[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v2 27/29] tools/xenstored: add helpers for filename handling


  • To: Julien Grall <julien@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • From: Juergen Gross <jgross@xxxxxxxx>
  • Date: Tue, 14 Nov 2023 07:45:15 +0100
  • Autocrypt: addr=jgross@xxxxxxxx; keydata= xsBNBFOMcBYBCACgGjqjoGvbEouQZw/ToiBg9W98AlM2QHV+iNHsEs7kxWhKMjrioyspZKOB ycWxw3ie3j9uvg9EOB3aN4xiTv4qbnGiTr3oJhkB1gsb6ToJQZ8uxGq2kaV2KL9650I1SJve dYm8Of8Zd621lSmoKOwlNClALZNew72NjJLEzTalU1OdT7/i1TXkH09XSSI8mEQ/ouNcMvIJ NwQpd369y9bfIhWUiVXEK7MlRgUG6MvIj6Y3Am/BBLUVbDa4+gmzDC9ezlZkTZG2t14zWPvx XP3FAp2pkW0xqG7/377qptDmrk42GlSKN4z76ELnLxussxc7I2hx18NUcbP8+uty4bMxABEB AAHNH0p1ZXJnZW4gR3Jvc3MgPGpncm9zc0BzdXNlLmNvbT7CwHkEEwECACMFAlOMcK8CGwMH CwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAAKCRCw3p3WKL8TL8eZB/9G0juS/kDY9LhEXseh mE9U+iA1VsLhgDqVbsOtZ/S14LRFHczNd/Lqkn7souCSoyWsBs3/wO+OjPvxf7m+Ef+sMtr0 G5lCWEWa9wa0IXx5HRPW/ScL+e4AVUbL7rurYMfwCzco+7TfjhMEOkC+va5gzi1KrErgNRHH kg3PhlnRY0Udyqx++UYkAsN4TQuEhNN32MvN0Np3WlBJOgKcuXpIElmMM5f1BBzJSKBkW0Jc Wy3h2Wy912vHKpPV/Xv7ZwVJ27v7KcuZcErtptDevAljxJtE7aJG6WiBzm+v9EswyWxwMCIO RoVBYuiocc51872tRGywc03xaQydB+9R7BHPzsBNBFOMcBYBCADLMfoA44MwGOB9YT1V4KCy vAfd7E0BTfaAurbG+Olacciz3yd09QOmejFZC6AnoykydyvTFLAWYcSCdISMr88COmmCbJzn sHAogjexXiif6ANUUlHpjxlHCCcELmZUzomNDnEOTxZFeWMTFF9Rf2k2F0Tl4E5kmsNGgtSa aMO0rNZoOEiD/7UfPP3dfh8JCQ1VtUUsQtT1sxos8Eb/HmriJhnaTZ7Hp3jtgTVkV0ybpgFg w6WMaRkrBh17mV0z2ajjmabB7SJxcouSkR0hcpNl4oM74d2/VqoW4BxxxOD1FcNCObCELfIS auZx+XT6s+CE7Qi/c44ibBMR7hyjdzWbABEBAAHCwF8EGAECAAkFAlOMcBYCGwwACgkQsN6d 1ii/Ey9D+Af/WFr3q+bg/8v5tCknCtn92d5lyYTBNt7xgWzDZX8G6/pngzKyWfedArllp0Pn fgIXtMNV+3t8Li1Tg843EXkP7+2+CQ98MB8XvvPLYAfW8nNDV85TyVgWlldNcgdv7nn1Sq8g HwB2BHdIAkYce3hEoDQXt/mKlgEGsLpzJcnLKimtPXQQy9TxUaLBe9PInPd+Ohix0XOlY+Uk QFEx50Ki3rSDl2Zt2tnkNYKUCvTJq7jvOlaPd6d/W0tZqpyy7KVay+K4aMobDsodB3dvEAs6 ScCnh03dDAFgIq5nsB11j3KPKdVoPlfucX2c7kGNH+LUMbzqV6beIENfNexkOfxHfw==
  • Cc: Wei Liu <wl@xxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Jason Andryuk <jandryuk@xxxxxxxxx>
  • Delivery-date: Tue, 14 Nov 2023 06:45:24 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 13.11.23 23:25, Julien Grall wrote:
Hi Juergen,

