Thanks for the report, but it is unlikely anyone would be able to help
just based on this code fragment. We need a small and minimal but
complete reproducible example. That example should not use any
contributed packages (a contributed package may be corrupting memory,
which may cause R to crash).
It is easy to get a bugzilla account - please see
https://www.r-project.org/bugs.html for more and for advice on how to
write bug reports. You could even send the bug report to this list, but
the key thing is the reproducible example.
Thanks
Tomas
On 5/11/20 9:40 PM, Russell Almond wrote:
I'm trying to implement a connection between two processes using a
simple socket mechanism. The messages are rather long object stored
as JSON.
R is crashing with a segmentation fault when I try to read my test
message (which is 5305 bytes long). I first send the length in bytes
and then I send the actual message.
Here is my R code:
library(jsonlite)
library(futile.logger)
listenerloop <- function (port) {
flog.trace("Opening Socket on port %d",port)
sock <- make.socket("localhost",port,server=TRUE)
on.exit({
close.socket(sock)
flog.trace("Closing Socket on port %d",port)
})
repeat {
## Input a hunk of stuff up to a blank line.
output <- character()
repeat {
inlen <- read.socket(sock,loop=TRUE)
flog.trace("Got message of length %s",inlen)
if (inlen=="quit") break
inmess <- fromJSON(read.socket(sock,as.integer(inlen)),false)
outmess <- doProcess(inmess)
output <- toJSON(outmess)
flog.trace("Sending message of length %s",nchar(output))
write.socket(sock,paste(nchar(output),"\n"))
write.socket(sock,output)
}
}
}
doProcess() is the payload, but it is not getting that far. Instead I
get:
> listenerloop(12525)
TRACE [2020-05-11 15:21:00] Opening Socket on port 12525
TRACE [2020-05-11 15:21:03] Got message of length 5305
{"StudentRecord":null,"Message":{"_id":624,"app":"ecd://terc.edu/Zoombinis/","uid":2,"context":"PIZZA_PASS1","sender":"DataArcade","mess":"Last
Transaction","timestamp":"1570279373.109","processed":false,"data":{"PP29_N_Rejects_Current_Z":0,"PP106_Avg
*** caught segfault ***
address 0x7ffdf533d0a8, cause 'memory not mapped'
Traceback:
1: read.socket(sock, as.integer(inlen))
2: fromJSON(read.socket(sock, as.integer(inlen)), false)
3: listenerloop(12525)
I have two questions:
1) Can somebody file a bug report on this? I strongly suspect that
there is an uncaught error in read.socket(). I'm happy to help, but I
don't have access to bugzilla.
2) Anybody know how to read/write long messages to a socket in R?
Thanks in advance.
--Russell Almond
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