System information:
Linux Fedora 26
Mariadb version 10.1.25
I have executed all the statements as described in MariaDB Insert BLOB Image.
In addition I have also disabled selinux.
But load_file still returns NULL without giving an error.
I followed these instructions (https://mariadb.com/kb/en/the-mariadb-library/general-query-log/) to enable general logging but 'queries.log' only reports that the query has been executed without giving information on why it returns NULL instead of the wanted output.
Does Mariadb log the reason for this failure? If so, where?
Verify the rest of the constraints:
LOAD_FILE(file_name)
Reads the file and returns the file contents as a string. To use this function, the file must be located on the server host, you must specify the full path name to the file, and you must have the FILE privilege. The file must be readable by all and its size less than max_allowed_packet bytes. If the secure_file_priv system variable is set to a nonempty directory name, the file to be loaded must be located in that directory.
If the file does not exist or cannot be read because one of the preceding conditions is not satisfied, the function returns NULL.
The character_set_filesystem system variable controls interpretation of file names that are given as literal strings.
You need ALL directories in the path have SET executable bit
Related
I'm using Gremlin Server.
I save the contents of the database in an XML file (GraphML) with this line:
g.io(path).write().iterate()
To load the file I use this line:
g.io(path).read().iterate();
And then I get this error:
connection.js:282
new ResponseError(util.format('Server error: %s (%d)', response.status.message, response.status.code), response.status));
^
ResponseError: Server error: For input string: "-2555865115" (500)
This error is coming from gremlin server.
If I search for this value in the XML file (-2555865115) and I remove the last character (-255586511) then the problem is solved.
Why this happens? How can I fix this issue? The database is always saving a file that I have to fix manually.
If I have to change something in the configuration files of Gremlin Server, can you please tell me which file to modify and how? because I never did that before.
I'm using Gremlin server in my local computer just for testing, without any changes.
EDIT:
I changed conf/tinkergraph-empty.properties to this:
gremlin.tinkergraph.vertexIdManager=ANY
gremlin.tinkergraph.edgeIdManager=ANY
gremlin.tinkergraph.vertexPropertyIdManager=ANY
I restarted, but I get the same error when loading the XML file.
Given that removing the last integer from your numerical value solved the problem, I'd speculate you're hitting a limit; specifically, the lowest value an integer can have.
In Java, that value is -2147483647, and that happens to be the language that the default implementation of Gremlin Server is written in. As such, it's likely that the deserialization process is failing while trying to interpret that value as an integer. Since the value is below the minimum value of an integer, and since the error message talks about it being an input string, Integer.parseInt("-2555865115") is probably the call that's failing behind the scenes.
If Gremlin is both serializing and de-serializing the data, it might be a bug in that implementation, and you might want to file an issue. In the mean time, consider implementing and registering a custom serializer to give yourself more control over how the IO process works.
The POSIX shm_open() function returns a file descriptor that can be used to access shared memory. This is extremely convenient because one can use all the traditional mechanisms for controlling file descriptors to also control shared memory.
The only drawback is that shm_open() always wants a filename. So I need to do this:
// Open with a clever temp file name and hope for the best.
fd = shm_open(tempfilename, O_RDWR | O_CREAT | O_EXCL, 0600);
// Immediately delete the temp file to keep the shm namespace clean.
shm_unlink(tempfilename);
// Then keep using fd -- the shm object remains as long as there are open fds.
This use of tempfilename is difficult to do portably and reliably. The interpretation of the filename (what the namespace is, how permissions are handled) differs among systems.
In many situations the processes using the shared memory object have no need for a filename because the object can be accessed more simply and safely by just passing a file descriptor from one process to another. So is there something that's just like shm_open() but can be used without touching the shared memory filename namespace?
mmap() with MAP_ANON|MAP_SHARED is great but instead of a file descriptor it gives a pointer. The pointer doesn't survive over an exec boundary and can't be sent to another process over a Unix domain socket like file descriptors can.
The file descriptor returned by shm_open() also doesn't survive an exec boundary by default: the POSIX definition says that the FD_CLOEXEC file descriptor flag associated with the new file descriptor is set. But it is possible to clear the flag using fcntl() on MacOS, Linux, FreeBSD, OpenBSD, NetBSD, DragonFlyBSD and possibly other operating systems.
