/* **********************************************************
 * Copyright (c) 2015 Google, Inc.  All rights reserved.
 * **********************************************************/

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#include "tools.h"
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>

/* Tests i#907: /proc/self/exe transparency with early injection. */

int
main(int argc, char *argv[])
{
    /* Test reading the symlink via readlink */
    char proc[64];
    char buf[512];
    ssize_t res;
    snprintf(proc, BUFFER_SIZE_ELEMENTS(proc), "/proc/%d/exe", getpid());
    NULL_TERMINATE_BUFFER(proc);
    res = readlink(proc, buf, BUFFER_SIZE_ELEMENTS(buf));
    NULL_TERMINATE_BUFFER(buf);
    if (res > 0 && strrchr(buf, '/') != NULL)
        print("/proc/pid/exe points to %s\n", strrchr(buf, '/') + 1);
    else {
        perror("readlink failed");
        return 1;
    }
    /* XXX: another good test would be to make a thread and use /proc/tid/exe */

    /* Test executing the symlink via execve.
     * We invoked ourselves initially with an arg, to avoid repeated execs.
     */
    if (argc > 1) {
        pid_t child = fork();
        if (child < 0) {
            perror("fork failed");
        } else if (child > 0) {
            pid_t result = waitpid(child, NULL, 0);
            assert(result == child);
            print("child has exited\n");
        } else {
            const char *arg[2] = { proc, NULL };
            /* Update for child's pid */
            snprintf(proc, BUFFER_SIZE_ELEMENTS(proc), "/proc/%d/exe", getpid());
            NULL_TERMINATE_BUFFER(proc);
            res = execve(proc, (char **)arg, NULL /*env*/);
            if (res < 0)
                perror("execve failed");
        }
    }
    return 0;
}