Re: [PATCH] error handling: Use TFR() macro where applicable

[Nikita Ivanov <nivanov@cloudlinux.com>]

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Hi! Are there any updates? I have not received any comments since the last
email.

On Mon, Aug 8, 2022 at 9:03 PM Nikita Ivanov <nivanov@cloudlinux.com> wrote:

> And summing up the discussion about TEMP_FAILURE_RETRY() usage examples,
> I've come up with a new patch for TFR() to TEMP_FAILURE_RETRY()
> refactoring. I've decided to stick to expression realisation.
>
> From 94217dfacf12b3211cfab6e19d750e57d679e851 Mon Sep 17 00:00:00 2001
> From: Nikita Ivanov <nivanov@cloudlinux.com>
> Date: Mon, 8 Aug 2022 20:43:45 +0300
> Subject: [PATCH] Refactoring: rename TFR() to TEMP_FAILURE_RETRY()
>
> glibc's unistd.h header provides the same macro with the
> subtle difference in type casting. Adjust macro name to the
> common standard and define conditionally.
>
> Signed-off-by: Nikita Ivanov <nivanov@cloudlinux.com>
> ---
>  block/file-posix.c        | 14 +++++++-------
>  chardev/char-fd.c         |  2 +-
>  chardev/char-pipe.c       | 12 +++++++++---
>  chardev/char-pty.c        |  2 +-
>  hw/9pfs/9p-local.c        |  6 ++++--
>  include/qemu/osdep.h      | 11 +++++++++--
>  net/l2tpv3.c              |  8 +++++---
>  net/socket.c              |  4 ++--
>  net/tap-bsd.c             |  6 +++---
>  net/tap-linux.c           |  2 +-
>  net/tap-solaris.c         |  8 ++++----
>  net/tap.c                 | 10 ++++++----
>  os-posix.c                |  2 +-
>  qga/commands-posix.c      |  2 +-
>  semihosting/syscalls.c    |  2 +-
>  tests/qtest/libqtest.c    | 10 +++++-----
>  tests/vhost-user-bridge.c |  4 +++-
>  util/main-loop.c          |  2 +-
>  util/osdep.c              |  2 +-
>  util/vfio-helpers.c       |  8 ++++----
>  20 files changed, 69 insertions(+), 48 deletions(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 0786cb76f9..28ce649ab9 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1238,8 +1238,8 @@ static int hdev_get_max_segments(int fd, struct stat
> *st)
>          ret = -errno;
>          goto out;
>      }
> -    TFR(
> -        ret = read(sysfd, buf, sizeof(buf) - 1)
> +    ret = TEMP_FAILURE_RETRY(
> +        read(sysfd, buf, sizeof(buf) - 1)
>      );
>      if (ret < 0) {
>          ret = -errno;
> @@ -1388,8 +1388,8 @@ static int handle_aiocb_ioctl(void *opaque)
>      RawPosixAIOData *aiocb = opaque;
>      int ret;
>
> -    TFR(
> -        ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf)
> +    ret = TEMP_FAILURE_RETRY(
> +        ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd, aiocb->ioctl.buf)
>      );
>      if (ret == -1) {
>          return -errno;
> @@ -1472,8 +1472,8 @@ static ssize_t
> handle_aiocb_rw_vector(RawPosixAIOData *aiocb)
>  {
>      ssize_t len;
>
> -    TFR(
> -        len = (aiocb->aio_type & QEMU_AIO_WRITE) ?
> +    len = TEMP_FAILURE_RETRY(
> +        (aiocb->aio_type & QEMU_AIO_WRITE) ?
>              qemu_pwritev(aiocb->aio_fildes,
>                             aiocb->io.iov,
>                             aiocb->io.niov,
> @@ -1907,7 +1907,7 @@ static int allocate_first_block(int fd, size_t
> max_size)
>      buf = qemu_memalign(max_align, write_size);
>      memset(buf, 0, write_size);
>
> -    TFR(n = pwrite(fd, buf, write_size, 0));
> +    n = TEMP_FAILURE_RETRY(pwrite(fd, buf, write_size, 0));
>
>      ret = (n == -1) ? -errno : 0;
>
> diff --git a/chardev/char-fd.c b/chardev/char-fd.c
> index cf78454841..1250a63236 100644
> --- a/chardev/char-fd.c
> +++ b/chardev/char-fd.c
> @@ -198,7 +198,7 @@ int qmp_chardev_open_file_source(char *src, int flags,
> Error **errp)
>  {
>      int fd = -1;
>
> -    TFR(fd = qemu_open_old(src, flags, 0666));
> +    fd = TEMP_FAILURE_RETRY(qemu_open_old(src, flags, 0666));
>      if (fd == -1) {
>          error_setg_file_open(errp, errno, src);
>      }
> diff --git a/chardev/char-pipe.c b/chardev/char-pipe.c
> index 66d3b85091..a59a055c87 100644
> --- a/chardev/char-pipe.c
> +++ b/chardev/char-pipe.c
> @@ -131,8 +131,12 @@ static void qemu_chr_open_pipe(Chardev *chr,
>
>      filename_in = g_strdup_printf("%s.in", filename);
>      filename_out = g_strdup_printf("%s.out", filename);
> -    TFR(fd_in = qemu_open_old(filename_in, O_RDWR | O_BINARY));
> -    TFR(fd_out = qemu_open_old(filename_out, O_RDWR | O_BINARY));
> +    fd_in = TEMP_FAILURE_RETRY(
> +        qemu_open_old(filename_in, O_RDWR | O_BINARY)
> +    );
> +    fd_out = TEMP_FAILURE_RETRY(
> +        qemu_open_old(filename_out, O_RDWR | O_BINARY)
> +    );
>      g_free(filename_in);
>      g_free(filename_out);
>      if (fd_in < 0 || fd_out < 0) {
