Force coreboot mconf to create temp files in the output directory

This change partially addresses the problem with attempting to
generate coreboot image out of tree. The configuration step fails when
in cheroot, if the destination directory is placed in /tmp.

The problem is that the mconf package tries renaming the temporary
file created in the local directory into the destination config file.
If the destination root and the local directory are located on
different file systems, the rename operation fails.

The proper fix (still upcoming) would be to identify all places where
mconf creates temp files, and make sure that all temp files get
created in the destination tree.

This change modifies just one location, which prevents building out of
tree in the most common case.

Test:
  run the following in the coreboot directory in chroot:
    (coreboot) cp config.lumpy .config
    (coreboot) /bin/rm -rf /tmp/cb
    (coreboot) CROSS_COMPILE=i686-pc-linux-gnu- make obj=/tmp/cb oldconfig
    (coreboot) CROSS_COMPILE=i686-pc-linux-gnu- make obj=/tmp/cb

  Observe the build succeed (it was failing during the config phase
  before this change)

Change-Id: If4506e984b8afc192a1689c7b0aa956dd35f66c6
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://review.coreboot.org/815
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 43 insertions, 10 deletions

diff --git a/util/kconfig/confdata.c b/util/kconfig/confdata.c
index 79e0b359ea..df39fcc243 100644
--- a/util/kconfig/confdata.c
+++ b/util/kconfig/confdata.c
@@ -674,6 +674,33 @@ out:
 	return res;
 }
 
+/*
+ * Return malloced string the contents of which are a concatenation of the
+ * directory name of the first argument and the second argument.
+ */
+static char* get_tmp_file_name(const char* base, const char *tmp_name)
+{
+        char *file_name, *p;
+        /* for sure a few bytes longer than needed */
+        int file_name_size = strlen(base) + sizeof(file_name) + 10;
+
+        file_name = malloc(file_name_size);
+        if (!file_name) {
+                fprintf(stderr, "%s:%d: failed to allocate %d bytes\n",
+                        __FILE__, __LINE__, file_name_size);
+               return 0;
+        }
+
+        strcpy(file_name, base);
+        p = strrchr(file_name, '/');
+        if (p)
+                strcpy(p + 1, tmp_name);
+        else
+                strcpy(file_name, tmp_name);
+
+        return file_name;
+}
+
 int conf_write_autoconf(void)
 {
 	struct symbol *sym;
@@ -682,10 +709,19 @@ int conf_write_autoconf(void)
 	FILE *out, *out_h;
 	time_t now;
 	int i, l;
-	char tmpname[128], tmpname_h[128];
+	char *tmp_conf, *tmp_conf_h;
 
 	sym_clear_all_valid();
 
+	name = getenv("KCONFIG_AUTOHEADER");
+	if (!name)
+		name = "include/linux/autoconf.h";
+
+	tmp_conf = get_tmp_file_name(name, ".tmpconfig");
+	tmp_conf_h = get_tmp_file_name(name, ".tmpconfig.h");
+	if (!tmp_conf || !tmp_conf_h)
+		return 1;
+
 	file_write_dep("build/auto.conf.cmd");
 
 #if 0
@@ -693,13 +729,11 @@ int conf_write_autoconf(void)
 		return 1;
 #endif
 
-	sprintf(tmpname, ".tmpconfig.%d", (int)getpid());
-	out = fopen(tmpname, "w");
+	out = fopen(tmp_conf, "w");
 	if (!out)
 		return 1;
 
-	sprintf(tmpname_h, ".tmpconfig.h.%d", (int)getpid());
-	out_h = fopen(tmpname_h, "w");
+	out_h = fopen(tmp_conf_h, "w");
 	if (!out_h) {
 		fclose(out);
 		return 1;
@@ -790,11 +824,8 @@ int conf_write_autoconf(void)
 	fclose(out);
 	fclose(out_h);
 
-	name = getenv("KCONFIG_AUTOHEADER");
-	if (!name)
-		name = "include/linux/autoconf.h";
 	UNLINK_IF_NECESSARY(name);
-	if (rename(tmpname_h, name))
+	if (rename(tmp_conf_h, name))
 		return 1;
 	name = getenv("KCONFIG_AUTOCONFIG");
 	if (!name)
@@ -804,9 +835,11 @@ int conf_write_autoconf(void)
 	 * and this marks the successful completion of the previous steps.
 	 */
 	UNLINK_IF_NECESSARY(name);
-	if (rename(tmpname, name))
+	if (rename(tmp_conf, name))
 		return 1;
 
+	free(tmp_conf_h);
+	free(tmp_conf);
 	return 0;
 }