From 9114e110a59a77909132af6d97bccdf5056adfa4 Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Mon, 29 Jun 2020 11:46:43 +0100
Subject: ash: avoid duplicated slashes in output of type/command builtins

Microsoft developers have a penchant for adding trailing slashes to
entries in PATH:

   C:/Windows/System32/WindowsPowerShell/v1.0/
   C:/Windows/System32/OpenSSH/

The 'type' and 'command -v' shell builtins return paths with duplicated
slashes for executables in those directories.  See GitHub issue #191.

Bonus fixes:

- handle backslashes as well as slashes in concat_path_file()
- convert backslashes to slashes in the output of 'type', 'command -v'
---
 libbb/concat_path_file.c | 6 ++++++
 shell/ash.c              | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/libbb/concat_path_file.c b/libbb/concat_path_file.c
index 5b4b7f113..81c7481ca 100644
--- a/libbb/concat_path_file.c
+++ b/libbb/concat_path_file.c
@@ -21,8 +21,14 @@ char* FAST_FUNC concat_path_file(const char *path, const char *filename)
 
 	if (!path)
 		path = "";
+#if ENABLE_PLATFORM_MINGW32
+	lc = last_char_is(path, '/') ?: last_char_is(path, '\\');
+	while (*filename == '/' || *filename == '\\')
+		filename++;
+#else
 	lc = last_char_is(path, '/');
 	while (*filename == '/')
 		filename++;
+#endif
 	return xasprintf("%s%s%s", path, (lc==NULL ? "/" : ""), filename);
 }
diff --git a/shell/ash.c b/shell/ash.c
index b51a3fb82..3c53b25ff 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2860,6 +2860,9 @@ padvance_magic(const char **path, const char *name, int magic)
 
 	if (len) {
 		q = mempcpy(q, start, len);
+#if ENABLE_PLATFORM_MINGW32
+		if (q[-1] != '/' && q[-1] != '\\')
+#endif
 		*q++ = '/';
 	}
 	strcpy(q, name);
@@ -9160,6 +9163,7 @@ describe_command(char *command, const char *path, int describe_command_verbose)
 		}
 #if ENABLE_PLATFORM_MINGW32
 		add_win32_extension(p);
+		bs_to_slash(p);
 #endif
 		if (describe_command_verbose) {
 			out1fmt(" is %s", p);
-- 
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