Syslinux - Sep 2010 - isohybrid: seek error - 6: Invalid argument

Hello

Recently while playing with bigger iso images (>2G) looks like isohybrid 
from syslinux-4.02 fails. Sometimes tunning heads/sectors (-h/-s) works, 
because no padding is needed depending of size of the image.

Some debug info provided, if more info is needed please just ask.

# isohybrid -v pandereta-2010.09.13-i686.iso
catalogue offset: 326
ve[0]: 1, cs: 1
ve[1]: 0, cs: 1
ve[2]: 25927, cs: 25928
ve[3]: 24946, cs: 50874
ve[4]: 25714, cs: 76588
ve[5]: 8303, cs: 84891
ve[6]: 30789, cs: 115680
ve[7]: 29029, cs: 144709
ve[8]: 26997, cs: 171706
ve[9]: 27749, cs: 199455
ve[10]: 20512, cs: 219967
ve[11]: 31343, cs: 251310
ve[12]: 27002, cs: 278312
ve[13]: 32, cs: 278344
ve[14]: 5731, cs: 284075
ve[15]: 43605, cs: 327680
de_boot: 136
de_media: 0
de_seg: 0
de_sys: 0
de_mbz1: 0
de_count: 4
de_lba: 327
de_mbz2: 0
imgsize: 2265417728, padding: 555008
isohybrid: Warning: more than 1024 cylinders: 2161
isohybrid: Not all BIOSes will be able to boot this device
id: 281396446
sizeof(MBR): 512 bytes
...
0432  1c 05 00 00 00 00 00 00  de c4 c5 10 00 00 80 00  |................|
0448  01 00 17 3f e0 ff 00 00  00 00 00 88 43 00 00 00  |...?........C...|
...
isohybrid: pandereta-2010.09.13-i686.iso: seek error - 6: Invalid argument


# strace -e trace=desc isohybrid pandereta-2010.09.13-i686.iso
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=22221, ...}) = 0
close(3)                                = 0
open("/lib/libc.so.6", O_RDONLY)        = 3
read(3, 
"\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320m\1\0004\0\0\0"...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1347988, ...}) = 0
close(3)                                = 0
open("pandereta-2010.09.13-i686.iso", O_RDWR|O_LARGEFILE) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=2265417728, ...}) = 0
_llseek(3, 32768, [32768], SEEK_SET)    = 0
read(3, "\1CD001\1\0LINUX                   "..., 2048) = 2048
read(3, "\0CD001\1EL TORITO SPECIFICATION\0\0"..., 4096) = 4096
_llseek(3, 667648, [667648], SEEK_SET)  = 0
read(3, "\1\0\0\0Gerardo Exequiel Pozzi \0c\26U\252"..., 4096) = 4096
_llseek(3, 671744, [671744], SEEK_SET)  = 0
write(2, "isohybrid: ", 11isohybrid: )             = 11
write(2, "Warning: more than 1024 cylinder"..., 39Warning: more than 
1024 cylinders: 2161) = 39
write(2, "\n", 1
)                       = 1
write(2, "isohybrid: ", 11isohybrid: )             = 11
write(2, "Not all BIOSes will be able to b"..., 47Not all BIOSes will
be
able to boot this device) = 47
write(2, "\n", 1
)                       = 1
_llseek(3, 0, [0], SEEK_SET)            = 0
read(3, 
"\3721\355\216\325\274\0|\373\374f1\333f1\311fSfQ\6W\216\335\216\305R\276\0|\277\0"...,
4096) = 4096
_llseek(3, 4096, [4096], SEEK_SET)      = 0
_llseek(3, -4096, [0], SEEK_CUR)        = 0
write(3, 
"\3721\355\216\325\274\0|\373\374f1\333f1\311fSfQ\6W\216\335\216\305R\276\0|\277\0"...,
512) = 512
_llseek(3, 18446744071680000000, 0xbfff6b50, SEEK_SET) = -1 EINVAL 
(Invalid argument)
write(2, "isohybrid: ", 11isohybrid: )             = 11
write(2, "pandereta-2010.09.13-i686.iso: s"..., 
45pandereta-2010.09.13-i686.iso: seek error - 6) = 45
write(2, ": ", 2: )                       = 2
write(2, "Invalid argument\n", 17Invalid argument
)      = 17

-- 
Gerardo Exequiel Pozzi
\cos^2\alpha + \sin^2\alpha = 1

Hello Gerardo,

--- On Mon, 13/9/10, Gerardo Exequiel Pozzi <vmlinuz386 at yahoo.com.ar>
> Recently while playing with bigger iso images (>2G)
> looks like isohybrid from syslinux-4.02 fails. Sometimes
> tunning heads/sectors (-h/-s) works, because no padding is
> needed depending of size of the image.
> 
> isohybrid: pandereta-2010.09.13-i686.iso: seek error - 6:
> Invalid argument
  Thanks for the update. The error seems to come while seeking(fseek(3)) to fix
the file pointer at the end of the file, just before adding required padding to
the iso.

---
    if (fseek(fp, isostat.st_size, SEEK_SET))
        err(1, "%s: seek error - 6", argv[0]);

    memset(buf, 0, padding);
    if (fwrite(buf, sizeof(char), padding, fp) != (size_t)padding)
        err(1, "%s: write error - 2", argv[0]);
---

Strange, that it should happen. I guess, may be, HPA could be better able to
explain why it should happen for 2G files.

