alexk / rpms / rpm

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commit da3a3a14e757ccd517e2eb2a3f0293ff48b3ff7f
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Author: Panu Matilainen <pmatilai@redhat.com>
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Date:   Wed Feb 5 13:36:31 2014 +0200
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    A boolean flag is not sufficient to cover three different states...
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    - HEADERFLAG_SORTED flag bit has been used to track the header
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      sort state since beginning of times, but the header sort actually
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      has three different states: truly unsorted (such as after additions),
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      sorted by index achieved with headerSort(), or sorted by offset which
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      is creatively called headerUnsort() in the API.
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      There's exactly one place that requires offset sorting, namely
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      headerExport(). It does call headerUnsort() explicitly, but
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      headerUnsort() would not do anything unless the header was in
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      index-sorted state. This is quite often the case, but data addition
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      would unset the sorted-flag, and causing headerUnsort() not to
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      do anything at all when it most certainly should have. That incorrect
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      sorting caused headerExport() calculations to be wildly off.
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      This ancient bug was unearthed by the innocent looking
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      commit eae671556470136c37951f53ca966cd1bd09aac4: prior to that,
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      in half the cases headerSizeof() used to be called first, causing
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      index-sorting to take place, after which the headerUnsort() in
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      headerExport() did the right thing. In the other two cases
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      headerSizeof() was called afterwards, and the headerExport() would
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      be garbage in cases where new data had been just added, such as package
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      installation. With headerExport() eliminating the need to call
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      headerSizeof() all the cases became broken as the header would
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      seem much bigger than it is due to the bad sort order and cause
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      cases like RhBug:953719 where a largish header suddenly appears
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      to be oversized, causing mysterious install failure. Prior to the
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      commit (which in itself IS innocent) the issue would've mainly
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      manifested in cases where the header needs to be rewritten, which
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      only happens when files are replaced and the header is rewritten for that.
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diff --git a/lib/header.c b/lib/header.c
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index ceffb32..f78ba78 100644
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--- a/lib/header.c
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+++ b/lib/header.c
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@@ -68,8 +68,13 @@ static const int typeSizes[16] =  {
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     0
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 };
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+enum headerSorted_e {
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+    HEADERSORT_NONE	= 0,	/* Not sorted */
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+    HEADERSORT_OFFSET	= 1,	/* Sorted by offset (on-disk format) */
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+    HEADERSORT_INDEX	= 2,	/* Sorted by index  */
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+};
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+
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 enum headerFlags_e {
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-    HEADERFLAG_SORTED    = (1 << 0), /*!< Are header entries sorted? */
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     HEADERFLAG_ALLOCATED = (1 << 1), /*!< Is 1st header region allocated? */
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     HEADERFLAG_LEGACY    = (1 << 2), /*!< Header came from legacy source? */
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     HEADERFLAG_DEBUG     = (1 << 3), /*!< Debug this header? */
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@@ -87,6 +92,7 @@ struct headerToken_s {
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     int indexAlloced;		/*!< Allocated size of tag array. */
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     unsigned int instance;	/*!< Rpmdb instance (offset) */
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     headerFlags flags;
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+    int sorted;			/*!< Current sort method */
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     int nrefs;			/*!< Reference count. */
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 };
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@@ -169,7 +175,7 @@ static Header headerCreate(void *blob, unsigned int pvlen, int32_t indexLen)
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 	h->indexUsed = 0;
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     }
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     h->instance = 0;
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-    h->flags |= HEADERFLAG_SORTED;
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+    h->sorted = HEADERSORT_NONE;
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     h->index = (h->indexAlloced
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 	? xcalloc(h->indexAlloced, sizeof(*h->index))
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@@ -219,9 +225,9 @@ static int indexCmp(const void * avp, const void * bvp)
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 void headerSort(Header h)
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 {
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-    if (!(h->flags & HEADERFLAG_SORTED)) {
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+    if (h->sorted != HEADERSORT_INDEX) {
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 	qsort(h->index, h->indexUsed, sizeof(*h->index), indexCmp);
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-	h->flags |= HEADERFLAG_SORTED;
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+	h->sorted = HEADERSORT_INDEX;
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     }
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 }
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@@ -242,9 +248,9 @@ static int offsetCmp(const void * avp, const void * bvp)
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 void headerUnsort(Header h)
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 {
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-    if (h->flags & HEADERFLAG_SORTED) {
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+    if (h->sorted != HEADERSORT_OFFSET) {
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 	qsort(h->index, h->indexUsed, sizeof(*h->index), offsetCmp);
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-	h->flags &= ~HEADERFLAG_SORTED;
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+	h->sorted = HEADERSORT_OFFSET;
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     }
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 }
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@@ -721,7 +727,8 @@ indexEntry findEntry(Header h, rpmTagVal tag, rpm_tagtype_t type)
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     struct indexEntry_s key;
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     if (h == NULL) return NULL;
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-    if (!(h->flags & HEADERFLAG_SORTED)) headerSort(h);
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+    if (h->sorted != HEADERSORT_INDEX)
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+	headerSort(h);
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     key.info.tag = tag;
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@@ -907,7 +914,8 @@ Header headerImport(void * blob, unsigned int bsize, headerImportFlags flags)
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 	    goto errxit;
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     }
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-    h->flags &= ~HEADERFLAG_SORTED;
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+    /* Force sorting, dribble lookups can cause early sort on partial header */
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+    h->sorted = HEADERSORT_NONE;
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     headerSort(h);
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     h->flags |= HEADERFLAG_ALLOCATED;
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@@ -1439,7 +1447,7 @@ static int intAddEntry(Header h, rpmtd td)
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     entry->length = length;
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     if (h->indexUsed > 0 && td->tag < h->index[h->indexUsed-1].info.tag)
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-	h->flags &= ~HEADERFLAG_SORTED;
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+	h->sorted = HEADERSORT_NONE;
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     h->indexUsed++;
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     return 1;