On Wed, 18 Jun 2025 16:40:53 GMT, Sergey Chernyshev <[email protected]> wrote:
>> Hi all, >> >> I would like to propose a fix for JDK-8319589. This will allow jcmd and jps >> running as root to get the complete list of JVMs running by all users, and >> to attach from root to non-root JVMs. Previously, JDK-8197387 introduced the >> same approach on Linux. >> >> This change affects macOS, that uses "secure" per-user temporary >> directories. It only affects JVMs running as root, the behavior in >> non-privileged JVMs remains unchanged. >> >> Jcmd and jps rely on LocalVmManager to get the initial list of the local >> VMs. The LocalVmManager uses sun.jvmstat.PlatformSupport to get the list of >> temp directories, where it searches for user's PerfData directory such as >> "hsperfdata_<username\>". In macosx the temp directories are per-user, the >> temp path is returned by confstr(_CS_DARWIN_USER_TEMP_DIR). The per-user >> directories are mode 700 and so they are read-protected from non-privileged >> users and can be accessed by the owner and the root. >> >> Both jps and jcmd (HotSpotAttachProvider) create MonitoredVm objects, that >> have PerfDataBuffer that performs attachment to the target. Only the >> attachable VMs are listed in jcmd output. >> >> The proposed patch changes the list of directories returned by the >> PlatformSupport#getTemporaryDirectories() in VMs running as root. The list >> is later used in VirtualMachineImpl (jdk.attach). It changes also the way >> mmap_attach_shared() searches for hsperfdata_<username\>/<pid\> files to map >> the shared memory. Mmap_attach_shared() and VirtualMachineImpl (via >> PlatformSupport) list the content of /var/folders, where the temp >> directories are located, more specificly the temp directories are >> /var/folders/<BUCKET\>/<ENCODED_UUID_UID\>/T as hinted in [1]. The full list >> is returned by newly added PlatformSupportImpl#getTemporaryDirectories(). >> >> The attaching client's VirtualMachineImpl needs the target process's temp >> directory to find .java<pid\> and create .attach<pid\> files. It uses the >> list returned by PlatformSupportImpl#getTemporaryDirectories() and the >> ProcessHandle of the target process to search for user's PerfData directory, >> e.g. hsperfdata_<username\>, which is in the target process's temp >> directory, exactly where it expects to see the .java<pid\> in return on >> sending SIGQUIT to the target VM. >> >> Mmap_attach_shared() traverses the /var/folders in get_user_tmp_dir() and >> looks for a hsperfdata_<username\> folder. If that folder is found in >> /var/folders/*/*/T, that means the temp folder corresponds to the >> <username\> and to the ... > > Sergey Chernyshev has updated the pull request incrementally with two > additional commits since the last revision: > > - Update > src/jdk.attach/macosx/classes/sun/tools/attach/VirtualMachineImpl.java > > Co-authored-by: Andrey Turbanov <[email protected]> > - addressed review comments will do! On 9/22/25 1:04 PM, Sergey Chernyshev wrote: > *sercher* left a comment (openjdk/jdk#25824) > <https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/25824*issuecomment-3321272195__;Iw!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2810uaE86kA$> > > @turbanoff > <https://urldefense.com/v3/__https://github.com/turbanoff__;!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2812g3XS-WA$> > > @dholmes-ora > <https://urldefense.com/v3/__https://github.com/dholmes-ora__;!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2813-Ly68vg$> > > @larry-cable > <https://urldefense.com/v3/__https://github.com/larry-cable__;!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2810J2TUJ4w$> > > Could you please take a look at this? > > — > Reply to this email directly, view it on GitHub > <https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/25824*issuecomment-3321272195__;Iw!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2810uaE86kA$>, > > or unsubscribe > <https://urldefense.com/v3/__https://github.com/notifications/unsubscribe-auth/ANTA67VRW3666Z2O5P7IMJT3UBI3LAVCNFSM6AAAAAB7MZH7WGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTGMRRGI3TEMJZGU__;!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2810UmUzuKQ$>. > You are receiving this because you were mentioned.Message ID: > ***@***.***> > --------------clQK6hO50V7lxYIyzZn4ddE5 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit <!DOCTYPE html><html><head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> </head> <body> will do!<br> <br> <div class="moz-cite-prefix">On 9/22/25 1:04 PM, Sergey Chernyshev wrote:<br> </div> <blockquote type="cite" ***@***.***"> <div style="display: flex; flex-wrap: wrap; white-space: pre-wrap; align-items: center; "><img height="20" width="20" style="border-radius:50%; margin-right: 4px;" decoding="async" src="https://avatars.githubusercontent.com/u/6394632?s=20&v=4"; moz-do-not-send="true"><strong>sercher</strong> left a comment <a href="https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/25824*issuecomment-3321272195__;Iw!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2810uaE86kA$"; moz-do-not-send="true">(openjdk/jdk#25824)</a></div> <p dir="auto"><a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/turbanoff/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://urldefense.com/v3/__https://github.com/turbanoff__;!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2812g3XS-WA$"; ***@***.***</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/dholmes-ora/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://urldefense.com/v3/__https://github.com/dholmes-ora__;!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2813-Ly68vg$"; ***@***.***</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/larry-cable/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://urldefense .com/v3/__https://github.com/larry-cable__;!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2810J2TUJ4w$"; ***@***.***</a> Could you please take a look at this?</p> <p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br> Reply to this email directly, <a href="https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/25824*issuecomment-3321272195__;Iw!!ACWV5N9M2RV99hQ!P9dALpheoPUoaoWeQ1rj6dzwU42yVWWmfrsbZt429ot-cdhEW8CspQyFVJ455ZjgbI2QssgWZS26ouu2810uaE86kA$"; 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