Thread: Why is create function bringing down the Backend server?
I'm trying to add additional functionality to the contrib/pgcrypto branch (at least for my own use, although ideally, I'd like to make whatever additions good enough as to be accepted as part of the PG distribution) Anyway, I wanted to add hash functions (SHA-1 is already there, so I'd like to add SHA-256 and SHA-512 at the very least, and maybe also, for completeness, SHA-224 and SHA-384). Anyway, I started with an implementation of SHA-1 that I already have (since it is easy to test/debug, as I only have to compare it with the already-existing sha1 function in pgcrypto). I got it to work nicely, and I tried several millions randomly- generated strings, and the result of my hash function matches the result of pgcrypto's sha1 function. The problem is, when I execute the SQL statement: create or replace function sha1 .... ; for the second time (i.e., after making modifications and recompiling), the *backend* crashes -- it then restarts automatically, and then I run again the create or replace statement, and it works now (and the function seems to work fine -- well, in its "final" version it does). I know the list of possible causes may be nearly infinite, so I put the modified file (I removed most of the other stuff from the original pgcrypto.c file, and left the pg_digest function, which is the one that computes hashes, and the one that I used as a model to create mine): http://www.mochima.com/tmp/pgcrypto.c I also modified the SQL script file to include my function; this (when I execute this script) is precisely the moment at which the PG backend crashes (well, it shuts down anyway): http://www.mochima.com/tmp/pgcrypto.sql Any ideas of what I'm doing wrong? BTW, I compiled with the provided Makefile, then copy the .so files to /usr/local/pgsql/lib directory, and ran /sbin/ldconfig (that directory is included in my /etc/ld.so.conf file). I'm running PG 7.4.9 on a Linux FC4 on a Dual-Core Athlon64 (kernel x86_64-smp). Thanks for any comments/feedback! (please by kind, as this is my first attempt ever at creating PG functions -- but please be tough! Don't hold back valuable feedback just because you don't want to hurt my baby feelings! :-)) Carlos --
Carlos Moreno <moreno_pg@mochima.com> writes:
> The problem is, when I execute the SQL statement:
> create or replace function sha1 .... ;
> for the second time (i.e., after making modifications and
> recompiling), the *backend* crashes
Getting a stack trace from that core dump might be illuminating.
Better yet, attach to the backend with gdb before you execute
the crash-triggering statement, and let gdb trap the crash.
regards, tom lane
On 12/22/05, Carlos Moreno <moreno_pg@mochima.com> wrote: > The problem is, when I execute the SQL statement: > > create or replace function sha1 .... ; > > for the second time (i.e., after making modifications and > recompiling), the *backend* crashes -- it then restarts > automatically, and then I run again the create or replace > statement, and it works now (and the function seems to > work fine -- well, in its "final" version it does). You should see if there's something in server log. And then indeed, try to gdb it. You can run Postgres in non-daemon mode with command 'postgres -D datadir database'. The stripped pgcrypto.c you posted - your wrapper function looks fine, only problem I see is that you deleted function find_provider that is used by pg_digest, so there will be undefined function in final .so. But that should not crash the server, so gdb trace could be still useful. > Anyway, I wanted to add hash functions (SHA-1 is already there, > so I'd like to add SHA-256 and SHA-512 at the very least, and > maybe also, for completeness, SHA-224 and SHA-384). For SHA2 hashes it should be enough to compile pgcrypto against OpenSSL 0.9.8. Or upgrade to PostgreSQL 8.1, where they are included. Ofcourse, that is no fun. If you want to hack, you could try adding SHA224 to the SHA2 implementation in 8.1. There are currently only SHA256/384/512 hashes implemented. (AFAIR it is basically truncated SHA256 but with different init vector) -- marko
