Part $1$ & $2$ Consider that the system calls do not fail, function f $()$ never returns or exits, f $()$ does not execute system calls, each new process inherits exactly the way signals are handled by the parent process. Assume that process $400$ executes this program, and thereon every new process forked has its pid incremented by $1.$

Part $1(4$ pts$)$: Explain how the program works.

Part $2(3$ pts$)$: Draw the process tree in its final form, i$.$e$.,$ when all processes have reached a steady state. Solve potential race condition, assuming that at least three processes arrive at the point marked $/*$ A $*/,$ passing the read $()$ in the order of their birth. At each node of the tree process please highlight:

$($i$)$ the system call or a function where the Program Counter of the corresponding process is found, $($ii$)$ the arguments with which the function f has been called,

$($iii$)$ the program line from which the call took place.

$($iv$)$ Complete the process tree to show the inter$-$process communication using arrows and type above the arrow the value that is transferred each time.

$1$ int fd$[2]$;

$2$

$3$ void handler$($int signum$)$

$4\{$ exit$(14)$; f$(14,-14)$; $\}$

$5$

$6$ int main$($void$)$

$7\{$

$8$ int i$,$ j$,$ n;

$9$ char c$[10]$;

$10$ pid$\_$t pid$[4]$;

$11$

$12$ signal$($SIGUSR$1,$ handler$)$;

$13$

$14$ pipe$($fd$)$;

$15$ for $($i $=0$; i $<mtext\; id="EditorElement\_1047009"></mtext><mn\; id="EditorElement\_1047010">4</mn>$; i$++)\{$

$16$ pid$[$i$]=$ fork$()$;

$17$ if $($pid$[$i$]==0)\{$

$18$ n $=$ read$($fd$[0],$ c$,$ i $+2)$;

$19/*$ A $*/$

$20$ for $($j $=0$; j $$ n; j$++)\{$

$21$ pid$[$i$]=$ fork$()$;

$22$ if $($pid$[$i$]==0)$

$23$ f$($getpid$(),$ j$)$;

$24\}$

$25$ for $($j $=0$; j $$ i; j$++)$

$26$ wait$($NULL$)$;

$27$ f$($i$,10)$;

$28$ exit$(2)$;

$29\}$

$30\}$

$31$

$32$ kill$($pid$[$i $-2],$ SIGUSR$1)$;

$33$ for $($i $=0$; i $<mtext\; id="EditorElement\_1047388"></mtext><mn\; id="EditorElement\_1047389">4</mn>$; i$++)\{$

$34$ wait$($&n$)$;

$35$ write$($fd$[1],$ c$,$ WEXITSTATUS$($n$))$;

$36\}$

$37$ f$($i$,-6)$;

$38$ return $0$;

$39\}$