Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 7 Apr 2002 01:41:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 7 Apr 2002 01:41:12 -0500 Received: from air-2.osdl.org ([65.201.151.6]:28422 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id ; Sun, 7 Apr 2002 01:41:11 -0500 Date: Sat, 6 Apr 2002 22:38:36 -0800 (PST) From: "Randy.Dunlap" X-X-Sender: To: cc: Subject: RE: Documentation or software - bug? Message-ID: MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="=-dlv5jHEj9+lkBRIG5jzZ" Content-ID: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. Send mail to mime@docserver.cac.washington.edu for more info. --=-dlv5jHEj9+lkBRIG5jzZ Content-Type: TEXT/PLAIN; CHARSET=US-ASCII Content-ID: Hi, Here's my conclusion/opinion. All of the (networking) BOOLEAN parameters expect newlen (in the sysctl system call) to be sizeof(int), not 1, but (your) sysctl program executes the syscall with newlen = 1. It ([your] sysctl program) should be modified to pass BOOLEANs as int's. In other words, BOOLEAN doesn't imply length = 1. ~Randy ---------- Forwarded message ---------- Hi there, I try to set up a box without procfs, thus I've to set some kernel parameters using _sysctl(). I wrote a little quick-n-dirty program to set at least integer and struct ( or better array ) parameters. I can set all struct, integer and boolean values with this program except ip_forward. Due to the docs ip_forward is a BOOLEAN parameter, so the length of the value array for _sysctl should be 1. ... but ... in ${KERNELSRC}/net/ipv4/sysctl_net_ipv4.c I find: snip --> <-- snap static int ipv4_sysctl_forward_strategy(ctl_table *table ... snip --> <-- snap if (newlen != sizeof(int)) return -EINVAL; snip --> If the config file for my program looks like this: # CTL_NET IPV4 FORWARD : YES 3 5 8 : 1 I get ``Invalid argument'' from my program. If the config file for my program looks like this: 3 5 8 : 1 1 1 1 it works and I have a ``1'' in /proc/sys/net/ipv4/ip_forward. ... sure sizeof(int) is 4 on my machine. My question: Is there something wrong with the documentation, and NET_IPV4_FORWARD awaits 4 integers to set/unset IP forwarding, or is something wrong in sysctl_net_ipv4.c, or did I understand something wrong, and my program has to be written in some other kind? My program itself is in the attachment. Thanks for every help Frank PS: If the configuration file looks like this: 3 5 16 1 : 1 (the ``3 5 8'' is due to sysctl.h only for compatibility with 2.0 kernels, and I run an 2.4.16) i get ENODIR. --=-dlv5jHEj9+lkBRIG5jzZ Content-Type: TEXT/X-C; CHARSET=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Content-ID: Content-Description: Content-Disposition: ATTACHMENT; FILENAME="sysctl.c" /**************************************************************************= *************** ** ** ** sysconf.c: Version 0.1 15.03.2002 ** ** ** ** Author: Frank Schaefer ** ** ** ** Purpose: ** ** For security reasons we decided NOT to enable procfs on our firewall. = ** ** Thus we had to realize an alternative for the settings of kernel parame= ters. ** ** Also for security reasons this program doesn't take any parameters, and= all paths ** ** etc. will be hardcoded into this program. ** ** ** ** Files: ** ** Configuration file for sysctl: /etc/sysconf.conf ** ** ** ** Configuration file syntax: ** ** - lines starting with a whitespace and lines starting with '#' are comme= nts ** ** empty lines are comnments ** ** <#> : integer ** ** : whitespace ** ** <#>[[...[<#>[...]...]]]:[...]<#>[...[<#>[...]...]] ** ** Whereas the part up to the colon is the syscontrol name as described in= ** ** /usr/include/linux/sysctl.h, and the part after the colon is the values= to set ** ** ** ** !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= ** ** !!!!!!!!!! EDIT THE CONFIGURATION FILE WITH EXTREME CAUTION !!!!!!!!!!!= ** ** !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= ** ** There isn't any possibility to check correct settings at this level. In= correct ** ** settings can cause a complete system crash. ** ** ** ** Return value: ** ** 0: all settings due to the configuration file succeeded ** ** n: number of attempts to set parameters failed ** ** ** ***************************************************************************= **************/ #include #include #include #include #include #include #include /* read one line from the configuration file, ignore comments and store the= name and the value in the arrays pointed to by name and value=09 INPUT: id - filehandle name - pointer to name array nlen - where to store length of the name value - pointer to value array vlen - where to store length of the value OUTPUT: 0 : O.K. name and value contain the next parameter to set 1 : end of configuratin file reached name and value doesn't make sense */ int readconf( FILE* id, int* name, int* nlen, int* value, int* vlen ) { char *buf, *buffer; unsigned char indx; int v_indx =3D 0, colon =3D 0; char c; int *target =3D name; buf =3D malloc( 80 * sizeof( char ) ); buffer =3D buf; do { if( ! fgets( buffer, 80 * sizeof( char ) , id ) ) { free( buf ); return( 1 ); } } while ( ( *buffer =3D=3D ' ' ) || ( *buffer =3D=3D '\t' ) || ( *buffer = =3D=3D '#' ) || \ ( *buffer =3D=3D '\n') ); do { indx =3D strspn( buffer, "0123456789" ); if( *(buffer + indx) =3D=3D ':' ) colon =3D 1; *(buffer + indx) =3D '\0'; *(target + v_indx++) =3D atoi( buffer ); buffer =3D buffer + indx + 1; indx =3D strcspn( buffer, "0123456789" ); c =3D *(buffer + indx); *(buffer + indx) =3D '\0'; if( strcspn( buffer, ":" ) !=3D strlen( buffer ) ) colon =3D 1; *(buffer + indx) =3D c; buffer =3D buffer + indx; if( colon && ( target !=3D value ) ) { target =3D value; *nlen =3D v_indx; v_indx =3D 0; } } while ( strlen( buffer ) > 0 ); *vlen =3D v_indx; free( buf ); return( 0 ); } /* Set one parameter in the OS kernel INPUT: name - pointer to the name array nlen - length of the array value - pointer to the value array vlen - length of the array OUTPUT: 0 - O.K. -1 - error */ _syscall1( int, _sysctl, struct __sysctl_args *, args ); int sysctl( int* name, int nlen, void* value, size_t vlen ) { size_t ovlen =3D 1; struct __sysctl_args args =3D { name, nlen, 0, &ovlen, value, vlen }; return _sysctl( &args ); } int main( ) { int name[5], value[16], nlen, vlen, ret =3D 0; char cfgfile[] =3D "/etc/sysconf.conf"; FILE* stream; stream =3D fopen( cfgfile, "r" ); if( ! stream ) { fprintf( stderr, "Could not read configuration file: %s\n", cfgfile ); exit( 1 ); } while( readconf( stream, name, &nlen, value, &vlen ) !=3D 1 ) { if( sysctl( name, nlen, (void*)value, (size_t)vlen ) ) { perror( "sysctl" ); ret++; } } close( stream ); exit( ret ); } --=-dlv5jHEj9+lkBRIG5jzZ-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/