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-rw-r--r--scripts/kconfig/confdata.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 9fd6430c93d2..399973e35533 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -3,6 +3,7 @@
* Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
*/
+#include <sys/mman.h>
#include <sys/stat.h>
#include <ctype.h>
#include <errno.h>
@@ -36,6 +37,52 @@ static bool is_dir(const char *path)
return S_ISDIR(st.st_mode);
}
+/* return true if the given two files are the same, false otherwise */
+static bool is_same(const char *file1, const char *file2)
+{
+ int fd1, fd2;
+ struct stat st1, st2;
+ void *map1, *map2;
+ bool ret = false;
+
+ fd1 = open(file1, O_RDONLY);
+ if (fd1 < 0)
+ return ret;
+
+ fd2 = open(file2, O_RDONLY);
+ if (fd2 < 0)
+ goto close1;
+
+ ret = fstat(fd1, &st1);
+ if (ret)
+ goto close2;
+ ret = fstat(fd2, &st2);
+ if (ret)
+ goto close2;
+
+ if (st1.st_size != st2.st_size)
+ goto close2;
+
+ map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
+ if (map1 == MAP_FAILED)
+ goto close2;
+
+ map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
+ if (map2 == MAP_FAILED)
+ goto close2;
+
+ if (bcmp(map1, map2, st1.st_size))
+ goto close2;
+
+ ret = true;
+close2:
+ close(fd2);
+close1:
+ close(fd1);
+
+ return ret;
+}
+
/*
* Create the parent directory of the given path.
*
@@ -888,6 +935,13 @@ next:
fclose(out);
if (*tmpname) {
+ if (is_same(name, tmpname)) {
+ conf_message("No change to %s", name);
+ unlink(tmpname);
+ sym_set_change_count(0);
+ return 0;
+ }
+
snprintf(oldname, sizeof(oldname), "%s.old", name);
rename(name, oldname);
if (rename(tmpname, name))