Marko Kreen wrote: >On 12/22/05, Carlos Moreno <moreno_pg@mochima.com> wrote: > >>The problem is, when I execute the SQL statement: >> >>create or replace function sha1 .... ; >> >>for the second time (i.e., after making modifications and >>recompiling), the *backend* crashes -- it then restarts >>automatically, and then I run again the create or replace >>statement, and it works now (and the function seems to >>work fine -- well, in its "final" version it does). >> > >You should see if there's something in server log. > The only thing that does show does not seem to say much: LOG: server process (PID 12885) was terminated by signal 11 LOG: terminating any other active server processes LOG: all server processes terminated; reinitializing Not sure what the meaning of signal 11 is with PG (AFAIR, it's one of the SIGUSER values, right?) > >And then indeed, try to gdb it. You can run Postgres in non-daemon >mode with command 'postgres -D datadir database'. > >The stripped pgcrypto.c you posted - your wrapper function looks fine, >only problem I see is that you deleted function find_provider that is used >by pg_digest, so there will be undefined function in final .so. > Oh no!! That was only in the function I posted, so that the file is kept as short as possible -- in the one that I compiled, I left everything untouched, and only added my functions. > >But that should not crash the server, so gdb trace could be still useful. > > Ok, will try to do it and post any interesting discoveries (I can't find any core files, so I guess I'll have to try gdbing it) >>Anyway, I wanted to add hash functions (SHA-1 is already there, >>so I'd like to add SHA-256 and SHA-512 at the very least, and >>maybe also, for completeness, SHA-224 and SHA-384). >> > >For SHA2 hashes it should be enough to compile pgcrypto >against OpenSSL 0.9.8. Or upgrade to PostgreSQL 8.1, >where they are included. > >Ofcourse, that is no fun. > Hahahaha -- why do I keep being naive and making the same mistake over and over!!! :-) As much as it is indeed no fun, it is also good to know (and I didn't know that OpenSSL 0.9.8 had them either, so thanks for the double pointer!) > >If you want to hack, you could try adding SHA224 to the SHA2 >implementation in 8.1. > Sounds like a plan :-) Thanks, Carlos --
On 12/23/05, Carlos Moreno <moreno_pg@mochima.com> wrote: > Marko Kreen wrote: > > >On 12/22/05, Carlos Moreno <moreno_pg@mochima.com> wrote: > > > >>The problem is, when I execute the SQL statement: > >> > >>create or replace function sha1 .... ; > >> > >>for the second time (i.e., after making modifications and > >>recompiling), the *backend* crashes -- it then restarts > >>automatically, and then I run again the create or replace > >>statement, and it works now (and the function seems to > >>work fine -- well, in its "final" version it does). > >> > > > >You should see if there's something in server log. > > > > The only thing that does show does not seem to say much: > > LOG: server process (PID 12885) was terminated by signal 11 > LOG: terminating any other active server processes > LOG: all server processes terminated; reinitializing > > Not sure what the meaning of signal 11 is with PG (AFAIR, it's > one of the SIGUSER values, right?) Well, that does not help. Signal 11 is SIGSEGV. > >And then indeed, try to gdb it. You can run Postgres in non-daemon > >mode with command 'postgres -D datadir database'. > > > >The stripped pgcrypto.c you posted - your wrapper function looks fine, > >only problem I see is that you deleted function find_provider that is used > >by pg_digest, so there will be undefined function in final .so. > > > > Oh no!! That was only in the function I posted, so that the file > is kept as short as possible -- in the one that I compiled, I left > everything untouched, and only added my functions. Ah, that's not it. Then I'm clueless. > >But that should not crash the server, so gdb trace could be still useful. > > > > > Ok, will try to do it and post any interesting discoveries (I > can't find any core files, so I guess I'll have to try gdbing it) Core files should be in data directory somewhere. (If postmaster ulimit allows them.) > >>Anyway, I wanted to add hash functions (SHA-1 is already there, > >>so I'd like to add SHA-256 and SHA-512 at the very least, and > >>maybe also, for completeness, SHA-224 and SHA-384). > >> > > > >For SHA2 hashes it should be enough to compile pgcrypto > >against OpenSSL 0.9.8. Or upgrade to PostgreSQL 8.1, > >where they are included. > > > >Ofcourse, that is no fun. > > > > Hahahaha -- why do I keep being naive and making the same mistake > over and over!!! :-) > > As much as it is indeed no fun, it is also good to know (and I > didn't know that OpenSSL 0.9.8 had them either, so thanks for > the double pointer!) Hehe. If hacking on a project, it is usually good to check out the latest version. pgcrypto had a major update in 8.1. > >If you want to hack, you could try adding SHA224 to the SHA2 > >implementation in 8.1. > > > > Sounds like a plan :-) Cool! Look how SHA384 fits in and try to follow that. That way the code is in coherent style. -- marko