[Rpm-maint] [PATCH 3/3] Add RPMTAG_IDENTITY calculation as tag extension

[Vladimir D. Seleznev]

RPMTAG_IDENTITY is calculating as digest of part of package header that
marked for identity calculation in rpmtag.h. They are supposed to not
contain irrelevant to package build tag entries.

Mathematically RPMTAG_IDENTITY value is a result of function of two
variable: a package header and an rpm utility, thus this value can
differ for same package and different version of rpm.

Signed-off-by: Vladimir D. Seleznev <vseleznv at altlinux.org>
---
 lib/tagexts.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/lib/tagexts.c b/lib/tagexts.c
index 61e9b702b..1467bfcd3 100644
--- a/lib/tagexts.c
+++ b/lib/tagexts.c
@@ -954,6 +954,77 @@ static int filenlinksTag(Header h, rpmtd td, headerGetFlags hgflags)
 
 #include "identitymatch.C"
 
+static int identityTag(Header h, rpmtd td, headerGetFlags hgflags)
+{
+    int rc = 1;
+    DIGEST_CTX ctx;
+    char * identity = NULL;
+
+    struct rpmtd_s ttd;
+    Header ih;
+    HeaderIterator hi;
+
+    /* Return immediatly if there is no identity marker in rpmtag.h */
+    if (!identityMatch(0)) {
+	rc = 0;
+	goto exit;
+    }
+
+    /* rpm v3 packages dont have an immutable region */
+    if (!headerGet(h, RPMTAG_HEADERIMMUTABLE, &ttd, HEADERGET_DEFAULT)) {
+	rc = 0;
+	goto exit;
+    }
+
+    ih = headerImport(ttd.data, ttd.count, HEADERIMPORT_FAST);
+    if ((hi = headerInitIterator(ih)) == NULL) {
+	rc = 0;
+	goto exit;
+    }
+
+    if ((ctx = rpmDigestInit(PGPHASHALGO_SHA256, RPMDIGEST_NONE)) == NULL) {
+	rc = 0;
+	goto exit;
+    }
+
+    while (headerNext(hi, &ttd) && rc) {
+	if (rpmtdCount(&ttd) > 0) {
+	    if (identityMatch(ttd.tag)) {
+		int i;
+		rpmtdInit(&ttd);
+		while ((i = rpmtdNext(&ttd)) >= 0) {
+		    rpmDigestUpdate(ctx, &ttd.tag, sizeof(ttd.tag));
+		    rpmDigestUpdate(ctx, &i, sizeof(i));
+		    if (ttd.type == RPM_STRING_ARRAY_TYPE) {
+			for (int j = 0; j < ttd.count; j++)
+			    rpmDigestUpdate(ctx, ((char **) ttd.data)[j], strlen(((char **) ttd.data)[j]));
+			continue;
+		    }
+		    rpmDigestUpdate(ctx, ttd.data, ttd.size);
+		}
+	    }
+	}
+	rpmtdFreeData(&ttd);
+    }
+
+    if (!rc)
+	goto exit;
+
+    rpmDigestFinal(ctx, (void **) &identity, NULL, 1);
+    headerFree(ih);
+
+    td->data = xstrdup(identity);
+    td->type = RPM_STRING_TYPE;
+    td->count = 1;
+    td->flags = RPMTD_ALLOCED;
+
+exit:
+    headerFreeIterator(hi);
+    _free(identity);
+
+    return rc;
+}
+
 static const struct headerTagFunc_s rpmHeaderTagExtensions[] = {
     { RPMTAG_GROUP,		groupTag },
     { RPMTAG_DESCRIPTION,	descriptionTag },
@@ -992,6 +1063,7 @@ static const struct headerTagFunc_s rpmHeaderTagExtensions[] = {
     { RPMTAG_OBSOLETENEVRS,	obsoletenevrsTag },
     { RPMTAG_CONFLICTNEVRS,	conflictnevrsTag },
     { RPMTAG_FILENLINKS,	filenlinksTag },
+    { RPMTAG_IDENTITY,		identityTag },
     { 0, 			NULL }
 };
 
-- 
2.17.1