[rrd-developers] Segmentation fault when run from php cli.
FrankJ
dbkeebler at gmail.com
Fri Jul 17 06:10:34 CEST 2009
I've been looking into this alot lately because I find it easier to reuse my
RRD definitions and whatnot with PHP versus Perl and I never bothered to
learn Python. And I feel it should be unnecessary to have apache in the way
all the time.
Unfortunately I have no solutions, but I do have some information that might
be useful to someone more advanced than me. So far I've only been focusing
on rrd_create() if only for the chicken/egg factor. Can't manipulate an RRD
that doesn't exist yet now can we? I'm using PHP 5.1.6 and RRDtool 1.3.7 tho
I found the same problem with the 1.2.x series as well as PHP4 (32 and 64
bits alike).
That problem being that php-rrd functions work as expected when called thru
the webserver but seg fault when called from the command line ("/usr/bin/php
myscript.php")
Running it thru GDB I have determined that when rrd_parsetime() is called
from rrd_create() the first arg (const char *tspec) is magically transformed
from whatever pointer it was to 0x0! The second arg makes it thru completely
unharmed (rrd_time_value_t * ptv).
My GDB output:
67 if ((parsetime_error = rrd_parsetime(optarg,
&last_up_tv))) {
(gdb) p opt
$1 = 98
(gdb) p optarg
$2 = 0xf9ded28 "1247798125"
(gdb) p last_up_tv
$3 = {type = 48, offset = 262008040, tm = {tm_sec = 262004736, tm_min = 0,
tm_hour = 3, tm_mday = 0,
tm_mon = 1944558168, tm_year = 32767, tm_wday = -1215872982, tm_yday =
51, tm_isdst = 24,
tm_gmtoff = 24, tm_zone = 0xf9dece8 "RRA:AVERAGE:0.5:288:797"}}
(gdb) p &last_up_tv
$4 = (rrd_time_value_t *) 0x7fff73e79600
(gdb) s
rrd_parsetime (tspec=0x0, ptv=0x7fff73e79600) at rrd_parsetime.c:842
842 {
(gdb) bt
#0 rrd_parsetime (tspec=0x0, ptv=0x7fff73e79600) at rrd_parsetime.c:842
#1 0x00000031d4207737 in rrd_create (argc=11, argv=0xf9debb0) at
rrd_create.c:67
#2 0x00002b583a62d5a6 in zif_rrd_create (ht=3, return_value=0xf9deb68,
return_value_ptr=0x0,
this_ptr=0x0, return_value_used=0) at
/home/frank/src/phprrdtool-mine/rrdtool.c:161
#3 0x00000000005a56bf in ?? ()
#4 0x0000000000595ccc in execute ()
#5 0x0000000000579d48 in zend_execute_scripts ()
#6 0x00000000005404fa in php_execute_script ()
#7 0x00000000005f32c8 in main ()
Prior to calling rrd_parsetime(), optarg is clearly a pointer to a string
containing a valid unix timestamp, as expected. But as the backtrace shows,
it is passed to rrd_parsetime() as 0x0 (NULL). For the life of me I can't
figure out why. Obviously the rrdtool executable takes the same code path
but does not exhibit the same behavior.
I guess my next step will be to run it thru DDD and watch the registers and
whatnot as I step thru the CPU instructions one by one and hopefully that
will show me where it goes wrong. But it's been about 14 years since I've
dug down to that level so I'm not expecting any miracles.
I hope this information is useful to someone who might have a better
understanding as to why a function parameter would vanish like that between
the time the function was called and when it was entered but only with the
php cli.
-Frank
admin-14 wrote:
>
> Hello,
>
> I got strange problem. I hope you might help me.
>
> There is a script which works very properly from browser. No errors
> and files are generated ok. But when I run this script from command
> line I got segmentation fault. All permissions are ok. What can be the
> problem?
