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f7b425175c
This patch enables syscalls.list entries to specify both compat and non-compat symbol versions for the same syscall definition, making use of this for setrlimit / chown / lchown where the inability to specify such aliases showed up in the course of work on bug 14138. The change to make-syscalls.sh is minimal: adding a SHARED conditional on the compat_symbol calls. It remains the case that if a compat symbol version is specified, the syscall is only built for the shared library at all if an explicit symbol version is given for a non-compat symbol (so it's necessary to specify "lchown@@GLIBC_2.0 chown@GLIBC_2.0" rather than just "lchown chown@GLIBC_2.0"). It also remains the case, as already commented in make-syscalls.sh, that no SHLIB_COMPAT conditionals are generated, so there would be problems if the same syscalls.list file, with compat symbols, were used for both configurations that should have those symbols and configurations for which they should be conditioned out with SHLIB_COMPAT. Tested for x86. * sysdeps/unix/make-syscalls.sh (emit_weak_aliases): Condition compat_symbol calls on [SHARED]. * sysdeps/unix/sysv/linux/powerpc/lchown.S: Remove file. * sysdeps/unix/sysv/linux/i386/syscalls.list (oldsetrlimit): Remove. (setrlimit): Add setrlimit@GLIBC_2.0 alias. * sysdeps/unix/sysv/linux/m68k/m680x0/syscalls.list (oldsetrlimit): Remove. (setrlimit): Add setrlimit@GLIBC_2.0 alias. * sysdeps/unix/sysv/linux/powerpc/powerpc32/syscalls.list (lchown): New syscall entry. (oldsetrlimit): Remove. (setrlimit): Add setrlimit@GLIBC_2.0 alias. * sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list (oldsetrlimit): Remove. (setrlimit): Add setrlimit@GLIBC_2.0 alias.
313 lines
9.8 KiB
Bash
313 lines
9.8 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 $name | sed 's/.*@@//;s/\./_/g'`
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echo " echo '#ifndef NOT_IN_libc'; \\"
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if test -z "$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 $name | sed 's/.*@//;s/\./_/g'`
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echo " echo '#if defined SHARED && !defined NOT_IN_libc'; \\"
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if test -z "$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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[ $cancellable = 0 ] || echo "\
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echo '#define SYSCALL_CANCELLABLE 1'; \\"
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[ $noerrno = 0 ] || echo "\
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echo '#define SYSCALL_NOERRNO 1'; \\"
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[ $errval = 0 ] || echo "\
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echo '#define SYSCALL_ERRVAL 1'; \\"
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echo "\
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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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