| Message ID | 20210510120602.29288-1-fw@strlen.de (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | David Ahern |
| Headers | show |
| Series | [iproute2,v2] libgenl: make genl_add_mcast_grp set errno on error | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On 5/10/21 6:06 AM, Florian Westphal wrote: > diff --git a/lib/libgenl.c b/lib/libgenl.c > index 4c51d47af46b..8b22c06e7941 100644 > --- a/lib/libgenl.c > +++ b/lib/libgenl.c > @@ -84,6 +84,7 @@ static int genl_parse_grps(struct rtattr *attr, const char *name, unsigned int * > } > } > > + errno = ENOENT; > return -1; > } > > @@ -108,17 +109,22 @@ int genl_add_mcast_grp(struct rtnl_handle *grth, __u16 fnum, const char *group) > ghdr = NLMSG_DATA(answer); > len = answer->nlmsg_len; > > - if (answer->nlmsg_type != GENL_ID_CTRL) > + if (answer->nlmsg_type != GENL_ID_CTRL) { > + errno = EINVAL; > goto err_free; > + } > > len -= NLMSG_LENGTH(GENL_HDRLEN); > - if (len < 0) > + if (len < 0) { > + errno = EINVAL; > goto err_free; > + } > > attrs = (struct rtattr *) ((char *) ghdr + GENL_HDRLEN); > parse_rtattr(tb, CTRL_ATTR_MAX, attrs, len); > > if (tb[CTRL_ATTR_MCAST_GROUPS] == NULL) { > + errno = ENOENT; > fprintf(stderr, "Missing mcast groups TLV\n"); > goto err_free; > } > I get compile errors on Ubuntu 20.04: lib CC libgenl.o libgenl.c: In function ‘genl_parse_grps’: libgenl.c:87:2: error: ‘errno’ undeclared (first use in this function) 87 | errno = ENOENT; | ^~~~~ libgenl.c:12:1: note: ‘errno’ is defined in header ‘<errno.h>’; did you forget to ‘#include <errno.h>’? 11 | #include "libgenl.h" +++ |+#include <errno.h> 12 | libgenl.c:87:2: note: each undeclared identifier is reported only once for each function it appears in 87 | errno = ENOENT; | ^~~~~ libgenl.c:87:10: error: ‘ENOENT’ undeclared (first use in this function) 87 | errno = ENOENT; | ^~~~~~ libgenl.c: In function ‘genl_add_mcast_grp’: libgenl.c:113:3: error: ‘errno’ undeclared (first use in this function) 113 | errno = EINVAL; | ^~~~~ libgenl.c:113:3: note: ‘errno’ is defined in header ‘<errno.h>’; did you forget to ‘#include <errno.h>’? libgenl.c:113:11: error: ‘EINVAL’ undeclared (first use in this function) 113 | errno = EINVAL; | ^~~~~~ libgenl.c:127:11: error: ‘ENOENT’ undeclared (first use in this function) 127 | errno = ENOENT;
diff --git a/lib/libgenl.c b/lib/libgenl.c index 4c51d47af46b..8b22c06e7941 100644 --- a/lib/libgenl.c +++ b/lib/libgenl.c @@ -84,6 +84,7 @@ static int genl_parse_grps(struct rtattr *attr, const char *name, unsigned int * } } + errno = ENOENT; return -1; } @@ -108,17 +109,22 @@ int genl_add_mcast_grp(struct rtnl_handle *grth, __u16 fnum, const char *group) ghdr = NLMSG_DATA(answer); len = answer->nlmsg_len; - if (answer->nlmsg_type != GENL_ID_CTRL) + if (answer->nlmsg_type != GENL_ID_CTRL) { + errno = EINVAL; goto err_free; + } len -= NLMSG_LENGTH(GENL_HDRLEN); - if (len < 0) + if (len < 0) { + errno = EINVAL; goto err_free; + } attrs = (struct rtattr *) ((char *) ghdr + GENL_HDRLEN); parse_rtattr(tb, CTRL_ATTR_MAX, attrs, len); if (tb[CTRL_ATTR_MCAST_GROUPS] == NULL) { + errno = ENOENT; fprintf(stderr, "Missing mcast groups TLV\n"); goto err_free; }
genl_add_mcast_grp doesn't set errno in all cases. On kernels that support mptcp but lack event support (all kernels <= 5.11) MPTCP_PM_EV_GRP_NAME won't be found and ip will exit with "can't subscribe to mptcp events: Success" Set errno to a meaningful value (ENOENT) when the group name isn't found and also cover other spots where it returns nonzero with errno unset. Fixes: ff619e4fd370 ("mptcp: add support for event monitoring") Signed-off-by: Florian Westphal <fw@strlen.de> --- Change since v1: fix libgenl instead of setting errno in the caller. lib/libgenl.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)