$/*$ This still very simple ls with lstat and stat calls

for the file information in a directory.

$*/$

#include

#include

#include

#include

#include

#include

#include

#include

int

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

DIR $*$dp;

struct dirent $*$dirp;

if $($argc $!=2)\{$

fprintf$($stderr$,$ "usage: $\%$s dir$\_$name

$",$ argv$[0])$;

exit$($EXIT$\_$FAILURE$)$;

$\}$

if $(($dp $=$ opendir$($argv$[1]))==$ NULL $)\{$

fprintf$($stderr$,$ "can't open $\text{'}\%$s$\text{'}$: $\%$s

$",$ argv$[1],$ strerror$($errno$))$;

exit$($EXIT$\_$FAILURE$)$;

$\}$

if $($chdir$($argv$[1])==-1)\{$

fprintf$($stderr$,$ "can't chdir to $\text{'}\%$s$\text{'}$: $\%$s

$",$ argv$[1],$ strerror$($errno$))$;

exit$($EXIT$\_$FAILURE$)$;

$\}$

while $(($dirp $=$ readdir$($dp$))!=$ NULL $)\{$

struct stat sb;

if $($stat$($dirp$->$d$\_$name, &sb$)==-1)\{$

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

$",$ dirp$->$d$\_$name,

strerror$($errno$))$;

if $($lstat$($dirp$->$d$\_$name, &sb$)==-1)\{$

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

$",$ dirp$->$d$\_$name,

strerror$($errno$))$;

continue;

$\}$

$\}$

printf$("\%$s: $",$ dirp$->$d$\_$name$)$;

if $($S$\_$ISREG$($sb$.$st$\_$mode$))$

printf$("$regular file"$)$;

else if $($S$\_$ISDIR$($sb$.$st$\_$mode$))$

printf$("$directory$")$;

else if $($S$\_$ISCHR$($sb$.$st$\_$mode$))$

printf$("$character special"$)$;

else if $($S$\_$ISBLK$($sb$.$st$\_$mode$))$

printf$("$block special"$)$;

else if $($S$\_$ISFIFO$($sb$.$st$\_$mode$))$

printf$("$FIFO$")$;

else if $($S$\_$ISLNK$($sb$.$st$\_$mode$))$

printf$("$symbolic link"$)$;

else if $($S$\_$ISSOCK$($sb$.$st$\_$mode$))$

printf$("$socket$")$;

else

printf$("$unknown$")$;

printf$("--$ with stat

$")$;

if $($lstat$($dirp$->$d$\_$name, &sb$)==-1)\{$

fprintf$($stderr$,$"not for stat $\%$s: $\%$s

$",$ dirp$->$d$\_$name,

strerror$($errno$))$;

continue;

$\}$

printf$("\%$s: $",$ dirp$->$d$\_$name$)$;

if $($S$\_$ISREG$($sb$.$st$\_$mode$))$

printf$("$regular file"$)$;

else if $($S$\_$ISDIR$($sb$.$st$\_$mode$))$

printf$("$directory$")$;

else if $($S$\_$ISCHR$($sb$.$st$\_$mode$))$

printf$("$character special"$)$;

else if $($S$\_$ISBLK$($sb$.$st$\_$mode$))$

printf$("$block special"$)$;

else if $($S$\_$ISFIFO$($sb$.$st$\_$mode$))$

printf$("$FIFO$")$;

else if $($S$\_$ISLNK$($sb$.$st$\_$mode$))$

printf$("$symbolic link"$)$;

else if $($S$\_$ISSOCK$($sb$.$st$\_$mode$))$

printf$("$socket$")$;

else

printf$("$unknown$")$;

printf$("--$ with lstat

$")$;

$\}$

closedir$($dp$)$;

exit$($EXIT$\_$SUCCESS$)$;

$\}$

Part $1.30\%$

$($a$)$ Compile ls$1.$c program $($attached here$)$

$($b$)$ Run the program $($ls$1)$ witht the following arguments

$./$ls$1./$ ; ls $-$l

Note here that you are running the program with $./$ as an argument.

$./$ls$1/$etc $>$ out$1$a$.$txt ; tail $-30$ out$1$a$.$txt; $./$ls$1/$etc $|$ wc

$./$ls$1/$bin $>$ out$1$b$.$txt ; tail $-30$ out$1$b$.$txt; $./$ls$1/$bin $|$ wc

Note. When running the program, you may note a few warning or error messages $($to be ignored$).$

Can't stat grub$2.$cfg: Permission denied

Can't stat extlinux.conf: No such file or directory

Part $2.70\%$

$($a$)$ Modify ls$1.$c program and name it ls$2.$c

$($b$)$ Update ls$2.$c program to do:

$(1)$ count the file$-$type of each entry $($file$,$ dir, link, $...)$ and

$(2)$ print total count of each file$-$type at the end

Sample output would be:

Reading the directory: $/$etc

total count for regular file: $3($which is $2\%$ of total count$)$

total count for directory: $2($which is $1\mathrm{.}5\%$ of total count$)$

$...$

total count of the directory entries processed: $12345($which is $100\%)$

$($c$)$ Run the program with the following arguments and commands:

date; who $|$ grep $`$whoami$`$ ; w $|$ grep $`$whoami$`$ ; who $>$ out$2$who.txt

$./$ls$2./$ ; $./$ls$2./>$ out$2$a$.$txt ; tail $-30$ out$2$a$.$txt ; ls $-$l out$2$a$.$txt

$./$ls$2/$etc $>$ out$2$etc.txt ; tail $-30$ out$2$etc.txt ; wc out$2$etc.txt ; ls $-$l out$2$etc.txt

$./$ls$2/$bin $>$ out$2$bin.txt ; tail $-30$ out$2$bin.txt ; wc out$2$bin.txt ; ls $-$l out$2$bin.txt

time $./$ls$2/$etc $>$ out$3$etc.txt