Changeset 98472 in vbox for trunk

Timestamp:

Feb 3, 2023 6:56:59 PM (2 years ago)

Author:

vboxsync

Message:

Guest Library: Introduce VbglR3DaemonizeEx and VbglR3PidfileWait, bugref:10359.

VbglR3DaemonizeEx is a wrapper function for VbglR3Daemonize. In addition to the
original version it sets pidfile lock for the parent process and notifies caller
when child process terminates with exit status VBGLR3EXITCODERELOAD (currently
equal to 2) indicating that parent process should release its reference to vboxguest
kernel module and wait for SIGUSR2 in order to restart itself. This is a part of
the procedure to install and reload/restart Guest Additions kernel modules and
user services without requiring guest reboot. It is currently only has effect
on X11 guests.

VbglR3PidfileWait is a wrapper function for VbglR3Pidfile. In addition to the
original version, it waits specified amount of time until pidfile lock become
available or fails on timeout.

Location:

trunk

Files:

• include/VBox/VBoxGuestLib.h (modified) (2 diffs)
• src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibDaemonize.cpp (modified) (7 diffs)
• src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibPidFile.cpp (modified) (2 diffs)

trunk/include/VBox/VBoxGuestLib.h

@@ -554 +554 @@
 /** @name General-purpose functions
  * @{ */
+/** Exit code which is returned by VBoxClient child process to notify
+ * parent to release VBoxGuest driver resources on Unix-like guests. */
+#define VBGLR3EXITCODERELOAD    (2)
+
 VBGLR3DECL(int)     VbglR3Init(void);
 VBGLR3DECL(int)     VbglR3InitUser(void);
@@ -564 +568 @@
 VBGLR3DECL(int)     VbglR3CtlFilterMask(uint32_t fOr, uint32_t fNot);
 VBGLR3DECL(int)     VbglR3Daemonize(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn);
+VBGLR3DECL(int)     VbglR3DaemonizeEx(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn,
+                                      bool fReturnOnUpdate, bool *pfUpdateStarted, const char *szPidfile,
+                                      RTFILE *phPidfile);
 VBGLR3DECL(int)     VbglR3PidFile(const char *pszPath, PRTFILE phFile);
 VBGLR3DECL(void)    VbglR3ClosePidFile(const char *pszPath, RTFILE hFile);
+VBGLR3DECL(int)     VbglR3PidfileWait(const char *szPidfile, RTFILE *phPidfile, uint64_t u64TimeoutMs);
 VBGLR3DECL(int)     VbglR3SetGuestCaps(uint32_t fOr, uint32_t fNot);
 VBGLR3DECL(int)     VbglR3AcquireGuestCaps(uint32_t fOr, uint32_t fNot, bool fConfig);

trunk/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibDaemonize.cpp

@@ -64 +64 @@
 #include <iprt/process.h>
 #include <iprt/string.h>
+#include <VBox/err.h>
+#include <VBox/log.h>
+
 #include "VBoxGuestR3LibInternal.h"
 
@@ -74 +77 @@
  * @returns 0 on success
  *
- * @param   fNoChDir    Pass false to change working directory to root.
- * @param   fNoClose    Pass false to redirect standard file streams to /dev/null.
- * @param   fRespawn    Restart the daemonised process after five seconds if it
- *                      terminates abnormally.
- * @param   pcRespawn   Where to store a count of how often we have respawned,
- *                      intended for avoiding error spamming.  Optional.
+ * @param   fNoChDir        Pass false to change working directory to root.
+ * @param   fNoClose        Pass false to redirect standard file streams to /dev/null.
+ * @param   fRespawn        Restart the daemonised process after five seconds if it
+ *                          terminates abnormally.
+ * @param   pcRespawn       Where to store a count of how often we have respawned,
+ *                          intended for avoiding error spamming.  Optional.
+ * @param   fReturnOnUpdate If True, this function will return control to caller when
+ *                          child process will terminate with exit code of VBGLR3EXITCODERELOAD,
+ *                          indicating that Guest Additions update has been started and this running
+ *                          process will be asked to be restarted by arrival of the next SIGUSR1
+ *                          signal (caller should wait for SIGUSR1). If False, this functions will
+ *                          never return, but rather exit() when child process terminates with
+ *                          exit code 0.
+ * @param   pfUpdateStarted A flag which passed to caller if fReturnOnUpdate is True (can be NULL).
+ * @param   szPidfile       Optional path to parent process' pidfile (can be NULL).
+ * @param   phPidfile       Optional path to parent process' pidfile handle (can not be NULL if
+ *                          szPidfile was specified).
  *
  * @todo    Use RTProcDaemonize instead of this.
@@ -86 +100 @@
  *          actually needs that.
  */
-VBGLR3DECL(int) VbglR3Daemonize(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn)
+VBGLR3DECL(int) VbglR3DaemonizeEx(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn,
+                                  bool fReturnOnUpdate, bool *pfUpdateStarted, const char *szPidfile,
+                                  RTFILE *phPidfile)
 {
 #if defined(RT_OS_OS2)
@@ -92 +108 @@
     PTIB pTib;
     DosGetInfoBlocks(&pTib, &pPib);
+
+    RT_NOREF(fReturnOnUpdate);
+    RT_NOREF(pfUpdateStarted);
+    RT_NOREF(szPidfile);
+    RT_NOREF(phPidfile);
 
