sysdeps/unix/make-syscalls.sh

   1 #!/bin/sh
   2
   3 # Usage: make-syscalls.sh ../sysdeps/unix/common
   4 # Expects $sysdirs in environment.
   5
   6 ##############################################################################
   7 #
   8 # This script is used to process the syscall data encoded in the various
   9 # syscalls.list files to produce thin assembly syscall wrappers around the
  10 # appropriate OS syscall. See syscall-template.s for more details on the
  11 # actual wrapper.
  12 #
  13 # Syscall Signature Prefixes:
  14 #
  15 # C: cancellable (i.e., this syscall is a cancellation point)
  16 # E: errno and return value are not set by the call
  17 # V: errno is not set, but errno or zero (success) is returned from the call
  18 #
  19 # Syscall Signature Key Letters:
  20 #
  21 # a: unchecked address (e.g., 1st arg to mmap)
  22 # b: non-NULL buffer (e.g., 2nd arg to read; return value from mmap)
  23 # B: optionally-NULL buffer (e.g., 4th arg to getsockopt)
  24 # f: buffer of 2 ints (e.g., 4th arg to socketpair)
  25 # F: 3rd arg to fcntl
  26 # i: scalar (any signedness & size: int, long, long long, enum, whatever)
  27 # I: 3rd arg to ioctl
  28 # n: scalar buffer length (e.g., 3rd arg to read)
  29 # N: pointer to value/return scalar buffer length (e.g., 6th arg to recvfrom)
  30 # p: non-NULL pointer to typed object (e.g., any non-void* arg)
  31 # P: optionally-NULL pointer to typed object (e.g., 2nd argument to gettimeofday)
  32 # s: non-NULL string (e.g., 1st arg to open)
  33 # S: optionally-NULL string (e.g., 1st arg to acct)
  34 # v: vararg scalar (e.g., optional 3rd arg to open)
  35 # V: byte-per-page vector (3rd arg to mincore)
  36 # W: wait status, optionally-NULL pointer to int (e.g., 2nd arg of wait4)
  37 #
  38
  39 ##############################################################################
  40
  41 thisdir=$1; shift
  42
  43 echo ''
  44 echo \#### DIRECTORY = $thisdir
  45 # Check each sysdep dir with higher priority than this one,
  46 # and remove from $calls all the functions found in other dirs.
  47 # Punt when we reach the directory defining these syscalls.
  48 sysdirs=`for dir in $sysdirs; do
  49          test $dir = $thisdir && break; echo $dir; done`
  50 echo \#### SYSDIRS = $sysdirs
  51
  52 # Get the list of system calls for this directory.
  53 calls=`sed 's/#.*$//
  54 /^[     ]*$/d' $thisdir/syscalls.list`
  55
  56 calls=`echo "$calls" |
  57 while read file caller rest; do
  58   # Remove each syscall that is implemented by a file in $dir.
  59   # If a syscall specified a "caller", then only compile that syscall
  60   # if the caller function is also implemented in this directory.
  61   srcfile=-;
  62   for dir in $sysdirs; do
  63      { test -f $dir/$file.c && srcfile=$dir/$file.c; } ||
  64      { test -f $dir/$file.S && srcfile=$dir/$file.S; } ||
  65      { test x$caller != x- &&
  66         { { test -f $dir/$caller.c && srcfile=$dir/$caller.c; } ||
  67           { test -f $dir/$caller.S && srcfile=$dir/$caller.S; }; }; } && break;
  68   done;
  69   echo $file $srcfile $caller $rest;
  70 done`
  71
  72 # Any calls left?
  73 test -n "$calls" || exit 0
  74
  75 # This uses variables $weak, $strong, and $any_versioned.
  76 emit_weak_aliases()
  77 {
  78   # A shortcoming in the current gas is that it will only allow one
  79   # version-alias per symbol.  So we create new strong aliases as needed.
  80   vcount=""
  81
  82   # We use the <shlib-compat.h> macros to generate the versioned aliases
  83   # so that the version sets can be mapped to the configuration's
  84   # minimum version set as per shlib-versions DEFAULT lines.  If an
  85   # entry point is specified in the form NAME@VERSION:OBSOLETED, a
  86   # SHLIB_COMPAT conditional is generated.
