gistfile1.txt

/* for execvpe(...): */
#define _GNU_SOURCE

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>

int main(int argc, char **argv) {
        int rc, i;
        char **cmd, **envp;

        envp = argv+1;
        cmd  = NULL;
        for (i = 1; i < argc; i++) {
                if (strcmp(argv[i], "--") == 0) {
                        argv[i] = NULL;
                        cmd = argv+i+1;
                        break;
                }
        }
        if (!cmd || !*cmd) {
                fprintf(stderr, "USAGE: %s ENV=VALUE -- command --to --run --with /arg/u/ments\n", argv[0]);
                return 1;
        }

        fprintf(stderr, "setting up execution environment:\n");
        for (i = 0; envp[i]; i++) {
                fprintf(stderr, "  %s\n", envp[i]);
        }
        fprintf(stderr, "running command %s with arguments:\n", cmd[0]);
        for (i = 1; cmd[i]; i++) {
                fprintf(stderr, "  [%d]: '%s'\n", i-1, cmd[i]);
        }

        for (;;) {
                pid_t pid;
                int status;

                pid = fork();
                if (pid < 0) continue;

                if (pid == 0) {
                        execvpe(cmd[0], cmd, envp);
                        continue;
                }

                for (;;) {
                        rc = waitpid(pid, &status, 0);
                        if (rc == -1 && errno == EINTR) continue;
                        if (rc == -1 && errno == ECHILD) break;
                        break;
                }
        }
        return 0;
}