[Bug 1309818] [NEW] pwritev() doesn't work anymore on i386

[Gianluca Borello]

Public bug reported:

I just upgraded to Trusty, and the following programs fails on x86:

#include <stdio.h>
#include <stdint.h>
#include <sys/uio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main()
{
	char *str0 = "hello ";
	char *str1 = "world\n";
	struct iovec iov[2];
	ssize_t nwritten;
	int fd = open("test.txt", O_CREAT | O_WRONLY);

	iov[0].iov_base = str0;
	iov[0].iov_len = strlen(str0);
	iov[1].iov_base = str1;
	iov[1].iov_len = strlen(str1);

	nwritten = pwritev(fd, iov, 2, 0);
	if(nwritten < 0)
		perror("pwritev");

	return 0;
}

Compiled without any flags, I see:

$ ./test
pwritev: File too large

And, from strace, I can see the offset parameter is handled wrongly by
(presumably) libc:

...
pwritev(3, [{"hello ", 6}, {"world\n", 6}], 2, 577730142772658176) = -1 EFBIG (File too large)
...

If I compile with -D_FILE_OFFSET_BITS=64, everything is right, but is
not a solution for my problem as I can't use that flag in my program.

I reported this here because it doesn't seem to happen on Debian sid,
but let me know if I have to report it upstream.

$ lsb_release -rd
Description:	Ubuntu 14.04 LTS
Release:	14.04

$ apt-cache policy libc6
libc6:
  Installed: 2.19-0ubuntu6
  Candidate: 2.19-0ubuntu6

** Affects: eglibc (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1309818

Title:
  pwritev() doesn't work anymore on i386

Status in “eglibc” package in Ubuntu:
  New

Bug description:
  I just upgraded to Trusty, and the following programs fails on x86:

  #include <stdio.h>
  #include <stdint.h>
  #include <sys/uio.h>
  #include <string.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>

  int main()
  {
  	char *str0 = "hello ";
  	char *str1 = "world\n";
  	struct iovec iov[2];
  	ssize_t nwritten;
  	int fd = open("test.txt", O_CREAT | O_WRONLY);

  	iov[0].iov_base = str0;
  	iov[0].iov_len = strlen(str0);
  	iov[1].iov_base = str1;
  	iov[1].iov_len = strlen(str1);

  	nwritten = pwritev(fd, iov, 2, 0);
  	if(nwritten < 0)
  		perror("pwritev");

  	return 0;
  }

  Compiled without any flags, I see:

  $ ./test
  pwritev: File too large

  And, from strace, I can see the offset parameter is handled wrongly by
  (presumably) libc:

  ...
  pwritev(3, [{"hello ", 6}, {"world\n", 6}], 2, 577730142772658176) = -1 EFBIG (File too large)
  ...

  If I compile with -D_FILE_OFFSET_BITS=64, everything is right, but is
  not a solution for my problem as I can't use that flag in my program.

  I reported this here because it doesn't seem to happen on Debian sid,
  but let me know if I have to report it upstream.

  $ lsb_release -rd
  Description:	Ubuntu 14.04 LTS
  Release:	14.04

  $ apt-cache policy libc6
  libc6:
    Installed: 2.19-0ubuntu6
    Candidate: 2.19-0ubuntu6

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