glibc/sysdeps/unix/sysv/linux/mips/mips64/n32/lseek.c

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Fix MIPS n32 lseek, lseek64 (bug 21019). The lseek consolidation broke lseek64 for MIPS n32, so resulting in io/test-lfs failing with an incorrect return from ftello64. This configuration uses the lseek syscall with a 64-bit return value; as the C syscall macros return long, they cannot be used in this case and so an assembly implementation is needed; accordingly, this patch adds lseek64 back to syscalls.list for this configuration. lseek was also broken, truncating the result without checking for overflow. lseek however was already broken before the consolidation; it aliased lseek64 so would return an out-of-range value, resulting in architecturally undefined behavior in the caller if it tried to use a non-sign-extended value with a 32-bit instruction. This patch adds a custom lseek implementation in C for n32, which calls __lseek64 to get the 64-bit value then checks for overflow. Because the prior lseek breakage did not show in test results, and the lseek64 breakage showed only indirectly through tests of ftello64, test coverage was clearly inadequate. This patch extends io/test-lfs.c to test the lseek64 return value (at a point where it has already seeked over 2GB into a file), and then to test the lseek return value (with the latter's expectations depending on whether off_t is smaller than off64_t). Tested for mips64 n32. Also tested test-lfs for x86_64 and x86, where as expected it passes. [BZ #21019] * sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (lseek64): New syscall entry. * sysdeps/unix/sysv/linux/mips/mips64/n32/lseek.c: New file. * io/test-lfs.c (do_test): Test offset returned from lseek64 and lseek.
2017-01-02 23:09:25 +00:00
/* MIPS n32 lseek implementation.
Copyright (C) 2017-2019 Free Software Foundation, Inc.
Fix MIPS n32 lseek, lseek64 (bug 21019). The lseek consolidation broke lseek64 for MIPS n32, so resulting in io/test-lfs failing with an incorrect return from ftello64. This configuration uses the lseek syscall with a 64-bit return value; as the C syscall macros return long, they cannot be used in this case and so an assembly implementation is needed; accordingly, this patch adds lseek64 back to syscalls.list for this configuration. lseek was also broken, truncating the result without checking for overflow. lseek however was already broken before the consolidation; it aliased lseek64 so would return an out-of-range value, resulting in architecturally undefined behavior in the caller if it tried to use a non-sign-extended value with a 32-bit instruction. This patch adds a custom lseek implementation in C for n32, which calls __lseek64 to get the 64-bit value then checks for overflow. Because the prior lseek breakage did not show in test results, and the lseek64 breakage showed only indirectly through tests of ftello64, test coverage was clearly inadequate. This patch extends io/test-lfs.c to test the lseek64 return value (at a point where it has already seeked over 2GB into a file), and then to test the lseek return value (with the latter's expectations depending on whether off_t is smaller than off64_t). Tested for mips64 n32. Also tested test-lfs for x86_64 and x86, where as expected it passes. [BZ #21019] * sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (lseek64): New syscall entry. * sysdeps/unix/sysv/linux/mips/mips64/n32/lseek.c: New file. * io/test-lfs.c (do_test): Test offset returned from lseek64 and lseek.
2017-01-02 23:09:25 +00:00
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
off_t
__lseek (int fd, off_t offset, int whence)
{
off64_t res = __lseek64 (fd, offset, whence);
if (res != (off_t) res)
{
__set_errno (EOVERFLOW);
return (off_t) -1;
}
return (off_t) res;
}
libc_hidden_def (__lseek)
weak_alias (__lseek, lseek)
strong_alias (__lseek, __libc_lseek)