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