From 9b577bdbb1571982f5b7216838cb41d64b5d983e Mon Sep 17 00:00:00 2001
From: Kelvin Sherlock <ksherlock@gmail.com>
Date: Sat, 23 Jul 2016 23:50:28 -0400
Subject: [PATCH] builtin catenate (builtin so cr/lf conversion blocked)

---
 builtins.cpp | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 builtins.h   |  1 +
 command.cpp  |  1 +
 3 files changed, 56 insertions(+)

diff --git a/builtins.cpp b/builtins.cpp
index 639aaa2..babb912 100644
--- a/builtins.cpp
+++ b/builtins.cpp
@@ -19,6 +19,7 @@
 
 //MAXPATHLEN
 #include <sys/param.h>
+#include <fcntl.h>
 
 #include "version.h"
 
@@ -820,6 +821,59 @@ int builtin_which(Environment &env, const std::vector<std::string> &tokens, cons
 	return 2; // not found.
 }
 
+int cat_helper(int in, int out) {
+	static uint8_t buffer[4096];
+
+	for(;;) {
+		ssize_t rcount = read(in, buffer, sizeof(buffer));
+		if (rcount < 0) {
+			if (errno == EINTR) continue;
+			return 2;
+		}
+
+		if (rcount == 0) break;
+
+		for (;;) {
+			ssize_t wcount = write(out, buffer, rcount);
+			if (wcount < 0) {
+				if (errno == EINTR) continue;
+				return 2;	
+			}
+			if (wcount != rcount) return 2;
+			break;
+		}
+	}
+	return 0;
+}
+
+
+int builtin_catenate(Environment &env, const std::vector<std::string> &tokens, const fdmask &fds) {
+
+	if (tokens.size() == 1) {
+		int rv = cat_helper(stdin, stdout);
+		if (rv) fputs("### Catenate - I/O Error\n", stderr);
+		return rv;
+	}
+
+	for (const auto &s : make_offset_range(tokens, 1)) {
+
+		std::string path = ToolBox::MacToUnix(s);
+		int fd = open(path.c_str(), O_RDONLY);
+		if (fd < 0) {
+			fprintf(stderr, "### Catenate - Unable to open \"%s\".\n", path.c_str());
+			return 1;
+		}
+
+		int rv = cat_helper(fd, stdout);
+		close(fd);
+		if (rv) {
+			fputs("### Catenate - I/O Error\n", stderr);
+			return rv;
+		}
+	}
+	return 0;
+}
+
 int builtin_version(Environment &env, const std::vector<std::string> &tokens, const fdmask &fds) {
 
 
diff --git a/builtins.h b/builtins.h
index c86ff11..302aefa 100644
--- a/builtins.h
+++ b/builtins.h
@@ -9,6 +9,7 @@ class fdmask;
 class token;
 
 int builtin_aboutbox(Environment &e, const std::vector<std::string> &, const fdmask &);
+int builtin_catenate(Environment &e, const std::vector<std::string> &, const fdmask &);
 int builtin_directory(Environment &e, const std::vector<std::string> &, const fdmask &);
 int builtin_echo(Environment &e, const std::vector<std::string> &, const fdmask &);
 int builtin_exists(Environment &e, const std::vector<std::string> &, const fdmask &);
diff --git a/command.cpp b/command.cpp
index ca16790..a500eb5 100644
--- a/command.cpp
+++ b/command.cpp
@@ -191,6 +191,7 @@ namespace {
 	std::unordered_map<std::string, int (*)(Environment &, const std::vector<std::string> &, const fdmask &)> builtins = {
 		{"aboutbox", builtin_aboutbox},
 		{"alias", builtin_alias},
+		{"catenate", builtin_catenate},
 		{"directory", builtin_directory},
 		{"echo", builtin_echo},
 		{"exists", builtin_exists},