qemu

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/*
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 * systemd socket activation support
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 *
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 * Copyright 2017 Red Hat, Inc. and/or its affiliates
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 *
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 * Authors:
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 *  Richard W.M. Jones <rjones@redhat.com>
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or later.
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 * See the COPYING file in the top-level directory.
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 */
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#include "qemu/osdep.h"
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#include "qemu/systemd.h"
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#include "qemu/cutils.h"
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#include "qemu/error-report.h"
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#ifndef _WIN32
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unsigned int check_socket_activation(void)
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{
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    const char *s;
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    unsigned long pid;
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    unsigned long nr_fds;
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    unsigned int i;
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    int fd;
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    int f;
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    int err;
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    s = getenv("LISTEN_PID");
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    if (s == NULL) {
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        return 0;
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    }
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    err = qemu_strtoul(s, NULL, 10, &pid);
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    if (err) {
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        return 0;
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    }
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    if (pid != getpid()) {
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        return 0;
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    }
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    s = getenv("LISTEN_FDS");
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    if (s == NULL) {
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        return 0;
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    }
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    err = qemu_strtoul(s, NULL, 10, &nr_fds);
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    if (err) {
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        return 0;
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    }
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    assert(nr_fds <= UINT_MAX);
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    /* So these are not passed to any child processes we might start. */
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    unsetenv("LISTEN_FDS");
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    unsetenv("LISTEN_PID");
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    unsetenv("LISTEN_FDNAMES");
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    /* So the file descriptors don't leak into child processes. */
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    for (i = 0; i < nr_fds; ++i) {
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        fd = FIRST_SOCKET_ACTIVATION_FD + i;
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        f = fcntl(fd, F_GETFD);
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        if (f == -1 || fcntl(fd, F_SETFD, f | FD_CLOEXEC) == -1) {
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            /* If we cannot set FD_CLOEXEC then it probably means the file
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             * descriptor is invalid, so socket activation has gone wrong
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             * and we should exit.
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             */
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            error_report("Socket activation failed: "
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                         "invalid file descriptor fd = %d: %s",
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                         fd, g_strerror(errno));
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            exit(EXIT_FAILURE);
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        }
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    }
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    return (unsigned int) nr_fds;
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}
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#else /* !_WIN32 */
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unsigned int check_socket_activation(void)
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{
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    return 0;
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}
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#endif
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