A library to solve the problem
I managed to write a library that provides the simple interface:
int shm_open_anon(void);
The library compiles without warnings and successfully runs a test program on Linux, Solaris, MacOS, FreeBSD, OpenBSD, NetBSD, DragonFlyBSD and Haiku. You may be able to adapt it to other operating systems; please send a pull request if you do.
The library returns a file descriptor with the close-on-exec flag set. You can clear that flag using fcntl() on all supported operating systems, which will allow you to pass the fd over exec(). The test program demonstrates that this works.
Implementation techniques used in the library
The readme of the library has very precise notes on what was done and what wasn't done for each OS. Here's a summary of the main stuff.
There are several non-portable things that are more or less equivalent to shm_open() without a filename:
FreeBSD can take SHM_ANON as the pathname for shm_open() since 2008.
Linux has a memfd_create() system call since kernel version 3.17.
Earlier versions of Linux can use mkostemp(name, O_CLOEXEC | O_TMPFILE) where name is something like /dev/shm/XXXXXX. Note that we are not using shm_open() at all here -- mkostemp() is implicitly using a perfectly ordinary open() call. Linux mounts a special memory-backed file system in /dev/shm but some distros use /run/shm instead so there are pitfalls here. And you still have to shm_unlink() the temp file.
OpenBSD has a shm_mkstemp() call since release 5.4. You still have to shm_unlink() the temp file but at least it is easy to create safely.
For other OSes, I did the following:
Figure out an OS-dependent format for the name argument of POSIX shm_open(). Please note that there is no name you can pass that is absolutely portable. For example, NetBSD and DragonFlyBSD have conflicting demands about slashes in the name. This applies even if your goal is to use a named shm object (for which the POSIX API was designed) instead of an anonymous one (as we are doing here).
Append some random letters and numbers to the name (by reading from /dev/random). This is basically what mktemp() does, except we don't check whether our random name exists in the file system. The interpretation of the name argument varies wildly so there's no reasonable way to portably map it to an actual filename. Also Solaris doesn't always provide mktemp(). For all practical purposes, the randomness we put in will ensure a unique name for the fraction of a second that we need it.
Open the shm object with that name via shm_open(name, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW, 0600). In the astronomical chance that our random filename already exists, O_EXCL will cause this call to fail anyway, so no harm done. The 0600 permissions (owner read-write) are necessary on some systems instead of blank 0 permissions.
Immediately call shm_unlink() to get rid of the random name. The file descriptor remains for our use.
This technique is not quaranteed to work by POSIX, but:
The shm_open() name argument is underspecified by POSIX so nothing else is guaranteed to work either.
I'll let the above compatibility list speak for itself.
Enjoy.
No, there isn't. Since both System V shared memory model and POSIX shared file mapping for IPC require operations with a file, there is always need for a file in order to do mapping.
mmap() with MAP_ANON|MAP_SHARED is great but instead of a file
descriptor it gives a pointer. The pointer doesn't survive over an
exec boundary and can't be sent to another process over a Unix domain
socket like file descriptors can.
As John Bollinger says,
Neither memory mappings created via mmap() nor POSIX shared-memory
segments obtained via shm_open() nor System V shared-memory segments
obtained via shmat() are preserved across an exec.
There must be a well-known place on the memory to meet and exchange information. That's why a file is the requirement. By doing this, after exec, the child is able to reconnect to the appropriate shared memory.
This use of tempfilename is difficult to do portably and reliably. The interpretation of the filename (what the namespace is, how permissions are handled) differs among systems.
You can have mkstemp create a unique filename in /dev/shm/ or /tmp and open the file for you. You can then unlink the filename, so that no other process can open this file, apart from the process that have the file descriptor returned from mkstemp.
mkstemp(): CONFORMING TO 4.3BSD, POSIX.1-2001.
Why not creating it with access rights to 0?
Thus no process would be able to "open" it and let you unlink it safely just after?
*** Test cases ***
TestDB
Connect To Database Using Custom Params None database='TestDB', user='system', password='system', host='10.91.41.101', port=1521
Please help - the error is:
ImportError: No module named None
The error most probably comes from the way you call Connect To Database Using Custom Params - the first argument you're passing, which should be the value for the dbapiModuleName, is passed as a string object, with the value "None".
