For the entire month of January, we covered the idea of using the manual pages efficiently by using more includes and understanding the unistd.h include.

Other cool new features that we have learned by using the Linux Manual pages on C and other cool C functions was the stat struct and I believe the group struct.

The stat struct contains many useful functions such as it helped in the chmod project in setting file permissions. In order to setup the stat struct and obtain all it's members, an allocation must take place in order for it to properly work. To do so simply state,

struct stat *name = (struct stat*) malloc(sizeof(struct stat));

WALLA! You have obtained all of stat's secret's including the st_mode which helps set file permissions, for example

name → st_mode = 0777;

int chmod(FILE_NAME(I used argv[1], name → st_mode);

BAM! Permissions have been set.

Inside group it gets a little… Strange.

Using name's st_gid, we can set that to groups, another struct so malloc up bois.

groups = getgrgid(name → st_gid); Then now you have access to usernames and unsecured passwords that someone hasn't taken care of, scary stuff.

Overall we have covered

cat.c ls.c who.c and our very own chmod.c for those who did it and attempted it. Other cool features will be listed later inside the blog.

Currently in March, we have playing more with primes and utilizing primefork, primethread, and currently we are playing with different types of network interfaces.

PrimeFork.c

Contain(s) Primebrutefork.c Primesqrtfork.c

Primebrute utilizes our brute force method of accessing each individual number from 2 to the max number specified for that range.

Primesqrt utilizes our square root approach and lowers the number it has to search for in order to determine if it's prime.

The fork uses a process of quite literally multiplying the program itself but then the program has a check statement to make sure that the program multiplied is either the true parent or a child/forked process.

PrimeThread Contain(s) Primebrutethread.c Primesqrtthread.c

Primebrutethread again uses the brute force method but instead of multiplying the process and causing a ton of memory over head, instead we actually just enact a small void statement that loops until it's finished.

Like our friend fork, the thread divides up the number by using the threads given to it but like I said, it doesn't multiply the program. Instead of cloning the program, it runs a small statement that the pthread asks for.

Basically Thread → void statement to run.

The Primebrutethread does our traditional brute force method but with divided numbers and smaller memory allocation.

Primesqrthread.c does the same thing as the Primesqrtfork.c but with less memory overhead.

Sockets Next we have been playing with sockets and created two network like programs.

The first is timeserv.c that when you use your client/telnet into the timeserv port that's reserved, it will tell you the time and disconnect you from the server.

The second is ipaddr which returns to the user different network interfaces and the ip associated with them.