     AssertRelease(!fRespawn);
@@ -230 +251 @@
     if (pid != 0)
         exit(0);
+
+    /* Check if another instance is already running. */
+    if (szPidfile != NULL)
+    {
+        if (phPidfile != NULL)
+        {
+            int rc = VbglR3PidfileWait(szPidfile, phPidfile, 5000);
+
+             /* Another instance of process is already running. */
+            if (rc == VERR_FILE_LOCK_VIOLATION)
+            {
+                LogRel(("cannot aquire pidfile %s, exitting\n", szPidfile));
+                exit(1);
+            }
+
+            /* Unable to lock on pidfile. */
+            if (RT_FAILURE(rc))
+                exit(1);
+        }
+        else
+            return VERR_INVALID_PARAMETER;
+    }
 # endif /* RT_OS_LINUX */
 
@@ -254 +297 @@
             if (rcWait == -1)
                 exit(1);
-            if (WIFEXITED(iStatus) && WEXITSTATUS(iStatus) == 0)
-                exit(0);
+            if (WIFEXITED(iStatus))
+            {
+                if (WEXITSTATUS(iStatus) == 0)
+                    exit(0);
+                else if (fReturnOnUpdate && WEXITSTATUS(iStatus) == VBGLR3EXITCODERELOAD)
+                {
+                    /* Tell caller that update has been started. */
+                    if (pfUpdateStarted != NULL)
+                        *pfUpdateStarted = true;
+
+                    return VINF_SUCCESS;
+                }
+            }
             sleep(5);
             ++cRespawn;
@@ -263 +317 @@
 #endif
 }
+
+/**
+ * A wrapper function for VbglR3DaemonizeEx.
+ */
+VBGLR3DECL(int) VbglR3Daemonize(bool fNoChDir, bool fNoClose, bool fRespawn, unsigned *pcRespawn)
+{
+    return VbglR3DaemonizeEx(fNoChDir, fNoClose, fRespawn, pcRespawn, false, NULL, NULL, NULL);
+}

trunk/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibPidFile.cpp

@@ -43 +43 @@
 #include <iprt/string.h>
 #include <iprt/process.h>
+#include <iprt/err.h>
 #include "VBoxGuestR3LibInternal.h"
+
+/* A time to wait before starting the next attempt to check a pidfile. */
+#define VBGL_PIDFILE_WAIT_RELAX_TIME_MS (250)
 
 /**
@@ -117 +121 @@
 }
 
+
+/**
+ * Wait for other process to release pidfile.
+ *
+ * This function is a wrapper to VbglR3PidFile().
+ *
+ * @returns IPRT status code.
+ * @param   szPidfile       Path to pidfile.
+ * @param   phPidfile       Handle to pidfile.
+ * @param   u64TimeoutMs    A timeout value in milliseconds to wait for
+ *                          other process to release pidfile.
+ */
+VBGLR3DECL(int) VbglR3PidfileWait(const char *szPidfile, RTFILE *phPidfile, uint64_t u64TimeoutMs)
+{
+    int rc = VERR_FILE_LOCK_VIOLATION;
+    uint64_t u64Start = RTTimeSystemMilliTS();
+
+    AssertPtrReturn(szPidfile, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(phPidfile, VERR_INVALID_PARAMETER);
+
+    while (   !RT_SUCCESS((rc = VbglR3PidFile(szPidfile, phPidfile)))
+           && (RTTimeSystemMilliTS() - u64Start < u64TimeoutMs))
+    {
+        RTThreadSleep(VBGL_PIDFILE_WAIT_RELAX_TIME_MS);
+    }
+
+    return rc;
+}