#include

#include

#include

#define MFILE $10$

void cmp$($const char $*,$ time$\_$t$)$;

struct stat sb;

int main$($int argc, char $**$argv$)$

$\{$

int j;

time$\_$t last$\_$time$[$MFILE$+1]$;

if $($argc $<2)\{$

fprintf$($stderr$,$ "usage: lookout filename $...$

$")$;

exit$(1)$;

$\}$

if $(--$argc $>$ MFILE $)\{$

fprintf$($stderr$,$ "lookout: too many filenames

$")$;

exit$(1)$;

$\}$

$/*$Initialization$*/$

for$($j $=1,$ j $<=$ argc; j$++$;$)$

if$($stat$($argv$($j$),$ &sb$)==-1)$

$\{$

fprintf$($stderr$,$ "lookout: couldn't stat $\%$s

$",$ argv$($j$))$;

exit$(1)$;

$\}$

last$\_$time$($j$)=$ sb$.$st$\_$mtime;

$/*$loop until file changes$*/$

for$($;;$)$

$\{$

for$($j $=1$; j $<=$ argc; j$++)$

cmp$($argv$($j$),$ last$\_$time$($j$))$;

$/*$rest for $60$ SECONDS "sleep" is a standard UNIX library routine $*/$

sleep$(60)$;

$\}$

$\}$

void cmp$($const char $*$name$,$ time$\_$t last$)$

$\{$

$/*$as long as statics about the file can be read check the modification time $*/$

if$($stat$($name$,$ &sb$)==-1||$ sb$.$st$\_$mtime $!=$ last$)$

$\{$

fprintf$($stderr$,$ "lookout: $\%$s changed

$",$ name$)$;

exit$(0)$;

$\}$

$\}$

Modify the template program, $$lookout$.$c$$ on p$.56-57$ with the following additional capabilities

a$.$ Repeat the following steps $5$ times $($this means, after $5$ seconds of running, your program should terminate without printing anything if there is no change detected.$)$

i$.$ Wait $1$ seconds using $$sleep$(1)$ call

ii$.$ Call $$stat$$ system call to extract the file attributes against given files in command line arguments $($the lookout.c program in p$.56$ may accept up to $10$ files$).$ Your program should be able to accept up to $10$ files for monitoring.

iii. You program should check any changes in any of the following attributes:

$1.$ st$\_$mode

$2.$ st$\_$nlink

$3.$ st$\_$size

$4.$ st$\_$atime

$5.$ st$\_$mtime

iv$.$ When your program detects any changes, your program should immediately print out number codes given below and EXIT!

$1.$ Change of st$\_$mode $$ print $1$

$2.$ Change of st$\_$nlink $$ print $2$

$3.$ Change of st$\_$size $$ print $3$

$4.$ Change of st$\_$atime $$ print $4$

$5.$ Change of st$\_$mtime $$ print $5$

$6.$ Once printing is done, your program should terminate. Make sure your condition checking and printing should be done in the above order! Make sure you print number codes in one line $($without any newline character$)!$

$7.$ Example output when you change the file contents $($e$.$g$,$ using vi$)$: $345$

$8.$ If your program prints more than one number code, then place spaces in between.