From af1cb4eadcbe9289bd929c4f00b9327c511b4f3a Mon Sep 17 00:00:00 2001
From: Colin Finck <mail@colinfinck.de>
Date: Mon, 21 Oct 2024 13:34:25 +0200
Subject: [PATCH] Escape spaces in depfile with backslashes.

This matches how Linux escapes spaces in paths.
The same syntax is also used by other build tools that output depfiles,
e.g. https://github.com/rust-lang/cargo/blob/edd36eba5e0d6e0cfcb84bd0cc651ba8bf5e7f83/src/cargo/core/compiler/output_depinfo.rs#L19
---
 dtc.c    |  4 +++-
 srcpos.c |  6 ++++--
 util.c   | 16 ++++++++++++++++
 util.h   |  5 +++++
 4 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/dtc.c b/dtc.c
index 0655c2e2..beda8d56 100644
--- a/dtc.c
+++ b/dtc.c
@@ -289,7 +289,9 @@ int main(int argc, char *argv[])
 		if (!depfile)
 			die("Couldn't open dependency file %s: %s\n", depname,
 			    strerror(errno));
-		fprintf(depfile, "%s:", outname);
+
+		fprint_path_escaped(depfile, outname);
+		fputc(':', depfile);
 	}
 
 	if (inform == NULL)
diff --git a/srcpos.c b/srcpos.c
index 8e4d18a9..5e2f7dd2 100644
--- a/srcpos.c
+++ b/srcpos.c
@@ -160,8 +160,10 @@ FILE *srcfile_relative_open(const char *fname, char **fullnamep)
 			    strerror(errno));
 	}
 
-	if (depfile)
-		fprintf(depfile, " %s", fullname);
+	if (depfile) {
+		fputc(' ', depfile);
+		fprint_path_escaped(depfile, fullname);
+	}
 
 	if (fullnamep)
 		*fullnamep = fullname;
diff --git a/util.c b/util.c
index 507f0120..41259232 100644
--- a/util.c
+++ b/util.c
@@ -23,6 +23,22 @@
 #include "util.h"
 #include "version_gen.h"
 
+void fprint_path_escaped(FILE *fp, const char *path)
+{
+	const char *p = path;
+
+	while (*p) {
+		if (*p == ' ') {
+			fputc('\\', fp);
+			fputc(' ', fp);
+		} else {
+			fputc(*p, fp);
+		}
+
+		p++;
+	}
+}
+
 char *xstrdup(const char *s)
 {
 	int len = strlen(s) + 1;
diff --git a/util.h b/util.h
index b448cd79..800f2e2c 100644
--- a/util.h
+++ b/util.h
@@ -42,6 +42,11 @@ static inline void NORETURN PRINTF(1, 2) die(const char *str, ...)
 	exit(1);
 }
 
+/**
+ * Writes path to fp, escaping spaces with a backslash.
+ */
+void fprint_path_escaped(FILE *fp, const char *path);
+
 static inline void *xmalloc(size_t len)
 {
 	void *new = malloc(len);