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Comment:When opening the *-shm file for a readonly database, try to open it in read-write mode before falling back to readonly. This is in case some other read/write connection within the same process uses the same file descriptor.
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SHA1:a07c581e88aa4d9835f6144c0fd5e58ef42f14ac
User & Date: dan 2016-11-17 14:02:50
Context
2017-02-17
21:23
Increase the estimated cost of sorting when sorting wide results sets, to account for the extra storage space and I/O required for the external sort. Leaf check-in: 38298ef9 user: drh tags: apple-increased-sorting-cost
2016-11-26
20:12
Update test case for opening SHM files read/write on a read-only connection so that they are only attempted on Darwin with SQLITE_ENABLE_PRESIST_WAL. check-in: d6a7bf80 user: drh tags: apple-osx
2016-11-17
14:02
When opening the *-shm file for a readonly database, try to open it in read-write mode before falling back to readonly. This is in case some other read/write connection within the same process uses the same file descriptor. check-in: a07c581e user: dan tags: apple-osx
2016-11-04
19:09
Merge recent trunk changes, including all the fixes that appeared in version 3.15.1. check-in: 0e5ffd91 user: drh tags: apple-osx
Changes
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Changes to src/os_unix.c.

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        rc = SQLITE_NOMEM_BKPT;
        goto shm_open_err;
      }
    }

    if( pInode->bProcessLock==0 ){
      int openFlags = O_RDWR | O_CREAT;

      if( sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0)











#if defined(SQLITE_ENABLE_PERSIST_WAL)&&(SQLITE_ENABLE_LOCKING_STYLE \
    || defined(__APPLE__))

         || (pDbFd->openFlags & O_RDWR) != O_RDWR
#endif
         ){
        openFlags = O_RDONLY;

        pShmNode->isReadonly = 1;
      }
      pShmNode->h = robust_open(zShmFilename, openFlags, (sStat.st_mode&0777));
      if( pShmNode->h<0 ){


        rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShmFilename);
        goto shm_open_err;
      }


      /* If this process is running as root, make sure that the SHM file
      ** is owned by the same user that owns the original database.  Otherwise,
      ** the original owner will not be able to connect.
      */
      robustFchown(pShmNode->h, sStat.st_uid, sStat.st_gid);
  







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        rc = SQLITE_NOMEM_BKPT;
        goto shm_open_err;
      }
    }

    if( pInode->bProcessLock==0 ){
      int openFlags = O_RDWR | O_CREAT;
      int fd;                     /* File descriptor for *-shm file */
      if( sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){
        openFlags = O_RDONLY;
        pShmNode->isReadonly = 1;
      }
      fd = robust_open(zShmFilename, openFlags, (sStat.st_mode&0777));

      /* If it was not possible to open the *-shm file in read/write mode,
      ** and the database file itself has been opened in read-only mode,
      ** try to open the *-shm file in read-only mode as well. Even if the
      ** database connection is read-only, it is still better to try opening
      ** the *-shm file in read/write mode first, as the same file descriptor
      ** may be also be used by a read/write database connection.  */
#if defined(SQLITE_ENABLE_PERSIST_WAL)&&(SQLITE_ENABLE_LOCKING_STYLE \
    || defined(__APPLE__))
      if( fd<0 && errno!=EISDIR && pShmNode->isReadonly==0 
       && (pDbFd->openFlags & O_RDWR)!=O_RDWR

      ){

        fd = robust_open(zShmFilename, O_RDONLY, (sStat.st_mode&0777));
        pShmNode->isReadonly = 1;
      }


#endif
      if( fd<0 ){
        rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShmFilename);
        goto shm_open_err;
      }
      pShmNode->h = fd;

      /* If this process is running as root, make sure that the SHM file
      ** is owned by the same user that owns the original database.  Otherwise,
      ** the original owner will not be able to connect.
      */
      robustFchown(pShmNode->h, sStat.st_uid, sStat.st_gid);
  

Changes to test/walro.test.

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  do_test 2.1.4 { set res } {0 {0 2 2}}

  do_test 2.1.5 {
    code1 { db close }
    code1 { tv delete }
  } {}
}

forcedelete $shmpath



























































finish_test










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  do_test 2.1.4 { set res } {0 {0 2 2}}

  do_test 2.1.5 {
    code1 { db close }
    code1 { tv delete }
  } {}
}

forcedelete $shmpath

#----------------------------------------------------------------------------

catch {db2 close}
reset_db
do_execsql_test 3.1 {
  CREATE TABLE t1(a, b);
  PRAGMA journal_mode = wal;
  INSERT INTO t1 VALUES(1, 2);
} {wal}
db_save
db close
db_restore

sqlite3 db test.db -readonly 1

do_execsql_test 3.2 { SELECT * FROM t1 } {1 2}
do_catchsql_test 3.3 { 
  INSERT INTO t1 VALUES(3, 4) 
} {1 {attempt to write a readonly database}}

sqlite3 db2 test.db
do_test 3.4 { 
  db2 eval { INSERT INTO t1 VALUES(3, 4) }
} {}
do_execsql_test 3.5 { SELECT * FROM t1 } {1 2 3 4}

db close
db2 close
db_restore
file attributes $shmpath -permissions r--r--r--
sqlite3 db test.db -readonly 1
do_execsql_test 3.6 { SELECT * FROM t1 } {1 2}

db close
db_restore
file attributes $shmpath -permissions r--r--r--
sqlite3 db test.db
do_test 3.7 {
  catchsql { SELECT * FROM t1 } 
} {1 {unable to open database file}}

db close
db_restore
file attributes $shmpath -permissions r--r--r--
sqlite3 db test.db -readonly 1
do_execsql_test 3.8 { SELECT * FROM t1 } {1 2}

sqlite3 db2 test.db
do_test 3.9 { db2 eval { SELECT * FROM t1 } } {1 2}
do_test 3.10 { 
  catchsql { INSERT INTO t1 VALUES(3, 4) } db2 
} {1 {attempt to write a readonly database}}

catch { db close }
catch { db2 close }

forcedelete $shmpath

finish_test