> @@ -142,7 +146,9 @@ static void qemu_chr_open_pipe(Chardev *chr,
>          if (fd_out >= 0) {
>              close(fd_out);
>          }
> -        TFR(fd_in = fd_out = qemu_open_old(filename, O_RDWR | O_BINARY));
> +        fd_in = fd_out = TEMP_FAILURE_RETRY(
> +            qemu_open_old(filename, O_RDWR | O_BINARY)
> +        );
>          if (fd_in < 0) {
>              error_setg_file_open(errp, errno, filename);
>              return;
> diff --git a/chardev/char-pty.c b/chardev/char-pty.c
> index b2f490bacf..913a98250b 100644
> --- a/chardev/char-pty.c
> +++ b/chardev/char-pty.c
> @@ -93,7 +93,7 @@ static void pty_chr_update_read_handler(Chardev *chr)
>      pfd.fd = fioc->fd;
>      pfd.events = G_IO_OUT;
>      pfd.revents = 0;
> -    TFR(rc = g_poll(&pfd, 1, 0));
> +    rc = TEMP_FAILURE_RETRY(g_poll(&pfd, 1, 0));
>      assert(rc >= 0);
>
>      if (pfd.revents & G_IO_HUP) {
> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> index c90ab947ba..6a3b4fac4a 100644
> --- a/hw/9pfs/9p-local.c
> +++ b/hw/9pfs/9p-local.c
> @@ -470,7 +470,7 @@ static ssize_t local_readlink(FsContext *fs_ctx,
> V9fsPath *fs_path,
>          if (fd == -1) {
>              return -1;
>          }
> -        TFR(tsize = read(fd, (void *)buf, bufsz));
> +        tsize = TEMP_FAILURE_RETRY(read(fd, (void *)buf, bufsz));
>          close_preserve_errno(fd);
>      } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
>                 (fs_ctx->export_flags & V9FS_SM_NONE)) {
> @@ -906,7 +906,9 @@ static int local_symlink(FsContext *fs_ctx, const char
> *oldpath,
>          }
>          /* Write the oldpath (target) to the file. */
>          oldpath_size = strlen(oldpath);
> -        TFR(write_size = write(fd, (void *)oldpath, oldpath_size));
> +        write_size = TEMP_FAILURE_RETRY(
> +            write(fd, (void *)oldpath, oldpath_size)
> +        );
>          close_preserve_errno(fd);
>
>          if (write_size != oldpath_size) {
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index b1c161c035..6cd0de8e38 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -242,8 +242,15 @@ void QEMU_ERROR("code path is reachable")
>  #if !defined(ESHUTDOWN)
>  #define ESHUTDOWN 4099
>  #endif
> -
> -#define TFR(expr) do { if ((expr) != -1) break; } while (errno == EINTR)
> +#if !defined(TEMP_FAILURE_RETRY)
> +#define TEMP_FAILURE_RETRY(expr) \
> +    (__extension__                                          \
> +        ({ long int __result;                               \
> +           do {                                             \
> +                __result = (long int) (expression);         \
> +           } while (__result == -1L && errno == EINTR);     \
> +           __result; }))
> +#endif
>
>  /* time_t may be either 32 or 64 bits depending on the host OS, and
>   * can be either signed or unsigned, so we can't just hardcode a
> diff --git a/net/l2tpv3.c b/net/l2tpv3.c
> index adfdbdb84c..cbde9332fe 100644
> --- a/net/l2tpv3.c
> +++ b/net/l2tpv3.c
> @@ -240,7 +240,7 @@ static ssize_t
> net_l2tpv3_receive_dgram_iov(NetClientState *nc,
>      message.msg_control = NULL;
>      message.msg_controllen = 0;
>      message.msg_flags = 0;
> -    TFR(ret = sendmsg(s->fd, &message, 0));
> +    ret = TEMP_FAILURE_RETRY(sendmsg(s->fd, &message, 0));
>      if (ret > 0) {
>          ret -= s->offset;
>      } else if (ret == 0) {
> @@ -283,7 +283,7 @@ static ssize_t net_l2tpv3_receive_dgram(NetClientState
> *nc,
>      message.msg_control = NULL;
>      message.msg_controllen = 0;
>      message.msg_flags = 0;
> -    TFR(ret = sendmsg(s->fd, &message, 0));
> +    ret = TEMP_FAILURE_RETRY(sendmsg(s->fd, &message, 0));
>      if (ret > 0) {
>          ret -= s->offset;
>      } else if (ret == 0) {
> @@ -430,7 +430,9 @@ static void net_l2tpv3_send(void *opaque)
>
>      msgvec = s->msgvec + s->queue_head;
>      if (target_count > 0) {
> -        TFR(count = recvmmsg(s->fd, msgvec, target_count, MSG_DONTWAIT,
> NULL));
> +        count = TEMP_FAILURE_RETRY(
> +            recvmmsg(s->fd, msgvec, target_count, MSG_DONTWAIT, NULL)
> +        );
>          if (count < 0) {
>              /* Recv error - we still need to flush packets here,
>               * (re)set queue head to current position
> diff --git a/net/socket.c b/net/socket.c
> index a3397660c2..cfb893b183 100644
> --- a/net/socket.c
> +++ b/net/socket.c
> @@ -117,8 +117,8 @@ static ssize_t net_socket_receive_dgram(NetClientState
> *nc, const uint8_t *buf,
>      NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
>      ssize_t ret;
>
> -    TFR(
> -        ret = s->dgram_dst.sin_family != AF_UNIX ?
> +    ret = TEMP_FAILURE_RETRY(
> +        s->dgram_dst.sin_family != AF_UNIX ?
