From 6150b00b6025918da8c28e5c2f929ecdf480a9d6 Mon Sep 17 00:00:00 2001
From: Sean Anderson <sean.anderson@seco.com>
Date: Thu, 30 Dec 2021 15:34:28 -0500
Subject: [PATCH] img2simg: Add support for converting holes to "don't care"
 chunks

This adds support for converting files with holes to "don't care"
chunks. This can result in a substantial reduction in the time it takes
to program an image if it has many holes.

Generally, constants compared to argc have been reduced by one, since we
no longer have the program name as the first argument.

Change-Id: I00750edc07d6415dcc07ae0351e9397b0222b7ba
---
 libsparse/img2simg.cpp | 41 ++++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/libsparse/img2simg.cpp b/libsparse/img2simg.cpp
index 3e24cc014..51580f706 100644
--- a/libsparse/img2simg.cpp
+++ b/libsparse/img2simg.cpp
@@ -38,24 +38,41 @@
 #endif
 
 void usage() {
-  fprintf(stderr, "Usage: img2simg <raw_image_file> <sparse_image_file> [<block_size>]\n");
+  fprintf(stderr, "Usage: img2simg [-s] <raw_image_file> <sparse_image_file> [<block_size>]\n");
 }
 
 int main(int argc, char* argv[]) {
+  char *arg_in;
+  char *arg_out;
+  enum sparse_read_mode mode = SPARSE_READ_MODE_NORMAL;
+  int extra;
   int in;
+  int opt;
   int out;
   int ret;
   struct sparse_file* s;
   unsigned int block_size = 4096;
   off64_t len;
 
-  if (argc < 3 || argc > 4) {
+  while ((opt = getopt(argc, argv, "s")) != -1) {
+    switch (opt) {
+      case 's':
+        mode = SPARSE_READ_MODE_HOLE;
+        break;
+      default:
+        usage();
+        exit(-1);
+    }
+  }
+
+  extra = argc - optind;
+  if (extra < 2 || extra > 3) {
     usage();
     exit(-1);
   }
 
-  if (argc == 4) {
-    block_size = atoi(argv[3]);
+  if (extra == 3) {
+    block_size = atoi(argv[optind + 2]);
   }
 
   if (block_size < 1024 || block_size % 4 != 0) {
@@ -63,22 +80,24 @@ int main(int argc, char* argv[]) {
     exit(-1);
   }
 
-  if (strcmp(argv[1], "-") == 0) {
+  arg_in = argv[optind];
+  if (strcmp(arg_in, "-") == 0) {
     in = STDIN_FILENO;
   } else {
-    in = open(argv[1], O_RDONLY | O_BINARY);
+    in = open(arg_in, O_RDONLY | O_BINARY);
     if (in < 0) {
-      fprintf(stderr, "Cannot open input file %s\n", argv[1]);
+      fprintf(stderr, "Cannot open input file %s\n", arg_in);
       exit(-1);
     }
   }
 
-  if (strcmp(argv[2], "-") == 0) {
+  arg_out = argv[optind + 1];
+  if (strcmp(arg_out, "-") == 0) {
     out = STDOUT_FILENO;
   } else {
-    out = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
+    out = open(arg_out, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
     if (out < 0) {
-      fprintf(stderr, "Cannot open output file %s\n", argv[2]);
+      fprintf(stderr, "Cannot open output file %s\n", arg_out);
       exit(-1);
     }
   }
@@ -93,7 +112,7 @@ int main(int argc, char* argv[]) {
   }
 
   sparse_file_verbose(s);
-  ret = sparse_file_read(s, in, SPARSE_READ_MODE_NORMAL, false);
+  ret = sparse_file_read(s, in, mode, false);
   if (ret) {
     fprintf(stderr, "Failed to read file\n");
     exit(-1);