[Qemu-devel] [Bug 1716292] Re: User mode emulation returns wrong value for write(fd, NULL, 0)

2018-12-12 Thread Thomas Huth 
** Changed in: qemu
   Status: Fix Committed => Fix Released

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Title:
  User mode emulation returns wrong value for write(fd, NULL, 0)

Status in QEMU:
  Fix Released

Bug description:
  QEMU version: latest master (fcea73709b966a7ded9efa7b106ea50c7fe9025c)
  OS version: Ubuntu 14.04.5
  Configured with: ../configure --target-list=x86_64-linux-user

  QEMU Linux usermode emulation does not handle write() syscalls with
  zero length and a null pointer correctly: on Linux this returns 0, but
  in emulation this returns -1.

  I ran into this while using an aarch64 abuild-tar from Alpine Linux in
  user-mode emulation; here's the minimized reproduction test case:

  zhuowei@zhuowei-tablet:/tmp$ cat writezerobytes.c
  #include 
  #include 
  #include 

  int main() {
   ssize_t ret = write(STDOUT_FILENO, NULL, 0);
   fprintf(stderr, "write returned %ld\n", ret);
   return 0;
  }
  zhuowei@zhuowei-tablet:/tmp$ gcc -o writezerobytes writezerobytes.c
  zhuowei@zhuowei-tablet:/tmp$ uname -a
  Linux zhuowei-tablet 3.13.0-129-generic #178-Ubuntu SMP Fri Aug 11 12:48:20 
UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
  zhuowei@zhuowei-tablet:/tmp$ ./writezerobytes
  write returned 0
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
./writezerobytes
  write returned -1
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
--version
  qemu-x86_64 version 2.10.50 (v2.10.0-471-gfcea737-dirty)
  Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

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[Qemu-devel] [Bug 1716292] Re: User mode emulation returns wrong value for write(fd, NULL, 0)

2018-10-04 Thread Thomas Huth 
Fix has been committed here:
https://git.qemu.org/?p=qemu.git;a=commitdiff;h=58cfa6c2e6eb51b23cc98

** Changed in: qemu
   Status: New => Fix Committed

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1716292

Title:
  User mode emulation returns wrong value for write(fd, NULL, 0)

Status in QEMU:
  Fix Committed

Bug description:
  QEMU version: latest master (fcea73709b966a7ded9efa7b106ea50c7fe9025c)
  OS version: Ubuntu 14.04.5
  Configured with: ../configure --target-list=x86_64-linux-user

  QEMU Linux usermode emulation does not handle write() syscalls with
  zero length and a null pointer correctly: on Linux this returns 0, but
  in emulation this returns -1.

  I ran into this while using an aarch64 abuild-tar from Alpine Linux in
  user-mode emulation; here's the minimized reproduction test case:

  zhuowei@zhuowei-tablet:/tmp$ cat writezerobytes.c
  #include 
  #include 
  #include 

  int main() {
   ssize_t ret = write(STDOUT_FILENO, NULL, 0);
   fprintf(stderr, "write returned %ld\n", ret);
   return 0;
  }
  zhuowei@zhuowei-tablet:/tmp$ gcc -o writezerobytes writezerobytes.c
  zhuowei@zhuowei-tablet:/tmp$ uname -a
  Linux zhuowei-tablet 3.13.0-129-generic #178-Ubuntu SMP Fri Aug 11 12:48:20 
UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
  zhuowei@zhuowei-tablet:/tmp$ ./writezerobytes
  write returned 0
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
./writezerobytes
  write returned -1
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
--version
  qemu-x86_64 version 2.10.50 (v2.10.0-471-gfcea737-dirty)
  Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

To manage notifications about this bug go to:
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Re: [Qemu-devel] [Bug 1716292] Re: User mode emulation returns wrong value for write(fd, NULL, 0)

2018-09-07 Thread Eric Blake 

On 09/07/2018 06:51 AM, Tony Garnock-Jones wrote:

** Patch added: 
"0001-Bring-linux-user-write-2-handling-into-line-with-lin.patch"

https://bugs.launchpad.net/qemu/+bug/1716292/+attachment/5186008/+files/0001-Bring-linux-user-write-2-handling-into-line-with-lin.patch


While a developer can chase a URL, our CI tools can't.  Can you please 
also send that patch directly to qemu-devel@nongnu.org, so that it gets 
the same level of review as other patches?


