vos: Mark longjmp-used variables as 'volatile'

vsprocs tries to do error recovery by calling longjmp from a signal
handler. Although this is quite error-prone since we call a ton of
non-async-signal-safe functions, make it a bit more likely to work by
marking variables that are used after the longjmp as volatile. This
reduces how often (depending on the platform) these values will be
completely worthless after a longjmp since they were cached in a
register or similar.

FIXES 125535

Change-Id: I8566f8cffde6cfdffd99a11d637645494e0a0514
Reviewed-on: http://gerrit.openafs.org/1557
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/volser/vsprocs.c b/src/volser/vsprocs.c
index 5d48c4d..caeaf4a 100644 (file)
--- a/src/volser/vsprocs.c
+++ b/src/volser/vsprocs.c
@@ -1172,21 +1172,33 @@ int
 UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
               afs_int32 atoserver, afs_int32 atopart, int flags)
 {
-    struct rx_connection *toconn, *fromconn;
-    afs_int32 fromtid, totid, clonetid;
+    /* declare stuff 'volatile' that may be used from setjmp/longjmp and may
+     * be changing during the move */
+    struct rx_connection * volatile toconn;
+    struct rx_connection * volatile fromconn;
+    afs_int32 volatile fromtid;
+    afs_int32 volatile totid;
+    afs_int32 volatile clonetid;
+    afs_uint32 volatile newVol;
+    afs_uint32 volatile volid;
+    afs_uint32 volatile backupId;
+    int volatile islocked;
+    int volatile pntg;
+
     char vname[64];
     char *volName = 0;
     char tmpName[VOLSER_MAXVOLNAME + 1];
     afs_int32 rcode;
     afs_int32 fromDate;
+    afs_int32 tmp;
+    afs_uint32 tmpVol;
     struct restoreCookie cookie;
     register afs_int32 vcode, code;
-    afs_uint32 newVol, volid, backupId;
     struct volser_status tstatus;
     struct destServer destination;
 
     struct nvldbentry entry, storeEntry;
-    int i, islocked, pntg;
+    int i;
     afs_int32 error;
     char in, lf;               /* for test code */
     int same;
@@ -1292,9 +1304,11 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        fromtid = 0;
        pntg = 1;
 
+       tmp = fromtid;
        code =
            AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITOffline,
-                                   &fromtid);
+                                   &tmp);
+       fromtid = tmp;
 
        if (!code) {            /* volume exists - delete it */
            VPRINT1("Setting flags on leftover source volume %u ...",
@@ -1330,7 +1344,8 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        fromtid = 0;
        code =
            AFSVolTransCreate_retry(fromconn, backupId, afrompart, ITOffline,
-                                   &fromtid);
+                                   &tmp);
+       fromtid = tmp;
 
        if (!code) {            /* backup volume exists - delete it */
            VPRINT1("Setting flags on leftover backup volume %u ...",
@@ -1393,7 +1408,8 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
      * ***/
 
     VPRINT1("Starting transaction on source volume %u ...", afromvol);
-    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &fromtid);
+    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &tmp);
+    fromtid = tmp;
     EGOTO1(mfail, code, "Failed to create transaction on the volume %u\n",
           afromvol);
     VDONE;
@@ -1402,8 +1418,9 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        /* Get a clone id */
        VPRINT1("Allocating new volume id for clone of volume %u ...",
                afromvol);
-       newVol = 0;
-       vcode = ubik_VL_GetNewVolumeId(cstruct, 0, 1, &newVol);
+       newVol = tmpVol = 0;
+       vcode = ubik_VL_GetNewVolumeId(cstruct, 0, 1, &tmpVol);
+       newVol = tmpVol;
        EGOTO1(mfail, vcode,
               "Could not get an ID for the clone of volume %u from the VLDB\n",
               afromvol);
@@ -1413,7 +1430,8 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        VPRINT1("Cloning source volume %u ...", afromvol);
        strcpy(vname, "move-clone-temp");
        code =
-           AFSVolClone(fromconn, fromtid, 0, readonlyVolume, vname, &newVol);
+           AFSVolClone(fromconn, fromtid, 0, readonlyVolume, vname, &tmpVol);
+       newVol = tmpVol;
        EGOTO1(mfail, code, "Failed to clone the source volume %u\n",
               afromvol);
        VDONE;
@@ -1443,9 +1461,11 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     if (!(flags & RV_NOCLONE)) {
        /* All of this is to get the fromDate */
        VPRINT1("Starting transaction on the cloned volume %u ...", newVol);
+       tmp = clonetid;
        code =
            AFSVolTransCreate_retry(fromconn, newVol, afrompart, ITOffline,
-                             &clonetid);
+                             &tmp);
+       clonetid = tmp;
        EGOTO1(mfail, code,
               "Failed to start a transaction on the cloned volume%u\n",
               newVol);
@@ -1495,7 +1515,9 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
 
