->d_name, X_OK)==0){  //Check execution rights
-    else
+     if((pid=fork())) ; //do nothing
-      execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
+     else
+   }
@@ Line 45: / Line 47: @@
 </syntaxhighlight>
 -Eduardo

@@ Line 7: / Line 7: @@
   *  Eduardo Santarelli
   */
 #include <dirent.h>
 #include <string.h>
 #include <unistd.h>
 /*  Selector function, called by scandir. Only selects
@@ Line 44: / Line 41: @@
+   }
-   return EXIT_SUCCESS;
+   return 0;
+}
 </syntaxhighlight>
 -Eduardo

@@ Line 2: / Line 2: @@
 <syntaxhighlight lang="C">
 /*
-  *	Prova Pratica di Lab SO 2013.02.15
+  *  Prova Pratica di Lab SO 2013.02.15
-  *	http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf
+  *  http://www.cs.unibo.it/~renzo/so/pratiche/2013.02.15.pdf
-  *	Es.1
+  *  Es.1
-  *	Eduardo Santarelli
+  *  Eduardo Santarelli
   */
 #include <stdio.h>
@@ Line 14: / Line 14: @@
 #include <stdlib.h>
-/*	Selector function, called by scandir. Only selects
+/*  Selector function, called by scandir. Only selects
-  *	palindrome file names. Discards implied directories.
+  *  palindrome file names. Discards implied directories.
   */
 int dir_is_pal(const struct dirent* dir){
    int i,j;
-	//discard implied dirs
+  //discard implied dirs
-	if(dir->d_name[0]=='.' && strlen(dir->d_name)<3)
+  if(dir->d_name[0]=='.' && strlen(dir->d_name)<3)
-		return 0;
+    return 0;
    for(i=0, j=strlen(dir->d_name)-1; i<j; i++, j--)
@@ Line 32: / Line 32: @@
 int main(int argc, char** argv){
-	struct dirent** entry;
+  struct dirent** entry;
-	int i, items;
+  int i, items;
-	pid_t pid;
+  pid_t pid;
-	items=scandir("./", &entry, dir_is_pal, alphasort);
+  items=scandir("./", &entry, dir_is_pal, alphasort);
-	for(i=0; i<items; i++){
+  for(i=0; i<items; i++){
-		int status;
+    int status;
-	  if((pid=fork())) ; //do nothing
+    if((pid=fork())) ; //do nothing
-  	else
+    else
-		execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
+      execl(entry[i]->d_name, entry[i]->d_name, (char*)0);
-−
+  }
-	return 0;
+  return EXIT_SUCCESS;
+}
 </syntaxhighlight>
 -Eduardo