>
> RRDtool 1.3.8
>
> System:
> Linux version 2.6.18-128.el5PAE (mockbuild at builder16.centos.org) (gcc
> version 4.1.2 20080704 (Red Hat 4.1.2-44)) #1 SMP Wed Jan 21 11:19:46 EST
> 2009
> (Centos5+Directadmin)
>
> PHP:
> PHP 5.2.9 (cli) (built: May 11 2009 23:11:30)
> Copyright (c) 1997-2009 The PHP Group
> Zend Engine v2.2.0, Copyright (c) 1998-2009 Zend Technologies
> with XCache v1.2.2, Copyright (c) 2005-2007, by mOo
> with the ionCube PHP Loader v3.1.34, Copyright (c) 2002-2009, by
> ionCube Ltd.
>
> Perl:
> perl-5.8.8-18.el5_3.1
>
>
> Here is example:
> [root at server public_html]# php con.php
> openvz-6130.rrd
> Segmentation fault
> [root at server public_html]#
>
> strace show:
> lseek(5, 0, SEEK_SET) = 0
> getdents(5, /* 41 entries */, 4096) = 1148
> stat64("/home/testuser/rrd/traffic/openvz-6130.rrd",
> {st_mode=S_IFREG|0777, st_size=71152, ...}) = 0
> access("/home/testuser/rrd/traffic/openvz-6130.rrd", R_OK) = 0
> lstat64("/home/testuser/rrd/traffic/openvz-6130.rrd",
> {st_mode=S_IFREG|0777, st_size=71152, ...}) = 0
> write(1, "openvz-6130.rrd\r\n ", 21openvz-6130.rrd
> ) = 21
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2679, ...}) = 0
> gettimeofday({1245184220, 320367}, NULL) = 0
> time(NULL) = 1245184220
> time(NULL) = 1245184220
> stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2679, ...}) = 0
> --- SIGSEGV (Segmentation fault) @ 0 (0) ---
> +++ killed by SIGSEGV +++
> [root at server public_html]#
>
>
>
>
>
>
> The php script below:
> <?php
>
> $di=new DirectoryIterator("/home/testuser/rrd/traffic/");
> $i= 0;
> foreach($di as $file) {
> if( !$file -> isDir() && !$file -> isDot() && $file ->
> isReadable() && !$file -> isLink() )
> {
> $i++;
> // if( $i < 3)
> // continue;
> echo $file -> getFilename( ).'
> ';
>
> $opts = array(
> "--title", "Server traffic ".$file -> getFilename( ),
> "--start", mktime (0,0,0,date("m") ,date("d"),date("Y")),
> "--step", '300',
> "--width", "600",
> "--height", "480",
> "--vertical-label", "kB/s",
> "--rigid",
> "--color", "BACK#000000",
> "--color", "SHADEA#000000",
> "--color", "SHADEB#000000",
> "--color", "FONT#DDDDDD",
> "--color", "CANVAS#202020",
> "--color", "GRID#666666",
> "--color", "MGRID#AAAAAA",
> "--color", "FRAME#202020",
> "--color", "ARROW#FFFFFF",
> // "HRULE:60000#0000FF:Maximum allowed",
> "DEF:in=/home/testuser/rrd/traffic/".$file ->
> getFilename( ).":incoming:AVERAGE",
> "DEF:out=/home/testuser/rrd/traffic/".$file ->
> getFilename( ).":outgoing:AVERAGE",
> "DEF:tot=/home/testuser/rrd/traffic/".$file ->
> getFilename( ).":total:AVERAGE",
> "LINE2:in#0000ff:Incoming Traffic Avg.",
> "LINE2:out#00ff00:Outgoing Traffic Avg.",
> "LINE2:tot#ff0000:Total Traffic Avg.",
> "PRINT:in:AVERAGE:incoming\: %1.2lf b/s",
> "PRINT:out:AVERAGE:outgoing\: %1.2lf b/s",
> "PRINT:tot:AVERAGE:total\: %1.2lf b/s"
> );
>
> $ret =
> rrd_graph("/home/testuser/domains/testuser.mydomain.com/public_html/_rrd/".$file
> -> getFilename( ).".gif", $opts, count($opts));
>
> if( !is_array($ret) )
> {
> $err = rrd_error();
>
> echo "rrd_graph() ERROR: $err\n";
> }
>
> }
> }
>
> ?>[
>
> --
> regards,
> Marcin
>
> _______________________________________________
> rrd-developers mailing list
> rrd-developers at lists.oetiker.ch
> https://lists.oetiker.ch/cgi-bin/listinfo/rrd-developers
>
>
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