     /* create a volume on the target machine */
     volid = afromvol;
-    code = AFSVolTransCreate_retry(toconn, volid, atopart, ITOffline, &totid);
+    tmp = totid;
+    code = AFSVolTransCreate_retry(toconn, volid, atopart, ITOffline, &tmp);
+    totid = tmp;
     if (!code) {
        /* Delete the existing volume.
         * While we are deleting the volume in these steps, the transaction
@@ -1523,9 +1545,13 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     }
 
     VPRINT1("Creating the destination volume %u ...", volid);
+    tmp = totid;
+    tmpVol = volid;
     code =
-       AFSVolCreateVolume(toconn, atopart, volName, volser_RW, volid, &volid,
-                          &totid);
+       AFSVolCreateVolume(toconn, atopart, volName, volser_RW, volid, &tmpVol,
+                          &tmp);
+    totid = tmp;
+    volid = tmpVol;
     EGOTO1(mfail, code, "Failed to create the destination volume %u\n",
           volid);
     VDONE;
@@ -1580,7 +1606,9 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
      * ***/
 
     VPRINT1("Starting transaction on source volume %u ...", afromvol);
-    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &fromtid);
+    tmp = fromtid;
+    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &tmp);
+    fromtid = tmp;
     EGOTO1(mfail, code,
           "Failed to create a transaction on the source volume %u\n",
           afromvol);
@@ -1731,8 +1759,10 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     /* Delete the backup volume on the original site */
     VPRINT1("Creating transaction for backup volume %u on source ...",
            backupId);
+    tmp = fromtid;
     code =
-       AFSVolTransCreate_retry(fromconn, backupId, afrompart, ITOffline, &fromtid);
+       AFSVolTransCreate_retry(fromconn, backupId, afrompart, ITOffline, &tmp);
+    fromtid = tmp;
     VDONE;
     if (!code) {
        VPRINT1("Setting flags on backup volume %u on source ...", backupId);
@@ -1767,9 +1797,11 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     fromtid = 0;
     if (!(flags & RV_NOCLONE)) {
        VPRINT1("Starting transaction on the cloned volume %u ...", newVol);
+       tmp = clonetid;
        code =
            AFSVolTransCreate_retry(fromconn, newVol, afrompart, ITOffline,
-                             &clonetid);
+                             &tmp);
+       clonetid = tmp;
        EGOTO1(mfail, code,
               "Failed to start a transaction on the cloned volume%u\n",
               newVol);
@@ -1954,8 +1986,10 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
            VPRINT1
                ("Recovery: Creating transaction for destination volume %u ...",
                 volid);
+           tmp = totid;
            code =
-               AFSVolTransCreate_retry(toconn, volid, atopart, ITOffline, &totid);
+               AFSVolTransCreate_retry(toconn, volid, atopart, ITOffline, &tmp);
+           totid = tmp;
 
            if (!code) {
                VDONE;
@@ -1988,9 +2022,11 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        if (fromconn) {
            VPRINT1("Recovery: Creating transaction on source volume %u ...",
                    afromvol);
+           tmp = fromtid;
            code =
                AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy,
-                                 &fromtid);
+                                 &tmp);
+           fromtid = tmp;
            if (!code) {
                VDONE;
 
