9-4

#include <unistd.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/stat.h>
#include <limits.h>

enum
{
    BASE = 10,
    ENV = 5
};

char*
mkpath(char *tmp)
{
    char *path = (char*)malloc(sizeof(*path) * PATH_MAX);
    sprintf(path, "%s/prog%d.py", tmp, getpid());
    return path;
}

int
main(int argc, char *argv[])
{
    setbuf(stdout, NULL);
    char *env = getenv("XDG_RUNTIME_DIR");
    if (!env) {
        env = getenv("TMPDIR");
        if (!env) {
            env = (char*)malloc(ENV);
            sprintf(env, "/tmp");
        }
    }
    printf("%s\n", env);
    char *tmpname = mkpath(env);
    printf("%s\n", tmpname);
    FILE *fl = fopen(tmpname, "w");
    chmod(tmpname, 0700);
    fprintf(fl, "#!usr/bin/env python\nprint(");
    int i = 1;
    while (i < argc) {
        fprintf(fl, "%s * ", argv[i]);
        i++;
    }
    fprintf(fl, "1)\n");
    fclose(fl);
    char *path = (char*)malloc(sizeof(*path) * (PATH_MAX * 2 + BASE * 2));
    sprintf(path, "%s && rm %s", tmpname, tmpname);execl("bin/sh", "sh", "-c", path, NULL);
    printf("%s\n", path);
    execl("bin/sh", "sh", "-c", path, NULL);
    return 1;
}