From 1048a6510710acb5bef352d0acb2dd13ecce0e01 Mon Sep 17 00:00:00 2001
From: Michael Vrable <mvrable@cs.ucsd.edu>
Date: Thu, 9 Aug 2007 20:36:51 -0700
Subject: [PATCH] Write out a .sha1sums file with checksums for segments in
 this snapshot.

Some segments might be left out; we only write out lines for those segments
that we know a checksum for.  These checksums are stored in the local
database (so we can find checksums for old segments), but entries might be
missing.
---
 localdb.cc | 40 ++++++++++++++++++++++++++++++++++++++++
 localdb.h  |  2 ++
 scandir.cc | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+)

diff --git a/localdb.cc b/localdb.cc
index 8a5e1f1..e946d18 100644
--- a/localdb.cc
+++ b/localdb.cc
@@ -325,3 +325,43 @@ void LocalDb::SetSegmentChecksum(const std::string &segment,
 
     sqlite3_finalize(stmt);
 }
+
+bool LocalDb::GetSegmentChecksum(const string &segment,
+                                 string *seg_path,
+                                 string *seg_checksum)
+{
+    int rc;
+    sqlite3_stmt *stmt;
+    ObjectReference ref;
+    int found = false;
+
+    stmt = Prepare("select path, checksum from segments where segment = ?");
+    sqlite3_bind_text(stmt, 1, segment.c_str(), segment.size(),
+                      SQLITE_TRANSIENT);
+
+    rc = sqlite3_step(stmt);
+    if (rc == SQLITE_DONE) {
+    } else if (rc == SQLITE_ROW) {
+        found = true;
+        const char *val;
+
+        val = (const char *)sqlite3_column_text(stmt, 0);
+        if (val == NULL)
+            found = false;
+        else
+            *seg_path = val;
+
+        val = (const char *)sqlite3_column_text(stmt, 1);
+        if (val == NULL)
+            found = false;
+        else
+            *seg_checksum = val;
+    } else {
+        fprintf(stderr, "Could not execute SELECT statement!\n");
+        ReportError(rc);
+    }
+
+    sqlite3_finalize(stmt);
+
+    return found;
+}
diff --git a/localdb.h b/localdb.h
index e8a350e..6d28cd8 100644
--- a/localdb.h
+++ b/localdb.h
@@ -33,6 +33,8 @@ public:
 
     void SetSegmentChecksum(const std::string &segment, const std::string &path,
                             const std::string &checksum);
+    bool GetSegmentChecksum(const std::string &segment,
+                            std::string *seg_path, std::string *seg_checksum);
 private:
     sqlite3 *db;
     int64_t snapshotid;
diff --git a/scandir.cc b/scandir.cc
index 82160a1..9075e51 100644
--- a/scandir.cc
+++ b/scandir.cc
@@ -723,6 +723,40 @@ int main(int argc, char *argv[])
     tss->dump_stats();
     delete tss;
 
+    /* Write out a checksums file which lists the checksums for all the
+     * segments included in this snapshot.  The format is designed so that it
+     * may be easily verified using the sha1sums command. */
+    const char csum_type[] = "sha1";
+    string checksum_filename = backup_dest + "/snapshot-";
+    if (backup_scheme.size() > 0)
+        checksum_filename += backup_scheme + "-";
+    checksum_filename = checksum_filename + desc_buf + "." + csum_type + "sums";
+    FILE *checksums = fopen(checksum_filename.c_str(), "w");
+    if (checksums != NULL) {
+        for (std::set<string>::iterator i = segment_list.begin();
+             i != segment_list.end(); ++i) {
+            string seg_path, seg_csum;
+            if (db->GetSegmentChecksum(*i, &seg_path, &seg_csum)) {
+                const char *raw_checksum = NULL;
+                if (strncmp(seg_csum.c_str(), csum_type,
+                            strlen(csum_type)) == 0) {
+                    raw_checksum = seg_csum.c_str() + strlen(csum_type);
+                    if (*raw_checksum == '=')
+                        raw_checksum++;
+                    else
+                        raw_checksum = NULL;
+                }
+
+                if (raw_checksum != NULL)
+                    fprintf(checksums, "%s *%s\n",
+                            raw_checksum, seg_path.c_str());
+            }
+        }
+        fclose(checksums);
+    } else {
+        fprintf(stderr, "ERROR: Unable to write checksums file: %m\n");
+    }
+
     db->Close();
 
     /* Write a backup descriptor file, which says which segments are needed and
@@ -742,6 +776,11 @@ int main(int argc, char *argv[])
         descriptor << "Scheme: " << backup_scheme << "\n";
     descriptor << "Root: " << backup_root << "\n";
 
+    SHA1Checksum checksum_csum;
+    if (checksum_csum.process_file(checksum_filename.c_str())) {
+        descriptor << "Checksum-File: " << checksum_csum.checksum_str() << "\n";
+    }
+
     descriptor << "Segments:\n";
     for (std::set<string>::iterator i = segment_list.begin();
          i != segment_list.end(); ++i) {
-- 
2.20.1