RE: UDF writing to unix socket - segfaults?
Martin Gainty wrote: > this is pure speculation unless we can get ahold of the source code > for your specific version of glibc and determine what the maximum > sizes are .. otherwise anything I suggest would be speculative..lets > take a look at > http://fossies.org/dox/glibc-2.16.0/sysdeps_2mach_2hurd_2sendto_8c_source.html > > ssize_t >29 __sendto (int fd, >30 const void *buf, >31 size_t n, >32 int flags, >33 const struct sockaddr_un *addr, >34 socklen_t addr_len) > Here his maximum buffer length for sending is unsigned int > specifically size_t so.. > are both send and receive entities IPv4 or both entities are IPv6 > if thats the case.. > can you send > 0 Bytes > 2 bytes > 4 bytes > 8 bytes > at what maximum length of buffer does the segfault occur > ? Interesting that you should pick on the length - I think that might be it. When I switched to using a UDP socket, sendto() did complain about the length. (error 90, message too long). Hmm, that's probably a UDP packet-size restriction, whereas no such restriction exist for a unix socket (I presume). Thanks for the idea! -- Per Jessen, Zürich (24.4°C) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
RE: UDF writing to unix socket - segfaults?
this is pure speculation unless we can get ahold of the source code for your specific version of glibc and determine what the maximum sizes are .. otherwise anything I suggest would be speculative..lets take a look at http://fossies.org/dox/glibc-2.16.0/sysdeps_2mach_2hurd_2sendto_8c_source.html ssize_t 29 __sendto (int fd, 30 const void *buf, 31 size_t n, 32 int flags, 33 const struct sockaddr_un *addr, 34 socklen_t addr_len) Here his maximum buffer length for sending is unsigned int specifically size_t so.. are both send and receive entities IPv4 or both entities are IPv6 if thats the case.. can you send 0 Bytes 2 bytes 4 bytes 8 bytes at what maximum length of buffer does the segfault occur ? Martin __ Verzicht und Vertraulichkeitanmerkung/Note de déni et de confidentialité Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene Empfaenger sein, so bitten wir hoeflich um eine Mitteilung. Jede unbefugte Weiterleitung oder Fertigung einer Kopie ist unzulaessig. Diese Nachricht dient lediglich dem Austausch von Informationen und entfaltet keine rechtliche Bindungswirkung. Aufgrund der leichten Manipulierbarkeit von E-Mails koennen wir keine Haftung fuer den Inhalt uebernehmen. Ce message est confidentiel et peut être privilégié. Si vous n'êtes pas le destinataire prévu, nous te demandons avec bonté que pour satisfaire informez l'expéditeur. N'importe quelle diffusion non autorisée ou la copie de ceci est interdite. Ce message sert à l'information seulement et n'aura pas n'importe quel effet légalement obligatoire. Étant donné que les email peuvent facilement être sujets à la manipulation, nous ne pouvons accepter aucune responsabilité pour le contenu fourni. > From: p...@computer.org > Subject: RE: UDF writing to unix socket - segfaults? > Date: Wed, 8 Aug 2012 15:39:09 +0200 > To: mysql@lists.mysql.com > > Martin Gainty wrote: > > > assuming you worked out the access to network by your code permissions > > When I open the unix socket, I give it 0777. > > > that means memory heap or stack is being overrun...you would be well > > advised to download the connect() and sendto() code from the OS vendor > > I'm running on Linux, so that is glibc - they work fine in a lot of > other code. I find it hard to suspect those two. > > > /Per > > -- > Per Jessen, Zürich (23.0°C) > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe:http://lists.mysql.com/mysql >
RE: UDF writing to unix socket - segfaults?
Martin Gainty wrote: > assuming you worked out the access to network by your code permissions When I open the unix socket, I give it 0777. > that means memory heap or stack is being overrun...you would be well > advised to download the connect() and sendto() code from the OS vendor I'm running on Linux, so that is glibc - they work fine in a lot of other code. I find it hard to suspect those two. /Per -- Per Jessen, Zürich (23.0°C) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
RE: UDF writing to unix socket - segfaults?
assuming you worked out the access to network by your code permissions that means memory heap or stack is being overrun...you would be well advised to download the connect() and sendto() code from the OS vendor and toss in plenty of codeguard and debug statements and recompile and rebuild. Mit Fruendlichen Grüßen Martin (12.2°C) __ Verzicht und Vertraulichkeitanmerkung/Note de déni et de confidentialité Diese Nachricht ist vertraulich. Sollten Sie nicht der vorgesehene Empfaenger sein, so bitten wir hoeflich um eine Mitteilung. Jede unbefugte Weiterleitung oder Fertigung einer Kopie ist unzulaessig. Diese Nachricht dient lediglich dem Austausch von Informationen und entfaltet keine rechtliche Bindungswirkung. Aufgrund der leichten Manipulierbarkeit von E-Mails koennen wir keine Haftung fuer den Inhalt uebernehmen. Ce message est confidentiel et peut être privilégié. Si vous n'êtes pas le destinataire prévu, nous te demandons avec bonté que pour satisfaire informez l'expéditeur. N'importe quelle diffusion non autorisée ou la copie de ceci est interdite. Ce message sert à l'information seulement et n'aura pas n'importe quel effet légalement obligatoire. Étant donné que les email peuvent facilement être sujets à la manipulation, nous ne pouvons accepter aucune responsabilité pour le contenu fourni. > From: p...@computer.org > Subject: UDF writing to unix socket - segfaults? > Date: Wed, 8 Aug 2012 08:26:23 +0200 > To: mysql@lists.mysql.com > > I am writing a UDF for sending messages to a local daemon. I've been > trying to make it use a UNIX socket, but it keeps segfaulting on > connect() or sendto(). I have double and tripled checked everything, > but I'm not finding anything. > > After a day or two, I finally decided to switch to UDP and writing to > localhost instead, which works fine. I still feel writing to a UNIX > socket ought to work and even if I've got a permission issue or > similar, a segfault is not the appropriate handling. Any clues? > > > -- > Per Jessen, Zürich (16.5°C) > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe:http://lists.mysql.com/mysql >
UDF writing to unix socket - segfaults?
I am writing a UDF for sending messages to a local daemon. I've been trying to make it use a UNIX socket, but it keeps segfaulting on connect() or sendto(). I have double and tripled checked everything, but I'm not finding anything. After a day or two, I finally decided to switch to UDP and writing to localhost instead, which works fine. I still feel writing to a UNIX socket ought to work and even if I've got a permission issue or similar, a segfault is not the appropriate handling. Any clues? -- Per Jessen, Zürich (16.5°C) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
