add revwords package

packages/fizzbuzz/service/fizzbuzz/go

@@ -0,0 +1,3 @@
+#! /bin/sh
+
+exec /opt/fizzbuzz/bin/fizzbuzz 3</opt/fizzbuzz/token.enc

packages/fizzbuzz/service/fizzbuzz/run

@@ -5,4 +5,4 @@ exec 2>&1
 IP=$(cat ip.txt)
 ip addr add $IP dev eth0 || true
 
-exec tcpsvd -u nobody ${IP%/*} 1013 /opt/fizzbuzz/bin/fizzbuzz 3</opt/fizzbuzz/token.enc
+exec tcpsvd -u nobody ${IP%/*} 1013 ./go

packages/revwords/revwords.mk

@@ -0,0 +1,20 @@
+REVWORDS_PKGDIR = $(TARGET)/revwords
+REVWORDS_BUILDDIR = $(BUILD)/revwords
+
+revwords-install: revwords-build
+	mkdir -p $(REVWORDS_PKGDIR)/bin/
+
+	$(call COPYTREE, packages/revwords/service, $(REVWORDS_PKGDIR)/service)
+
+	cp packages/revwords/tokens.txt $(REVWORDS_PKGDIR)/
+	cp $(REVWORDS_BUILDDIR)/token.enc $(REVWORDS_PKGDIR)/
+	cp packages/revwords/src/revwords $(REVWORDS_PKGDIR)/bin/
+
+revwords-clean:
+	rm -rf $(REVWORDS_PKGDIR) $(REVWORDS_BUILDDIR)
+	$(MAKE) -C packages/revwords/src clean
+
+revwords-build: $(REVWORDS_BUILDDIR)/token.enc
+	$(MAKE) -C packages/revwords/src build
+
+PACKAGES += revwords

packages/revwords/service/revwords/go

@@ -0,0 +1,3 @@
+#! /bin/sh
+
+exec /opt/revwords/bin/revwords 3</opt/revwords/tokens.txt

packages/revwords/service/revwords/ip.txt

@@ -0,0 +1 @@
+fd84:b410:3441::c3/64

packages/revwords/service/revwords/log/run

@@ -0,0 +1,3 @@
+#! /bin/sh
+
+exec svlogd -tt $PWD

packages/revwords/service/revwords/run

@@ -0,0 +1,9 @@
+#! /bin/sh -e
+
+exec 2>&1
+
+IP=$(cat ip.txt)
+ip addr add $IP dev eth0 || true
+
+exec tcpsvd -u nobody ${IP%/*} 1013 ./go
+

packages/revwords/src/Makefile

@@ -0,0 +1,6 @@
+CFLAGS = -Wall -Werror
+
+build: revwords
+
+clean:
+	rm -f revwords

packages/revwords/src/revwords.c

@@ -0,0 +1,105 @@
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <time.h>
+#include <stdio.h>
+
+#define XDEBUG
+
+int
+once()
+{
+  char sdrow[25][10];
+  int  nwords = 5 + (rand() % 2);
+  int  i;
+
+#ifdef DEBUG
+  nwords = 2;
+#endif
+
+  for (i = 0; i < nwords; i += 1) {
+    char *drow = sdrow[i];
+    int   len  = 4 + (rand() % 6);
+    int   j;
+
+    if (i > 0) putchar(' ');
+    for (j = 0; j < len; j += 1) {
+      char c = 'a' + (rand() % 26);
+
+      putchar(c);
+      drow[len-j-1] = c;
+    }
+
+    drow[j] = 0;
+  }
+
+#ifdef DEBUG
+  printf ("    (answer: ");
+  for (i = 0; i < nwords; i += 1) {
+    if (i > 0) putchar(' ');
+    printf("%s", sdrow[i]);
+  }
+  putchar(')');
+#endif
+
+  putchar('\n');
+  fflush(stdout);
+
+  for (i = 0; i < nwords; i += 1) {
+    char *p;
+
+    if (i > 0) {
+      if (getchar() != ' ') return -1;
+    }
+    for (p = sdrow[i]; *p; p += 1) {
+      int c = getchar();
+
+      if (c != *p) return -1;
+    }
+  }
+  if (getchar() != '\n') return -1;
+
+  return 0;
+}
+
+
+int
+main(int argc, char *argv[])
+{
+  char   token[100];
+  int    i;
+
+  {
+    FILE *tokenin = fdopen(3, "r");
+
+    if (! tokenin) {
+      fprintf(stderr, "Somebody didn't read the instructions.\n");
+      return 1;
+    }
+
+    if (NULL == fgets(token, sizeof(token), tokenin)) {
+      fprintf(stderr, "Error reading token.\n");
+      return 1;
+    }
+
+    fclose(tokenin);
+  }
+
+
+#ifndef DEBUG
+  /* don't hang around forever waiting for input */
+  alarm(3);
+#endif
+
+  srandom(time(NULL) * getpid());
+
+  for (i = 0; i < 12; i += 1) {
+    if (-1 == once()) {
+      printf("tahT saw ton tahw I saw gnitcepxe\n");
+      return 1;
+    }
+  }
+  fputs(token, stdout);
+
+  return 0;
+}

packages/revwords/src/solution.sh

@@ -0,0 +1,19 @@
+#! /bin/sh
+
+## Run like this:
+##
+##    socat EXEC:./solution.sh EXEC:./revwords 3<token.txt
+##
+
+lrev () {
+    while [ -n "$1" ]; do
+        echo $1 | rev
+        shift
+    done
+}
+
+while read line; do
+    echo $line 1>&2
+    enil=$(lrev $line)
+    echo $enil
+done

packages/revwords/tokens.txt

@@ -0,0 +1 @@
+net:xetil-tuhet-calyx