On 01/11/2014 08:35 AM, Tilman Schmidt wrote: > Hello Michael, > > Am 10.01.2014 18:52, schrieb Michael Kerrisk (man-pages): >> On 01/10/2014 12:30 PM, Tilman Schmidt wrote: >>> Add the missing description of the possibility to call SIOCGIFCONF >>> with ifc_req==NULL to determine the needed buffer size, as described >>> in http://lkml.indiana.edu/hypermail/linux/kernel/0110.1/0506.html >>> and verified against source files net/core/dev_ioctl.c and >>> net/ipv4/devinet.c in the current kernel git tree. > [...]> >> Thanks for the patch. I'm trying to verify this from the code, but >> am having some trouble finding the relevant pieces. Could you point >> me more specifically at the points in the kernel source where this >> case is handled? > > Gladly. > > Function dev_ifconf() [net/core/dev_ioctl.c line 67ff.] is the main > handler for SIOCGIFCONF. It calls the registered protocol specific > handlers via the table gifconf_list[]. The current kernel has only > one such handler, inet_gifconf() [net/ipv4/devinet.c line 1115ff.] > > If ifc.ifc_buf is NULL, dev_ifconf() calls the protocol specific > handlers with NULL as second argument. [net/core/dev_ioctl.c line 96] > > If inet_gifconf() is called with NULL as second argument it just > adds up the data sizes, skipping the size check and data transfer. > [net/ipv4/devinet.c line 1127f.] Thanks. Patch applied. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