If you wanted to call it with the value None object (as it's written in the library's help), that should have been ${None} in robotframework format.
I doubt that's going to work though - the DatabaseLibrary probably needs some DB type identifier. So if you are using postgres for example, you'd call it with "psycopg2":
Connect To Database Using Custom Params psycopg2 database='TestDB', user='username', password='mypass', host='10.1.1.2', port=1521
Have in mind you'd need the DB driver already installed through pip, psycopg2 in the case of the example here.
P.S. please don't paste actual credentials in SO.
I assume your question should have been posted something like this...
Issue
When attempting to execute the following test case in Robot Framework, I receive the following error: ImportError: No module named None
Here is the test case in question:
*** Test Cases ***
TestDB
Connect To Database Using Custom Params None database='TestDB', user='system', password='system', host='10.91.41.101', port=1521
If so, your issue may be as simple as spacing. Robot Framework can accept pipes as delimiters, but if you choose to use spaces, you must use 2 or more.
Based on your copy/paste, it looks like you have only one space between Connect To Database Using Custom Params and None (which, I'm assuming you're specifying as the DB API Python module the system default - not sure if that's recommended or supported). Make sure you have at least two spaces (I generally try for 4 unless I have a lot of parameters) between keywords and their parameters.
So:
Make sure you have at least two spaces between the keyword and parameters. Here is the keyword in question's reference.
Verify that you don't need to specify the Python database driver for the database you are using. Based on the port you've specified, I'm guessing it's an Oracle database. Here's a list of Python Oracle drivers.
I had a similar error and read on it for hours not knowing I hadn't created a .env file yet. credit to a friend who brought me to this page. (which gave me the hint on what I was missing).
I created a .env file in my root folder where the manage.py file is and configured my database settings and voila. Thanks Suraj
I have a compiled c binary (setch) which takes the parameters HIGH/LOW/OFF so I am trying to execute the command eg setch OFF from javascript/jquery thus:
$.get("cgi-bin/setch.cgi","OFF"); -or
$.get("cgi-bin/setch OFF");
As it's a get then the space is encoded into %20, of course. However the server then tries to execute the command setch%20OFF and returns:
404 Not Found
Without the parameter the program executes and returns my message:
no parameters
ie all paths, permissions etc are OK
Am I trying to do the impossible here? Or am I missing something in the server (lighttpd) config?
Thanks
You want to pass a parameter to a CGI. The way to do that is not to separate them with a space, instead you want to put the parameter behind a "?" character. The HTTP server will then store everything that follows behind the question mark in the QUERY_STRING environment variable that your CGI can then read.
I.e.
$.get("cgi-bin/setch?OFF");
In your C program use getenv("QUERY_STRING") to access the passed parameter.
Check https://en.wikipedia.org/wiki/Common_Gateway_Interface for a list of all environment variables that the HTTP server set for CGI programs. Be sure to treat the values as untrusted data.
We're getting a server error saying "Parameter count does not match Parameter Value count." Anyone have any idea what this could mean?
Our site's on ASP.NET Webforms running DotNetNuke as a CMS.
I've tried uploading an older version of the web.config file but it doesn't seem to have changed since the error came up. It wasn't in any of our recent module file uploads because I reuploaded the old files from this morning that we changed.
Could any changes in the database cause this or would it have to originate from an error in the code?
Thanks.
Some SQL query or stored procedure has more parameters specified then parameters' values received.
Something like this:
command.CommandText = "EXEC test #a";
command.Parameters.Add("#a", "a");
command.Parameters.Add("#b", "b");
i.e. look at the database scheme. Was it changed? Were stored procedures changed?
I've found that if you are using parameters that have default values, certain libraries can't handle.
For instance, we have an application that uses an older version of Microsoft Enterprise Library Data Access method that allows you to pass parameters as an array.
It fails if the amount of items in the array doesn't match exactly the number of parameters on the stored procedure, regardless if some are 'optional' or not.
In cases like this have to use straight ADO.NET and use the cmd.Parameters.AddWithValues("#parameterName", value)
syntax for the required stored procedure parameters. You will not have to add, when using this method, command parameters for the 'optional' stored procedure parameters.
I had the same problem and I found that it was picking the fields from a temporary cache which was being maintained by MySQLHelper.