309 lines
9.7 KiB
Bash
309 lines
9.7 KiB
Bash
#! /bin/sh
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# Usage: make-syscalls.sh ../sysdeps/unix/common
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# Expects $sysdirs in environment.
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##############################################################################
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#
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# This script is used to process the syscall data encoded in the various
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# syscalls.list files to produce thin assembly syscall wrappers around the
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# appropriate OS syscall. See syscall-template.s for more details on the
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# actual wrapper.
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#
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# Syscall Signature Prefixes:
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#
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# C: cancellable (i.e., this syscall is a cancellation point)
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# E: errno and return value are not set by the call
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# V: errno is not set, but errno or zero (success) is returned from the call
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#
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# Syscall Signature Key Letters:
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#
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# a: unchecked address (e.g., 1st arg to mmap)
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# b: non-NULL buffer (e.g., 2nd arg to read; return value from mmap)
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# B: optionally-NULL buffer (e.g., 4th arg to getsockopt)
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# f: buffer of 2 ints (e.g., 4th arg to socketpair)
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# F: 3rd arg to fcntl
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# i: scalar (any signedness & size: int, long, long long, enum, whatever)
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# I: 3rd arg to ioctl
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# n: scalar buffer length (e.g., 3rd arg to read)
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# N: pointer to value/return scalar buffer length (e.g., 6th arg to recvfrom)
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# p: non-NULL pointer to typed object (e.g., any non-void* arg)
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# P: optionally-NULL pointer to typed object (e.g., 2nd argument to gettimeofday)
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# s: non-NULL string (e.g., 1st arg to open)
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# S: optionally-NULL string (e.g., 1st arg to acct)
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# v: vararg scalar (e.g., optional 3rd arg to open)
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# V: byte-per-page vector (3rd arg to mincore)
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# W: wait status, optionally-NULL pointer to int (e.g., 2nd arg of wait4)
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#
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##############################################################################
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thisdir=$1; shift
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echo ''
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echo \#### DIRECTORY = $thisdir
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# Check each sysdep dir with higher priority than this one,
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# and remove from $calls all the functions found in other dirs.
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# Punt when we reach the directory defining these syscalls.
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sysdirs=`for dir in $sysdirs; do
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test $dir = $thisdir && break; echo $dir; done`
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echo \#### SYSDIRS = $sysdirs
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# Get the list of system calls for this directory.
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calls=`sed 's/#.*$//
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/^[ ]*$/d' $thisdir/syscalls.list`
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calls=`echo "$calls" |
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while read file caller rest; do
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# Remove each syscall that is implemented by a file in $dir.
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# If a syscall specified a "caller", then only compile that syscall
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# if the caller function is also implemented in this directory.
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srcfile=-;
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for dir in $sysdirs; do
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{ test -f $dir/$file.c && srcfile=$dir/$file.c; } ||
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{ test -f $dir/$file.S && srcfile=$dir/$file.S; } ||
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{ test x$caller != x- &&
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{ { test -f $dir/$caller.c && srcfile=$dir/$caller.c; } ||
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{ test -f $dir/$caller.S && srcfile=$dir/$caller.S; }; }; } && break;
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done;
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echo $file $srcfile $caller $rest;
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done`
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# Any calls left?
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test -n "$calls" || exit 0
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# This uses variables $weak, $strong, and $any_versioned.
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emit_weak_aliases()
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{
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# A shortcoming in the current gas is that it will only allow one
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# version-alias per symbol. So we create new strong aliases as needed.
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vcount=""
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# We use the <shlib-compat.h> macros to generate the versioned aliases
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# so that the version sets can be mapped to the configuration's
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# minimum version set as per shlib-versions DEFAULT lines. But note
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# we don't generate any "#if SHLIB_COMPAT (...)" conditionals. To do
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# that we'd need to change the syscalls.list format so that it can
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# list the "obsoleted" version set too. If it ever arises that we
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# have a syscall entry point that is obsoleted by a newer version set,
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# we'll have to revamp all this.
