Question

I am working on a mini-shell, and am trying to set the execution path dynamically.
I am using setvar() to set the PATH and when I check it with getvar() it reads the new PATH.
Here are the two things I tried to execute:
1. I change the PATH to /bin which I know contains most system functions, but no programs can work. I can also verify that the path has been set in the environment. I execute the commands using execvp()
2. I then used extern char** environ to get the environment and pass it into execvpe() but it still doesn’t work.

Answer 1

I solved this by using istringstream to manually search the PATH and then use that to execute the process:

string dir;
string path = get_var("PATH");
istringstream search(path);
while(search.good()) {
    getline(search, dir, ':');
    if(dir != "") {
        struct stat st;
        if(dir[dir.length()] != '/') dir.append("/");
        string file = dir + cmdArg[0];
        //is file in dir?
        if(stat(file.c_str(), &st) == 0) {
            execvp(file.c_str(), cmdArg);
        }
    }
}