* [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system
@ 2019-08-20 9:31 Quentin Monnet
2019-08-20 9:31 ` [PATCH bpf-next v2 1/5] bpf: add new BPF_BTF_GET_NEXT_ID syscall command Quentin Monnet
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: Quentin Monnet @ 2019-08-20 9:31 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann
Cc: bpf, netdev, oss-drivers, Quentin Monnet
Hi,
This set adds a new command BPF_BTF_GET_NEXT_ID to the bpf() system call,
adds the relevant API function in libbpf, and uses it in bpftool to list
all BTF objects loaded on the system (and to dump the ids of maps and
programs associated with them, if any).
The main motivation of listing BTF objects is introspection and debugging
purposes. By getting BPF program and map information, it should already be
possible to list all BTF objects associated to at least one map or one
program. But there may be unattached BTF objects, held by a file descriptor
from a user space process only, and we may want to list them too.
As a side note, it also turned useful for examining the BTF objects
attached to offloaded programs, which would not show in program information
because the BTF id is not copied when retrieving such info. A fix is in
progress on that side.
v2:
- Rebase patch with new libbpf function on top of Andrii's changes
regarding libbpf versioning.
Quentin Monnet (5):
bpf: add new BPF_BTF_GET_NEXT_ID syscall command
tools: bpf: synchronise BPF UAPI header with tools
libbpf: refactor bpf_*_get_next_id() functions
libbpf: add bpf_btf_get_next_id() to cycle through BTF objects
tools: bpftool: implement "bpftool btf show|list"
include/linux/bpf.h | 3 +
include/uapi/linux/bpf.h | 1 +
kernel/bpf/btf.c | 4 +-
kernel/bpf/syscall.c | 4 +
.../bpf/bpftool/Documentation/bpftool-btf.rst | 7 +
tools/bpf/bpftool/bash-completion/bpftool | 20 +-
tools/bpf/bpftool/btf.c | 342 +++++++++++++++++-
tools/include/uapi/linux/bpf.h | 1 +
tools/lib/bpf/bpf.c | 24 +-
tools/lib/bpf/bpf.h | 1 +
tools/lib/bpf/libbpf.map | 2 +
11 files changed, 389 insertions(+), 20 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH bpf-next v2 1/5] bpf: add new BPF_BTF_GET_NEXT_ID syscall command 2019-08-20 9:31 [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Quentin Monnet @ 2019-08-20 9:31 ` Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 2/5] tools: bpf: synchronise BPF UAPI header with tools Quentin Monnet ` (4 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: Quentin Monnet @ 2019-08-20 9:31 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann Cc: bpf, netdev, oss-drivers, Quentin Monnet Add a new command for the bpf() system call: BPF_BTF_GET_NEXT_ID is used to cycle through all BTF objects loaded on the system. The motivation is to be able to inspect (list) all BTF objects presents on the system. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> --- include/linux/bpf.h | 3 +++ include/uapi/linux/bpf.h | 1 + kernel/bpf/btf.c | 4 ++-- kernel/bpf/syscall.c | 4 ++++ 4 files changed, 10 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 15ae49862b82..5b9d22338606 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -24,6 +24,9 @@ struct seq_file; struct btf; struct btf_type; +extern struct idr btf_idr; +extern spinlock_t btf_idr_lock; + /* map is generic key/value storage optionally accesible by eBPF programs */ struct bpf_map_ops { /* funcs callable from userspace (via syscall) */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 0ef594ac3899..8aa6126f0b6e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -106,6 +106,7 @@ enum bpf_cmd { BPF_TASK_FD_QUERY, BPF_MAP_LOOKUP_AND_DELETE_ELEM, BPF_MAP_FREEZE, + BPF_BTF_GET_NEXT_ID, }; enum bpf_map_type { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 5fcc7a17eb5a..e716a64b2f7f 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -195,8 +195,8 @@ i < btf_type_vlen(struct_type); \ i++, member++) -static DEFINE_IDR(btf_idr); -static DEFINE_SPINLOCK(btf_idr_lock); +DEFINE_IDR(btf_idr); +DEFINE_SPINLOCK(btf_idr_lock); struct btf { void *data; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index