From 84ffdf0ed52f936b0976d8dad09bc2c309917532 Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Mon, 25 Dec 2017 03:01:33 +0800
Subject: [PATCH] Eliminate a possbility to cause segfault

---
 core/jni/include/vector.h | 2 +-
 core/jni/magiskboot/dtb.c | 5 ++---
 core/jni/utils/cpio.c     | 2 +-
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/core/jni/include/vector.h b/core/jni/include/vector.h
index 9156b0c6d..9984734af 100644
--- a/core/jni/include/vector.h
+++ b/core/jni/include/vector.h
@@ -29,7 +29,7 @@ struct vector *vec_dup(struct vector *v);
 	for (int _ = 0; v && _ < (v)->size; ++_, e = (v)->data[_])
 
 #define vec_for_each_r(v, e) \
-	e = v ? (v)->data[(v)->size - 1] : NULL; \
+	e = (v && (v)->size > 0) ? (v)->data[(v)->size - 1] : NULL; \
 	for (int _ = ((int) (v)->size) - 1; v && _ >= 0; --_, e = (v)->data[_])
 
 #define vec_cur(v) vec_entry(v)[_]
diff --git a/core/jni/magiskboot/dtb.c b/core/jni/magiskboot/dtb.c
index 0bd57cac8..c1106d826 100644
--- a/core/jni/magiskboot/dtb.c
+++ b/core/jni/magiskboot/dtb.c
@@ -49,7 +49,7 @@ static void dtb_dump(const char *file) {
 	for (int i = 0; i < size; ++i) {
 		if (memcmp(dtb + i, DTB_MAGIC, 4) == 0) {
 			fdt = dtb + i;
-			fprintf(stderr, "Dumping dtb.%04d\n\n", dtb_num++);
+			fprintf(stderr, "Dumping dtb.%04d\n", dtb_num++);
 			print_subnode(fdt, 0, 0);
 		}
 	}
@@ -61,7 +61,7 @@ static void dtb_dump(const char *file) {
 static void dtb_patch(const char *file, int patch) {
 	size_t size ;
 	void *dtb, *fdt;
-	fprintf(stderr, "Loading dtbs from [%s]\n\n", file);
+	fprintf(stderr, "Loading dtbs from [%s]\n", file);
 	if (patch)
 		mmap_rw(file, &dtb, &size);
 	else
@@ -84,7 +84,6 @@ static void dtb_patch(const char *file, int patch) {
 			}
 		}
 	}
-	fprintf(stderr, "\n");
 	munmap(dtb, size);
 	exit(!found);
 }
diff --git a/core/jni/utils/cpio.c b/core/jni/utils/cpio.c
index 0307d29e6..0ec3c088f 100644
--- a/core/jni/utils/cpio.c
+++ b/core/jni/utils/cpio.c
@@ -57,9 +57,9 @@ void cpio_vec_insert(struct vector *v, cpio_entry *n) {
 
 // Parse cpio file to a vector of cpio_entry
 void parse_cpio(struct vector *v, const char *filename) {
-	fprintf(stderr, "Loading cpio: [%s]\n", filename);
 	int fd = open(filename, O_RDONLY);
 	if (fd < 0) return;
+	fprintf(stderr, "Loading cpio: [%s]\n", filename);
 	cpio_newc_header header;
 	cpio_entry *f;
 	while(xxread(fd, &header, 110) != -1) {