*/mk: mkdir -p (and install -d) are safe to use

There are no race conditions, contrary to what some sources say.
Previously, we had each directory depend on its parent directory, so
that only a few parent-most directories would be created with parents,
and all others would be created when their parents exist.  That was due
to FUD about TOCTOU race conditions with mkdir -p and parallel make, but
it was just FUD.

This patch makes it so that each directory is directly created with
parents without specifying any dependency.  This simplifies the makefile
at some cost: calling mkdir -p so many times is a bit slower.  However,
it's only about 5%, so we can live with it, since we're talking about
hundreds of a second for creating all the directories that this build
system knows about.

Reported-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

6 files changed, 5 insertions, 16 deletions

diff --git a/share/mk/build/_.mk b/share/mk/build/_.mk
index b5fbca92a..41b3a8ab9 100644
--- a/share/mk/build/_.mk
+++ b/share/mk/build/_.mk
@@ -31,10 +31,6 @@ NONSO_MDOC := $(shell $(FIND) $(MANDIR)/man*/ -type f \
 		| $(GREP) '$(MANEXT)' \
 		| $(XARGS) $(GREP) -l '^\.Dt ' \
 		| $(SORT))
-_MANDIRS := $(patsubst $(MANDIR)/%,$(_MANDIR)/%/,$(MANDIRS))
-
-
-$(_MANDIRS): %/: | $$(dir %) $(_MANDIR)/
 
 
 $(builddir)/%/:
diff --git a/share/mk/build/html.mk b/share/mk/build/html.mk
index cf8e54107..b68f97213 100644
--- a/share/mk/build/html.mk
+++ b/share/mk/build/html.mk
@@ -24,7 +24,6 @@ MAN2HTML              := man2html
 
 
 _HTMLPAGES := $(patsubst $(MANDIR)/%,$(_HTMLDIR)/%$(htmlext),$(MANPAGES))
-_HTMLDIRS  := $(patsubst $(MANDIR)/%,$(_HTMLDIR)/%/,$(MANDIRS))
 
 
 # Use with
@@ -35,8 +34,6 @@ $(_HTMLPAGES): $(_HTMLDIR)/%$(htmlext): $(MANDIR)/% | $$(@D)/
 	$(MAN2HTML) $(MAN2HTMLFLAGS) $< \
 	| $(SED) -e 1,2d >$@
 
-$(_HTMLDIRS): %/: | $$(dir %) $(_HTMLDIR)/
-
 
 .PHONY: build-html html
 build-html html: $(_HTMLPAGES)
diff --git a/share/mk/build/src.mk b/share/mk/build/src.mk
index ee429eb21..e273fbf4e 100644
--- a/share/mk/build/src.mk
+++ b/share/mk/build/src.mk
@@ -54,7 +54,7 @@ CC  := cc
 LD  := $(CC) $(CFLAGS)
 
 
-_SRCPAGEDIRS   := $(patsubst $(MANDIR)/%,$(_MANDIR)/%.d,$(NONSO_MAN))
+_SRCPAGEDIRS   := $(patsubst $(MANDIR)/%,$(_MANDIR)/%.d/,$(NONSO_MAN))
 
 _UNITS_src_src := $(patsubst $(MANDIR)/%,$(_MANDIR)/%,$(shell \
 		$(FIND) $(MANDIR)/man*/ -type f \
@@ -69,12 +69,12 @@ _UNITS_src_o   := $(patsubst %.c,%.o,$(_UNITS_src_c))
 _UNITS_src_bin := $(patsubst %.c,%,$(_UNITS_src_c))
 
 
-$(_SRCPAGEDIRS): $(_MANDIR)/%.d: $(MANDIR)/% | $$(@D)/
+$(_SRCPAGEDIRS): $(_MANDIR)/%.d/: $(MANDIR)/%
 	+$(info MKDIR	$@)
 	+$(MKDIR) $@
 	+touch $@
 
-$(_UNITS_src_src): $$(patsubst $(_MANDIR)/%.d,$(MANDIR)/%,$$(@D)) | $$(@D)
+$(_UNITS_src_src): $$(patsubst $(_MANDIR)/%.d,$(MANDIR)/%,$$(@D)) | $$(@D)/
 $(_UNITS_src_c):   $$(filter $$(@D)/%.h,$(_UNITS_src_h))
 $(_UNITS_src_src):
 	$(info SED	$@)
diff --git a/share/mk/install/_.mk b/share/mk/install/_.mk
index bffce03fb..66788d8f7 100644
--- a/share/mk/install/_.mk
+++ b/share/mk/install/_.mk
@@ -19,7 +19,7 @@ docdir      := $(datarootdir)/doc
 
 
 %/:
-	+$(info INSTALL	$@/)
+	+$(info INSTALL	$@)
 	+$(INSTALL_DIR) $@
 
 %-rm:
diff --git a/share/mk/install/html.mk b/share/mk/install/html.mk
index 2b1af838c..4b6dfa262 100644
--- a/share/mk/install/html.mk
+++ b/share/mk/install/html.mk
@@ -18,7 +18,7 @@ _htmldir := $(DESTDIR)$(htmldir_)
 
 
 _htmlpages      := $(patsubst $(_HTMLDIR)/%,$(_htmldir)/%,$(_HTMLPAGES))
-_htmldirs       := $(patsubst $(_HTMLDIR)/%,$(_htmldir)/%,$(_HTMLDIRS))
+_htmldirs       := $(patsubst $(MANDIR)/%,$(_htmldir)/%,$(MANDIRS))
 _htmlpages_rm   := $(addsuffix -rm,$(wildcard $(_htmlpages)))
 _htmldirs_rmdir := $(addsuffix -rmdir,$(wildcard $(_htmldirs)))
 _htmldir_rmdir  := $(addsuffix -rmdir,$(wildcard $(_htmldir)/))
@@ -28,8 +28,6 @@ $(_htmlpages): $(_htmldir)/%: $(_HTMLDIR)/% | $$(@D)/
 	$(info INSTALL	$@)
 	$(INSTALL_DATA) -T $< $@
 
-$(_htmldirs): %/: | $$(dir %) $(_htmldir)/
-
 
 .PHONY: install-html
 install-html: $(_htmlpages)
diff --git a/share/mk/install/man.mk b/share/mk/install/man.mk
index 0d81b657e..128f20833 100644
--- a/share/mk/install/man.mk
+++ b/share/mk/install/man.mk
@@ -187,8 +187,6 @@ else ifeq ($(Z),.xz)
 	fi
 endif
 
-$(_mandirs): %/: | $$(dir %) $(_mandir)/
-
 $(_mandirs_rmdir): $(_mandir)/man%/-rmdir: $$(_man%pages_rm) FORCE
 $(_mandir_rmdir): $(uninstall_manX) FORCE