Consider the following programs
exec1.c
#include <unistd.h>
#include <stdio.h>
int main() {
    execl("./exec2", "./exec2", NULL);
}
exec2.c
#include <unistd.h>
#include <stdio.h>
int main() {
    execl("/bin/ls", "/bin/ls", NULL);
   printf("hello\n");
}
Compiled as
cc     exec1.c   -o exec1
cc     exec2.c   -o exec2
And run as
$ ./exec1
Explain the output of the above command (./exec1)
Assume that /bin/ls , i.e. the 'ls' program exists.

Question

Consider the following programs

exec1.c

#include <unistd.h>

#include <stdio.h>

int main() {

execl("./exec2", "./exec2", NULL);

}

exec2.c

#include <unistd.h>

#include <stdio.h>

int main() {

execl("/bin/ls", "/bin/ls", NULL);

printf("hello\n");

}

Compiled as

cc exec1.c -o exec1

cc exec2.c -o exec2

And run as

$ ./exec1

Explain the output of the above command (./exec1)

Assume that /bin/ls , i.e. the 'ls' program exists.

Answer

Execution fails as one exec can't invoke another exec

Answer

"ls" runs on current directory

Answer

Program prints hello

Answer

Execution fails as the call to execl() in exec1 fails

Answer

Execution fails as the call to execl() in exec2 fails

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