>              sendto(s->fd, buf, size, 0,
>                       (struct sockaddr *)&s->dgram_dst,
>                       sizeof(s->dgram_dst)) :
> diff --git a/net/tap-bsd.c b/net/tap-bsd.c
> index 005ce05c6e..720090244e 100644
> --- a/net/tap-bsd.c
> +++ b/net/tap-bsd.c
> @@ -56,7 +56,7 @@ int tap_open(char *ifname, int ifname_size, int
> *vnet_hdr,
>          } else {
>              snprintf(dname, sizeof dname, "/dev/tap%d", i);
>          }
> -        TFR(fd = open(dname, O_RDWR));
> +        fd = TEMP_FAILURE_RETRY(open(dname, O_RDWR));
>          if (fd >= 0) {
>              break;
>          }
> @@ -111,7 +111,7 @@ static int tap_open_clone(char *ifname, int
> ifname_size, Error **errp)
>      int fd, s, ret;
>      struct ifreq ifr;
>
> -    TFR(fd = open(PATH_NET_TAP, O_RDWR));
> +    fd = TEMP_FAILURE_RETRY(open(PATH_NET_TAP, O_RDWR));
>      if (fd < 0) {
>          error_setg_errno(errp, errno, "could not open %s", PATH_NET_TAP);
>          return -1;
> @@ -159,7 +159,7 @@ int tap_open(char *ifname, int ifname_size, int
> *vnet_hdr,
>      if (ifname[0] != '\0') {
>          char dname[100];
>          snprintf(dname, sizeof dname, "/dev/%s", ifname);
> -        TFR(fd = open(dname, O_RDWR));
> +        fd = TEMP_FAILURE_RETRY(open(dname, O_RDWR));
>          if (fd < 0 && errno != ENOENT) {
>              error_setg_errno(errp, errno, "could not open %s", dname);
>              return -1;
> diff --git a/net/tap-linux.c b/net/tap-linux.c
> index 304ff45071..bf3ce44329 100644
> --- a/net/tap-linux.c
> +++ b/net/tap-linux.c
> @@ -45,7 +45,7 @@ int tap_open(char *ifname, int ifname_size, int
> *vnet_hdr,
>      int len = sizeof(struct virtio_net_hdr);
>      unsigned int features;
>
> -    TFR(fd = open(PATH_NET_TUN, O_RDWR));
> +    fd = TEMP_FAILURE_RETRY(open(PATH_NET_TUN, O_RDWR));
>      if (fd < 0) {
>          error_setg_errno(errp, errno, "could not open %s", PATH_NET_TUN);
>          return -1;
> diff --git a/net/tap-solaris.c b/net/tap-solaris.c
> index a44f8805c2..73e0e9f196 100644
> --- a/net/tap-solaris.c
> +++ b/net/tap-solaris.c
> @@ -84,13 +84,13 @@ static int tap_alloc(char *dev, size_t dev_size, Error
> **errp)
>      if( ip_fd )
>         close(ip_fd);
>
> -    TFR(ip_fd = open("/dev/udp", O_RDWR, 0));
> +    ip_fd = TEMP_FAILURE_RETRY(open("/dev/udp", O_RDWR, 0));
>      if (ip_fd < 0) {
>          error_setg(errp, "Can't open /dev/ip (actually /dev/udp)");
>          return -1;
>      }
>
> -    TFR(tap_fd = open("/dev/tap", O_RDWR, 0));
> +    tap_fd = TEMP_FAILURE_RETRY(open("/dev/tap", O_RDWR, 0));
>      if (tap_fd < 0) {
>          error_setg(errp, "Can't open /dev/tap");
>          return -1;
> @@ -104,7 +104,7 @@ static int tap_alloc(char *dev, size_t dev_size, Error
> **errp)
>      if ((ppa = ioctl (tap_fd, I_STR, &strioc_ppa)) < 0)
>          error_report("Can't assign new interface");
>
> -    TFR(if_fd = open("/dev/tap", O_RDWR, 0));
> +    if_fd = TEMP_FAILURE_RETRY(open("/dev/tap", O_RDWR, 0));
>      if (if_fd < 0) {
>          error_setg(errp, "Can't open /dev/tap (2)");
>          return -1;
> @@ -137,7 +137,7 @@ static int tap_alloc(char *dev, size_t dev_size, Error
> **errp)
>      if (ioctl (ip_fd, I_PUSH, "arp") < 0)
>          error_report("Can't push ARP module (3)");
>      /* Open arp_fd */
> -    TFR(arp_fd = open ("/dev/tap", O_RDWR, 0));
> +    arp_fd = TEMP_FAILURE_RETRY(open("/dev/tap", O_RDWR, 0));
>      if (arp_fd < 0)
>          error_report("Can't open %s", "/dev/tap");
>
> diff --git a/net/tap.c b/net/tap.c
> index b047eca8b5..dfd220a184 100644
> --- a/net/tap.c
> +++ b/net/tap.c
> @@ -102,7 +102,7 @@ static ssize_t tap_write_packet(TAPState *s, const
> struct iovec *iov, int iovcnt
>  {
>      ssize_t len;
>
> -    TFR(len = writev(s->fd, iov, iovcnt));
> +    len = TEMP_FAILURE_RETRY(writev(s->fd, iov, iovcnt));
>
>      if (len == -1 && errno == EAGAIN) {
>          tap_write_poll(s, true);
> @@ -575,7 +575,7 @@ static int net_bridge_run_helper(const char *helper,
> const char *bridge,
>
>          close(sv[1]);
>
> -        TFR(fd = recv_fd(sv[0]));
> +        fd = TEMP_FAILURE_RETRY(recv_fd(sv[0]));
>          saved_errno = errno;
>
>          close(sv[0]);
> @@ -647,8 +647,10 @@ static int net_tap_init(const NetdevTapOptions *tap,
> int *vnet_hdr,
>          vnet_hdr_required = 0;
>      }
>
> -    TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
> -                      mq_required, errp));
> +    fd = TEMP_FAILURE_RETRY(
> +        tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
> +                      mq_required, errp)
> +    );
>      if (fd < 0) {
>          return -1;
>      }
> diff --git a/os-posix.c b/os-posix.c
> index 321fc4bd13..59cac65585 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -266,7 +266,7 @@ void os_setup_post(void)
>              error_report("not able to chdir to /: %s", strerror(errno));
>              exit(1);
>          }
> -        TFR(fd = qemu_open_old("/dev/null", O_RDWR));
> +        fd = TEMP_FAILURE_RETRY(qemu_open_old("/dev/null", O_RDWR));
>          if (fd == -1) {
>              exit(1);
>          }