cf8052b016e7..c0f62fd67c6b 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2884,6 +2884,10 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz err = bpf_obj_get_next_id(&attr, uattr, &map_idr, &map_idr_lock); break; + case BPF_BTF_GET_NEXT_ID: + err = bpf_obj_get_next_id(&attr, uattr, + &btf_idr, &btf_idr_lock); + break; case BPF_PROG_GET_FD_BY_ID: err = bpf_prog_get_fd_by_id(&attr); break; -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH bpf-next v2 2/5] tools: bpf: synchronise BPF UAPI header with tools 2019-08-20 9:31 [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 1/5] bpf: add new BPF_BTF_GET_NEXT_ID syscall command Quentin Monnet @ 2019-08-20 9:31 ` Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 3/5] libbpf: refactor bpf_*_get_next_id() functions Quentin Monnet ` (3 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: Quentin Monnet @ 2019-08-20 9:31 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann Cc: bpf, netdev, oss-drivers, Quentin Monnet Synchronise the bpf.h header under tools, to report the addition of the new BPF_BTF_GET_NEXT_ID syscall command for bpf(). Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> --- tools/include/uapi/linux/bpf.h | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 0ef594ac3899..8aa6126f0b6e 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -106,6 +106,7 @@ enum bpf_cmd { BPF_TASK_FD_QUERY, BPF_MAP_LOOKUP_AND_DELETE_ELEM, BPF_MAP_FREEZE, + BPF_BTF_GET_NEXT_ID, }; enum bpf_map_type { -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH bpf-next v2 3/5] libbpf: refactor bpf_*_get_next_id() functions 2019-08-20 9:31 [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 1/5] bpf: add new BPF_BTF_GET_NEXT_ID syscall command Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 2/5] tools: bpf: synchronise BPF UAPI header with tools Quentin Monnet @ 2019-08-20 9:31 ` Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 4/5] libbpf: add bpf_btf_get_next_id() to cycle through BTF objects Quentin Monnet ` (2 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: Quentin Monnet @ 2019-08-20 9:31 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann Cc: bpf, netdev, oss-drivers, Quentin Monnet In preparation for the introduction of a similar function for retrieving the id of the next BTF object, consolidate the code from bpf_prog_get_next_id() and bpf_map_get_next_id() in libbpf. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> --- tools/lib/bpf/bpf.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index c7d7993c44bb..1439e99c9be5 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -568,7 +568,7 @@ int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr) return ret; } -int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id) +static int bpf_obj_get_next_id(__u32 start_id, __u32 *next_id, int cmd) { union bpf_attr attr; int err; @@ -576,26 +576,21 @@ int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id) memset(&attr, 0, sizeof(attr)); attr.start_id = start_id; - err = sys_bpf(BPF_PROG_GET_NEXT_ID, &attr, sizeof(attr)); + err = sys_bpf(cmd, &attr, sizeof(attr)); if (!err) *next_id = attr.next_id; return err; } -int bpf_map_get_next_id(__u32 start_id, __u32 *next_id) +int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id) { - union bpf_attr attr; - int err; - - memset(&attr, 0, sizeof(attr)); - attr.start_id = start_id; - - err = sys_bpf(BPF_MAP_GET_NEXT_ID, &attr, sizeof(attr)); - if (!err) - *next_id = attr.next_id; + return bpf_obj_get_next_id(start_id, next_id, BPF_PROG_GET_NEXT_ID); +} - return err; +int bpf_map_get_next_id(__u32 start_id, __u32 *next_id) +{ + return bpf_obj_get_next_id(start_id, next_id, BPF_MAP_GET_NEXT_ID); } int bpf_prog_get_fd_by_id(__u32 id) -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH bpf-next v2 4/5] libbpf: add bpf_btf_get_next_id() to cycle through BTF objects 2019-08-20 9:31 [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Quentin Monnet ` (2 preceding siblings ...) 