edash.c

edash.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

char *findbin(char *b);

int main(int argc, char **argv, char **envp)
{
    char *s = "dash";
    char *e = "-E";
    char *a[argc + 2];
    char *f = findbin(s);
    a[0] = f;
    a[1] = e;
    // https://wiki.gentoo.org/wiki/Embedded_Handbook/General/Compiling_with_qemu_user_chroot
    if(argc > 1){
        memcpy(&a[2], &argv[1], sizeof(*argv) * (argc - 1));
    }
    a[argc + 1] = NULL;
    return(execve(f, a, envp));
}

char *findbin(char *s)
{
    char *p = getenv("PATH");
    char *a = "/";
    char *t = strtok(p, ":");
    while(t != NULL){
        char *e;
        e = malloc(strlen(t) + strlen(a) + strlen(s) + 1);
        sprintf(e, "%s%s%s", t, a, s);
        if(access(e, X_OK) != -1){
            return(e);
        }
        free(e);
        t = strtok(NULL, ":");
    }
    return(NULL);
}