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 90f83aa9b6..feb0fab807 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -68,7 +68,7 @@ static void ga_wait_child(pid_t pid, int *status, Error
> **errp)
>
>      *status = 0;
>
> -    TFR(rpid = waitpid(pid, status, 0));
> +    rpid = TEMP_FAILURE_RETRY(waitpid(pid, status, 0));
>
>      if (rpid == -1) {
>          error_setg_errno(errp, errno, "failed to wait for child (pid:
> %d)",
> diff --git a/semihosting/syscalls.c b/semihosting/syscalls.c
> index 025c08147a..0cbef7d22b 100644
> --- a/semihosting/syscalls.c
> +++ b/semihosting/syscalls.c
> @@ -317,7 +317,7 @@ static void host_read(CPUState *cs,
> gdb_syscall_complete_cb complete,
>          complete(cs, -1, EFAULT);
>          return;
>      }
> -    TFR(ret = read(gf->hostfd, ptr, len));
> +    ret = TEMP_FAILURE_RETRY(read(gf->hostfd, ptr, len));
>      if (ret == -1) {
>          complete(cs, -1, errno);
>          unlock_user(ptr, buf, 0);
> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
> index d4022966b3..4a12824dc4 100644
> --- a/tests/qtest/libqtest.c
> +++ b/tests/qtest/libqtest.c
> @@ -102,8 +102,8 @@ static int socket_accept(int sock)
>      }
>
>      addrlen = sizeof(addr);
> -    TFR(
> -        ret = accept(sock, (struct sockaddr *)&addr, &addrlen)
> +    ret = TEMP_FAILURE_RETRY(
> +        accept(sock, (struct sockaddr *)&addr, &addrlen)
>      );
>      if (ret == -1) {
>          fprintf(stderr, "%s failed: %s\n", __func__, strerror(errno));
> @@ -140,7 +140,7 @@ void qtest_kill_qemu(QTestState *s)
>      /* Skip wait if qtest_probe_child already reaped.  */
>      if (pid != -1) {
>          kill(pid, SIGTERM);
> -        TFR(pid = waitpid(s->qemu_pid, &s->wstatus, 0));
> +        pid = TEMP_FAILURE_RETRY(waitpid(s->qemu_pid, &s->wstatus, 0));
>          assert(pid == s->qemu_pid);
>          s->qemu_pid = -1;
>      }
> @@ -578,8 +578,8 @@ int qtest_socket_server(const char *socket_path)
>      addr.sun_family = AF_UNIX;
>      snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", socket_path);
>
> -    TFR(
> -        ret = bind(sock, (struct sockaddr *)&addr, sizeof(addr))
> +    ret = TEMP_FAILURE_RETRY(
> +        bind(sock, (struct sockaddr *)&addr, sizeof(addr))
>      );
>      g_assert_cmpint(ret, !=, -1);
>      ret = listen(sock, 1);
> diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c
> index 4d8f933ed5..624a211f3d 100644
> --- a/tests/vhost-user-bridge.c
> +++ b/tests/vhost-user-bridge.c
> @@ -331,7 +331,9 @@ vubr_backend_recv_cb(int sock, void *ctx)
>              .msg_iovlen = num,
>              .msg_flags = MSG_DONTWAIT,
>          };
> -        TFR(ret = recvmsg(vubr->backend_udp_sock, &msg, 0));
> +        ret = TEMP_FAILURE_RETRY(
> +                recvmsg(vubr->backend_udp_sock, &msg, 0)
> +        );
>
>          if (i == 0) {
>              iov_restore_front(elem->in_sg, sg, hdrlen);
> diff --git a/util/main-loop.c b/util/main-loop.c
> index 58e14db2d4..5f65f928bd 100644
> --- a/util/main-loop.c
> +++ b/util/main-loop.c
> @@ -64,7 +64,7 @@ static void sigfd_handler(void *opaque)
>      ssize_t len;
>
>      while (1) {
> -        TFR(len = read(fd, &info, sizeof(info)));
> +        len = TEMP_FAILURE_RETRY(read(fd, &info, sizeof(info)));
>
>          if (len == -1 && errno == EAGAIN) {
>              break;
> diff --git a/util/osdep.c b/util/osdep.c
> index d35c473ac7..2c287e75e7 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -244,7 +244,7 @@ static int qemu_lock_fcntl(int fd, int64_t start,
> int64_t len, int fl_type)
>          .l_type   = fl_type,
>      };
>      qemu_probe_lock_ops();
> -    TFR(ret = fcntl(fd, fcntl_op_setlk, &fl));
> +    ret = TEMP_FAILURE_RETRY(fcntl(fd, fcntl_op_setlk, &fl));
>      return ret == -1 ? -errno : 0;
>  }
>
> diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
> index c878be1c5f..e1422666eb 100644
> --- a/util/vfio-helpers.c
> +++ b/util/vfio-helpers.c
> @@ -240,8 +240,8 @@ static int qemu_vfio_pci_read_config(QEMUVFIOState *s,
> void *buf,
>                                      s->config_region_info.offset,
>                                      s->config_region_info.size);
>      assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
> -    TFR(
> -        ret = pread(s->device, buf, size, s->config_region_info.offset +
> ofs)
> +    ret = TEMP_FAILURE_RETRY(
> +        pread(s->device, buf, size, s->config_region_info.offset + ofs)
>      );
>      return ret == size ? 0 : -errno;
>  }
> @@ -254,8 +254,8 @@ static int qemu_vfio_pci_write_config(QEMUVFIOState
> *s, void *buf, int size, int
>                                       s->config_region_info.offset,
>                                       s->config_region_info.size);
>      assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
> -    TFR(
> -        ret = pwrite(s->device, buf, size, s->config_region_info.offset +
> ofs)
> +    ret = TEMP_FAILURE_RETRY(
> +        pwrite(s->device, buf, size, s->config_region_info.offset + ofs)
>      );
>      return ret == size ? 0 : -errno;
>  }
> --
> 2.37.1
>
>
> On Mon, Aug 8, 2022 at 9:00 PM Nikita Ivanov <nivanov@cloudlinux.com>
> wrote:
>
>> Hi!
