I should also note that on other *nix'es (where there is no /proc to
introspect) the default behavior is simply to send the QUIT regardless.
In the case of Linux, this addition obviates the chance of an attach
killing the target should it not be catching QUIT!
On 11/12/24 3:45 PM, Laurence Cable wrote:
On 11/12/24 3:33 PM, Serguei Spitsyn wrote:
On Thu, 7 Nov 2024 04:48:28 GMT, Serguei Spitsyn
<sspit...@openjdk.org> wrote:
Larry Cable has updated the pull request incrementally with one
additional commit since the last revision:
JDK-8342449: fixed missing param in throws msg and renamed local
var
src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java
line 268:
266: * however we can also check the target pid's signal
masks to see if it catches SIGQUIT and only do so if in
267: * fact it does ... this reduces the risk of killing
an innocent process in the current ns as opposed to
268: * attaching to the actual target JVM ... c.f:
checkCatchesAndSendQuitTo() below.
This still looks pretty risky and dangerous. I'm thinking if it'd
make sense to check that the target process is a VM process. At
least, we know how VM processes can use the signal mask. Another
concern is that the target VM process might be not exactly the same
VM the client was expecting to attach. I don't know what can be done
to ensure this correctness.
It should be okay to file a bug/rfe on this.
it is not feasible to introspect on the target process to determine if
it is a JVM or not, this is the best case not to send SIGQUIT to a
process that is neither catching nor blocking it, where the default is
to terminate it!
-------------
PR Review Comment:
https://git.openjdk.org/jdk/pull/21688#discussion_r1838967163
