Something I did in a commit broke my code. I have a git bisect that shows me the last good commit and the first bad one.
Continue readingHow Did I break my Code
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Category Archives: C
recvfrom system call in python
With a socket created, and a message sent, the next step in our networking journey is to receive data.
Continue readingsendto system call from python
Once we open a socket, we probably want to send and receive data across it.Here is the system call we need to make in order to send data as I wrote about in my last post:
c = sendto(sd, buf, sizeof(buf), 0,
(struct sockaddr *)&addr, sizeof(addr));Updated MCTP send code
While the existing documentation is good, there are a couple things that have changed since it was originally written, and I had to make a couple minor adjustments to get it to work. Here’s the code to send a message. The receive part should work as originally published; what is important is the set of headers. I built and ran this on an AARCH64 platform running Fedora 38.
Continue readingsocket system call from python
While the Python socket API is mature, it does not yet support MCTP. I thought I would thus try to make a call from python into native code. The first step is to create a socket. Here is my code to do that.
Note that this is not the entire C code needed to make network call, just the very first step.I did include the code to read errno if the call fails.
#!/usr/bin/python3
from ctypes import *
libc = CDLL("/lib64/libc.so.6")
AF_MCTP = 45
SOCK_DGRAM = 2
rc = libc.socket (AF_MCTP, SOCK_DGRAM, 0)
#print("rc = %d " % rc)
get_errno_loc = libc.__errno_location
get_errno_loc.restype = POINTER(c_int)
errno = get_errno_loc()[0]
print("rc = %d errno = %d" % (rc, errno) )
print("OK")Running this code on my machine shows success
# ./spdm.py
rc = 3 errno = 0
OK