On Sat, Aug 09, 2014 at 12:30:12AM +0000, Serge Hallyn wrote: > A long enough lxcpath (and small PATH_MAX through crappy defines) can cause > the creation of the string to be hashed to fail. So just use alloca to > get the size string we need. > > More importantly, while I can't explain it, if lxcpath is too long, setting > sockname[sizeof(addr->sun_path)-2] to \0 simply doesn't seem to work. So set > sockname[sizeof(addr->sun_path)-3] to \0, which does work. > > With this, and with > > lxc.lxcpath = > /opt/lxc0123456789/lxc0123456789/lxc0123456789/lxc0123456789/lxc0123456789/lxc0123456789/lxc0123456789/lxc0123456789/lxc0123456789/lxc0123456789 > > in /etc/lxc/lxc.conf, I can run lxc-wait just fine. Without it, it fails > (as does lxc-start -d, which uses lxc_wait to verify the container started) > > Signed-off-by: Serge Hallyn <serge.hal...@ubuntu.com>
Acked-by: Stéphane Graber <stgra...@ubuntu.com>
> ---
> src/lxc/monitor.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/src/lxc/monitor.c b/src/lxc/monitor.c
> index 7c6dbb4..59b02b3 100644
> --- a/src/lxc/monitor.c
> +++ b/src/lxc/monitor.c
> @@ -142,7 +142,7 @@ int lxc_monitor_sock_name(const char *lxcpath, struct
> sockaddr_un *addr) {
> size_t len;
> int ret;
> char *sockname = &addr->sun_path[1];
> - char path[PATH_MAX+18];
> + char *path;
> uint64_t hash;
>
> /* addr.sun_path is only 108 bytes, so we hash the full name and
> @@ -150,18 +150,20 @@ int lxc_monitor_sock_name(const char *lxcpath, struct
> sockaddr_un *addr) {
> */
> memset(addr, 0, sizeof(*addr));
> addr->sun_family = AF_UNIX;
> - len = sizeof(addr->sun_path) - 1;
> - ret = snprintf(path, sizeof(path), "lxc/%s/monitor-sock", lxcpath);
> - if (ret < 0 || ret >= sizeof(path)) {
> - ERROR("lxcpath %s too long for monitor unix socket", lxcpath);
> + len = strlen(lxcpath) + 18;
> + path = alloca(len);
> + ret = snprintf(path, len, "lxc/%s/monitor-sock", lxcpath);
> + if (ret < 0 || ret >= len) {
> + ERROR("memory error creating monitor path");
> return -1;
> }
>
> + len = sizeof(addr->sun_path) - 1;
> hash = fnv_64a_buf(path, ret, FNV1A_64_INIT);
> ret = snprintf(sockname, len, "lxc/%016" PRIx64 "/%s", hash, lxcpath);
> if (ret < 0)
> return -1;
> - sockname[sizeof(addr->sun_path)-2] = '\0';
> + sockname[sizeof(addr->sun_path)-3] = '\0';
> INFO("using monitor sock name %s", sockname);
> return 0;
> }
> --
> 2.1.0.rc1
>
> _______________________________________________
> lxc-devel mailing list
> lxc-devel@lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel
--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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