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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

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Overview
Comment:Use memmove() instead of memcpy() in a place where buffers might overlap if the database file is badly corrupted, to prevent warnings from ASAN and valgrind.
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SHA3-256: 65ad6c55f1ba9bc2f75afffa3adaf19f145fad7ac9a00ccce6372e9a2cc4341b
User & Date: drh 2019-01-24 13:36:47
Context
2019-01-24
14:16
Change a integer variable in sqlite3VdbeRecordUnpack() to unsigned in order to avoid any possibility of an integer overflow. check-in: 1b536f6f user: drh tags: trunk
13:36
Use memmove() instead of memcpy() in a place where buffers might overlap if the database file is badly corrupted, to prevent warnings from ASAN and valgrind. check-in: 65ad6c55 user: drh tags: trunk
04:44
Remove an unreachable branch. check-in: 4c976f17 user: drh tags: trunk
Changes
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Changes to src/btree.c.

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                                 iAmt-nData);
      if( rc ) return rc;
      iAmt = nData;
    }
    if( memcmp(pDest, ((u8*)pX->pData) + iOffset, iAmt)!=0 ){
      int rc = sqlite3PagerWrite(pPage->pDbPage);
      if( rc ) return rc;




      memcpy(pDest, ((u8*)pX->pData) + iOffset, iAmt);
    }
  }
  return SQLITE_OK;
}

/*
** Overwrite the cell that cursor pCur is pointing to with fresh content







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                                 iAmt-nData);
      if( rc ) return rc;
      iAmt = nData;
    }
    if( memcmp(pDest, ((u8*)pX->pData) + iOffset, iAmt)!=0 ){
      int rc = sqlite3PagerWrite(pPage->pDbPage);
      if( rc ) return rc;
      /* In a corrupt database, it is possible for the source and destination
      ** buffers to overlap.  This is harmless since the database is already
      ** corrupt but it does cause valgrind and ASAN warnings.  So use
      ** memmove(). */
      memmove(pDest, ((u8*)pX->pData) + iOffset, iAmt);
    }
  }
  return SQLITE_OK;
}

/*
** Overwrite the cell that cursor pCur is pointing to with fresh content

Changes to test/fuzzdata7.db.

cannot compute difference between binary files