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Merge branch 'bpf-fs-mount-options-parsing-follow-ups'
Andrii Nakryiko says: ==================== BPF FS mount options parsing follow ups Original BPF token patch set ([0]) added delegate_xxx mount options which supported only special "any" value and hexadecimal bitmask. This patch set attempts to make specifying and inspecting these mount options more human-friendly by supporting string constants matching corresponding bpf_cmd, bpf_map_type, bpf_prog_type, and bpf_attach_type enumerators. This implementation relies on BTF information to find all supported symbolic names. If kernel wasn't built with BTF, BPF FS will still support "any" and hex-based mask. [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=805707&state=* v1->v2: - strip BPF_, BPF_MAP_TYPE_, and BPF_PROG_TYPE_ prefixes, do case-insensitive comparison, normalize to lower case (Alexei). ==================== Link: https://lore.kernel.org/r/20231214225016.1209867-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Alexei Starovoitov
commit
0f5d5454c7
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@ -595,6 +595,136 @@ struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type typ
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}
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EXPORT_SYMBOL(bpf_prog_get_type_path);
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struct bpffs_btf_enums {
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const struct btf *btf;
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const struct btf_type *cmd_t;
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const struct btf_type *map_t;
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const struct btf_type *prog_t;
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const struct btf_type *attach_t;
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};
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static int find_bpffs_btf_enums(struct bpffs_btf_enums *info)
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{
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const struct btf *btf;
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const struct btf_type *t;
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const char *name;
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int i, n;
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memset(info, 0, sizeof(*info));
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btf = bpf_get_btf_vmlinux();
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if (IS_ERR(btf))
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return PTR_ERR(btf);
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if (!btf)
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return -ENOENT;
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info->btf = btf;
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for (i = 1, n = btf_nr_types(btf); i < n; i++) {
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t = btf_type_by_id(btf, i);
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if (!btf_type_is_enum(t))
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continue;
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name = btf_name_by_offset(btf, t->name_off);
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if (!name)
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continue;
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if (strcmp(name, "bpf_cmd") == 0)
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info->cmd_t = t;
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else if (strcmp(name, "bpf_map_type") == 0)
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info->map_t = t;
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else if (strcmp(name, "bpf_prog_type") == 0)
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info->prog_t = t;
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else if (strcmp(name, "bpf_attach_type") == 0)
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info->attach_t = t;
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else
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continue;
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if (info->cmd_t && info->map_t && info->prog_t && info->attach_t)
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return 0;
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}
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return -ESRCH;
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}
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static bool find_btf_enum_const(const struct btf *btf, const struct btf_type *enum_t,
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const char *prefix, const char *str, int *value)
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{
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const struct btf_enum *e;
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const char *name;
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int i, n, pfx_len = strlen(prefix);
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*value = 0;
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if (!btf || !enum_t)
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return false;
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for (i = 0, n = btf_vlen(enum_t); i < n; i++) {
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e = &btf_enum(enum_t)[i];
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name = btf_name_by_offset(btf, e->name_off);
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if (!name || strncasecmp(name, prefix, pfx_len) != 0)
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continue;
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/* match symbolic name case insensitive and ignoring prefix */
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if (strcasecmp(name + pfx_len, str) == 0) {
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*value = e->val;
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return true;
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}
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}
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return false;
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}
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static void seq_print_delegate_opts(struct seq_file *m,
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const char *opt_name,
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const struct btf *btf,
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const struct btf_type *enum_t,
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const char *prefix,
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u64 delegate_msk, u64 any_msk)
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{
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const struct btf_enum *e;
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bool first = true;
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const char *name;
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u64 msk;
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int i, n, pfx_len = strlen(prefix);
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delegate_msk &= any_msk; /* clear unknown bits */
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if (delegate_msk == 0)
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return;
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seq_printf(m, ",%s", opt_name);
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if (delegate_msk == any_msk) {
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seq_printf(m, "=any");
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return;
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}
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if (btf && enum_t) {
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for (i = 0, n = btf_vlen(enum_t); i < n; i++) {
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e = &btf_enum(enum_t)[i];
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name = btf_name_by_offset(btf, e->name_off);
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if (!name || strncasecmp(name, prefix, pfx_len) != 0)
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continue;
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msk = 1ULL << e->val;
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if (delegate_msk & msk) {
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/* emit lower-case name without prefix */
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seq_printf(m, "%c", first ? '=' : ':');
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name += pfx_len;
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while (*name) {
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seq_printf(m, "%c", tolower(*name));
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name++;
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}
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delegate_msk &= ~msk;
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first = false;
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}
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}
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}
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if (delegate_msk)
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seq_printf(m, "%c0x%llx", first ? '=' : ':', delegate_msk);
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}
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/*
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* Display the mount options in /proc/mounts.
