From 40936af68ea8fcbb8e7dd9ce9af7fae88b79535a Mon Sep 17 00:00:00 2001
From: Cody Boone Ferguson <53008573+xexyl@users.noreply.github.com>
Date: Mon, 18 Dec 2023 10:03:59 -0800
Subject: [PATCH] Add 2019/endoh/try.sh, helper program + formatting

The helper program ascii.c converts args passed to it to char values (if
isascii() returns non-zero) which with try.sh allows one to reconstruct
the code with the backtrace rather than having to memorise ascii(7) (and
even if they did it would be hard to put it together). One should of
course use xargs(1) and try.sh does.

The try.sh script checks that gdb is installed first, telling the user
to install it if they don't have it. The README.md file notes that for
macOS It's not a simple matter of just installing gdb - there are
additional steps.
---
 2019/endoh/.gitignore |  1 +
 2019/endoh/Makefile   |  5 ++++-
 2019/endoh/README.md  | 15 +++++++++++++++
 2019/endoh/ascii.c    | 19 +++++++++++++++++++
 2019/endoh/try.sh     | 43 +++++++++++++++++++++++++++++++++++++++++++
 thanks-for-help.md    |  6 ++++++
 6 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 2019/endoh/ascii.c
 create mode 100755 2019/endoh/try.sh

diff --git a/2019/endoh/.gitignore b/2019/endoh/.gitignore
index f63f9f19d..31ac2bf7a 100644
--- a/2019/endoh/.gitignore
+++ b/2019/endoh/.gitignore
@@ -1,6 +1,7 @@
 #
 # sort with: sort -d -u
 *.dSYM
+ascii
 indent
 indent.c
 indent.o
diff --git a/2019/endoh/Makefile b/2019/endoh/Makefile
index dd5a64307..473de4155 100644
--- a/2019/endoh/Makefile
+++ b/2019/endoh/Makefile
@@ -111,7 +111,7 @@ PROG= prog
 OBJ= ${PROG}.o
 CSRC= ${PROG}.o
 DATA=
-TARGET= ${PROG}
+TARGET= ${PROG} ascii
 #
 ALT_OBJ=
 ALT_TARGET=
@@ -132,6 +132,9 @@ all: data ${TARGET}
 ${PROG}: ${PROG}.c
 	${CC} ${CFLAGS} -g $< -o $@ ${LDFLAGS}
 
+ascii: ascii.c
+	${CC} $< -o $@
+
 # alternative executable
 #
 alt: data ${ALT_TARGET}
diff --git a/2019/endoh/README.md b/2019/endoh/README.md
index 2130710bf..b4ce509d8 100644
--- a/2019/endoh/README.md
+++ b/2019/endoh/README.md
@@ -25,10 +25,24 @@ For more detailed information see [2019 endoh in bugs.md](/bugs.md#2019-endoh).
 
 ### Try:
 
+If you have `gdb(1)` installed:
+
+```sh
+./try.sh
+```
+
+Note that in macOS installing `gdb(1)` takes multiple steps - it's not just a
+matter of installing `gdb(1)` and that's that. The [try.sh](try.sh) script has
+only been tested with linux.
+
+You might also wish to try:
+
 ```sh
 gdb ./prog || lldb ./prog
 ```
 
+and then type in `r` (to run program) and then `bt` (for backtrace).
+
 
 ## Judges' remarks:
 
@@ -38,6 +52,7 @@ ascii` when debugging it to reveal its purpose.
 
 ## Author's remarks:
 
+
 ### backtrace quine:
 
 Compile prog.c with no optimization.
diff --git a/2019/endoh/ascii.c b/2019/endoh/ascii.c
new file mode 100644
index 000000000..f09ba521f
--- /dev/null
+++ b/2019/endoh/ascii.c
@@ -0,0 +1,19 @@
+/*
+ * ascii.c - simple program that shows the character value of ASCII values, if
+ * isascii() is true, to help demonstrate IOCCC winner 2019/endoh.
+ *
+ * Will not do anything if no args specified. Use xargs(1) to pass args to
+ * program if it's a lot of characters.
+ */
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+int main(int argc, char **argv)
+{
+    int i;
+    for (argc = 1; argv[argc]; ++argc)
+    {
+	i=atoi(argc[argv]);
+	if (isascii(i)) printf("%c", i);
+    }
+}
diff --git a/2019/endoh/try.sh b/2019/endoh/try.sh
new file mode 100755
index 000000000..764447e0e
--- /dev/null
+++ b/2019/endoh/try.sh
@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+#
+# try.sh - demonstrate IOCCC winner 2019/endoh
+#
+
+# make sure CC is set so that when we do make CC="$CC" it isn't empty. Doing it
+# this way allows us to have the user specify a different compiler in an easy
+# way.
+if [[ -z "$CC" ]]; then
+    CC="cc"
+fi
+
+# Before we do anything we have to make sure we have GDB available
+#
+GDB="$(type -P gdb)"
+
+if [[ -z "$GDB" ]]; then
+    echo "No gdb found, install gdb and try again." 1>&2
+    exit 1
+fi
+
+make CC="$CC" all >/dev/null || exit 1
+
+# clear screen after compilation so that only the entry is shown
+clear
+
+echo "$ $GDB -q -x prog.c ./prog | head -n 25" 1>&2
+read -r -n 1 -p "Press any key to use source code as GDB command file (first 25 lines): "
+echo >&2
+"$GDB" -q -x prog.c ./prog | head -n 25
+
+echo "$ $GDB -q -x prog.c ./prog | cat | grep : | cut -f 2 -d:|xargs ./ascii"
+read -r -n 1 -p "Press any key to use the backtrace to reconstruct prog.c (space = next page, q = quit): "
+echo 1>&2
+"$GDB" -q -x prog.c ./prog | cat | grep : | cut -f 2 -d: | xargs ./ascii | less -rEXF
+echo 1>&2
+
+read -r -n 1 -p "Press any key to compare reconstructed code with original: "
+echo 1>&2
+echo "$ "$GDB" -q -x prog.c ./prog | cat | grep : | cut -f 2 -d: | xargs ./ascii > prog2.c" 1>&2
+"$GDB" -q -x prog.c ./prog | cat | grep : | cut -f 2 -d: | xargs ./ascii > prog2.c
+echo "$ diff -s prog.c prog2.c" 1>&2
+diff -s prog.c prog2.c
diff --git a/thanks-for-help.md b/thanks-for-help.md
index ffe0b7e9f..a111c8f0b 100644
--- a/thanks-for-help.md
+++ b/thanks-for-help.md
@@ -4214,6 +4214,12 @@ As this is a backtrace quine having the optimiser enabled is not a good idea so
 compilation as debugging symbols might just be useful for an entry that's
 supposed to segfault :-)
 
+Cody also added the simple [ascii.c](/2019/endoh/ascii.c) that (while it has an
+arg) prints out the character of the ASCII value (uses `isascii(3)` first). This
+combined with the [try.sh](/2019/endoh/try.sh) script that he added allows one
+to easily reconstruct the source code through GDB by the fact it's a backtrace
+quine.
+
 
 ## <a name="2019_karns"></a>[2019/karns](/2019/karns/prog.c) ([README.md](/2019/karns/README.md]))