I try to make my code work under chroot('/root/test1'), but it doesn't work correctly.
But when I delete chroot('/root/test1'), and modify execl("/test2", "test2", NULL) to execl("/root/test1/test2", "test2", NULL), it will work very well as expected. Why is that?
In addition, I would like to ask that if I set fp redirect to stdin, and then use execl function to work another program, the child program will get input at fp whether or not?
The file in '/root/test1/':
test2
test2.cpp
test3
test3.cpp
The value return by execl funtion is -1 and errno is 2.
test3.cpp
int main() {
FILE *fp;
errno = 0;
fp = fopen("log.txt", "r");
dup2(fileno(fp), fileno(stdin));
cout << chdir("/root/test1") << endl;
cout << chroot("/root/test1") << endl;
DIR *dir = opendir("/");
dirent *list;
while ((list = readdir(dir)) != NULL) {
cout << list -> d_name << " ";
}
cout << endl;
closedir(dir);
errno = 0;
cout << execl("/test2", "test2", NULL) << endl;
cout << errno << endl;
cout << strerror(errno) << endl;
return 0;
}
test2.cpp
#include <cstdio>
#include <iostream>
using namespace std;
int main() {
int a,b;
cin >> a;
scanf("%d",&b);
cout << a+b << endl;
printf("%d",a+b);
return 0;
}
log.txt
111 222
output*
0
0
. test3.cpp test3 .. test2 test2.cpp log.txt
-1
2
No such file or directory
