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From 3c31ef05ba732e3ab5d23761c5f84768ca8de68e Mon Sep 17 00:00:00 2001
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From: Yu Watanabe <watanabe.yu+github@gmail.com>
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Date: Sun, 15 Dec 2019 21:32:25 +0900
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Subject: [PATCH] sd-netlink: introduce sd_netlink_message_read_strv()
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The combination of sd_netlink_message_enter_container() and
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sd_netlink_message_read_string() only reads the last element if the attribute is
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duplicated, such a situation easily happens for IFLA_ALT_IFNAME.
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The function introduced here reads all matched attributes.
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(cherry picked from commit 8f3c1859669230c2c8458675f41de13e369b47e7)
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Related: #1850986
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---
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 src/libsystemd/sd-netlink/netlink-message.c | 58 +++++++++++++++++++++
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 src/systemd/sd-netlink.h                    |  1 +
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 2 files changed, 59 insertions(+)
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diff --git a/src/libsystemd/sd-netlink/netlink-message.c b/src/libsystemd/sd-netlink/netlink-message.c
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index db9101c163..5723e1d21c 100644
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--- a/src/libsystemd/sd-netlink/netlink-message.c
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+++ b/src/libsystemd/sd-netlink/netlink-message.c
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@@ -14,6 +14,7 @@
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 #include "netlink-util.h"
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 #include "refcnt.h"
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 #include "socket-util.h"
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+#include "strv.h"
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 #include "util.h"
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 #define GET_CONTAINER(m, i) ((i) < (m)->n_containers ? (struct rtattr*)((uint8_t*)(m)->hdr + (m)->containers[i].offset) : NULL)
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@@ -754,6 +755,63 @@ int sd_netlink_message_read_in6_addr(sd_netlink_message *m, unsigned short type,
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         return 0;
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 }
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+int sd_netlink_message_read_strv(sd_netlink_message *m, unsigned short container_type, unsigned short type_id, char ***ret) {
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+        _cleanup_strv_free_ char **s = NULL;
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+        const NLTypeSystem *type_system;
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+        const NLType *nl_type;
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+        struct rtattr *rta;
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+        void *container;
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+        unsigned short rt_len;
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+        int r;
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+
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+        assert_return(m, -EINVAL);
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+        assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -EINVAL);
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+
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+        r = type_system_get_type(m->containers[m->n_containers].type_system,
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+                                 &nl_type,
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+                                 container_type);
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+        if (r < 0)
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+                return r;
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+
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+        if (type_get_type(nl_type) != NETLINK_TYPE_NESTED)
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+                return -EINVAL;
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+
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+        r = type_system_get_type_system(m->containers[m->n_containers].type_system,
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+                                        &type_system,
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+                                        container_type);
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+        if (r < 0)
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+                return r;
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+
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+        r = type_system_get_type(type_system, &nl_type, type_id);
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+        if (r < 0)
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+                return r;
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+
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+        if (type_get_type(nl_type) != NETLINK_TYPE_STRING)
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+                return -EINVAL;
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+
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+        r = netlink_message_read_internal(m, container_type, &container, NULL);
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+        if (r < 0)
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+                return r;
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+
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+        rt_len = (unsigned short) r;
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+        rta = container;
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+
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+        for (; RTA_OK(rta, rt_len); rta = RTA_NEXT(rta, rt_len)) {
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+                unsigned short type;
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+
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+                type = RTA_TYPE(rta);
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+                if (type != type_id)
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+                        continue;
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+
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+                r = strv_extend(&s, RTA_DATA(rta));
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+                if (r < 0)
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+                        return r;
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+        }
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+
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+        *ret = TAKE_PTR(s);
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+        return 0;
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+}
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+
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 static int netlink_container_parse(sd_netlink_message *m,
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                                    struct netlink_container *container,
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                                    int count,
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diff --git a/src/systemd/sd-netlink.h b/src/systemd/sd-netlink.h
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index 51f0fa16b4..1f5c093f11 100644
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--- a/src/systemd/sd-netlink.h
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+++ b/src/systemd/sd-netlink.h
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@@ -82,6 +82,7 @@ int sd_netlink_message_open_container_union(sd_netlink_message *m, unsigned shor
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 int sd_netlink_message_close_container(sd_netlink_message *m);
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 int sd_netlink_message_read_string(sd_netlink_message *m, unsigned short type, const char **data);
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+int sd_netlink_message_read_strv(sd_netlink_message *m, unsigned short container_type, unsigned short type_id, char ***ret);
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 int sd_netlink_message_read_u8(sd_netlink_message *m, unsigned short type, uint8_t *data);
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 int sd_netlink_message_read_u16(sd_netlink_message *m, unsigned short type, uint16_t *data);
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 int sd_netlink_message_read_u32(sd_netlink_message *m, unsigned short type, uint32_t *data);