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Message-ID: <20140710065006.GB4777@newbook>
Date: Wed, 9 Jul 2014 23:50:08 -0700
From: Isaac Dunham <ibid.ag@...il.com>
To: musl@...ts.openwall.com
Cc: Jeff Pohlmeyer <yetanothergeek@...il.com>,
	Alpine <alpine-devel@...ts.alpinelinux.org>
Subject: Re: Re: [alpine-devel] Attempting to debug C++ library and
 command via valgrind

On Thu, Jul 10, 2014 at 12:47:16AM -0400, Rich Felker wrote:
> On Wed, Jul 09, 2014 at 09:13:49PM -0700, Isaac Dunham wrote:
> > On Wed, Jul 09, 2014 at 10:30:11AM -0500, Jeff Pohlmeyer wrote:
> > > On Tue, Jul 8, 2014 at 11:39 PM, Isaac Dunham wrote:
> > > 
> > > > I've been trying to get Sword 1.7.3 (crosswire.org/sword) running on Alpine.
> > > > valgrind was recommended, but I can't get valgrind to run the command properly.
> > > > But when I do this, diatheke errors out:
> > > > diatheke: cannot load -b: No such file or directory
> > > 
> > > 
> > > I think it's a problem with the way valgrind tries to run musl's program loader.
> > > 
> > > Try adding "/lib/ld-musl-i386.so.1" to the command line, just before
> > > the prgram name,
> > > e.g.
> > > 
> > > valgrind --leak-check=full --track-origins=yes \
> > >  --keep-stacktraces=alloc-and-free \
> > >   /lib/ld-musl-i386.so.1 \
> > >    diatheke  -b KJV -k Ps117
> > 
> > Thanks, this works for me.
> > 
> > Of course it really runs slow and spits out a ton of information;
> > the log is over 400 kb at 5464 lines. (I suppose sending it to these lists
> > might be inappropriate, given the size...)
> 
> If you have a reasonable place to dump the file you could just send a
> link to the list. But I think you're getting ahead of things. What
> actual failure is the program exhibiting? (Crash? Incorrect or no
> output? Error messages?) Depending on what happens, a gdb backtrace or
> an strace log may be more useful than the valgrind output.
> 
Incorrect output: specifically, it repeats (most of) the last line of the
intended output.
strace was my first resort, but it did not seem helpful to me;
since the program in question is using a large C++ library to access a
compressed text with a good deal of processing in memory, I could not
figure out how the syscalls mapped to code.
When I asked on the sword-devel list, valgrind was recommended.

The output compresses down to ~4k when bzipped, so I guess it
isn't a big issue.

Now I looked at strace again; here's what I found:
-100k lines of output, compressing to 500 kb (!).
-the relevant bit is likely this:

open("/home/idunham/.sword/modules/texts/ztext/kjv/ot.bzz", O_RDWR|O_LARGEFILE) = 5
_llseek(5, 0, [0], SEEK_SET)            = 0
_llseek(5, 1261942, [1261942], SEEK_SET) = 0
mmap2(NULL, 180224, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb57d5000
read(5, "x\234\354\275\353\222\343F\222&\372*\30\375\3325\253\321\20w\240\324S2iz\325\225\323\322hl"..., 177216) = 177216
mmap2(NULL, 180224, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb57a9000
mmap2(NULL, 3547136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb5447000
mmap2(NULL, 1024000, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb534d000
munmap(0xb5447000, 3547136)             = 0
mmap2(NULL, 1024000, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb56af000
munmap(0xb57d5000, 180224)              = 0
ioctl(1, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 0xbfc21fa4) = -1 ENOTTY (Not a tty)
writev(1, [{"Psalms 117:1: O praise the LORD,"..., 75}, {"\n", 1}], 2Psalms 117:1: O praise the LORD, all ye nations: praise him, all ye people.
) = 76
_llseek(3, 164840, [164840], SEEK_SET)  = 0
read(3, "\23\0\0\0", 4)                 = 4
read(3, "\207\204\f\0", 4)              = 4
read(3, "\34\1", 2)                     = 2
_llseek(3, 164850, [164850], SEEK_SET)  = 0
read(3, "\23\0\0\0", 4)                 = 4
read(3, "\243\205\f\0", 4)              = 4
read(3, "'\2", 2)                       = 2
_llseek(3, 164850, [164850], SEEK_SET)  = 0
read(3, "\23\0\0\0", 4)                 = 4
read(3, "\243\205\f\0", 4)              = 4
read(3, "'\2", 2)                       = 2
_llseek(3, 164850, [164850], SEEK_SET)  = 0
read(3, "\23\0\0\0", 4)                 = 4
read(3, "\243\205\f\0", 4)              = 4
read(3, "'\2", 2)                       = 2
munmap(0xb56af000, 1024000)             = 0
munmap(0xb57a9000, 180224)              = 0
munmap(0xb534d000, 1024000)             = 0
close(4)                                = 0
close(5)                                = 0
close(3)                                = 0
writev(1, [{"Psalms 117:2: For his merciful k"..., 246}, {NULL, 0}], 2Psalms 117:2: For his merciful kindness is great toward us: and the truth of the LORD endureth for ever. Praise ye the LORD. 
: For his merciful kindness is great toward us: and the truth of the LORD endureth for ever. Praise ye the LORD. 
(KJV)
) = 246

Which looks like it's going through a loop twice when it reaches the exit condition.

Thanks,
Isaac Dunham

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