I've hacked a python interface onto vblade by embedding python into vblade.
This means that instead of pointing vblade at a block device or file,
you can point it at a python program.
Eg
sudo ./vblade -p 1 2 lo file_driver.py params
This is very useful for experimenting with block devices, and for
implementing more "interesting" storage backends.
The python interface looks like this (this driver does the same thing as
vblade)
class Driver(object):
SECTOR_SIZE = 512
def __init__(self, *args, **kwargs):
"""
Initialise
"""
self.size = 16*1024*1024
self.path = "/tmp/aoe_test_file"
self.fd = open(self.path, "wb+")
def getsec(self, position, size):
"""
Reads size bytes at position, returning a string with them in
"""
self.fd.seek(position, os.SEEK_SET)
return self.fd.read(size)
def putsec(self, position, bytes):
"""
Writes the bytes passed in at the position
Returns an integer bytes written, -1 for failure
"""
self.fd.seek(position, os.SEEK_SET)
self.fd.write(bytes)
return len(bytes)
def getsize(self):
"""
Returns the size of the image in bytes
"""
return self.size
I've attached a preliminary patch against the release v20 tarball.
I'd be interested to know
* is this the kind of thing you'd like to merge?
* should the python interface be a compile time option or not?
* any comments on implementation
Things not done yet
* BSD interface
* Restart script on errors
* Use the passed in parameters
Cheers
Nick
--
Nick Craig-Wood <n...@craig-wood.com> -- http://www.craig-wood.com/nick
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..304077f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.o
+*~
+/vblade
diff --git a/aoe.c b/aoe.c
index 0ab0b99..76353b4 100644
--- a/aoe.c
+++ b/aoe.c
@@ -11,6 +11,7 @@
#include <netinet/in.h>
#include "dat.h"
#include "fns.h"
+#include "pi.h"
enum {
Nmasks= 32,
@@ -379,7 +380,7 @@ aoe(void)
void
usage(void)
{
- fprintf(stderr, "usage: %s [-b bufcnt] [-d ] [-s] [-r] [ -m mac[,mac...] ] shelf slot netif filename\n",
+ fprintf(stderr, "usage: %s [-b bufcnt] [-d ] [-s] [-r] [ -m mac[,mac...] ] [-p] shelf slot netif filename [options]\n",
progname);
exit(1);
}
@@ -466,7 +467,7 @@ main(int argc, char **argv)
bufcnt = Bufcount;
setbuf(stdin, NULL);
progname = *argv;
- while ((ch = getopt(argc, argv, "b:dsrm:")) != -1) {
+ while ((ch = getopt(argc, argv, "b:dsrm:p")) != -1) {
switch (ch) {
case 'b':
bufcnt = atoi(optarg);
@@ -485,6 +486,9 @@ main(int argc, char **argv)
case 'm':
setmask(optarg);
break;
+ case 'p':
+ using_python_interface = 1;
+ break;
case '?':
default:
usage();
@@ -492,13 +496,17 @@ main(int argc, char **argv)
}
argc -= optind;
argv += optind;
- if (argc != 4 || bufcnt <= 0)
+ if (argc < 4 || bufcnt <= 0)
usage();
omode |= readonly ? O_RDONLY : O_RDWR;
- bfd = open(argv[3], omode);
- if (bfd == -1) {
- perror("open");
- exit(1);
+ if (using_python_interface) {
+ pi_init(argc-3, &argv[3]); /* call with script name and any extra arguments */
+ } else {
+ bfd = open(argv[3], omode);
+ if (bfd == -1) {
+ perror("open");
+ exit(1);
+ }
}
shelf = atoi(argv[0]);
slot = atoi(argv[1]);
diff --git a/file_driver.py b/file_driver.py
new file mode 100644
index 0000000..d69389a
--- /dev/null
+++ b/file_driver.py
@@ -0,0 +1,43 @@
+import os
+
+class Driver(object):
+ """
+ Driver for AOE
+ """
+ SECTOR_SIZE = 512
+ def __init__(self, *args, **kwargs):
+ """
+ Initialise
+ """
+ print "args = %r, kwargs = %r" % (args, kwargs)
+ self.size = 16*1024*1024
+ self.path = "/tmp/aoe_test_file"
+ if not os.path.exists(self.path):
+ self.fd = open(self.path, "wb+")
+ self.fd.truncate(self.size)
+ else:
+ self.fd = open(self.path, "rb+")
+ self.size = os.path.getsize(self.path)
+ def getsec(self, position, size):
+ """