2019-08-20 9:31 ` [PATCH bpf-next v2 3/5] libbpf: refactor bpf_*_get_next_id() functions Quentin Monnet @ 2019-08-20 9:31 ` Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 5/5] tools: bpftool: implement "bpftool btf show|list" Quentin Monnet 2019-08-20 16:55 ` [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Alexei Starovoitov 5 siblings, 0 replies; 7+ messages in thread From: Quentin Monnet @ 2019-08-20 9:31 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann Cc: bpf, netdev, oss-drivers, Quentin Monnet Add an API function taking a BTF object id and providing the id of the next BTF object in the kernel. This can be used to list all BTF objects loaded on the system. v2: - Rebase on top of Andrii's changes regarding libbpf versioning. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> --- tools/lib/bpf/bpf.c | 5 +++++ tools/lib/bpf/bpf.h | 1 + tools/lib/bpf/libbpf.map | 2 ++ 3 files changed, 8 insertions(+) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 1439e99c9be5..cbb933532981 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -593,6 +593,11 @@ int bpf_map_get_next_id(__u32 start_id, __u32 *next_id) return bpf_obj_get_next_id(start_id, next_id, BPF_MAP_GET_NEXT_ID); } +int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id) +{ + return bpf_obj_get_next_id(start_id, next_id, BPF_BTF_GET_NEXT_ID); +} + int bpf_prog_get_fd_by_id(__u32 id) { union bpf_attr attr; diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index ff42ca043dc8..0db01334740f 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -156,6 +156,7 @@ LIBBPF_API int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 *retval, __u32 *duration); LIBBPF_API int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_map_get_next_id(__u32 start_id, __u32 *next_id); +LIBBPF_API int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id); LIBBPF_API int bpf_map_get_fd_by_id(__u32 id); LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 4e72df8e98ba..664ce8e7a60e 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -186,4 +186,6 @@ LIBBPF_0.0.4 { } LIBBPF_0.0.3; LIBBPF_0.0.5 { + global: + bpf_btf_get_next_id; } LIBBPF_0.0.4; -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH bpf-next v2 5/5] tools: bpftool: implement "bpftool btf show|list" 2019-08-20 9:31 [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Quentin Monnet ` (3 preceding siblings ...) 2019-08-20 9:31 ` [PATCH bpf-next v2 4/5] libbpf: add bpf_btf_get_next_id() to cycle through BTF objects Quentin Monnet @ 2019-08-20 9:31 ` Quentin Monnet 2019-08-20 16:55 ` [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Alexei Starovoitov 5 siblings, 0 replies; 7+ messages in thread From: Quentin Monnet @ 2019-08-20 9:31 UTC (permalink / raw) To: Alexei Starovoitov, Daniel Borkmann Cc: bpf, netdev, oss-drivers, Quentin Monnet Add a "btf list" (alias: "btf show") subcommand to bpftool in order to dump all BTF objects loaded on a system. When running the command, hash tables are built in bpftool to retrieve all the associations between BTF objects and BPF maps and programs. This allows for printing all such associations when listing the BTF objects. The command is added at the top of the subcommands for "bpftool btf", so that typing only "bpftool btf" also comes down to listing the programs. We could not have this with the previous command ("dump"), which required a BTF object id, so it should not break any previous behaviour. This also makes the "btf" command behaviour consistent with "prog" or "map". Bash completion is updated to use "bpftool btf" instead of "bpftool prog" to list the BTF ids, as it looks more consistent. Example output (plain): # bpftool btf show 9: size 2989B prog_ids 21 map_ids 15 17: size 2847B prog_ids 36 map_ids 30,29,28 26: size 2847B Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> --- .../bpf/bpftool/Documentation/bpftool-btf.rst | 7 + tools/bpf/bpftool/bash-completion/bpftool | 20 +- tools/bpf/bpftool/btf.c | 342 +++++++++++++++++- 3 files changed, 363 insertions(+), 6 deletions(-) diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst index 6694a0fc8f99..39615f8e145b 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-btf.