On 10/11/2023 16:08, Juergen Gross wrote:
Add some helpers for handling filenames which might need different
implementations between stubdom and daemon environments:

- expansion of relative filenames (those are not really defined today,
   just expand them to be relative to /var/lib/xen/xenstore)
- expansion of xenstore_daemon_rundir() (used e.g. for saving the state
   file in case of live update - needs to be unchanged in the daemon
   case, but should result in /var/lib/xen/xenstore for stubdom)

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx>
---
  tools/xenstored/core.c      | 9 ++++++++-
  tools/xenstored/core.h      | 3 +++
  tools/xenstored/lu_daemon.c | 4 ++--
  tools/xenstored/minios.c    | 5 +++++
  tools/xenstored/posix.c     | 5 +++++
  5 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/tools/xenstored/core.c b/tools/xenstored/core.c
index 4a9d874f17..77befd24c9 100644
--- a/tools/xenstored/core.c
+++ b/tools/xenstored/core.c
@@ -158,6 +158,13 @@ void trace_destroy(const void *data, const char *type)
          trace("obj: DESTROY %s %p\n", type, data);
  }
+char *absolute_filename(const void *ctx, const char *filename)

Can the return be const?

I'll have a look.


+{
+    if (filename[0] != '/')
+        return talloc_asprintf(ctx, XENSTORE_LIB_DIR "/%s", filename);

Looking at the rest of patch, you will be using xenstore_rundir(). I wonder whether it would not be better to switch to xenstore_rundir() so...

+    return talloc_strdup(ctx, filename);
+}
+
  /**
   * Signal handler for SIGHUP, which requests that the trace log is reopened
   * (in the main loop).  A single byte is written to reopen_log_pipe, to awaken
@@ -2983,7 +2990,7 @@ int main(int argc, char *argv[])
      signal(SIGHUP, trigger_reopen_log);
      if (tracefile)
-        tracefile = talloc_strdup(NULL, tracefile);
+        tracefile = absolute_filename(NULL, tracefile);
  #ifndef NO_LIVE_UPDATE
      /* Read state in case of live update. */
diff --git a/tools/xenstored/core.h b/tools/xenstored/core.h
index a0d3592961..51e1dddb22 100644
--- a/tools/xenstored/core.h
+++ b/tools/xenstored/core.h
@@ -393,6 +393,9 @@ void early_init(void);
  void mount_9pfs(void);
  #endif
+const char *xenstore_rundir(void);
+char *absolute_filename(const void *ctx, const char *filename);
+
  /* Write out the pidfile */
  void write_pidfile(const char *pidfile);
diff --git a/tools/xenstored/lu_daemon.c b/tools/xenstored/lu_daemon.c
index 71bcabadd3..6351111ab0 100644
--- a/tools/xenstored/lu_daemon.c
+++ b/tools/xenstored/lu_daemon.c
@@ -24,7 +24,7 @@ void lu_get_dump_state(struct lu_dump_state *state)
      state->size = 0;
      state->filename = talloc_asprintf(NULL, "%s/state_dump",
-                      xenstore_daemon_rundir());
+                      xenstore_rundir());

... call and ...

      if (!state->filename)
          barf("Allocation failure");
@@ -65,7 +65,7 @@ FILE *lu_dump_open(const void *ctx)
      int fd;
      filename = talloc_asprintf(ctx, "%s/state_dump",
-                   xenstore_daemon_rundir());
+                   xenstore_rundir());

... this one could be replaced with absolute_filename().

No, I don't think this is a good idea.

I don't want the daemon to store trace files specified as relative files
to be stored in /var/run/xen, while I want all files of the stubdom to be
stored under /var/lib/xen.


Juergen

Attachment: OpenPGP_0xB0DE9DD628BF132F.asc
Description: OpenPGP public key

Attachment: OpenPGP_signature.asc
Description: OpenPGP digital signature


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.