From a2750dee0e4c374ae51f83eead7eb7df3c018d95 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Sat, 4 May 2019 23:20:28 +0200
Subject: rdsquashfs: malloc extraction buffers ahead of time

Instead of malloc/freeing the buffers for every file, allocate them
once, ahead of time.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
 unpack/extract_file.c | 43 +++++++++++++++++--------------------------
 unpack/rdsquashfs.c   | 25 +++++++++++++++++++++++++
 unpack/rdsquashfs.h   |  3 +++
 3 files changed, 45 insertions(+), 26 deletions(-)

(limited to 'unpack')

diff --git a/unpack/extract_file.c b/unpack/extract_file.c
index 4d5997a..62d1086 100644
--- a/unpack/extract_file.c
+++ b/unpack/extract_file.c
@@ -3,19 +3,12 @@
 
 int extract_file(file_info_t *fi, unsqfs_info_t *info, int outfd)
 {
-	void *buffer, *scratch, *ptr;
 	size_t i, count, fragsz;
 	bool compressed;
 	uint32_t bs;
 	ssize_t ret;
+	void *ptr;
 
-	buffer = malloc(info->block_size * 2);
-	if (buffer == NULL) {
-		perror("allocating scratch buffer");
-		return -1;
-	}
-
-	scratch = (char *)buffer + info->block_size;
 	count = fi->size / info->block_size;
 
 	if (count > 0) {
@@ -31,7 +24,7 @@ int extract_file(file_info_t *fi, unsqfs_info_t *info, int outfd)
 			if (bs > info->block_size)
 				goto fail_bs;
 
-			ret = read_retry(info->sqfsfd, buffer, bs);
+			ret = read_retry(info->sqfsfd, info->buffer, bs);
 			if (ret < 0)
 				goto fail_rd;
 
@@ -39,16 +32,17 @@ int extract_file(file_info_t *fi, unsqfs_info_t *info, int outfd)
 				goto fail_trunc;
 
 			if (compressed) {
-				ret = info->cmp->do_block(info->cmp, buffer, bs,
-							  scratch,
+				ret = info->cmp->do_block(info->cmp,
+							  info->buffer, bs,
+							  info->scratch,
 							  info->block_size);
 				if (ret <= 0)
-					goto fail;
+					return -1;
 
 				bs = ret;
-				ptr = scratch;
+				ptr = info->scratch;
 			} else {
-				ptr = buffer;
+				ptr = info->buffer;
 			}
 
 			ret = write_retry(outfd, ptr, bs);
@@ -64,11 +58,12 @@ int extract_file(file_info_t *fi, unsqfs_info_t *info, int outfd)
 
 	if (fragsz > 0) {
 		if (frag_reader_read(info->frag, fi->fragment,
-				     fi->fragment_offset, buffer, fragsz)) {
-			goto fail;
+				     fi->fragment_offset, info->buffer,
+				     fragsz)) {
+			return -1;
 		}
 
-		ret = write_retry(outfd, buffer, fragsz);
+		ret = write_retry(outfd, info->buffer, fragsz);
 		if (ret < 0)
 			goto fail_wr;
 
@@ -76,27 +71,23 @@ int extract_file(file_info_t *fi, unsqfs_info_t *info, int outfd)
 			goto fail_wr_trunc;
 	}
 
-	free(buffer);
 	return 0;
 fail_seek:
 	perror("seek on squashfs");
-	goto fail;
+	return -1;
 fail_wr:
 	perror("writing uncompressed block");
-	goto fail;
+	return -1;
 fail_wr_trunc:
 	fputs("writing uncompressed block: truncated write\n", stderr);
-	goto fail;
+	return -1;
 fail_rd:
 	perror("reading from squashfs");
-	goto fail;
+	return -1;
 fail_trunc:
 	fputs("reading from squashfs: unexpected end of file\n", stderr);
-	goto fail;
+	return -1;
 fail_bs:
 	fputs("found compressed block larger than block size\n", stderr);
-	goto fail;
-fail:
-	free(buffer);
 	return -1;
 }
diff --git a/unpack/rdsquashfs.c b/unpack/rdsquashfs.c
index 3c80853..c286a78 100644
--- a/unpack/rdsquashfs.c
+++ b/unpack/rdsquashfs.c
@@ -110,6 +110,23 @@ static char *get_path(char *old, const char *arg)
 	return path;
 }
 
+static int alloc_buffers(unsqfs_info_t *info, sqfs_super_t *super)
+{
+	info->buffer = malloc(super->block_size);
+	if (info->buffer == NULL) {
+		perror("allocating block buffer");
+		return -1;
+	}
+
+	info->scratch = malloc(super->block_size);
+	if (info->scratch == NULL) {
+		perror("allocating scrtach buffer for extracting blocks");
+		return -1;
+	}
+
+	return 0;
+}
+
 static int load_fragment_table(unsqfs_info_t *info, sqfs_super_t *super)
 {
 	if (super->fragment_entry_count == 0)
@@ -274,6 +291,9 @@ int main(int argc, char **argv)
 		if (load_fragment_table(&info, &super))
 			goto out_fs;
 
+		if (alloc_buffers(&info, &super))
+			goto out_fs;
+
 		if (extract_file(n->data.file, &info, STDOUT_FILENO))
 			goto out_fs;
 		break;
@@ -291,6 +311,9 @@ int main(int argc, char **argv)
 		if (load_fragment_table(&info, &super))
 			goto out_fs;
 
+		if (alloc_buffers(&info, &super))
+			goto out_fs;
+
 		if (restore_fstree(unpack_root, n, &info))
 			goto out_fs;
 		break;
@@ -307,6 +330,8 @@ out_fd:
 	close(info.sqfsfd);
 out_cmd:
 	free(cmdpath);
+	free(info.buffer);
+	free(info.scratch);
 	return status;
 fail_arg:
 	fprintf(stderr, "Try `%s --help' for more information.\n", __progname);
diff --git a/unpack/rdsquashfs.h b/unpack/rdsquashfs.h
index 0961591..c06afb2 100644
--- a/unpack/rdsquashfs.h
+++ b/unpack/rdsquashfs.h
@@ -35,6 +35,9 @@ typedef struct {
 	frag_reader_t *frag;
 	int sqfsfd;
 	int flags;
+
+	void *buffer;
+	void *scratch;
 } unsqfs_info_t;
 
 tree_node_t *tree_node_from_inode(sqfs_inode_generic_t *inode,
-- 
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