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst @@ -19,6 +19,7 @@ SYNOPSIS BTF COMMANDS ============= +| **bpftool** **btf** { **show** | **list** } [**id** *BTF_ID*] | **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*] | **bpftool** **btf help** | @@ -29,6 +30,12 @@ BTF COMMANDS DESCRIPTION =========== + **bpftool btf { show | list }** [**id** *BTF_ID*] + Show information about loaded BTF objects. If a BTF ID is + specified, show information only about given BTF object, + otherwise list all BTF objects currently loaded on the + system. + **bpftool btf dump** *BTF_SRC* Dump BTF entries from a given *BTF_SRC*. diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index 4549fd424069..2ffd351f9dbf 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -73,8 +73,8 @@ _bpftool_get_prog_tags() _bpftool_get_btf_ids() { - COMPREPLY+=( $( compgen -W "$( bpftool -jp prog 2>&1 | \ - command sed -n 's/.*"btf_id": \(.*\),\?$/\1/p' )" -- "$cur" ) ) + COMPREPLY+=( $( compgen -W "$( bpftool -jp btf 2>&1 | \ + command sed -n 's/.*"id": \(.*\),$/\1/p' )" -- "$cur" ) ) } _bpftool_get_obj_map_names() @@ -670,7 +670,7 @@ _bpftool() map) _bpftool_get_map_ids ;; - dump) + $command) _bpftool_get_btf_ids ;; esac @@ -698,9 +698,21 @@ _bpftool() ;; esac ;; + show|list) + case $prev in + $command) + COMPREPLY+=( $( compgen -W "id" -- "$cur" ) ) + ;; + id) + _bpftool_get_btf_ids + ;; + esac + return 0 + ;; *) [[ $prev == $object ]] && \ - COMPREPLY=( $( compgen -W 'dump help' -- "$cur" ) ) + COMPREPLY=( $( compgen -W 'dump help show list' \ + -- "$cur" ) ) ;; esac ;; diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 8805637f1a7e..9a9376d1d3df 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -11,6 +11,7 @@ #include <bpf.h> #include <libbpf.h> #include <linux/btf.h> +#include <linux/hashtable.h> #include "btf.h" #include "json_writer.h" @@ -35,6 +36,16 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_DATASEC] = "DATASEC", }; +struct btf_attach_table { + DECLARE_HASHTABLE(table, 16); +}; + +struct btf_attach_point { + __u32 obj_id; + __u32 btf_id; + struct hlist_node hash; +}; + static const char *btf_int_enc_str(__u8 encoding) { switch (encoding) { @@ -522,6 +533,330 @@ static int do_dump(int argc, char **argv) return err; } +static int btf_parse_fd(int *argc, char ***argv) +{ + unsigned int id; + char *endptr; + int fd; + + if (!is_prefix(*argv[0], "id")) { + p_err("expected 'id', got: '%s'?", **argv); + return -1; + } + NEXT_ARGP(); + + id = strtoul(**argv, &endptr, 0); + if (*endptr) { + p_err("can't parse %s as ID", **argv); + return -1; + } + NEXT_ARGP(); + + fd = bpf_btf_get_fd_by_id(id); + if (fd < 0) + p_err("can't get BTF object by id (%u): %s", + id, strerror(errno)); + + return fd; +} + +static void delete_btf_table(struct btf_attach_table *tab) +{ + struct btf_attach_point *obj; + struct hlist_node *tmp; + + unsigned int bkt; + + hash_for_each_safe(tab->table, bkt, tmp, obj, hash) { + hash_del(&obj->hash); + free(obj); + } +} + +static int +build_btf_type_table(struct btf_attach_table *tab, enum bpf_obj_type type, + void *info, __u32 *len) +{ + static const char * const names[] = { + [BPF_OBJ_UNKNOWN] = "unknown", + [BPF_OBJ_PROG] = "prog", + [BPF_OBJ_MAP] = "map", + }; + struct btf_attach_point *obj_node; + __u32 btf_id, id = 0; + int err; + int fd; + + while (true) { + switch (type) { + case BPF_OBJ_PROG: + err = bpf_prog_get_next_id(id, &id); + break; + case BPF_OBJ_MAP: + err = bpf_map_get_next_id(id, &id); + break; + default: + err = -1; + p_err("unexpected object type: %d", type); + goto err_free; + } + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + p_err("can't get next %s: %s%s", names[type], + strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + goto err_free; + } + + switch (type) { + case BPF_OBJ_PROG: + fd = bpf_prog_get_fd_by_id(id); + break; + case BPF_OBJ_MAP: + fd = bpf_map_get_fd_by_id(id); + break; + default: + err = -1; + p_err("unexpected object type: %d", type); + goto