@@ -2021,9 +2057,11 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        if (fromconn) {
            VPRINT1("Recovery: Creating transaction on backup volume %u ...",
                    backupId);
+           tmp = fromtid;
            code =
                AFSVolTransCreate_retry(fromconn, backupId, afrompart, ITOffline,
-                                 &fromtid);
+                                 &tmp);
+           fromtid = tmp;
            if (!code) {
                VDONE;
 
@@ -2051,9 +2089,11 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
            /* delete source volume */
            VPRINT1("Recovery: Creating transaction on source volume %u ...",
                    afromvol);
+           tmp = fromtid;
            code =
                AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy,
-                                 &fromtid);
+                                 &tmp);
+           fromtid = tmp;
            if (!code) {
                VDONE;
 
@@ -2090,9 +2130,11 @@ UV_MoveVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     if (newVol) {
        VPRINT1("Recovery: Creating transaction on clone volume %u ...",
                newVol);
+       tmp = clonetid;
        code =
            AFSVolTransCreate_retry(fromconn, newVol, afrompart, ITOffline,
-                             &clonetid);
+                             &tmp);
+       clonetid = tmp;
        if (!code) {
            VDONE;
 
@@ -2165,21 +2207,30 @@ UV_CopyVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
               char *atovolname, afs_int32 atoserver, afs_int32 atopart,
               afs_uint32 atovolid, int flags)
 {
-    struct rx_connection *toconn, *fromconn;
-    afs_int32 fromtid, totid, clonetid;
+    /* declare stuff 'volatile' that may be used from setjmp/longjmp and may
+     * be changing during the copy */
+    int volatile pntg;
+    afs_int32 volatile clonetid;
+    afs_int32 volatile totid;
+    afs_int32 volatile fromtid;
+    struct rx_connection * volatile fromconn;
+    struct rx_connection * volatile toconn;
+    afs_uint32 volatile cloneVol;
+
     char vname[64];
     afs_int32 rcode;
     afs_int32 fromDate, cloneFromDate;
     struct restoreCookie cookie;
     register afs_int32 vcode, code;
-    afs_uint32 cloneVol, newVol;
+    afs_uint32 newVol;
     afs_int32 volflag;
     struct volser_status tstatus;
     struct destServer destination;
-
     struct nvldbentry entry, newentry, storeEntry;
-    int islocked, pntg;
+    int islocked;
     afs_int32 error;
+    afs_int32 tmp;
+    afs_uint32 tmpVol;
     int justclone = 0;
 
     islocked = 0;
@@ -2221,8 +2272,10 @@ UV_CopyVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     cloneVol = 0;
     if (!(flags & RV_NOCLONE)) {
        VPRINT1("Starting transaction on source volume %u ...", afromvol);
+       tmp = fromtid;
        code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy,
-                                &fromtid);
+                                &tmp);
+       fromtid = tmp;
        EGOTO1(mfail, code, "Failed to create transaction on the volume %u\n",
               afromvol);
        VDONE;
@@ -2231,7 +2284,9 @@ UV_CopyVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        VPRINT1("Allocating new volume id for clone of volume %u ...",
                afromvol);
        cloneVol = 0;
-       vcode = ubik_VL_GetNewVolumeId(cstruct, 0, 1, &cloneVol);
+       tmpVol = cloneVol;
+       vcode = ubik_VL_GetNewVolumeId(cstruct, 0, 1, &tmpVol);
+       cloneVol = tmpVol;
        EGOTO1(mfail, vcode,
           "Could not get an ID for the clone of volume %u from the VLDB\n",
           afromvol);
@@ -2255,9 +2310,11 @@ UV_CopyVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
        /* Do the clone. Default flags on clone are set to delete on salvage and out of service */
        VPRINT1("Cloning source volume %u ...", afromvol);
        strcpy(vname, "copy-clone-temp");
+       tmpVol = cloneVol;
        code =
            AFSVolClone(fromconn, fromtid, 0, readonlyVolume, vname,
-                       &cloneVol);
+                       &tmpVol);
+       cloneVol = tmpVol;
        EGOTO1(mfail, code, "Failed to clone the source volume %u\n",
               afromvol);
        VDONE;
@@ -2280,9 +2337,11 @@ UV_CopyVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
 
     if (!(flags & RV_NOCLONE)) {
        VPRINT1("Starting transaction on the cloned volume %u ...", cloneVol);
+       tmp = clonetid;
        code =
            AFSVolTransCreate_retry(fromconn, cloneVol, afrompart, ITOffline,
-                         &clonetid);
+                         &tmp);
+       clonetid = tmp;
        EGOTO1(mfail, code,
               "Failed to start a transaction on the cloned volume%u\n",
               cloneVol);
@@ -2311,7 +2370,9 @@ UV_CopyVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
 
