From e35d8cf13627092b9605023f5d288dee1ae90759 Mon Sep 17 00:00:00 2001
From: "Chloe M." <chloe@mirocom.org>
Date: Thu, 30 Apr 2026 21:28:09 -0400
Subject: [PATCH] core: blob+stream: Store stream/blob hashes

Signed-off-by: Chloe M. <chloe@mirocom.org>
---
 Makefile               | 4 +++-
 core/blob_list.c       | 3 +++
 core/blob_subr.c       | 1 +
 core/stream_file.c     | 2 ++
 inc/blobchain/blob.h   | 3 +++
 inc/blobchain/common.h | 2 ++
 inc/blobchain/stream.h | 4 ++++
 7 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index acaa4bc..c300eb2 100644
--- a/Makefile
+++ b/Makefile
@@ -8,6 +8,8 @@ DFILES = $(CFILES:.c=.d)
 OFILES = $(CFILES:.c=.o)
 
 CC = gcc
+LIBS = $(shell pkg-config --libs "openssl")
+
 CFLAGS =		\
 	-Wall		\
 	-pedantic	\
@@ -19,7 +21,7 @@ all: blobchain
 
 .PHONY: blobchain
 blobchain: $(OFILES)
-	$(CC) $^ -o $@
+	$(CC) $(LIBS) $^ -o $@
 
 -include $(DFILES)
 %.o: %.c
diff --git a/core/blob_list.c b/core/blob_list.c
index d7d254b..6c7502e 100644
--- a/core/blob_list.c
+++ b/core/blob_list.c
@@ -95,6 +95,9 @@ blob_list_dump(struct blob_list *lp)
     while (blob != NULL) {
         printf("blob %zd/%zd\n", count++, lp->count);
         printf("... length :: %zd\n", blob->length);
+        printf("... hash   :: ");
+        dump_bytes(blob->hash, SHA256_N_BYTES);
+
         printf("... data   :: ");
         dump_bytes(blob->data, blob->length < DUMP_SIZE
             ? blob->length
diff --git a/core/blob_subr.c b/core/blob_subr.c
index 305f407..b8c6202 100644
--- a/core/blob_subr.c
+++ b/core/blob_subr.c
@@ -22,5 +22,6 @@ blob_allocate(struct data_stream *stmp)
         memcpy(bp->data, stmp->data, stmp->length);
     }
 
+    memcpy(bp->hash, stmp->hash, SHA256_N_BYTES);
     return bp;
 }
diff --git a/core/stream_file.c b/core/stream_file.c
index e169bbb..90b6845 100644
--- a/core/stream_file.c
+++ b/core/stream_file.c
@@ -9,6 +9,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <openssl/sha.h>
 #include "blobchain/memlib.h"
 #include "blobchain/stream.h"
 
@@ -56,6 +57,7 @@ stream_from_file(struct data_stream *stmp, const char *path)
         return -1;
     }
 
+    SHA256(stmp->data, stmp->length, stmp->hash);
     return 0;
 }
 
diff --git a/inc/blobchain/blob.h b/inc/blobchain/blob.h
index df4562c..55265b1 100644
--- a/inc/blobchain/blob.h
+++ b/inc/blobchain/blob.h
@@ -9,17 +9,20 @@
 #include <stdint.h>
 #include <stddef.h>
 #include "blobchain/stream.h"
+#include "blobchain/common.h"
 
 /*
  * Represents a single blob of data
  *
  * @data:   Buffer containing blob data
  * @length: Length of blob
+ * @hash:   Hash of file contents
  * @next:   Next blob
  */
 struct blob {
     void *data;
     size_t length;
+    uint8_t hash[SHA256_N_BYTES];
     struct blob *next;
 };
 
diff --git a/inc/blobchain/common.h b/inc/blobchain/common.h
index 1505c85..390c5f6 100644
--- a/inc/blobchain/common.h
+++ b/inc/blobchain/common.h
@@ -6,6 +6,8 @@
 #ifndef BLOBCHAIN_COMMON_H
 #define BLOBCHAIN_COMMON_H 1
 
+#define SHA256_N_BYTES 32
+
 #define BLOBCHAIN_DEBUG 1
 #define BLOBCHAIN_VERSION "0.0.1"
 
diff --git a/inc/blobchain/stream.h b/inc/blobchain/stream.h
index 5e9c523..eee475a 100644
--- a/inc/blobchain/stream.h
+++ b/inc/blobchain/stream.h
@@ -6,17 +6,21 @@
 #ifndef BLOBCHAIN_STREAM_H
 #define BLOBCHAIN_STREAM_H 1
 
+#include <stdint.h>
 #include <stddef.h>
+#include "blobchain/common.h"
 
 /*
  * Represents a data stream
  *
  * @data:   Data buffer
  * @length: Number of bytes in data buffer
+ * @hash:   SHA256 hash of file contents
  */
 struct data_stream {
     void *data;
     size_t length;
+    uint8_t hash[SHA256_N_BYTES];
 };
 
 /*