From 862e1bd8d6117d5b44e3ab431b3a6837d8e44040 Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Mon, 28 Aug 2017 19:04:26 +0100
Subject: win32: shrink code to detect .exe files

Add a function (has_exe_suffix) to replace explicit code to check
if a filename ends with '.exe. or '.com'.

Also shrink code that checks for '.exe' or '.com' on PATH in shell's
find_command function.
---
 include/mingw.h |  1 +
 shell/ash.c     | 13 ++++---------
 win32/mingw.c   | 38 ++++++++++++++++++++------------------
 win32/process.c |  5 +----
 4 files changed, 26 insertions(+), 31 deletions(-)

diff --git a/include/mingw.h b/include/mingw.h
index d7dabacaf..dd676bf2c 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -471,6 +471,7 @@ char **env_setenv(char **env, const char *name);
 const char *get_busybox_exec_path(void);
 void init_winsock(void);
 
+int has_exe_suffix(const char *p);
 char *file_is_win32_executable(const char *p);
 
 int err_win_to_posix(DWORD winerr);
diff --git a/shell/ash.c b/shell/ash.c
index af0c68dcf..e47836d70 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -13564,10 +13564,7 @@ find_command(char *name, struct cmdentry *entry, int act, const char *path)
 			goto success;
 		}
 #if ENABLE_PLATFORM_MINGW32
-		len = strlen(fullname);
-		if (len > 4 &&
-		    (!strcasecmp(fullname+len-4, ".exe") ||
-		     !strcasecmp(fullname+len-4, ".com"))) {
+		if (has_exe_suffix(fullname)) {
 			if (stat(fullname, &statb) < 0) {
 				if (errno != ENOENT && errno != ENOTDIR)
 					e = errno;
@@ -13576,14 +13573,12 @@ find_command(char *name, struct cmdentry *entry, int act, const char *path)
 		}
 		else {
 			/* path_advance() has reserved space for .exe */
-			memcpy(fullname+len, ".exe", 5);
+			len = strlen(fullname);
+			strcat(fullname, ".exe");
 			if (stat(fullname, &statb) < 0) {
-				if (errno != ENOENT && errno != ENOTDIR)
-					e = errno;
 				memcpy(fullname+len, ".com", 5);
 				if (stat(fullname, &statb) < 0) {
-					if (errno != ENOENT && errno != ENOTDIR)
-						e = errno;
+					/* check for script */
 					fullname[len] = '\0';
 					if (stat(fullname, &statb) < 0) {
 						if (errno != ENOENT && errno != ENOTDIR)
diff --git a/win32/mingw.c b/win32/mingw.c
index 1170cd9d5..7f37eadda 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -240,15 +240,12 @@ static int do_lstat(int follow, const char *file_name, struct mingw_stat *buf)
 	mode_t usermode;
 
 	if (!(err = get_file_attr(file_name, &fdata))) {
-		int len = strlen(file_name);
-
 		buf->st_ino = 0;
 		buf->st_uid = DEFAULT_UID;
 		buf->st_gid = DEFAULT_GID;
 		buf->st_nlink = 1;
 		buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes);
-		if (len > 4 && (!strcasecmp(file_name+len-4, ".exe") ||
-						!strcasecmp(file_name+len-4, ".com")))
+		if (has_exe_suffix(file_name))
 			buf->st_mode |= S_IEXEC;
 		buf->st_size = fdata.nFileSizeLow |
 			(((off64_t)fdata.nFileSizeHigh)<<32);
@@ -1002,6 +999,14 @@ int mingw_rmdir(const char *path)
 	return rmdir(path);
 }
 
+int has_exe_suffix(const char *name)
+{
+	int len = strlen(name);
+
+	return len > 4 && (!strcasecmp(name+len-4, ".exe") ||
+				!strcasecmp(name+len-4, ".com"));
+}
+
 /* check if path can be made into an executable by adding a suffix;
  * return an allocated string containing the path if it can;
  * return NULL if not.
@@ -1011,26 +1016,23 @@ int mingw_rmdir(const char *path)
 char *file_is_win32_executable(const char *p)
 {
 	char *path;
-	int len = strlen(p);
 
-	if (len > 4 && (!strcasecmp(p+len-4, ".exe") ||
-					!strcasecmp(p+len-4, ".com"))) {
+	if (has_exe_suffix(p)) {
 		return NULL;
 	}
 
-	if ( (path=malloc(len+5)) != NULL ) {
-		memcpy(path, p, len);
-		memcpy(path+len, ".exe", 5);
-		if (file_is_executable(path)) {
-			return path;
-		}
-		memcpy(path+len, ".com", 5);
-		if (file_is_executable(path)) {
-			return path;
-		}
-		free(path);
+	path = xasprintf("%s.exe", p);
+	if (file_is_executable(path)) {
+		return path;
 	}
 
+	memcpy(path+strlen(p), ".com", 5);
+	if (file_is_executable(path)) {
+		return path;
+	}
+
+	free(path);
+
 	return NULL;
 }
 
diff --git a/win32/process.c b/win32/process.c
index 5eb52828b..919d46043 100644
--- a/win32/process.c
+++ b/win32/process.c
@@ -52,10 +52,7 @@ parse_interpreter(const char *cmd, char ***opts, int *nopts)
 	*opts = opt;
 
 	/* don't even try a .exe */
-	n = strlen(cmd);
-	if (n >= 4 &&
-	    (!strcasecmp(cmd+n-4, ".exe") ||
-	     !strcasecmp(cmd+n-4, ".com")))
+	if (has_exe_suffix(cmd))
 		return NULL;
 
 	fd = open(cmd, O_RDONLY);
-- 
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