  87   if [ $any_versioned = t ]; then
  88     echo "       echo '#include <shlib-compat.h>'; \\"
  89   fi
  90
  91   for name in $weak; do
  92     case $name in
  93       *@@*)
  94         base=`echo $name | sed 's/@@.*//'`
  95         ver=`echo $name | sed 's/.*@@//;s/\./_/g'`
  96         echo "   echo '#if IS_IN (libc)'; \\"
  97         if test -z "$vcount" ; then
  98           source=$strong
  99           vcount=1
 100         else
 101           source="${strong}_${vcount}"
 102           vcount=`expr $vcount + 1`
 103           echo "         echo 'strong_alias ($strong, $source)'; \\"
 104         fi
 105         echo "   echo 'versioned_symbol (libc, $source, $base, $ver)'; \\"
 106         echo "   echo '#else'; \\"
 107         echo "   echo 'strong_alias ($strong, $base)'; \\"
 108         echo "   echo '#endif'; \\"
 109         ;;
 110       *@*)
 111         base=`echo $name | sed 's/@.*//'`
 112         ver=`echo $name | sed 's/.*@//;s/\./_/g'`
 113         case $ver in
 114           *:*)
 115             compat_ver=${ver#*:}
 116             ver=${ver%%:*}
 117             compat_cond=" && SHLIB_COMPAT (libc, $ver, $compat_ver)"
 118             ;;
 119           *)
 120             compat_cond=
 121             ;;
 122         esac
 123         echo "   echo '#if defined SHARED && IS_IN (libc)$compat_cond'; \\"
 124         if test -z "$vcount" ; then
 125           source=$strong
 126           vcount=1
 127         else
 128           source="${strong}_${vcount}"
 129           vcount=`expr $vcount + 1`
 130           echo "         echo 'strong_alias ($strong, $source)'; \\"
 131         fi
 132         echo "   echo 'compat_symbol (libc, $source, $base, $ver)'; \\"
 133         echo "   echo '#endif'; \\"
 134         ;;
 135       !*)
 136         name=`echo $name | sed 's/.//'`
 137         echo "   echo 'strong_alias ($strong, $name)'; \\"
 138         echo "   echo 'hidden_def ($name)'; \\"
 139         ;;
 140       *)
 141         echo "   echo 'weak_alias ($strong, $name)'; \\"
 142         echo "   echo 'hidden_weak ($name)'; \\"
 143         ;;
 144     esac
 145   done
 146 }
 147
 148
 149 # Emit rules to compile the syscalls remaining in $calls.
 150 echo "$calls" |
 151 while read file srcfile caller syscall args strong weak; do
 152
 153   vdso_syscall=
 154   case x"$syscall" in
 155   *:*@*)
 156     vdso_syscall="${syscall#*:}"
 157     syscall="${syscall%:*}"
 158     ;;
 159   esac
 160
 161   case x"$syscall" in
 162   x-) callnum=_ ;;
 163   *)
 164   # Figure out if $syscall is defined with a number in syscall.h.
 165   callnum=-
 166   eval `{ echo "#include <sysdep.h>";
 167         echo "callnum=SYS_ify ($syscall)"; } |
 168           $asm_CPP -D__OPTIMIZE__ - |
 169           sed -n -e "/^callnum=.*$syscall/d" \
 170                  -e "/^\(callnum=\)[    ]*\(.*\)/s//\1'\2'/p"`
 171   ;;
 172   esac
 173
 174   cancellable=0
 175   noerrno=0
 176   errval=0
 177   case $args in
 178   C*) cancellable=1; args=`echo $args | sed 's/C:\?//'`;;
 179   E*) noerrno=1; args=`echo $args | sed 's/E:\?//'`;;
 180   V*) errval=1; args=`echo $args | sed 's/V:\?//'`;;
 181   esac
 182
 183   # Derive the number of arguments from the argument signature
 184   case $args in
 185   [0-9]) nargs=$args;;
 186   ?:) nargs=0;;
 187   ?:?) nargs=1;;
 188   ?:??) nargs=2;;
 189   ?:???) nargs=3;;
 190   ?:????) nargs=4;;
 191   ?:?????) nargs=5;;
 192   ?:??????) nargs=6;;
 193   ?:???????) nargs=7;;
 194   ?:????????) nargs=8;;
 195   ?:?????????) nargs=9;;
 196   esac
 197
 198   # Make sure only the first syscall rule is used, if multiple dirs
 199   # define the same syscall.
 200   echo ''
 201   echo "#### CALL=$file NUMBER=$callnum ARGS=$args SOURCE=$srcfile"
 202
 203   # If there are versioned aliases the entry is only generated for the
 204   # shared library, unless it is a default version.
 205   any_versioned=f
 206   shared_only=f
 207   case $weak in
 208     *@@*) any_versioned=t ;;
 209     *@*) any_versioned=t shared_only=t ;;
 210   esac
 211
 212  case x$srcfile"$callnum" in
 213  x--)
 214   # Undefined callnum for an extra syscall.