+ Reads size bytes at position, returning a string with them in
+ """
+ print "< getsec(%d,%d)" % (position, size)
+ self.fd.seek(position, os.SEEK_SET)
+ return self.fd.read(size)
+ def putsec(self, position, bytes):
+ """
+ Writes the bytes passed in at the position
+
+ Returns an integer bytes written, -1 for failure
+ """
+ print "> putsec(%d,%d)" % (position, len(bytes))
+ self.fd.seek(position, os.SEEK_SET)
+ self.fd.write(bytes)
+ return len(bytes)
+ def getsize(self):
+ """
+ Returns the size of the image in bytes
+ """
+ print "= getsize = %d" % self.size
+ return self.size
diff --git a/linux.c b/linux.c
index 11aa2e7..f59b9b6 100644
--- a/linux.c
+++ b/linux.c
@@ -27,6 +27,7 @@
#include "dat.h"
#include "fns.h"
+#include "pi.h"
int getindx(int, char *);
int getea(int, char *, uchar *);
@@ -119,12 +120,16 @@ getmtu(int s, char *name)
int
getsec(int fd, uchar *place, vlong lba, int nsec)
{
+ if (using_python_interface)
+ return pi_getsec(place, lba, nsec);
return pread(fd, place, nsec * 512, lba * 512);
}
int
putsec(int fd, uchar *place, vlong lba, int nsec)
{
+ if (using_python_interface)
+ return pi_putsec(place, lba, nsec);
return pwrite(fd, place, nsec * 512, lba * 512);
}
@@ -147,6 +152,9 @@ getsize(int fd)
struct stat s;
int n;
+ if (using_python_interface)
+ return pi_getsize();
+
n = ioctl(fd, BLKGETSIZE64, &size);
if (n == -1) { // must not be a block special
n = fstat(fd, &s);
diff --git a/makefile b/makefile
index 9613087..0788855 100644
--- a/makefile
+++ b/makefile
@@ -8,12 +8,13 @@ sbindir = ${prefix}/sbin
sharedir = ${prefix}/share
mandir = ${sharedir}/man
-O=aoe.o bpf.o ${PLATFORM}.o ata.o
-CFLAGS += -Wall -g -O2
+LIBS=$(shell python-config --libs)
+O=aoe.o bpf.o ${PLATFORM}.o ata.o pi.o
+CFLAGS += -Wall -g -O2 $(shell python-config --includes)
CC = gcc
vblade: $O
- ${CC} -o vblade $O
+ ${CC} -o vblade $O $(LIBS)
aoe.o : aoe.c config.h dat.h fns.h makefile
${CC} ${CFLAGS} -c $<
diff --git a/pi.c b/pi.c
new file mode 100644
index 0000000..1e1370a
--- /dev/null
+++ b/pi.c
@@ -0,0 +1,201 @@
+/* Python interface */
+
+#include <Python.h>
+#include <stdio.h>
+#include <netinet/in.h> /* for ushort */
+#include "dat.h"
+#include "pi.h"
+
+
+int using_python_interface = 0;
+static PyObject *pi_driver_class = NULL;
+static PyObject *pi_driver = NULL;
+
+static PyObject *pi_load_driver(const char *script)
+{
+ PyObject *globals = NULL;
+ PyObject *result = NULL;
+ PyObject *driver_class = NULL;
+ FILE *fp = NULL;
+
+ /* load in the code */
+ globals = Py_BuildValue( /* new ref */
+ (char *)"{sO}",
+ "__builtins__", PyEval_GetBuiltins()
+ );
+ if (globals == 0)
+ {
+ fprintf(stderr, "Failed to allocate globals for '%s'\n", script);
+ exit(1);
+ }
+
+ fp = fopen(script, "r");
+ if (!fp)
+ {
+ fprintf(stderr, "Couldn't open '%s'\n", script);
+ exit(1);
+ }
+
+ result = PyRun_FileEx(fp, script, Py_file_input, globals, globals, 0); /* new ref */
+ if (!result)
+ {
+ PyErr_Print();
+ fprintf(stderr, "Failed to run '%s'\n", script);
+ exit(1);
+ }
+
+ /* load the Driver class from the module */
+ driver_class = PyDict_GetItemString(globals, "Driver"); /* borrowed */
+ if (!driver_class)
+ {
+ PyErr_Print();
+ fprintf(stderr, "Failed to load 'Driver' class from '%s'\n", script);
+ exit(1);;
+ }
+ Py_INCREF(driver_class); /* keep our own reference please */
+
+ if (fp)
+ fclose(fp);
+ Py_XDECREF(result);
+ Py_XDECREF(globals);
+ return driver_class;
+}
+
+static PyObject *pi_instantiate_driver(PyObject *driver_class, int argc, char *argv[])
+{
+ PyObject *args = NULL;
+ PyObject *kwargs = NULL;
+ PyObject *driver = NULL;
+
+ /* Cheap and nasty code alert ;-) */
+ switch (argc) {
+ case 0:
+ args = Py_BuildValue((char *)"()"); /* new ref */
+ break;
+ case 1:
+ args = Py_BuildValue((char *)"(s)", argv[0]); /* new ref */
+ break;
+ case 2:
+ args = Py_BuildValue((char *)"(ss)", argv[0], argv[1]); /* new ref */
+ break;
+ case 3:
+ args = Py_BuildValue((char *)"(sss)", argv[0], argv[1], argv[2]); /* new ref */
+ break;
+ case 4:
+ args = Py_BuildValue((char *)"(ssss)", argv[0], argv[1], argv[2], argv[3]); /* new ref */
+ break;
+ default:
+ fprintf(stderr, "Too many arguments to python driver\n");
+ exit(1);
+ break;
+ }
+ kwargs = Py_BuildValue((char *)"{}"); /* new ref */
+ driver = PyObject_Call(driver_class, args, kwargs); /* new ref */
+ if (!driver)
+ {
+ PyErr_Print();
+ fprintf(stderr, "Failed to create an instance of python driver\n");
+ exit(1);
+ }
+
+ Py_XDECREF(args);
+ Py_XDECREF(kwargs);
+ return driver;
+}
+
+/*
+Initialise the python driver
+Called with the script name and any remaining arguments
+ */
+
+void
+pi_init(int argc, char *argv[]) {
+ Py_Initialize();
+ pi_driver_class = pi_load_driver(argv[0]);
+ pi_driver = pi_instantiate_driver(pi_driver_class, argc-1, &argv[1]);
+}
+
+int
+pi_getsec(uchar *place, vlong lba, int nsec)
+{
+ int in_size = 512 * nsec;
+ PyObject *py_result = PyObject_CallMethod(pi_driver, (char *)"getsec", (char *)"(li)", lba * 512, in_size); /* new ref */
+ int result;
+ if (py_result)
+ {
+ char *buffer;
+ Py_ssize_t length;
+ if (PyString_AsStringAndSize(py_result, &buffer, &length) != -1) {
+ if (length > in_size) {
+ length = in_size;
+ }
+ memcpy(place, buffer, length);
+ result = length;
+ } else {
+ PyErr_Print();
+ result = 0;
+ }
+ Py_DECREF(py_result);
+ }
+ else
+ {
+ PyErr_Print();
+ result = 0;
+ }
+ return result;
+}
+
+int
+pi_putsec(uchar *place, vlong lba, int nsec)
+{
+ int in_size = 512 * nsec;
+ PyObject *in_buffer = PyString_FromStringAndSize((const char *)place, in_size); /* new ref */
+ if (!in_buffer) {
+ PyErr_Print();
+ return 0;
+ }
+ PyObject *py_result = PyObject_CallMethod(pi_driver, (char *)"putsec", (char *)"(lO)", lba * 512, in_buffer); /* new ref */
+ Py_DECREF(in_buffer);
+ int result;
+ if (py_result)
+ {
+ result = PyInt_AsLong(py_result);
+ Py_DECREF(py_result);
+ if (result == -1 && PyErr_Occurred())
+ {
+ PyErr_Print();
+ result = -1;
+ }
+ }
+ else
+ {
+ PyErr_Print();
+ result = -1;
+ }
+ return result;
+}
+
+vlong
+pi_getsize(void)
+{
+ PyObject *py_result = PyObject_CallMethod(pi_driver, (char *)"getsize", NULL); /* new ref */
+ vlong result;
+ if (py_result)
+ {
+ result = PyInt_AsLong(py_result);
+ Py_DECREF(py_result);
+ if (result == -1 && PyErr_Occurred())
+ {
+ PyErr_Print();
+ fprintf(stderr, "Failed to read size from python driver\n");
+ exit(1);
+ }
+ }
+ else
+ {
+ PyErr_Print();
+ fprintf(stderr, "Failed to read size from python driver\n");
+ exit(1);
+ }
+ return result;
+}
diff --git a/pi.h b/pi.h
new file mode 100644
index 0000000..f00549d
--- /dev/null
+++ b/pi.h
@@ -0,0 +1,15 @@
+/* Python interface */
+
+extern int using_python_interface;
+
+void
+pi_init(int argc, char *argv[]);
+
+int
+pi_getsec(uchar *place, vlong lba, int nsec);
+
+int
+pi_putsec(uchar *place, vlong lba, int nsec);
+
+vlong
+pi_getsize(void);
diff --git a/vblade.8 b/vblade.8
index 2cd2b2c..ef5b2c5 100644
--- a/vblade.8
+++ b/vblade.8
@@ -55,6 +55,10 @@ The -r flag restricts the export of the device to be read-only.
The -m flag takes an argument, a comma separated list of MAC addresses
permitted access to the vblade. A MAC address can be specified in upper
or lower case, with or without colons.
+.TP
+\fB-p\fP
+The -p flag indicates that the device is actually a python script to
+be loaded and called to read and write blocks
.SH EXAMPLE
In this example, the root user on a host named
.I nai
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