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if [ $any_versioned = t ]; then
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echo " echo '#include <shlib-compat.h>'; \\"
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fi
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for name in $weak; do
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case $name in
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*@@*)
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base=`echo $name | sed 's/@@.*//'`
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ver=`echo $name | sed 's/.*@@//;s/\./_/g'`
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echo " echo '#if IS_IN (libc)'; \\"
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if test -z "$vcount" ; then
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source=$strong
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vcount=1
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else
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source="${strong}_${vcount}"
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vcount=`expr $vcount + 1`
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echo " echo 'strong_alias ($strong, $source)'; \\"
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fi
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echo " echo 'versioned_symbol (libc, $source, $base, $ver)'; \\"
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echo " echo '#else'; \\"
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echo " echo 'strong_alias ($strong, $base)'; \\"
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echo " echo '#endif'; \\"
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;;
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*@*)
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base=`echo $name | sed 's/@.*//'`
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ver=`echo $name | sed 's/.*@//;s/\./_/g'`
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echo " echo '#if defined SHARED && IS_IN (libc)'; \\"
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if test -z "$vcount" ; then
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source=$strong
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vcount=1
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else
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source="${strong}_${vcount}"
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vcount=`expr $vcount + 1`
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echo " echo 'strong_alias ($strong, $source)'; \\"
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fi
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echo " echo 'compat_symbol (libc, $source, $base, $ver)'; \\"
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echo " echo '#endif'; \\"
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;;
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!*)
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name=`echo $name | sed 's/.//'`
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echo " echo 'strong_alias ($strong, $name)'; \\"
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echo " echo 'libc_hidden_def ($name)'; \\"
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;;
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*)
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echo " echo 'weak_alias ($strong, $name)'; \\"
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echo " echo 'libc_hidden_weak ($name)'; \\"
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;;
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esac
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done
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}
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# Emit rules to compile the syscalls remaining in $calls.
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echo "$calls" |
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while read file srcfile caller syscall args strong weak; do
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vdso_syscall=
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case x"$syscall" in
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*:*@*)
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vdso_syscall="${syscall#*:}"
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syscall="${syscall%:*}"
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;;
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esac
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case x"$syscall" in
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x-) callnum=_ ;;
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*)
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# Figure out if $syscall is defined with a number in syscall.h.
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callnum=-
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eval `{ echo "#include <sysdep.h>";
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echo "callnum=SYS_ify ($syscall)"; } |
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$asm_CPP -D__OPTIMIZE__ - |
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sed -n -e "/^callnum=.*$syscall/d" \
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-e "/^\(callnum=\)[ ]*\(.*\)/s//\1'\2'/p"`
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;;
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esac
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cancellable=0
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noerrno=0
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errval=0
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case $args in
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C*) cancellable=1; args=`echo $args | sed 's/C:\?//'`;;
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E*) noerrno=1; args=`echo $args | sed 's/E:\?//'`;;
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V*) errval=1; args=`echo $args | sed 's/V:\?//'`;;
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esac
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# Derive the number of arguments from the argument signature
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case $args in
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[0-9]) nargs=$args;;
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?:) nargs=0;;
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?:?) nargs=1;;
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?:??) nargs=2;;
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?:???) nargs=3;;
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?:????) nargs=4;;
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?:?????) nargs=5;;
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?:??????) nargs=6;;
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?:???????) nargs=7;;
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?:????????) nargs=8;;
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?:?????????) nargs=9;;
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esac
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# Make sure only the first syscall rule is used, if multiple dirs
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# define the same syscall.
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echo ''
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echo "#### CALL=$file NUMBER=$callnum ARGS=$args SOURCE=$srcfile"
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# If there are versioned aliases the entry is only generated for the
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# shared library, unless it is a default version.
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any_versioned=f
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shared_only=f
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case $weak in
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*@@*) any_versioned=t ;;
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*@*) any_versioned=t shared_only=t ;;
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esac
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case x$srcfile"$callnum" in
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x--)
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# Undefined callnum for an extra syscall.
