sudo-baron-samedit-1.cpp

//sudo_1.8.23-9.el7/plugins/sudoers/logging.c
/*
 * Send a message to MAILTO user
 */
static bool
send_mail(const char *fmt, ...)
{
    ...
    /* If mailer is disabled just return. */
[0] if (!def_mailerpath || !def_mailto)
        debug_return_bool(true);

[1] /* Make sure the mailer exists and is a regular file. */
    if (stat(def_mailerpath, &sb) != 0 || !S_ISREG(sb.st_mode))
        debug_return_bool(false);

[2] ...

    switch (pid = sudo_debug_fork()) {
        case -1:
            /* Error. */
            ...
        case 0:
            {
                char *last, *argv[MAX_MAILFLAGS + 1];
[3]             char *mflags, *mpath = def_mailerpath;
                int i;

                ...
                if ((argv[0] = strrchr(mpath, '/')))
                    argv[0]++;
                else
                    argv[0] = mpath;

                i = 1;
                ...
                argv[i] = NULL;

                /*
                 * Depending on the config, either run the mailer as root
                 * (so user cannot kill it) or as the user (for the paranoid).
                 */
#ifndef NO_ROOT_MAILER
[4]             (void) set_perms(PERM_ROOT);
                execve(mpath, argv, root_envp);
#else
[5]             (void) set_perms(PERM_FULL_USER);
                execv(mpath, argv);
#endif /* NO_ROOT_MAILER */
                ...
                _exit(127);
            }
            break;
    }
    ...