>> During our discussion, I found that I've missed a couple of places where
>> TFR() macro could be applied. Here is an updated first patch:
>>
>> From 8a68f50aac4a8549f416b9350cf339cf0501a712 Mon Sep 17 00:00:00 2001
>> From: Nikita Ivanov <nivanov@cloudlinux.com>
>> Date: Wed, 3 Aug 2022 12:54:00 +0300
>> Subject: [PATCH] error handling: Use TFR() macro where applicable
>>
>> There is a defined TFR() macro in qemu/osdep.h which
>> handles the same while loop.
>> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/415
>>
>> Signed-off-by: Nikita Ivanov <nivanov@cloudlinux.com>
>> ---
>>  block/file-posix.c        | 39 ++++++++++++++++++---------------------
>>  chardev/char-pty.c        |  4 +---
>>  hw/9pfs/9p-local.c        |  8 ++------
>>  net/l2tpv3.c              | 15 +++------------
>>  net/socket.c              | 16 +++++++---------
>>  net/tap.c                 |  8 ++------
>>  qga/commands-posix.c      |  4 +---
>>  semihosting/syscalls.c    |  4 +---
>>  tests/qtest/libqtest.c    | 14 +++++++-------
>>  tests/vhost-user-bridge.c |  4 +---
>>  util/main-loop.c          |  4 +---
>>  util/osdep.c              |  4 +---
>>  util/vfio-helpers.c       | 12 ++++++------
>>  13 files changed, 51 insertions(+), 85 deletions(-)
>>
>> diff --git a/block/file-posix.c b/block/file-posix.c
>> index 48cd096624..0786cb76f9 100644
>> --- a/block/file-posix.c
>> +++ b/block/file-posix.c
>> @@ -1238,9 +1238,9 @@ static int hdev_get_max_segments(int fd, struct
>> stat *st)
>>          ret = -errno;
>>          goto out;
>>      }
>> -    do {
>> -        ret = read(sysfd, buf, sizeof(buf) - 1);
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(
>> +        ret = read(sysfd, buf, sizeof(buf) - 1)
>> +    );
>>      if (ret < 0) {
>>          ret = -errno;
>>          goto out;
>> @@ -1388,9 +1388,9 @@ static int handle_aiocb_ioctl(void *opaque)
>>      RawPosixAIOData *aiocb = opaque;
>>      int ret;
>>
>> -    do {
>> -        ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd,
>> aiocb->ioctl.buf);
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(
>> +        ret = ioctl(aiocb->aio_fildes, aiocb->ioctl.cmd,
>> aiocb->ioctl.buf)
>> +    );
>>      if (ret == -1) {
>>          return -errno;
>>      }
>> @@ -1472,18 +1472,17 @@ static ssize_t
>> handle_aiocb_rw_vector(RawPosixAIOData *aiocb)
>>  {
>>      ssize_t len;
>>
>> -    do {
>> -        if (aiocb->aio_type & QEMU_AIO_WRITE)
>> -            len = qemu_pwritev(aiocb->aio_fildes,
>> -                               aiocb->io.iov,
>> -                               aiocb->io.niov,
>> -                               aiocb->aio_offset);
>> -         else
>> -            len = qemu_preadv(aiocb->aio_fildes,
>> -                              aiocb->io.iov,
>> -                              aiocb->io.niov,
>> -                              aiocb->aio_offset);
>> -    } while (len == -1 && errno == EINTR);
>> +    TFR(
>> +        len = (aiocb->aio_type & QEMU_AIO_WRITE) ?