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if [ x$caller != x- ]; then
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if [ $noerrno != 0 ]; then
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echo >&2 "$0: no number for $fileno, no-error syscall ($strong $weak)"
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exit 2
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fi
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echo "unix-stub-syscalls += $strong $weak"
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fi
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;;
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x*-) ;; ### Do nothing for undefined callnum
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x-*)
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echo "ifeq (,\$(filter $file,\$(unix-syscalls)))"
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if test $shared_only = t; then
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# The versioned symbols are only in the shared library.
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echo "ifneq (,\$(filter .os,\$(object-suffixes)))"
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fi
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# Accumulate the list of syscall files for this directory.
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echo "unix-syscalls += $file"
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test x$caller = x- || echo "unix-extra-syscalls += $file"
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# Emit a compilation rule for this syscall.
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if test $shared_only = t; then
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# The versioned symbols are only in the shared library.
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echo "shared-only-routines += $file"
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test -n "$vdso_syscall" || echo "\$(objpfx)${file}.os: \\"
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else
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object_suffixes='$(object-suffixes)'
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test -z "$vdso_syscall" || object_suffixes='$(object-suffixes-noshared)'
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echo "\
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\$(foreach p,\$(sysd-rules-targets),\
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\$(foreach o,${object_suffixes},\$(objpfx)\$(patsubst %,\$p,$file)\$o)): \\"
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fi
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echo " \$(..)sysdeps/unix/make-syscalls.sh"
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case x"$callnum" in
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x_)
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echo "\
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\$(make-target-directory)
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(echo '/* Dummy module requested by syscalls.list */'; \\"
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;;
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x*)
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echo "\
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\$(make-target-directory)
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(echo '#define SYSCALL_NAME $syscall'; \\
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echo '#define SYSCALL_NARGS $nargs'; \\
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echo '#define SYSCALL_SYMBOL $strong'; \\
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echo '#define SYSCALL_CANCELLABLE $cancellable'; \\
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echo '#define SYSCALL_NOERRNO $noerrno'; \\
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echo '#define SYSCALL_ERRVAL $errval'; \\
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echo '#include <syscall-template.S>'; \\"
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;;
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esac
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# Append any weak aliases or versions defined for this syscall function.
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emit_weak_aliases
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# And finally, pipe this all into the compiler.
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echo ' ) | $(compile-syscall) '"\
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\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
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if test -n "$vdso_syscall"; then
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# In the shared library, we're going to emit an IFUNC using a vDSO function.
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# $vdso_syscall looks like "name@KERNEL_X.Y" where "name" is the symbol
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# name in the vDSO and KERNEL_X.Y is its symbol version.
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vdso_symbol="${vdso_syscall%@*}"
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vdso_symver="${vdso_syscall#*@}"
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vdso_symver=`echo "$vdso_symver" | sed 's/\./_/g'`
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echo "\
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\$(foreach p,\$(sysd-rules-targets),\$(objpfx)\$(patsubst %,\$p,$file).os): \\
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\$(..)sysdeps/unix/make-syscalls.sh\
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\$(make-target-directory)
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(echo '#include <dl-vdso.h>'; \\
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echo 'extern void *${strong}_ifunc (void) __asm (\"${strong}\");'; \\
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echo 'void *'; \\
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echo '${strong}_ifunc (void)'; \\
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echo '{'; \\
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echo ' PREPARE_VERSION_KNOWN (symver, ${vdso_symver});'; \\
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echo ' return _dl_vdso_vsym (\"${vdso_symbol}\", &symver);'; \\
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echo '}'; \\
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echo 'asm (\".type ${strong}, %gnu_indirect_function\");'; \\"
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# This is doing "libc_hidden_def (${strong})", but the compiler
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# doesn't know that we've defined ${strong} in the same file, so
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# we can't do it the normal way.
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echo "\
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echo 'asm (\".globl __GI_${strong}\\n\"'; \\
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echo ' \"__GI_${strong} = ${strong}\");'; \\"
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emit_weak_aliases
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echo ' ) | $(compile-stdin.c) '"\
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\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
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fi
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if test $shared_only = t; then
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# The versioned symbols are only in the shared library.
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echo endif
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fi
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echo endif
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;;
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esac
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done
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