Can I have the iso file?

Thank you.
---
Regards
    -Prasad
PS: Please don't send me html/attachment/Fwd mails

Most likely it was compiled without -D_FILE_OFFSET_BITS=64.

	-hpa

On 09/12/2010 10:25 PM, P J P wrote:
>     Hello Gerardo,
>
> --- On Mon, 13/9/10, Gerardo Exequiel Pozzi<vmlinuz386 at
yahoo.com.ar>
>> Recently while playing with bigger iso images (>2G)
>> looks like isohybrid from syslinux-4.02 fails. Sometimes
>> tunning heads/sectors (-h/-s) works, because no padding is
>> needed depending of size of the image.
>>
>> isohybrid: pandereta-2010.09.13-i686.iso: seek error - 6:
>> Invalid argument
>
>    Thanks for the update. The error seems to come while seeking(fseek(3))
to fix the file pointer at the end of the file, just before adding required
padding to the iso.
>
> ---
>      if (fseek(fp, isostat.st_size, SEEK_SET))
>          err(1, "%s: seek error - 6", argv[0]);
>
>      memset(buf, 0, padding);
>      if (fwrite(buf, sizeof(char), padding, fp) != (size_t)padding)
>          err(1, "%s: write error - 2", argv[0]);
> ---
>
> Strange, that it should happen. I guess, may be, HPA could be better able
to explain why it should happen for 2G files.
>
> Can I have the iso file?
>
> Thank you.
> ---
> Regards
>      -Prasad
> PS: Please don't send me html/attachment/Fwd mails
>
>
>

By the way, using seek + write for this is pretty broken.  A much better 
option is to use ftruncate().

	-hpa


On 09/12/2010 10:25 PM, P J P wrote:
>     Hello Gerardo,
>
> --- On Mon, 13/9/10, Gerardo Exequiel Pozzi<vmlinuz386 at
yahoo.com.ar>
>> Recently while playing with bigger iso images (>2G)
>> looks like isohybrid from syslinux-4.02 fails. Sometimes
>> tunning heads/sectors (-h/-s) works, because no padding is
>> needed depending of size of the image.
>>
>> isohybrid: pandereta-2010.09.13-i686.iso: seek error - 6:
>> Invalid argument
>
>    Thanks for the update. The error seems to come while seeking(fseek(3))
to fix the file pointer at the end of the file, just before adding required
padding to the iso.
>
> ---
>      if (fseek(fp, isostat.st_size, SEEK_SET))
>          err(1, "%s: seek error - 6", argv[0]);
>
>      memset(buf, 0, padding);
>      if (fwrite(buf, sizeof(char), padding, fp) != (size_t)padding)
>          err(1, "%s: write error - 2", argv[0]);
> ---
>
> Strange, that it should happen. I guess, may be, HPA could be better able
to explain why it should happen for 2G files.
>
> Can I have the iso file?
>
> Thank you.
> ---
> Regards
>      -Prasad
> PS: Please don't send me html/attachment/Fwd mails
>
>
>

???Hi,

Bellow is a patch to replace fseek-memset-fwrite padding sequence with a more
clean and simple truncate(3) call.

==
diff --git a/utils/isohybrid.c b/utils/isohybrid.c
index 57c1015..fbff06f 100644
--- a/utils/isohybrid.c
+++ b/utils/isohybrid.c
@@ -541,21 +541,11 @@ main(int argc, char *argv[])
? ???if (fwrite(buf, sizeof(char), i, fp) != (size_t)i)
? ? ? ???err(1, "%s: write error - 1", argv[0]);
 
-? ? if (padding)
-? ? {
-? ? ? ? if (!(buf = realloc(buf, padding)))
-? ? ? ? ? ? err(1, "%s: could not re-size buffer", argv[0]);
-
-? ? ? ? if (fseek(fp, isostat.st_size, SEEK_SET))
-? ? ? ? ? ? err(1, "%s: seek error - 6", argv[0]);
-
-? ? ? ? memset(buf, 0, padding);
-? ? ? ? if (fwrite(buf, sizeof(char), padding, fp) != (size_t)padding)
-? ? ? ? ? ? err(1, "%s: write error - 2", argv[0]);
-? ? }
-
? ???free(buf);
? ???fclose(fp);
 
+? ? if (padding && truncate(argv[0], padding))
+? ? ? ? err(1, "%s: could not add padding bytes", argv[0]);
+

==

Thank you.
---
Regards
? ? -Prasad
PS: Please don't send me html/attachment/Fwd mails

On 09/13/2010 02:29 AM, Thomas Schmitt wrote:
> Hi,
> 
>> -D_FILE_OFFSET_BITS=64
>>>      if (fseek(fp, isostat.st_size, SEEK_SET))
> 
> fseek(3) expects type long for the address parameter.
>   int fseek(FILE *stream, long offset, int whence);
> 
> The _FILE_OFFSET_BITS=64 macro has an effect on type off_t.
> 
> So you will either have to use fseeko(3) (and eventually ftello(3))
> 
>   int fseeko(FILE *stream, off_t offset, int whence);
> 
> or you have to define macro
>   _LARGEFILE_SOURCE
> which makes fseek/ftell aliases of fseeko/ftello.
> 
Ah yes... there is that braindamage.
	
	-hpa