     /* create a volume on the target machine */
     cloneFromDate = 0;
-    code = AFSVolTransCreate_retry(toconn, newVol, atopart, ITOffline, &totid);
+    tmp = totid;
+    code = AFSVolTransCreate_retry(toconn, newVol, atopart, ITOffline, &tmp);
+    totid = tmp;
     if (!code) {
        if ((flags & RV_CPINCR)) {
            VPRINT1("Getting status of pre-existing volume %u ...", newVol);
@@ -2359,10 +2420,12 @@ UV_CopyVolume2(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     }
 
     VPRINT1("Creating the destination volume %u ...", newVol);
+    tmp = totid;
     code =
        AFSVolCreateVolume(toconn, atopart, atovolname,
                           (flags & RV_RDONLY) ? volser_RO : volser_RW,
-                          newVol, &newVol, &totid);
+                          newVol, &newVol, &tmp);
+    totid = tmp;
     EGOTO1(mfail, code, "Failed to create the destination volume %u\n",
           newVol);
     VDONE;
@@ -2420,7 +2483,9 @@ cpincr:
      * ***/
 
     VPRINT1("Starting transaction on source volume %u ...", afromvol);
-    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &fromtid);
+    tmp = fromtid;
+    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &tmp);
+    fromtid = tmp;
     EGOTO1(mfail, code,
           "Failed to create a transaction on the source volume %u\n",
           afromvol);
@@ -2471,9 +2536,11 @@ cpincr:
 
     if (!(flags & RV_NOCLONE)) {
        VPRINT1("Starting transaction on the cloned volume %u ...", cloneVol);
+       tmp = clonetid;
        code =
            AFSVolTransCreate_retry(fromconn, cloneVol, afrompart, ITOffline,
-                             &clonetid);
+                             &tmp);
+       clonetid = tmp;
        EGOTO1(mfail, code,
               "Failed to start a transaction on the cloned volume%u\n",
               cloneVol);
@@ -2620,9 +2687,11 @@ cpincr:
     if (cloneVol) {
        VPRINT1("Recovery: Creating transaction on clone volume %u ...",
                cloneVol);
+       tmp = clonetid;
        code =
            AFSVolTransCreate_retry(fromconn, cloneVol, afrompart, ITOffline,
-                             &clonetid);
+                             &tmp);
+       clonetid = tmp;
        if (!code) {
            VDONE;
 
@@ -3998,10 +4067,15 @@ UV_DumpVolume(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
              afs_int32(*DumpFunction) (struct rx_call *, void *), void *rock,
              afs_int32 flags)
 {
-    struct rx_connection *fromconn = (struct rx_connection *)0;
-    struct rx_call *fromcall = (struct rx_call *)0;
-    afs_int32 fromtid = 0, rxError = 0, rcode = 0;
-    afs_int32 code, error = 0, retry = 0;
+    /* declare stuff 'volatile' that may be used from setjmp/longjmp and may
+     * be changing during the dump */
+    struct rx_call * volatile fromcall = NULL;
+    struct rx_connection * volatile fromconn = NULL;
+    afs_int32 volatile fromtid = 0;
+
+    afs_int32 rxError = 0, rcode = 0;
+    afs_int32 code, error = 0;
+    afs_int32 tmp;
     time_t tmv = fromdate;
 
     if (setjmp(env))
@@ -4022,7 +4096,9 @@ UV_DumpVolume(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     fromconn = UV_Bind(afromserver, AFSCONF_VOLUMEPORT);
 