>> +            qemu_pwritev(aiocb->aio_fildes,
>> +                           aiocb->io.iov,
>> +                           aiocb->io.niov,
>> +                           aiocb->aio_offset) :
>> +            qemu_preadv(aiocb->aio_fildes,
>> +                          aiocb->io.iov,
>> +                          aiocb->io.niov,
>> +                          aiocb->aio_offset)
>> +    );
>>
>>      if (len == -1) {
>>          return -errno;
>> @@ -1908,9 +1907,7 @@ static int allocate_first_block(int fd, size_t
>> max_size)
>>      buf = qemu_memalign(max_align, write_size);
>>      memset(buf, 0, write_size);
>>
>> -    do {
>> -        n = pwrite(fd, buf, write_size, 0);
>> -    } while (n == -1 && errno == EINTR);
>> +    TFR(n = pwrite(fd, buf, write_size, 0));
>>
>>      ret = (n == -1) ? -errno : 0;
>>
>> diff --git a/chardev/char-pty.c b/chardev/char-pty.c
>> index 53f25c6bbd..b2f490bacf 100644
>> --- a/chardev/char-pty.c
>> +++ b/chardev/char-pty.c
>> @@ -93,9 +93,7 @@ static void pty_chr_update_read_handler(Chardev *chr)
>>      pfd.fd = fioc->fd;
>>      pfd.events = G_IO_OUT;
>>      pfd.revents = 0;
>> -    do {
>> -        rc = g_poll(&pfd, 1, 0);
>> -    } while (rc == -1 && errno == EINTR);
>> +    TFR(rc = g_poll(&pfd, 1, 0));
>>      assert(rc >= 0);
>>
>>      if (pfd.revents & G_IO_HUP) {
>> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
>> index d42ce6d8b8..c90ab947ba 100644
>> --- a/hw/9pfs/9p-local.c
>> +++ b/hw/9pfs/9p-local.c
>> @@ -470,9 +470,7 @@ static ssize_t local_readlink(FsContext *fs_ctx,
>> V9fsPath *fs_path,
>>          if (fd == -1) {
>>              return -1;
>>          }
>> -        do {
>> -            tsize = read(fd, (void *)buf, bufsz);
>> -        } while (tsize == -1 && errno == EINTR);
>> +        TFR(tsize = read(fd, (void *)buf, bufsz));
>>          close_preserve_errno(fd);
>>      } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
>>                 (fs_ctx->export_flags & V9FS_SM_NONE)) {
>> @@ -908,9 +906,7 @@ static int local_symlink(FsContext *fs_ctx, const
>> char *oldpath,
>>          }
>>          /* Write the oldpath (target) to the file. */
>>          oldpath_size = strlen(oldpath);
>> -        do {
>> -            write_size = write(fd, (void *)oldpath, oldpath_size);
>> -        } while (write_size == -1 && errno == EINTR);
>> +        TFR(write_size = write(fd, (void *)oldpath, oldpath_size));
>>          close_preserve_errno(fd);
>>
>>          if (write_size != oldpath_size) {
>> diff --git a/net/l2tpv3.c b/net/l2tpv3.c
>> index af373e5c30..adfdbdb84c 100644
>> --- a/net/l2tpv3.c
>> +++ b/net/l2tpv3.c
>> @@ -240,9 +240,7 @@ static ssize_t
>> net_l2tpv3_receive_dgram_iov(NetClientState *nc,
>>      message.msg_control = NULL;
>>      message.msg_controllen = 0;
>>      message.msg_flags = 0;
>> -    do {
>> -        ret = sendmsg(s->fd, &message, 0);
>> -    } while ((ret == -1) && (errno == EINTR));
>> +    TFR(ret = sendmsg(s->fd, &message, 0));
>>      if (ret > 0) {
>>          ret -= s->offset;
>>      } else if (ret == 0) {
>> @@ -285,9 +283,7 @@ static ssize_t
>> net_l2tpv3_receive_dgram(NetClientState *nc,
>>      message.msg_control = NULL;
>>      message.msg_controllen = 0;
>>      message.msg_flags = 0;
>> -    do {
>> -        ret = sendmsg(s->fd, &message, 0);
>> -    } while ((ret == -1) && (errno == EINTR));
>> +    TFR(ret = sendmsg(s->fd, &message, 0));
>>      if (ret > 0) {
>>          ret -= s->offset;
>>      } else if (ret == 0) {
>> @@ -434,12 +430,7 @@ static void net_l2tpv3_send(void *opaque)
>>
>>      msgvec = s->msgvec + s->queue_head;
>>      if (target_count > 0) {
>> -        do {
>> -            count = recvmmsg(
>> -                s->fd,
>> -                msgvec,
>> -                target_count, MSG_DONTWAIT, NULL);
>> -        } while ((count == -1) && (errno == EINTR));
>> +        TFR(count = recvmmsg(s->fd, msgvec, target_count, MSG_DONTWAIT,
>> NULL));
>>          if (count < 0) {
>>              /* Recv error - we still need to flush packets here,
>>               * (re)set queue head to current position
>> diff --git a/net/socket.c b/net/socket.c
>> index bfd8596250..a3397660c2 100644
>> --- a/net/socket.c
>> +++ b/net/socket.c
>> @@ -117,15 +117,13 @@ static ssize_t
>> net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf,
>>      NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
>>      ssize_t ret;
>>
>> -    do {
>> -        if (s->dgram_dst.sin_family != AF_UNIX) {
>> -            ret = sendto(s->fd, buf, size, 0,
>> -                         (struct sockaddr *)&s->dgram_dst,
>> -                         sizeof(s->dgram_dst));
>> -        } else {
>> -            ret = send(s->fd, buf, size, 0);
>> -        }
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(
>> +        ret = s->dgram_dst.sin_family != AF_UNIX ?