err_free; + } + if (fd < 0) { + if (errno == ENOENT) + continue; + p_err("can't get %s by id (%u): %s", names[type], id, + strerror(errno)); + err = -1; + goto err_free; + } + + memset(info, 0, *len); + err = bpf_obj_get_info_by_fd(fd, info, len); + close(fd); + if (err) { + p_err("can't get %s info: %s", names[type], + strerror(errno)); + goto err_free; + } + + switch (type) { + case BPF_OBJ_PROG: + btf_id = ((struct bpf_prog_info *)info)->btf_id; + break; + case BPF_OBJ_MAP: + btf_id = ((struct bpf_map_info *)info)->btf_id; + break; + default: + err = -1; + p_err("unexpected object type: %d", type); + goto err_free; + } + if (!btf_id) + continue; + + obj_node = calloc(1, sizeof(*obj_node)); + if (!obj_node) { + p_err("failed to allocate memory: %s", strerror(errno)); + goto err_free; + } + + obj_node->obj_id = id; + obj_node->btf_id = btf_id; + hash_add(tab->table, &obj_node->hash, obj_node->btf_id); + } + + return 0; + +err_free: + delete_btf_table(tab); + return err; +} + +static int +build_btf_tables(struct btf_attach_table *btf_prog_table, + struct btf_attach_table *btf_map_table) +{ + struct bpf_prog_info prog_info; + __u32 prog_len = sizeof(prog_info); + struct bpf_map_info map_info; + __u32 map_len = sizeof(map_info); + int err = 0; + + err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info, + &prog_len); + if (err) + return err; + + err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info, + &map_len); + if (err) { + delete_btf_table(btf_prog_table); + return err; + } + + return 0; +} + +static void +show_btf_plain(struct bpf_btf_info *info, int fd, + struct btf_attach_table *btf_prog_table, + struct btf_attach_table *btf_map_table) +{ + struct btf_attach_point *obj; + int n; + + printf("%u: ", info->id); + printf("size %uB", info->btf_size); + + n = 0; + hash_for_each_possible(btf_prog_table->table, obj, hash, info->id) { + if (obj->btf_id == info->id) + printf("%s%u", n++ == 0 ? " prog_ids " : ",", + obj->obj_id); + } + + n = 0; + hash_for_each_possible(btf_map_table->table, obj, hash, info->id) { + if (obj->btf_id == info->id) + printf("%s%u", n++ == 0 ? " map_ids " : ",", + obj->obj_id); + } + + printf("\n"); +} + +static void +show_btf_json(struct bpf_btf_info *info, int fd, + struct btf_attach_table *btf_prog_table, + struct btf_attach_table *btf_map_table) +{ + struct btf_attach_point *obj; + + jsonw_start_object(json_wtr); /* btf object */ + jsonw_uint_field(json_wtr, "id", info->id); + jsonw_uint_field(json_wtr, "size", info->btf_size); + + jsonw_name(json_wtr, "prog_ids"); + jsonw_start_array(json_wtr); /* prog_ids */ + hash_for_each_possible(btf_prog_table->table, obj, hash, + info->id) { + if (obj->btf_id == info->id) + jsonw_uint(json_wtr, obj->obj_id); + } + jsonw_end_array(json_wtr); /* prog_ids */ + + jsonw_name(json_wtr, "map_ids"); + jsonw_start_array(json_wtr); /* map_ids */ + hash_for_each_possible(btf_map_table->table, obj, hash, + info->id) { + if (obj->btf_id == info->id) + jsonw_uint(json_wtr, obj->obj_id); + } + jsonw_end_array(json_wtr); /* map_ids */ + jsonw_end_object(json_wtr); /* btf object */ +} + +static int +show_btf(int fd, struct btf_attach_table *btf_prog_table, + struct btf_attach_table *btf_map_table) +{ + struct bpf_btf_info info = {}; + __u32 len = sizeof(info); + int err; + + err = bpf_obj_get_info_by_fd(fd, &info, &len); + if (err) { + p_err("can't get BTF object info: %s", strerror(errno)); + return -1; + } + + if (json_output) + show_btf_json(&info, fd, btf_prog_table, btf_map_table); + else + show_btf_plain(&info, fd, btf_prog_table, btf_map_table); + + return 0; +} + +static int do_show(int argc, char **argv) +{ + struct btf_attach_table btf_prog_table; + struct btf_attach_table btf_map_table; + int err, fd = -1; + __u32 id = 0; + + if (argc == 2) { + fd = btf_parse_fd(&argc, &argv); + if (fd < 0) + return -1; + } + + if (argc) { + if (fd >= 0) + close(fd); + return BAD_ARG(); + } + + hash_init(btf_prog_table.table); + hash_init(btf_map_table.table); + err = build_btf_tables(&btf_prog_table, &btf_map_table); + if (err) { + if (fd >= 0) + close(fd); + return err; + } + + if (fd >= 0) { + err = show_btf(fd, &btf_prog_table, &btf_map_table); + close(fd); + goto exit_free; + } + + if (json_output) + jsonw_start_array(json_wtr); /* root array */ + + while (true) { + err = bpf_btf_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + p_err("can't get next BTF object: %s%s", + strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + err = -1; + break; + } + + fd = bpf_btf_get_fd_by_id(id); + if (fd < 0) { + if (errno == ENOENT) + continue; + p_err("can't get BTF object by id (%u): %s", + id, strerror(errno)); + err = -1; + break; + } + + err = show_btf(fd, &btf_prog_table, &btf_map_table); + close(fd); + if (err) + break; + } + + if (json_output) + jsonw_end_array(json_wtr); /* root array */ + +exit_free: + delete_btf_table(&btf_prog_table); + delete_btf_table(&btf_map_table); + + return err; +} + static int do_help(int argc, char **argv) { if (json_output) { @@ -530,7 +865,8 @@ static int do_help(int argc, char **argv) } fprintf(stderr, - "Usage: %s btf dump BTF_SRC [format FORMAT]\n" + "Usage: %s btf { show | list } [id BTF_ID]\n" + " %s btf dump BTF_SRC [format FORMAT]\n" " %s btf help\n" "\n" " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n" @@ -539,12 +875,14 @@ static int do_help(int argc, char **argv) " " HELP_SPEC_PROGRAM "\n" " " HELP_SPEC_OPTIONS "\n" "", - bin_name, bin_name); + bin_name, bin_name, bin_name); return 0; } static const struct cmd cmds[] = { + { "show", do_show }, + { "list", do_show }, { "help", do_help }, { "dump", do_dump }, { 0 } -- 2.17.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system 2019-08-20 9:31 [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Quentin Monnet ` (4 preceding siblings ...) 2019-08-20 9:31 ` [PATCH bpf-next v2 5/5] tools: bpftool: implement "bpftool btf show|list" Quentin Monnet @ 2019-08-20 16:55 ` Alexei Starovoitov 5 siblings, 0 replies; 7+ messages in thread From: Alexei Starovoitov @ 2019-08-20 16:55 UTC (permalink / raw) To: Quentin Monnet Cc: Alexei Starovoitov, Daniel Borkmann, bpf, Network Development, oss-drivers On Tue, Aug 20, 2019 at 2:32 AM Quentin Monnet <quentin.monnet@netronome.com> wrote: > > Hi, > This set adds a new command BPF_BTF_GET_NEXT_ID to the bpf() system call, > adds the relevant API function in libbpf, and uses it in bpftool to list > all BTF objects loaded on the system (and to dump the ids of maps and > programs associated with them, if any). > > The main motivation of listing BTF objects is introspection and debugging > purposes. By getting BPF program and map information, it should already be > possible to list all BTF objects associated to at least one map or one > program. But there may be unattached BTF objects, held by a file descriptor > from a user space process only, and we may want to list them too. > > As a side note, it also turned useful for examining the BTF objects > attached to offloaded programs, which would not show in program information > because the BTF id is not copied when retrieving such info. A fix is in > progress on that side. > > v2: > - Rebase patch with new libbpf function on top of Andrii's changes > regarding libbpf versioning. Applied. Thanks ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-08-20 16:55 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2019-08-20 9:31 [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 1/5] bpf: add new BPF_BTF_GET_NEXT_ID syscall command Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 2/5] tools: bpf: synchronise BPF UAPI header with tools Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 3/5] libbpf: refactor bpf_*_get_next_id() functions Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 4/5] libbpf: add bpf_btf_get_next_id() to cycle through BTF objects Quentin Monnet 2019-08-20 9:31 ` [PATCH bpf-next v2 5/5] tools: bpftool: implement "bpftool btf show|list" Quentin Monnet 2019-08-20 16:55 ` [PATCH bpf-next v2 0/5] bpf: list BTF objects loaded on system Alexei Starovoitov
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