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*/
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@ -614,29 +744,34 @@ static int bpf_show_options(struct seq_file *m, struct dentry *root)
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if (mode != S_IRWXUGO)
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seq_printf(m, ",mode=%o", mode);
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mask = (1ULL << __MAX_BPF_CMD) - 1;
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if ((opts->delegate_cmds & mask) == mask)
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seq_printf(m, ",delegate_cmds=any");
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else if (opts->delegate_cmds)
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seq_printf(m, ",delegate_cmds=0x%llx", opts->delegate_cmds);
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if (opts->delegate_cmds || opts->delegate_maps ||
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opts->delegate_progs || opts->delegate_attachs) {
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struct bpffs_btf_enums info;
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mask = (1ULL << __MAX_BPF_MAP_TYPE) - 1;
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if ((opts->delegate_maps & mask) == mask)
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seq_printf(m, ",delegate_maps=any");
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else if (opts->delegate_maps)
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seq_printf(m, ",delegate_maps=0x%llx", opts->delegate_maps);
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/* ignore errors, fallback to hex */
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(void)find_bpffs_btf_enums(&info);
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mask = (1ULL << __MAX_BPF_PROG_TYPE) - 1;
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if ((opts->delegate_progs & mask) == mask)
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seq_printf(m, ",delegate_progs=any");
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else if (opts->delegate_progs)
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seq_printf(m, ",delegate_progs=0x%llx", opts->delegate_progs);
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mask = (1ULL << __MAX_BPF_CMD) - 1;
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seq_print_delegate_opts(m, "delegate_cmds",
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info.btf, info.cmd_t, "BPF_",
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opts->delegate_cmds, mask);
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mask = (1ULL << __MAX_BPF_MAP_TYPE) - 1;
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seq_print_delegate_opts(m, "delegate_maps",
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info.btf, info.map_t, "BPF_MAP_TYPE_",
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opts->delegate_maps, mask);
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mask = (1ULL << __MAX_BPF_PROG_TYPE) - 1;
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seq_print_delegate_opts(m, "delegate_progs",
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info.btf, info.prog_t, "BPF_PROG_TYPE_",
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opts->delegate_progs, mask);
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mask = (1ULL << __MAX_BPF_ATTACH_TYPE) - 1;
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seq_print_delegate_opts(m, "delegate_attachs",
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info.btf, info.attach_t, "BPF_",
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opts->delegate_attachs, mask);
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}
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mask = (1ULL << __MAX_BPF_ATTACH_TYPE) - 1;
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if ((opts->delegate_attachs & mask) == mask)
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seq_printf(m, ",delegate_attachs=any");
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else if (opts->delegate_attachs)
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seq_printf(m, ",delegate_attachs=0x%llx", opts->delegate_attachs);
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return 0;
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}
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@ -686,7 +821,6 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
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kuid_t uid;
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kgid_t gid;
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int opt, err;
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u64 msk;
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opt = fs_parse(fc, bpf_fs_parameters, param, &result);
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if (opt < 0) {
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@ -741,24 +875,63 @@ static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param)
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case OPT_DELEGATE_CMDS:
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case OPT_DELEGATE_MAPS:
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case OPT_DELEGATE_PROGS:
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case OPT_DELEGATE_ATTACHS:
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if (strcmp(param->string, "any") == 0) {
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msk = ~0ULL;
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} else {
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err = kstrtou64(param->string, 0, &msk);
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if (err)
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return err;
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case OPT_DELEGATE_ATTACHS: {
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struct bpffs_btf_enums info;
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const struct btf_type *enum_t;
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const char *enum_pfx;
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u64 *delegate_msk, msk = 0;
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char *p;
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int val;
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/* ignore errors, fallback to hex */
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(void)find_bpffs_btf_enums(&info);
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switch (opt) {
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case OPT_DELEGATE_CMDS:
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delegate_msk = &opts->delegate_cmds;
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enum_t = info.cmd_t;
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enum_pfx = "BPF_";
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break;
