Fix freeze in config's interrupt trap with some shells

With bash and zsh, the trap on the 5 second read does respond, but
doesn't break out of the read.  What's worse is that it takes away the
5 second timer, and therefore has the read hang indefinitely and
(almost) unbreakable.

Having the trap do 'exit 0' after reseting the tty params has it break
out of read and continue with the configuration.

Other shells do not appear to have the issue described here, but
neither does the extra 'exit 0' appear to harm them.

Reviewed-by: Andy Polyakov <appro@openssl.org>

diff --git a/config b/config
index ae349ecb0c625187f24baf7a5e7493f5a6081dd2..fb24a5dea3aa780c4125e200083def29cd2d693b 100755 (executable)
--- a/config
+++ b/config
@@ -480,7 +480,7 @@ case "$GUESSOS" in
        echo "         invoke '$THERE/Configure irix64-mips4-$CC' *manually*."
        if [ "$TEST" = "false" -a -t 1 ]; then
          echo "         You have about 5 seconds to press Ctrl-C to abort."
-         (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+         (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
        fi
         #CPU=`(hinv -t cpu) 2>/dev/null | head -1 | sed 's/^CPU:[^R]*R\([0-9]*\).*/\1/'`
         #CPU=${CPU:-0}
@@ -499,7 +499,7 @@ case "$GUESSOS" in
            echo "         invoke '$THERE/Configure darwin64-ppc-cc' *manually*."
            if [ "$TEST" = "false" -a -t 1 ]; then
              echo "         You have about 5 seconds to press Ctrl-C to abort."
-             (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+             (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
            fi
        fi
        if [ "$ISA64" = "1" -a "$KERNEL_BITS" = "64" ]; then
@@ -552,7 +552,7 @@ case "$GUESSOS" in
            echo "         invoke '$THERE/Configure linux-ppc64' *manually*."
            if [ "$TEST" = "false" -a -t 1 ]; then
                echo "         You have about 5 seconds to press Ctrl-C to abort."
-               (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+               (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
            fi
        fi
        if [ "$KERNEL_BITS" = "64" ]; then
@@ -569,7 +569,7 @@ case "$GUESSOS" in
        echo "         invoke '$THERE/Configure linux64-mips64' *manually*."
        if [ "$TEST" = "false" -a -t 1 ]; then
            echo "         You have about 5 seconds to press Ctrl-C to abort."
-           (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+           (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
        fi
        OUT="linux-mips64"
        ;;
@@ -586,7 +586,7 @@ case "$GUESSOS" in
        echo "         invoke '$THERE/Configure linux64-sparcv9' *manually*."
        if [ "$TEST" = "false" -a -t 1 ]; then
          echo "          You have about 5 seconds to press Ctrl-C to abort."
-         (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+         (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
        fi
        OUT="linux-sparcv9" ;;
   sparc-*-linux2)
@@ -634,7 +634,7 @@ case "$GUESSOS" in
        #  echo "         have to invoke './Configure linux32-s390x' *manually*."
        #  if [ "$TEST" = "false" -a -t -1 ]; then
        #    echo "         You have about 5 seconds to press Ctrl-C to abort."
-       #    (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+       #    (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
        #  fi
        #fi
        OUT="linux64-s390x"
@@ -663,7 +663,7 @@ case "$GUESSOS" in
                echo "         invoke '$THERE/Configure solaris64-sparcv9-cc' *manually*."
                if [ "$TEST" = "false" -a -t 1 ]; then
                  echo "         You have about 5 seconds to press Ctrl-C to abort."
-                 (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+                 (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
                fi
            elif [ "$CC" = "gcc" -a "$GCC_ARCH" = "-m64" ]; then
                # $GCC_ARCH denotes default ABI chosen by compiler driver
@@ -675,7 +675,7 @@ case "$GUESSOS" in
                echo "         invoke '$THERE/Configure solaris-sparcv9-gcc' *manually*."
                if [ "$TEST" = "false" -a -t 1 ]; then
                  echo "         You have about 5 seconds to press Ctrl-C to abort."
-                 (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+                 (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
                fi
            elif [ "$GCC_ARCH" = "-m32" ]; then
                echo "NOTICE! If you *know* that your GNU C supports 64-bit/V9 ABI"
@@ -683,7 +683,7 @@ case "$GUESSOS" in
                echo "        invoke '$THERE/Configure solaris64-sparcv9-gcc' *manually*."
                if [ "$TEST" = "false" -a -t 1 ]; then
                  echo "         You have about 5 seconds to press Ctrl-C to abort."
-                 (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+                 (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
                fi
            fi
        fi
@@ -764,7 +764,7 @@ case "$GUESSOS" in
                echo "         invoke '$THERE/Configure hpux64-parisc2-cc' *manually*."
                if [ "$TEST" = "false" -a -t 1 ]; then
                  echo "         You have about 5 seconds to press Ctrl-C to abort."
-                 (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+                 (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
                fi
             fi
        elif [ $CPU_VERSION -ge 528 ]; then     # PA-RISC 1.1+ CPU
@@ -796,7 +796,7 @@ case "$GUESSOS" in
                echo "         invoke '$THERE/Configure aix64-cc' *manually*."
                if [ "$TEST" = "false" -a -t 1 ]; then
                    echo "         You have ~5 seconds to press Ctrl-C to abort."
-                   (trap "stty `stty -g`" 2 0; stty -icanon min 0 time 50; read waste) <&1
+                   (trap "stty `stty -g`; exit 0" 2 0; stty -icanon min 0 time 50; read waste) <&1
                fi
            fi
        fi