diff options
Diffstat (limited to 'guix/build/syscalls.scm')
| -rw-r--r-- | guix/build/syscalls.scm | 53 |
1 files changed, 50 insertions, 3 deletions
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm index cd2797219f..06f69e119e 100644 --- a/guix/build/syscalls.scm +++ b/guix/build/syscalls.scm @@ -31,7 +31,13 @@ mount umount processes - network-interfaces)) + + IFF_UP + IFF_BROADCAST + IFF_LOOPBACK + network-interfaces + network-interface-flags + loopback-network-interface?)) ;;; Commentary: ;;; @@ -190,6 +196,18 @@ user-land process." (if (string-contains %host-type "linux") #x8912 ;GNU/Linux #xf00801a4)) ;GNU/Hurd +(define SIOCGIFFLAGS + (if (string-contains %host-type "linux") + #x8913 ;GNU/Linux + #xc4804191)) ;GNU/Hurd + +;; Flags and constants from <net/if.h>. + +(define IFF_UP #x1) ;Interface is up +(define IFF_BROADCAST #x2) ;Broadcast address valid. +(define IFF_LOOPBACK #x8) ;Is a loopback net. + +(define IF_NAMESIZE 16) ;maximum interface name size (define ifconf-struct ;; 'struct ifconf', from <net/if.h>. @@ -197,8 +215,9 @@ user-land process." '*)) ;struct ifreq *ifc_ifcu (define ifreq-struct-size - ;; 'struct ifreq' begins with a char array containing the interface name, - ;; followed by a bunch of stuff. This is its size in bytes. + ;; 'struct ifreq' begins with an array of IF_NAMESIZE bytes containing the + ;; interface name (nul-terminated), followed by a bunch of stuff. This is + ;; its size in bytes. (if (= 8 (sizeof '*)) 40 32)) @@ -245,4 +264,32 @@ most LEN bytes from BV." (list (strerror err)) (list err))))) +(define (network-interface-flags socket name) + "Return a number that is the bit-wise or of 'IFF*' flags for network +interface NAME." + (let ((req (make-bytevector ifreq-struct-size))) + (bytevector-copy! (string->utf8 name) 0 req 0 + (min (string-length name) (- IF_NAMESIZE 1))) + (let* ((ret (%ioctl (fileno socket) SIOCGIFFLAGS + (bytevector->pointer req))) + (err (errno))) + (if (zero? ret) + + ;; The 'ifr_flags' field is IF_NAMESIZE bytes after the beginning of + ;; 'struct ifreq', and it's a short int. + (bytevector-sint-ref req IF_NAMESIZE (native-endianness) + (sizeof short)) + + (throw 'system-error "network-interface-flags" + "network-interface-flags on ~A: ~A" + (list name (strerror err)) + (list err)))))) + +(define (loopback-network-interface? name) + "Return true if NAME designates a loopback network interface." + (let* ((sock (socket SOCK_STREAM AF_INET 0)) + (flags (network-interface-flags sock name))) + (close-port sock) + (not (zero? (logand flags IFF_LOOPBACK))))) + ;;; syscalls.scm ends here |