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case OPT_DELEGATE_MAPS:
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delegate_msk = &opts->delegate_maps;
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enum_t = info.map_t;
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enum_pfx = "BPF_MAP_TYPE_";
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break;
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case OPT_DELEGATE_PROGS:
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delegate_msk = &opts->delegate_progs;
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enum_t = info.prog_t;
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enum_pfx = "BPF_PROG_TYPE_";
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break;
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case OPT_DELEGATE_ATTACHS:
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delegate_msk = &opts->delegate_attachs;
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enum_t = info.attach_t;
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enum_pfx = "BPF_";
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break;
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default:
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return -EINVAL;
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}
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while ((p = strsep(¶m->string, ":"))) {
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if (strcmp(p, "any") == 0) {
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msk |= ~0ULL;
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} else if (find_btf_enum_const(info.btf, enum_t, enum_pfx, p, &val)) {
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msk |= 1ULL << val;
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} else {
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err = kstrtou64(p, 0, &msk);
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if (err)
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return err;
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}
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}
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/* Setting delegation mount options requires privileges */
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if (msk && !capable(CAP_SYS_ADMIN))
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return -EPERM;
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switch (opt) {
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case OPT_DELEGATE_CMDS: opts->delegate_cmds |= msk; break;
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case OPT_DELEGATE_MAPS: opts->delegate_maps |= msk; break;
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case OPT_DELEGATE_PROGS: opts->delegate_progs |= msk; break;
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case OPT_DELEGATE_ATTACHS: opts->delegate_attachs |= msk; break;
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default: return -EINVAL;
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}
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*delegate_msk |= msk;
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break;
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}
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default:
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/* ignore unknown mount options */
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break;
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}
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@ -66,14 +66,22 @@ static int restore_priv_caps(__u64 old_caps)
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return cap_enable_effective(old_caps, NULL);
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}
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static int set_delegate_mask(int fs_fd, const char *key, __u64 mask)
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static int set_delegate_mask(int fs_fd, const char *key, __u64 mask, const char *mask_str)
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{
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char buf[32];
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int err;
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snprintf(buf, sizeof(buf), "0x%llx", (unsigned long long)mask);
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if (!mask_str) {
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if (mask == ~0ULL) {
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mask_str = "any";
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} else {
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snprintf(buf, sizeof(buf), "0x%llx", (unsigned long long)mask);
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mask_str = buf;
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}
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}
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err = sys_fsconfig(fs_fd, FSCONFIG_SET_STRING, key,
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mask == ~0ULL ? "any" : buf, 0);
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mask_str, 0);
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if (err < 0)
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err = -errno;
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return err;
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@ -86,6 +94,10 @@ struct bpffs_opts {
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__u64 maps;
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__u64 progs;
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__u64 attachs;
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const char *cmds_str;
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const char *maps_str;
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const char *progs_str;
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const char *attachs_str;
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};
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static int create_bpffs_fd(void)
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@ -104,16 +116,16 @@ static int materialize_bpffs_fd(int fs_fd, struct bpffs_opts *opts)
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int mnt_fd, err;
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/* set up token delegation mount options */
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err = set_delegate_mask(fs_fd, "delegate_cmds", opts->cmds);
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err = set_delegate_mask(fs_fd, "delegate_cmds", opts->cmds, opts->cmds_str);
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if (!ASSERT_OK(err, "fs_cfg_cmds"))
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return err;
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err = set_delegate_mask(fs_fd, "delegate_maps", opts->maps);
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err = set_delegate_mask(fs_fd, "delegate_maps", opts->maps, opts->maps_str);