 215   if [ x$caller != x- ]; then
 216     if [ $noerrno != 0 ]; then
 217       echo >&2 "$0: no number for $fileno, no-error syscall ($strong $weak)"
 218       exit 2
 219     fi
 220     echo "unix-stub-syscalls += $strong $weak"
 221   fi
 222   ;;
 223  x*-) ;; ### Do nothing for undefined callnum
 224  x-*)
 225   echo "ifeq (,\$(filter $file,\$(unix-syscalls)))"
 226
 227   if test $shared_only = t; then
 228     # The versioned symbols are only in the shared library.
 229     echo "ifneq (,\$(filter .os,\$(object-suffixes)))"
 230   fi
 231   # Accumulate the list of syscall files for this directory.
 232   echo "unix-syscalls += $file"
 233   test x$caller = x- || echo "unix-extra-syscalls += $file"
 234
 235   # Emit a compilation rule for this syscall.
 236   if test $shared_only = t; then
 237     # The versioned symbols are only in the shared library.
 238     echo "shared-only-routines += $file"
 239     test -n "$vdso_syscall" || echo "\$(objpfx)${file}.os: \\"
 240   else
 241     object_suffixes='$(object-suffixes)'
 242     test -z "$vdso_syscall" || object_suffixes='$(object-suffixes-noshared)'
 243     echo "\
 244 \$(foreach p,\$(sysd-rules-targets),\
 245 \$(foreach o,${object_suffixes},\$(objpfx)\$(patsubst %,\$p,$file)\$o)): \\"
 246   fi
 247
 248   echo "                \$(..)sysdeps/unix/make-syscalls.sh"
 249   case x"$callnum" in
 250   x_)
 251   echo "\
 252         \$(make-target-directory)
 253         (echo '/* Dummy module requested by syscalls.list */'; \\"
 254   ;;
 255   x*)
 256   echo "\
 257         \$(make-target-directory)
 258         (echo '#define SYSCALL_NAME $syscall'; \\
 259          echo '#define SYSCALL_NARGS $nargs'; \\
 260          echo '#define SYSCALL_SYMBOL $strong'; \\
 261          echo '#define SYSCALL_CANCELLABLE $cancellable'; \\
 262          echo '#define SYSCALL_NOERRNO $noerrno'; \\
 263          echo '#define SYSCALL_ERRVAL $errval'; \\
 264          echo '#include <syscall-template.S>'; \\"
 265   ;;
 266   esac
 267
 268   # Append any weak aliases or versions defined for this syscall function.
 269   emit_weak_aliases
 270
 271   # And finally, pipe this all into the compiler.
 272   echo '        ) | $(compile-syscall) '"\
 273 \$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
 274
 275   if test -n "$vdso_syscall"; then
 276     # In the shared library, we're going to emit an IFUNC using a vDSO function.
 277     # $vdso_syscall looks like "name@KERNEL_X.Y" where "name" is the symbol
 278     # name in the vDSO and KERNEL_X.Y is its symbol version.
 279     vdso_symbol="${vdso_syscall%@*}"
 280     vdso_symver="${vdso_syscall#*@}"
 281     vdso_symver=`echo "$vdso_symver" | sed 's/\./_/g'`
 282     cat <<EOF
 283
 284 \$(foreach p,\$(sysd-rules-targets),\$(objpfx)\$(patsubst %,\$p,$file).os): \\
 285                 \$(..)sysdeps/unix/make-syscalls.sh
 286         \$(make-target-directory)
 287         (echo '#include <dl-vdso.h>'; \\
 288          echo 'extern void *${strong}_ifunc (void) __asm ("${strong}");'; \\
 289          echo 'void *'; \\
 290          echo '${strong}_ifunc (void)'; \\
 291          echo '{'; \\
 292          echo '  PREPARE_VERSION_KNOWN (symver, ${vdso_symver});'; \\
 293          echo '  return _dl_vdso_vsym ("${vdso_symbol}", &symver);'; \\
 294          echo '}'; \\
 295          echo 'asm (".type ${strong}, %gnu_indirect_function");'; \\
 296 EOF
 297     # This is doing "hidden_def (${strong})", but the compiler
 298     # doesn't know that we've defined ${strong} in the same file, so
 299     # we can't do it the normal way.
 300     cat <<EOF
 301          echo 'asm (".globl __GI_${strong}");'; \\
 302          echo 'asm ("__GI_${strong} = ${strong}");'; \\
 303 EOF
 304     emit_weak_aliases
 305     cat <<EOF
 306         ) | \$(compile-stdin.c) \
 307 \$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))
 308 EOF
 309   fi
 310
 311   if test $shared_only = t; then
 312     # The versioned symbols are only in the shared library.
 313     echo endif
 314   fi
 315
 316   echo endif
 317  ;;
 318  esac
 319
 320 done