ray2501 / tcl-lmdb Goto Github PK
View Code? Open in Web Editor NEWThe Tcl interface to the Lightning Memory-Mapped Database
License: Other
The Tcl interface to the Lightning Memory-Mapped Database
License: Other
Lines 152 to 161 in 992c681
This assumes that because one is building ON Linux that one is building FOR Linux, this does not hold true when cross-compiling.
So, I nailed down the environment where I can reproduce the failure to this:
./configure --enable-symbols --with-system-lmdb --with-tcl=/usr/local/lib/tcl8.6/
I see this failure:
# cat test.tcl
puts [info patchlevel]
set dir [file dirname [info script]]
load [file join $dir liblmdb0.3.4.so]
package require lmdb
set myenv [lmdb env]
$myenv open -path $dir -mode 0664
# tclsh8.6 test.tcl
8.6.5
ERROR: No such file or directory
while executing
"$myenv open -path $dir -mode 0664"
(file "test.tcl" line 7)
[email protected]:~/github/tcl-lmdb #
Which I nailed down to this snippet.
1371│ for(i=2; i+1<objc; i+=2){
1372│ zArg = Tcl_GetStringFromObj(objv[i], 0);
1373│ if( strcmp(zArg, "-path")==0 ){
1374│ path = Tcl_GetStringFromObj(objv[i+1], 0);
1375│ } else if( strcmp(zArg, "-mode")==0 ){
1376│ if(Tcl_GetIntFromObj(interp, objv[i+1], (int *)&mode) != TCL_OK) {
1377│ return TCL_ERROR;
1378│ }
1379├> }
The for loop is entered twice, the first time to parse the -path "."
arguments pair, the second time to parse the -mode 0664
arguments pair.
path
is nice until the call at 1376 returns, then it's junk. Here's an extract from my debugging session:
Breakpoint 5, LMDB_ENV (cd=0x0, interp=0x801c30010, objc=6, objv=0x801c632f0) at ./generic/tclmdb.c:1374
(gdb) next
(gdb) p path
$3 = 0x801ce4810 "."
(gdb) c
Continuing.
Breakpoint 6, LMDB_ENV (cd=0x0, interp=0x801c30010, objc=6, objv=0x801c632f0) at ./generic/tclmdb.c:1376
(gdb) next
(gdb) p path
$4 = 0x801ce0000 "\001\b"
I am not able to explain this yet.
I was trying out tcl-lmdb (thanks for making it!) and ran into a segfault issue. Details follow.
package require lmdb 0.3.5
set e [lmdb env]
set db [lmdb open -env $e]
> tclsh segfault-lmdb.tcl
fish: “tclsh segfault-lmdb.tcl” terminated by signal SIGSEGV (Address boundary error)
> valgrind tclsh segfault-lmdb.tcl
==28436== Memcheck, a memory error detector
==28436== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==28436== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==28436== Command: tclsh segfault-lmdb.tcl
==28436==
==28436== Invalid read of size 4
==28436== at 0x6339041: mdb_txn_renew0 (in /usr/lib64/tcl/lmdb0.3.5/liblmdb0.3.5.so)
==28436== by 0x633A373: mdb_txn_begin (in /usr/lib64/tcl/lmdb0.3.5/liblmdb0.3.5.so)
==28436== by 0x6334C71: LMDB_MAIN (in /usr/lib64/tcl/lmdb0.3.5/liblmdb0.3.5.so)
==28436== by 0x4E7E795: TclNRRunCallbacks (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4E805D9: ??? (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4F4AED8: ??? (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4E8049F: ??? (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4F37577: Tcl_FSEvalFileEx (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4F3ED2A: Tcl_MainEx (in /usr/lib64/libtcl8.6.so)
==28436== by 0x108933: ??? (in /usr/bin/tclsh8.6)
==28436== by 0x5213F49: (below main) (libc-start.c:308)
==28436== Address 0x7c is not stack'd, malloc'd or (recently) free'd
==28436==
==28436==
