43 lines
1.6 KiB
C
43 lines
1.6 KiB
C
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/* System call limits
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Copyright 2018-2020 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, see <https://www.gnu.org/licenses/>. */
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#ifndef _GL_SYS_LIMITS_H
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#define _GL_SYS_LIMITS_H
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#include <limits.h>
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/* Maximum number of bytes to read or write in a single system call.
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This can be useful for system calls like sendfile on GNU/Linux,
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which do not handle more than MAX_RW_COUNT bytes correctly.
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The Linux kernel MAX_RW_COUNT is at least INT_MAX >> 20 << 20,
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where the 20 comes from the Hexagon port with 1 MiB pages; use that
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as an approximation, as the exact value may not be available to us.
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Using this also works around a serious Linux bug before 2.6.16; see
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<https://bugzilla.redhat.com/show_bug.cgi?id=612839>.
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Using this also works around a Tru64 5.1 bug, where attempting
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to read INT_MAX bytes fails with errno == EINVAL. See
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<https://lists.gnu.org/r/bug-gnu-utils/2002-04/msg00010.html>.
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Using this is likely to work around similar bugs in other operating
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systems. */
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enum { SYS_BUFSIZE_MAX = INT_MAX >> 20 << 20 };
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#endif
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