From b5509037bc84a7380e3a9cb8a1033f010f4cdbb7 Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Sun, 9 Jun 2013 13:44:34 +0200
Subject: [PATCH] Add command-not-found utility.

---
 utils/.gitignore            |  1 +
 utils/Makefile              |  1 +
 utils/command-not-found.cpp | 54 +++++++++++++++++++++++++++++++++++++
 utils/mxsh.cpp              | 10 +++++--
 4 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 utils/command-not-found.cpp

diff --git a/utils/.gitignore b/utils/.gitignore
index ffd29a92..414487cd 100644
--- a/utils/.gitignore
+++ b/utils/.gitignore
@@ -6,6 +6,7 @@ chvideomode
 clear
 colormake
 column
+command-not-found
 cp
 date
 du
diff --git a/utils/Makefile b/utils/Makefile
index 4771f322..515d443c 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -22,6 +22,7 @@ chvideomode \
 clear \
 colormake \
 column \
+command-not-found \
 cp \
 date \
 du \
diff --git a/utils/command-not-found.cpp b/utils/command-not-found.cpp
new file mode 100644
index 00000000..4620b136
--- /dev/null
+++ b/utils/command-not-found.cpp
@@ -0,0 +1,54 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    This program is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    This program is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+    more details.
+
+    You should have received a copy of the GNU General Public License along with
+    this program. If not, see <http://www.gnu.org/licenses/>.
+
+    command-not-found.cpp
+    Prints a notice that the attempted command wasn't found and possibly
+    suggests how to install the command or suggests the proper spelling in case
+    of a typo.
+
+*******************************************************************************/
+
+#include <stdio.h>
+#include <string.h>
+
+void suggest_editor(const char* filename)
+{
+	fprintf(stderr, "No command '%s' found, did you mean:\n", filename);
+	fprintf(stderr, " Command 'editor' from package 'utils'\n");
+}
+
+void suggest_pager(const char* filename)
+{
+	fprintf(stderr, "No command '%s' found, did you mean:\n", filename);
+	fprintf(stderr, " Command 'pager' from package 'utils'\n");
+}
+
+int main(int argc, char* argv[])
+{
+	const char* filename = 2 <= argc ? argv[1] : argv[0];
+	if ( !strcmp(filename, "ed") ||
+	     !strcmp(filename, "emacs") ||
+	     !strcmp(filename, "nano") ||
+	     !strcmp(filename, "vi") ||
+	     !strcmp(filename, "vim") )
+		suggest_editor(filename);
+	else if ( !strcmp(filename, "less") ||
+	          !strcmp(filename, "more") )
+		suggest_pager(filename);
+	fprintf(stderr, "%s: command not found\n", filename);
+	return 127;
+}
diff --git a/utils/mxsh.cpp b/utils/mxsh.cpp
index beee7452..7a197eb5 100644
--- a/utils/mxsh.cpp
+++ b/utils/mxsh.cpp
@@ -68,7 +68,7 @@ void updateenv()
 	}
 }
 
-int runcommandline(const char** tokens, bool* exitexec)
+int runcommandline(const char** tokens, bool* exitexec, bool interactive)
 {
 	int result = 127;
 	size_t cmdnext = 0;
@@ -273,6 +273,12 @@ readcmd:
 	}
 
 	execvp(argv[0], argv);
+	if ( interactive )
+	{
+		int errno_saved = errno;
+		execlp("command-not-found", "command-not-found", argv[0], NULL);
+		errno = errno_saved;
+	}
 	error(127, errno, "%s", argv[0]);
 	return 127;
 
@@ -454,7 +460,7 @@ int get_and_run_command(FILE* fp, const char* fpname, bool interactive,
 		return status;
 
 	argv[argc] = NULL;
-	status = runcommandline(argv, exitexec);
+	status = runcommandline(argv, exitexec, interactive);
 	if ( status && exit_on_error )
 		*exitexec = true;
 	return status;