     VEPRINT1("Starting transaction on volume %u...", afromvol);
-    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &fromtid);
+    tmp = fromtid;
+    code = AFSVolTransCreate_retry(fromconn, afromvol, afrompart, ITBusy, &tmp);
+    fromtid = tmp;
     EGOTO1(error_exit, code,
           "Could not start transaction on the volume %u to be dumped\n",
           afromvol);
@@ -4034,7 +4110,6 @@ UV_DumpVolume(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     if (flags & VOLDUMPV2_OMITDIRS) 
        code = StartAFSVolDumpV2(fromcall, fromtid, fromdate, flags);
     else
-      retryold:
        code = StartAFSVolDump(fromcall, fromtid, fromdate);
     EGOTO(error_exit, code, "Could not start the dump process \n");
     VEDONE;
@@ -4068,8 +4143,6 @@ UV_DumpVolume(afs_uint32 afromvol, afs_int32 afromserver, afs_int32 afrompart,
     if (fromconn)
        rx_DestroyConnection(fromconn);
 
-    if (retry)
-       goto retryold;
     if (error != RXGEN_OPCODE)
        PrintError("", error);
     return (error);
@@ -4087,12 +4160,17 @@ UV_DumpClonedVolume(afs_uint32 afromvol, afs_int32 afromserver,
                    afs_int32(*DumpFunction) (struct rx_call *, void *),
                    void *rock, afs_int32 flags)
 {
-    struct rx_connection *fromconn = (struct rx_connection *)0;
-    struct rx_call *fromcall = (struct rx_call *)0;
+    /* declare stuff 'volatile' that may be used from setjmp/longjmp and may
+     * be changing during the dump */
+    struct rx_connection * volatile fromconn = NULL;
+    struct rx_call * volatile fromcall = NULL;
+    afs_int32 volatile clonetid = 0;
+    afs_uint32 volatile clonevol = 0;
+
+    afs_int32 tmp;
     afs_int32 fromtid = 0, rxError = 0, rcode = 0;
-    afs_int32 clonetid = 0;
     afs_int32 code = 0, error = 0;
-    afs_uint32 clonevol = 0;
+    afs_uint32 tmpVol;
     char vname[64];
     time_t tmv = fromdate;
 
@@ -4122,7 +4200,9 @@ UV_DumpClonedVolume(afs_uint32 afromvol, afs_int32 afromserver,
 
     /* Get a clone id */
     VEPRINT1("Allocating new volume id for clone of volume %u ...", afromvol);
-    code = ubik_VL_GetNewVolumeId(cstruct, 0, 1, &clonevol);
+    tmpVol = clonevol;
+    code = ubik_VL_GetNewVolumeId(cstruct, 0, 1, &tmpVol);
+    clonevol = tmpVol;
     EGOTO1(error_exit, code,
           "Could not get an ID for the clone of volume %u from the VLDB\n",
           afromvol);
@@ -4132,8 +4212,10 @@ UV_DumpClonedVolume(afs_uint32 afromvol, afs_int32 afromserver,
     VEPRINT2("Cloning source volume %u to clone volume %u...", afromvol,
            clonevol);
     strcpy(vname, "dump-clone-temp");
+    tmpVol = clonevol;
     code =
-       AFSVolClone(fromconn, fromtid, 0, readonlyVolume, vname, &clonevol);
+       AFSVolClone(fromconn, fromtid, 0, readonlyVolume, vname, &tmpVol);
+    clonevol = tmpVol;
     EGOTO1(error_exit, code, "Failed to clone the source volume %u\n",
           afromvol);
     VEDONE;
@@ -4150,9 +4232,11 @@ UV_DumpClonedVolume(afs_uint32 afromvol, afs_int32 afromserver,
 
 
     VEPRINT1("Starting transaction on the cloned volume %u ...", clonevol);
+    tmp = clonetid;
     code =
        AFSVolTransCreate_retry(fromconn, clonevol, afrompart, ITOffline,
-                         &clonetid);
+                         &tmp);
+    clonetid = tmp;
     EGOTO1(error_exit, code,
           "Failed to start a transaction on the cloned volume%u\n",
           clonevol);