>> +            sendto(s->fd, buf, size, 0,
>> +                     (struct sockaddr *)&s->dgram_dst,
>> +                     sizeof(s->dgram_dst)) :
>> +            send(s->fd, buf, size, 0)
>> +    );
>>
>>      if (ret == -1 && errno == EAGAIN) {
>>          net_socket_write_poll(s, true);
>> diff --git a/net/tap.c b/net/tap.c
>> index b3ddfd4a74..b047eca8b5 100644
>> --- a/net/tap.c
>> +++ b/net/tap.c
>> @@ -102,9 +102,7 @@ static ssize_t tap_write_packet(TAPState *s, const
>> struct iovec *iov, int iovcnt
>>  {
>>      ssize_t len;
>>
>> -    do {
>> -        len = writev(s->fd, iov, iovcnt);
>> -    } while (len == -1 && errno == EINTR);
>> +    TFR(len = writev(s->fd, iov, iovcnt));
>>
>>      if (len == -1 && errno == EAGAIN) {
>>          tap_write_poll(s, true);
>> @@ -577,9 +575,7 @@ static int net_bridge_run_helper(const char *helper,
>> const char *bridge,
>>
>>          close(sv[1]);
>>
>> -        do {
>> -            fd = recv_fd(sv[0]);
>> -        } while (fd == -1 && errno == EINTR);
>> +        TFR(fd = recv_fd(sv[0]));
>>          saved_errno = errno;
>>
>>          close(sv[0]);
>> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
>> index 954efed01b..90f83aa9b6 100644
>> --- a/qga/commands-posix.c
>> +++ b/qga/commands-posix.c
>> @@ -68,9 +68,7 @@ static void ga_wait_child(pid_t pid, int *status, Error
>> **errp)
>>
>>      *status = 0;
>>
>> -    do {
>> -        rpid = waitpid(pid, status, 0);
>> -    } while (rpid == -1 && errno == EINTR);
>> +    TFR(rpid = waitpid(pid, status, 0));
>>
>>      if (rpid == -1) {
>>          error_setg_errno(errp, errno, "failed to wait for child (pid:
>> %d)",
>> diff --git a/semihosting/syscalls.c b/semihosting/syscalls.c
>> index 508a0ad88c..025c08147a 100644
>> --- a/semihosting/syscalls.c
>> +++ b/semihosting/syscalls.c
>> @@ -317,9 +317,7 @@ static void host_read(CPUState *cs,
>> gdb_syscall_complete_cb complete,
>>          complete(cs, -1, EFAULT);
>>          return;
>>      }
>> -    do {
>> -        ret = read(gf->hostfd, ptr, len);
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(ret = read(gf->hostfd, ptr, len));
>>      if (ret == -1) {
>>          complete(cs, -1, errno);
>>          unlock_user(ptr, buf, 0);
>> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
>> index 8c159eacf5..d4022966b3 100644
>> --- a/tests/qtest/libqtest.c
>> +++ b/tests/qtest/libqtest.c
>> @@ -101,10 +101,10 @@ static int socket_accept(int sock)
>>          return -1;
>>      }
>>
>> -    do {
>> -        addrlen = sizeof(addr);
>> -        ret = accept(sock, (struct sockaddr *)&addr, &addrlen);
>> -    } while (ret == -1 && errno == EINTR);
>> +    addrlen = sizeof(addr);
>> +    TFR(
>> +        ret = accept(sock, (struct sockaddr *)&addr, &addrlen)
>> +    );
>>      if (ret == -1) {
>>          fprintf(stderr, "%s failed: %s\n", __func__, strerror(errno));
>>      }
>> @@ -578,9 +578,9 @@ int qtest_socket_server(const char *socket_path)
>>      addr.sun_family = AF_UNIX;
>>      snprintf(addr.sun_path, sizeof(addr.sun_path), "%s", socket_path);
>>
>> -    do {
>> -        ret = bind(sock, (struct sockaddr *)&addr, sizeof(addr));
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(
>> +        ret = bind(sock, (struct sockaddr *)&addr, sizeof(addr))
>> +    );
>>      g_assert_cmpint(ret, !=, -1);
>>      ret = listen(sock, 1);
>>      g_assert_cmpint(ret, !=, -1);
>> diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c
>> index 9b1dab2f28..4d8f933ed5 100644
>> --- a/tests/vhost-user-bridge.c
>> +++ b/tests/vhost-user-bridge.c
>> @@ -331,9 +331,7 @@ vubr_backend_recv_cb(int sock, void *ctx)
>>              .msg_iovlen = num,
>>              .msg_flags = MSG_DONTWAIT,
>>          };
>> -        do {
>> -            ret = recvmsg(vubr->backend_udp_sock, &msg, 0);
>> -        } while (ret == -1 && (errno == EINTR));
>> +        TFR(ret = recvmsg(vubr->backend_udp_sock, &msg, 0));
>>
>>          if (i == 0) {
>>              iov_restore_front(elem->in_sg, sg, hdrlen);
>> diff --git a/util/main-loop.c b/util/main-loop.c
>> index f00a25451b..58e14db2d4 100644
>> --- a/util/main-loop.c
>> +++ b/util/main-loop.c
>> @@ -64,9 +64,7 @@ static void sigfd_handler(void *opaque)
>>      ssize_t len;
>>
>>      while (1) {
>> -        do {
>> -            len = read(fd, &info, sizeof(info));
>> -        } while (len == -1 && errno == EINTR);
>> +        TFR(len = read(fd, &info, sizeof(info)));
>>
>>          if (len == -1 && errno == EAGAIN) {
>>              break;
>> diff --git a/util/osdep.c b/util/osdep.c
>> index 60fcbbaebe..d35c473ac7 100644
>> --- a/util/osdep.c
>> +++ b/util/osdep.c
>> @@ -244,9 +244,7 @@ static int qemu_lock_fcntl(int fd, int64_t start,
>> int64_t len, int fl_type)
>>          .l_type   = fl_type,
>>      };
>>      qemu_probe_lock_ops();
>> -    do {
>> -        ret = fcntl(fd, fcntl_op_setlk, &fl);
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(ret = fcntl(fd, fcntl_op_setlk, &fl));
>>      return ret == -1 ? -errno : 0;
>>  }
>>
>> diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
>> index 5ba01177bf..c878be1c5f 100644
>> --- a/util/vfio-helpers.c
>> +++ b/util/vfio-helpers.c
>> @@ -240,9 +240,9 @@ static int qemu_vfio_pci_read_config(QEMUVFIOState
>> *s, void *buf,
>>                                      s->config_region_info.offset,
>>                                      s->config_region_info.size);
>>      assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
>> -    do {
>> -        ret = pread(s->device, buf, size, s->config_region_info.offset +
>> ofs);
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(
>> +        ret = pread(s->device, buf, size, s->config_region_info.offset +
>> ofs)
>> +    );
>>      return ret == size ? 0 : -errno;
>>  }
>>
>> @@ -254,9 +254,9 @@ static int qemu_vfio_pci_write_config(QEMUVFIOState
>> *s, void *buf, int size, int
>>                                       s->config_region_info.offset,
>>                                       s->config_region_info.size);
>>      assert(QEMU_IS_ALIGNED(s->config_region_info.offset + ofs, size));
>> -    do {
>> -        ret = pwrite(s->device, buf, size, s->config_region_info.offset
>> + ofs);
>> -    } while (ret == -1 && errno == EINTR);
>> +    TFR(
>> +        ret = pwrite(s->device, buf, size, s->config_region_info.offset
>> + ofs)
>> +    );
>>      return ret == size ? 0 : -errno;
>>  }
>>
>> --
>> 2.37.1
>>
>>
>> On Mon, Aug 8, 2022 at 5:22 PM Markus Armbruster <armbru@redhat.com>
>> wrote:
>>
>>> Christian Schoenebeck <qemu_oss@crudebyte.com> writes:
>>>
>>> > On Montag, 8. August 2022 14:52:28 CEST Christian Schoenebeck wrote:
>>> >> On Montag, 8. August 2022 10:05:56 CEST Markus Armbruster wrote:
>>> >> > Nikita Ivanov <nivanov@cloudlinux.com> writes:
>>> >> > > Summing up the discussion above, I suggest the following patch
>>> for TFR()
>>> >> > > macro refactoring. (The patch is sequential to the first one I
>>> >> > > introduced
>>> >> > > in the start of the discussion).