==28436== Process terminating with default action of signal 11 (SIGSEGV)
==28436== Access not within mapped region at address 0x7C
==28436== at 0x6339041: mdb_txn_renew0 (in /usr/lib64/tcl/lmdb0.3.5/liblmdb0.3.5.so)
==28436== by 0x633A373: mdb_txn_begin (in /usr/lib64/tcl/lmdb0.3.5/liblmdb0.3.5.so)
==28436== by 0x6334C71: LMDB_MAIN (in /usr/lib64/tcl/lmdb0.3.5/liblmdb0.3.5.so)
==28436== by 0x4E7E795: TclNRRunCallbacks (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4E805D9: ??? (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4F4AED8: ??? (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4E8049F: ??? (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4F37577: Tcl_FSEvalFileEx (in /usr/lib64/libtcl8.6.so)
==28436== by 0x4F3ED2A: Tcl_MainEx (in /usr/lib64/libtcl8.6.so)
==28436== by 0x108933: ??? (in /usr/bin/tclsh8.6)
==28436== by 0x5213F49: (below main) (libc-start.c:308)
==28436== If you believe this happened as a result of a stack
==28436== overflow in your program's main thread (unlikely but
==28436== possible), you can try to increase the size of the
==28436== main thread stack using the --main-stacksize= flag.
==28436== The main thread stack size used in this run was 8388608.
==28436==
==28436== HEAP SUMMARY:
==28436== in use at exit: 1,370,532 bytes in 100 blocks
==28436== total heap usage: 212 allocs, 112 frees, 2,414,982 bytes allocated
==28436==
==28436== LEAK SUMMARY:
==28436== definitely lost: 0 bytes in 0 blocks
==28436== indirectly lost: 0 bytes in 0 blocks
==28436== possibly lost: 1,285,280 bytes in 72 blocks
==28436== still reachable: 85,252 bytes in 28 blocks
==28436== suppressed: 0 bytes in 0 blocks
==28436== Rerun with --leak-check=full to see details of leaked memory
==28436==
==28436== For counts of detected and suppressed errors, rerun with: -v
==28436== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
fish: “valgrind tclsh segfault-lmdb.tcl” terminated by signal SIGSEGV (Address boundary error)
The result of this script
package require lmdb
set key {Linn‘us}
set val {1707-05-23}
# Open
set myenv [lmdb env]
$myenv open -path [file dirname [info script]]
set mydbi [lmdb open -env $myenv]
# Write
set txn [$myenv txn]
$mydbi put $key $val -txn $txn
$txn commit
$txn close
# Read
set txn [$myenv txn -readonly 1]
set cur [$mydbi cursor -txn $txn]
lassign [$cur get -next] rkey rval
$cur close
$txn abort
$txn close
# Close
$mydbi close -env $myenv
$myenv close
# Compare
if {$rkey ne $key || $rval ne $val} {
puts stderr "Expected |$key, $val|, got |$rkey, $rval|"
}
is
Expected |Linn‘us, 1707-05-23|, got |Linnus, 1707-05-23|
mdb_dump -p
says
VERSION=3
format=print
type=btree
mapsize=1048576
mapaddr=0x80064f000
maxreaders=126
db_pagesize=4096
HEADER=END
Linn\18us
1707-05-23
DATA=END
Just dumping it here until I figure out whether it's a tcl-lmdb or pure lmdb issue.
Hi Danilo,
I see that the -fixedmap
param to env open
defaults to true.
https://github.com/ray2501/tcl-lmdb/blob/master/generic/tclmdb.c#L1363
This is very risky as mmap(2)
doesn't guarantee that the address hint is respected.
As you only open the env once - when doing $env open
- and copy data in/out via Tcl_Obj
s, I wonder why you chose to opt for having this default to true.
If there's no compelling reason, I think it would be better to change the default to false.
Thanks!
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