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if (!ASSERT_OK(err, "fs_cfg_maps"))
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return err;
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err = set_delegate_mask(fs_fd, "delegate_progs", opts->progs);
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err = set_delegate_mask(fs_fd, "delegate_progs", opts->progs, opts->progs_str);
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if (!ASSERT_OK(err, "fs_cfg_progs"))
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return err;
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err = set_delegate_mask(fs_fd, "delegate_attachs", opts->attachs);
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err = set_delegate_mask(fs_fd, "delegate_attachs", opts->attachs, opts->attachs_str);
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if (!ASSERT_OK(err, "fs_cfg_attachs"))
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return err;
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@ -295,13 +307,13 @@ static void child(int sock_fd, struct bpffs_opts *opts, child_callback_fn callba
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}
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/* ensure unprivileged child cannot set delegation options */
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err = set_delegate_mask(fs_fd, "delegate_cmds", 0x1);
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err = set_delegate_mask(fs_fd, "delegate_cmds", 0x1, NULL);
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ASSERT_EQ(err, -EPERM, "delegate_cmd_eperm");
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err = set_delegate_mask(fs_fd, "delegate_maps", 0x1);
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err = set_delegate_mask(fs_fd, "delegate_maps", 0x1, NULL);
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ASSERT_EQ(err, -EPERM, "delegate_maps_eperm");
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err = set_delegate_mask(fs_fd, "delegate_progs", 0x1);
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err = set_delegate_mask(fs_fd, "delegate_progs", 0x1, NULL);
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ASSERT_EQ(err, -EPERM, "delegate_progs_eperm");
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err = set_delegate_mask(fs_fd, "delegate_attachs", 0x1);
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err = set_delegate_mask(fs_fd, "delegate_attachs", 0x1, NULL);
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ASSERT_EQ(err, -EPERM, "delegate_attachs_eperm");
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/* pass BPF FS context object to parent */
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@ -325,22 +337,22 @@ static void child(int sock_fd, struct bpffs_opts *opts, child_callback_fn callba
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}
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/* ensure unprivileged child cannot reconfigure to set delegation options */
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err = set_delegate_mask(fs_fd, "delegate_cmds", ~0ULL);
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err = set_delegate_mask(fs_fd, "delegate_cmds", 0, "any");
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if (!ASSERT_EQ(err, -EPERM, "delegate_cmd_eperm_reconfig")) {
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err = -EINVAL;
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goto cleanup;
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}
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err = set_delegate_mask(fs_fd, "delegate_maps", ~0ULL);
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err = set_delegate_mask(fs_fd, "delegate_maps", 0, "any");
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if (!ASSERT_EQ(err, -EPERM, "delegate_maps_eperm_reconfig")) {
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err = -EINVAL;
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goto cleanup;
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}
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err = set_delegate_mask(fs_fd, "delegate_progs", ~0ULL);
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err = set_delegate_mask(fs_fd, "delegate_progs", 0, "any");
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if (!ASSERT_EQ(err, -EPERM, "delegate_progs_eperm_reconfig")) {
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err = -EINVAL;
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goto cleanup;
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}
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err = set_delegate_mask(fs_fd, "delegate_attachs", ~0ULL);
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err = set_delegate_mask(fs_fd, "delegate_attachs", 0, "any");
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if (!ASSERT_EQ(err, -EPERM, "delegate_attachs_eperm_reconfig")) {
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err = -EINVAL;
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goto cleanup;
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@ -933,8 +945,8 @@ void test_token(void)
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{
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if (test__start_subtest("map_token")) {
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struct bpffs_opts opts = {
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.cmds = 1ULL << BPF_MAP_CREATE,
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.maps = 1ULL << BPF_MAP_TYPE_STACK,
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.cmds_str = "map_create",
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.maps_str = "stack",
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};
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subtest_userns(&opts, userns_map_create);
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@ -948,9 +960,9 @@ void test_token(void)
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}
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if (test__start_subtest("prog_token")) {
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struct bpffs_opts opts = {
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.cmds = 1ULL << BPF_PROG_LOAD,
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.progs = 1ULL << BPF_PROG_TYPE_XDP,
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.attachs = 1ULL << BPF_XDP,
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.cmds_str = "PROG_LOAD",
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.progs_str = "XDP",
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.attachs_str = "xdp",
|
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};
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subtest_userns(&opts, userns_prog_load);
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||||
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