>>> >> > >
>>> >> > >>From 6318bee052900aa93bba6620b53c7cb2290e5001 Mon Sep 17 00:00:00
>>> 2001
>>> >> > >>
>>> >> > > From: Nikita Ivanov <nivanov@cloudlinux.com>
>>> >> > > Date: Mon, 8 Aug 2022 09:30:34 +0300
>>> >> > > Subject: [PATCH] Refactoring: rename TFR() to TEMP_FAILURE_RETRY()
>>> >> > >
>>> >> > > glibc's unistd.h header provides the same macro with the
>>> >> > > subtle difference in type casting. Adjust macro name to the
>>> >> > > common standard and define conditionally.
>>> >> > >
>>> >> > > Signed-off-by: Nikita Ivanov <nivanov@cloudlinux.com>
>>>
>>> [...]
>>>
>>> >> > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
>>> >> > > index b1c161c035..55f2927d8b 100644
>>> >> > > --- a/include/qemu/osdep.h
>>> >> > > +++ b/include/qemu/osdep.h
>>> >> > > @@ -242,8 +242,10 @@ void QEMU_ERROR("code path is reachable")
>>> >> > >
>>> >> > >  #if !defined(ESHUTDOWN)
>>> >> > >  #define ESHUTDOWN 4099
>>> >> > >  #endif
>>> >> > >
>>> >> > > -
>>> >> > > -#define TFR(expr) do { if ((expr) != -1) break; } while (errno ==
>>> >> > > EINTR)
>>> >> > > +#if !defined(TEMP_FAILURE_RETRY)
>>> >> > > +#define TEMP_FAILURE_RETRY(expr) \
>>> >> > > +    do { if ((expr) != -1) break; } while (errno == EINTR)
>>>
>>> To avoid / reduce confusion: this macro expands into a statement, and ...
>>>
>>> >> > > +#endif
>>> >> >
>>> >> > GLibc's version is
>>> >> >
>>> >> >    # define TEMP_FAILURE_RETRY(expression) \
>>> >> >      (__extension__
>>>               \
>>> >> >        ({ long int __result;
>>>              \
>>> >> >           do __result = (long int) (expression);
>>>              \
>>> >> >           while (__result == -1L && errno == EINTR);
>>>              \
>>> >> >           __result; }))
>>>
>>> ... this one expands into an expression.  It uses GCC's "a compound
>>> statement enclosed in parentheses may appear as an expression" extension.
>>>
>>> >> >
>>> >> > The difference isn't just "type casting", it's also statement
>>> >> > vs. expression.
>>> >> >
>>> >> > Is it a good idea to have the macro expand into a statement on some
>>> >> > hosts, and into an expression on others?  Sure, CI should catch any
>>> uses
>>> >> > as expression, but delaying compile errors to CI wastes developer
>>> time.
>>> >>
>>> >> For consistency and simplicity, I would define exactly one version (no
>>> >> ifdefs) of the macro with a different macro name than glibc's
>>> >> TEMP_FAILURE_RETRY(), and use that QEMU specific macro name in QEMU
>>> code
>>> >> everywhere.
>>>
>>> TFR()?  Can't resist closing the circle...
>>>
>>> >> As for statement vs. expression: The only advantage of the statement
>>> version
>>> >> is if you'd need __result as an rvalue, which is not needed ATM,
>>> right? So
>>> >> I would go for the expression version (with cast) for now.
>>>
>>> The expression-like macro is nicer where the return value matters.
>>> Example (stolen from "The GNU C Library Reference Manual"):
>>>
>>>     nbytes = TEMP_FAILURE_RETRY (write (desc, buffer, count));
>>>
>>> With the statement-like macro, you have to write
>>>
>>>     TEMP_FAILURE_RETRY (nbytes = write (desc, buffer, count));
>>>
>>> >> The glibc history does not reveal why they chose the statement
>>> version.
>>>
>>> The expression version, actually.
>>>
>>> >> Best regards,
>>> >> Christian Schoenebeck
>>> >
>>> > Sorry: s/rvalue/lvalue/ i.e. if you need the memory address of result
>>> or if
>>> > you need to take the result value of the last iteration in
>>> 'expression' into
>>> > account.
>>>
>>>
>>
>> --
>> Best Regards,
>> *Nikita Ivanov* | C developer
>> *Telephone:* +79140870696
>> *Telephone:* +79015053149
>>
>
>
> --
> Best Regards,
> *Nikita Ivanov* | C developer
> *Telephone:* +79140870696
> *Telephone:* +79015053149
>


-- 
Best Regards,
*Nikita Ivanov* | C developer
*Telephone:* +79140870696
*Telephone:* +79015053149

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