Date: Wed, 14 Apr 2010 22:02:19 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r206637 - in head: sbin/ifconfig share/man/man4 sys/net Message-ID: <201004142202.o3EM2KPU099977@svn.freebsd.org>
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Author: delphij Date: Wed Apr 14 22:02:19 2010 New Revision: 206637 URL: http://svn.freebsd.org/changeset/base/206637 Log: When an underlying ioctl(2) handler returns an error, our ioctl(2) interface considers that it hits a fatal error, and will not copyout the request structure back for _IOW and _IOWR ioctls, keeping them untouched. The previous implementation of the SIOCGIFDESCR ioctl intends to feed the buffer length back to userland. However, if we return an error, the feedback would be defeated and ifconfig(8) would trap into an infinite loop. This commit changes SIOCGIFDESCR to set buffer field to NULL to indicate the previous ENAMETOOLONG case. Reported by: bschmidt MFC after: 2 weeks Modified: head/sbin/ifconfig/ifconfig.c head/share/man/man4/netintro.4 head/sys/net/if.c Modified: head/sbin/ifconfig/ifconfig.c ============================================================================== --- head/sbin/ifconfig/ifconfig.c Wed Apr 14 21:59:22 2010 (r206636) +++ head/sbin/ifconfig/ifconfig.c Wed Apr 14 22:02:19 2010 (r206637) @@ -922,19 +922,20 @@ status(const struct afswtch *afp, const ifr.ifr_buffer.buffer = descr; ifr.ifr_buffer.length = descrlen; if (ioctl(s, SIOCGIFDESCR, &ifr) == 0) { - if (strlen(descr) > 0) - printf("\tdescription: %s\n", descr); - break; - } else if (errno == ENAMETOOLONG) - descrlen = ifr.ifr_buffer.length; - else - break; - } else { + if (ifr.ifr_buffer.buffer == descr) { + if (strlen(descr) > 0) + printf("\tdescription: %s\n", + descr); + } else if (ifr.ifr_buffer.length > descrlen) { + descrlen = ifr.ifr_buffer.length; + continue; + } + } + } else warn("unable to allocate memory for interface" "description"); - break; - } - }; + break; + } if (ioctl(s, SIOCGIFCAP, (caddr_t)&ifr) == 0) { if (ifr.ifr_curcap != 0) { Modified: head/share/man/man4/netintro.4 ============================================================================== --- head/share/man/man4/netintro.4 Wed Apr 14 21:59:22 2010 (r206636) +++ head/share/man/man4/netintro.4 Wed Apr 14 22:02:19 2010 (r206637) @@ -32,7 +32,7 @@ .\" @(#)netintro.4 8.2 (Berkeley) 11/30/93 .\" $FreeBSD$ .\" -.Dd January 26, 2010 +.Dd April 14, 2010 .Dt NETINTRO 4 .Os .Sh NAME @@ -292,8 +292,11 @@ field of struct passed in as parameter, and the length would include the terminating nul character. If there is not enough space to hold the interface length, -no copy would be done and an -error would be returned. +no copy would be done and the +.Va buffer +field of +.Va ifru_buffer +would be set to NULL. The kernel will store the buffer length in the .Va length field upon return, regardless whether the buffer itself is Modified: head/sys/net/if.c ============================================================================== --- head/sys/net/if.c Wed Apr 14 21:59:22 2010 (r206636) +++ head/sys/net/if.c Wed Apr 14 22:02:19 2010 (r206637) @@ -2049,14 +2049,13 @@ ifhwioctl(u_long cmd, struct ifnet *ifp, case SIOCGIFDESCR: error = 0; sx_slock(&ifdescr_sx); - if (ifp->if_description == NULL) { - ifr->ifr_buffer.length = 0; + if (ifp->if_description == NULL) error = ENOMSG; - } else { + else { /* space for terminating nul */ descrlen = strlen(ifp->if_description) + 1; if (ifr->ifr_buffer.length < descrlen) - error = ENAMETOOLONG; + ifr->ifr_buffer.buffer = NULL; else error = copyout(ifp->if_description, ifr->ifr_buffer.buffer, descrlen);
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