--
Eric Blake, Principal Software Engineer
Red Hat, Inc.   +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

[Qemu-devel] [Bug 1716292] Re: User mode emulation returns wrong value for write(fd, NULL, 0)

2018-09-07 Thread Tony Garnock-Jones 
** Patch added: 
"0001-Bring-linux-user-write-2-handling-into-line-with-lin.patch"
   
https://bugs.launchpad.net/qemu/+bug/1716292/+attachment/5186008/+files/0001-Bring-linux-user-write-2-handling-into-line-with-lin.patch

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1716292

Title:
  User mode emulation returns wrong value for write(fd, NULL, 0)

Status in QEMU:
  New

Bug description:
  QEMU version: latest master (fcea73709b966a7ded9efa7b106ea50c7fe9025c)
  OS version: Ubuntu 14.04.5
  Configured with: ../configure --target-list=x86_64-linux-user

  QEMU Linux usermode emulation does not handle write() syscalls with
  zero length and a null pointer correctly: on Linux this returns 0, but
  in emulation this returns -1.

  I ran into this while using an aarch64 abuild-tar from Alpine Linux in
  user-mode emulation; here's the minimized reproduction test case:

  zhuowei@zhuowei-tablet:/tmp$ cat writezerobytes.c
  #include 
  #include 
  #include 

  int main() {
   ssize_t ret = write(STDOUT_FILENO, NULL, 0);
   fprintf(stderr, "write returned %ld\n", ret);
   return 0;
  }
  zhuowei@zhuowei-tablet:/tmp$ gcc -o writezerobytes writezerobytes.c
  zhuowei@zhuowei-tablet:/tmp$ uname -a
  Linux zhuowei-tablet 3.13.0-129-generic #178-Ubuntu SMP Fri Aug 11 12:48:20 
UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
  zhuowei@zhuowei-tablet:/tmp$ ./writezerobytes
  write returned 0
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
./writezerobytes
  write returned -1
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
--version
  qemu-x86_64 version 2.10.50 (v2.10.0-471-gfcea737-dirty)
  Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

To manage notifications about this bug go to:
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[Qemu-devel] [Bug 1716292] Re: User mode emulation returns wrong value for write(fd, NULL, 0)

2018-09-07 Thread Tony Garnock-Jones 
This happens for me also, with qemu version 2.12.0 (Debian
1:2.12+dfsg-3).

An initial patch was proposed here: https://lists.gnu.org/archive/html
/qemu-devel/2017-09/msg08073.html

Discussion pointed out some problems, and the patch languished and was
not accepted.

Here is a summary of the changes needed for it to be more likely for the
patch to be accepted: https://lists.gnu.org/archive/html/qemu-
devel/2018-02/msg03964.html

 - change from "ret = 0" to something like "ret = get_errno(safe_write(arg1, 
NULL, 0))"
 - change TARGET_NR_read to do the same, instead of its current short-circuit 
behaviour for count==0
 - check pread64/pwrite64 to see if they need a similar change as well

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1716292

Title:
  User mode emulation returns wrong value for write(fd, NULL, 0)

Status in QEMU:
  New

Bug description:
  QEMU version: latest master (fcea73709b966a7ded9efa7b106ea50c7fe9025c)
  OS version: Ubuntu 14.04.5
  Configured with: ../configure --target-list=x86_64-linux-user

  QEMU Linux usermode emulation does not handle write() syscalls with
  zero length and a null pointer correctly: on Linux this returns 0, but
  in emulation this returns -1.

  I ran into this while using an aarch64 abuild-tar from Alpine Linux in
  user-mode emulation; here's the minimized reproduction test case:

  zhuowei@zhuowei-tablet:/tmp$ cat writezerobytes.c
  #include 
  #include 
  #include 

  int main() {
   ssize_t ret = write(STDOUT_FILENO, NULL, 0);
   fprintf(stderr, "write returned %ld\n", ret);
   return 0;
  }
  zhuowei@zhuowei-tablet:/tmp$ gcc -o writezerobytes writezerobytes.c
  zhuowei@zhuowei-tablet:/tmp$ uname -a
  Linux zhuowei-tablet 3.13.0-129-generic #178-Ubuntu SMP Fri Aug 11 12:48:20 
UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
  zhuowei@zhuowei-tablet:/tmp$ ./writezerobytes
  write returned 0
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
./writezerobytes
  write returned -1
  zhuowei@zhuowei-tablet:/tmp$ 
/media/zhuowei/redhd/docs/repos/qemu/build4/x86_64-linux-user/qemu-x86_64 
--version
  qemu-x86_64 version 2.10.50 (v2.10.0-471-gfcea737-dirty)
  Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1716292/+subscriptions