Ensure %rmbuild doesn't fail due to permissions in the built content

Packages may contain files without write permissions, read-only sources
and whatnot. Run %_fixperms on the whole builddir before trying to
remove it to ensure we don't fail doing our household duties, both
on post-cleanup but also before trying to remove an old run, as
eg 'rpmbuild -bi' will not run cleanup.

It's worth noting that prior to b5f6c64
the build could similarly fail while running it's default %clean.
If we hadn't removeed the default %clean, we'd have to do this
permission fixup first redundantly for the build root and then for the
rest of the %builddir.

Also worth noting is that the added test doesn't actually reproduce the
issue in the test-suite because it runs as root and root is not bothered
by such petty issues as missing read/write permissions to remove. But
at least we have a reproducer for the case once #3005 is done.

Fixes: #2519

build/build.c

@@ -203,7 +203,11 @@ rpmRC doScript(rpmSpec spec, rpmBuildFlags what, const char *name,
 	fprintf(fp, "cd '%s'\n", buildSubdir);
 
     if (what == RPMBUILD_RMBUILD) {
+	char *fix = rpmExpand("%{_fixperms}", NULL);
+	fprintf(fp, "test -d '%s' && %s '%s'\n",
+			spec->buildDir, fix, spec->buildDir);
 	fprintf(fp, "rm -rf '%s'\n", spec->buildDir);
+	free(fix);
     } else if (sb != NULL)
 	fprintf(fp, "%s", sb);
 
@@ -307,7 +311,10 @@ static int doCheckBuildRequires(rpmts ts, rpmSpec spec, int test)
 
 static rpmRC doBuildDir(rpmSpec spec, int test, StringBuf *sbp)
 {
+    char *fix = rpmExpand("%{_fixperms}", NULL);
     char *doDir = rstrscat(NULL,
+			   "test -d '", spec->buildDir, "' && ",
+			   fix, " '", spec->buildDir, "'\n",
 			   "rm -rf '", spec->buildDir, "'\n",
 			   "mkdir -p '", spec->buildDir, "'\n",
 			   NULL);
@@ -320,6 +327,7 @@ static rpmRC doBuildDir(rpmSpec spec, int test, StringBuf *sbp)
 		spec->buildDir, strerror(errno));
     }
     free(doDir);
+    free(fix);
     return rc;
 }
 

tests/data/SPECS/noperms.spec

@@ -0,0 +1,22 @@
+Name: noperms
+Version: 1.0
+Release: 1
+License: Public Domain
+Summary: Test read-only files in build
+
+%description
+%{summary}
+
+%prep
+%setup -c -T
+
+%build
+mkdir bad
+touch bad/foo
+chmod a-w bad
+
+%install
+cp -avp . ${RPM_BUILD_ROOT}
+
+%files
+/bad

tests/rpmbuild.at

@@ -2957,3 +2957,19 @@ runroot rpmbuild --quiet -bb /data/SPECS/bpf.spec
 [],
 [])
 RPMTEST_CLEANUP
+
+# XXX this always succeeds when rpmbuild is run as root so the test is
+# kinda meaningless until #3005 is done, but works as a manual reproducer.
+AT_SETUP([rpmbuild non-removable file in builddir])
+AT_KEYWORDS([build])
+RPMDB_INIT
+
+# -bi doesn't run cleanup, test that we manage that situation too
+RPMTEST_CHECK([
+runroot rpmbuild --quiet -bi /data/SPECS/noperms.spec
+runroot rpmbuild --quiet -bb /data/SPECS/noperms.spec
+],
+[0],
+[],
+[])
+RPMTEST_CLEANUP