From d7de72674af53c3839eff091899f18c221dd30d2 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 15 Jan 2020 15:00:19 -0800 Subject: [PATCH 1/5] bpftool: Fix a leak of btf object When testing a map has btf or not, maps_have_btf() tests it by actually getting a btf_fd from sys_bpf(BPF_BTF_GET_FD_BY_ID). However, it forgot to btf__free() it. In maps_have_btf() stage, there is no need to test it by really calling sys_bpf(BPF_BTF_GET_FD_BY_ID). Testing non zero info.btf_id is good enough. Also, the err_close case is unnecessary, and also causes double close() because the calling func do_dump() will close() all fds again. Fixes: 99f9863a0c45 ("bpftool: Match maps by name") Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Cc: Paul Chaignon Link: https://lore.kernel.org/bpf/20200115230019.1101352-1-kafai@fb.com --- tools/bpf/bpftool/map.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index c01f76fa6876..e00e9e19d6b7 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -915,32 +915,20 @@ static int maps_have_btf(int *fds, int nb_fds) { struct bpf_map_info info = {}; __u32 len = sizeof(info); - struct btf *btf = NULL; int err, i; for (i = 0; i < nb_fds; i++) { err = bpf_obj_get_info_by_fd(fds[i], &info, &len); if (err) { p_err("can't get map info: %s", strerror(errno)); - goto err_close; + return -1; } - err = btf__get_from_id(info.btf_id, &btf); - if (err) { - p_err("failed to get btf"); - goto err_close; - } - - if (!btf) + if (!info.btf_id) return 0; } return 1; - -err_close: - for (; i < nb_fds; i++) - close(fds[i]); - return -1; } static int From 188a486619e6c9d7b8531ba6c4215b31304d293f Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 15 Jan 2020 15:00:25 -0800 Subject: [PATCH 2/5] bpftool: Fix missing BTF output for json during map dump The btf availability check is only done for plain text output. It causes the whole BTF output went missing when json_output is used. This patch simplifies the logic a little by avoiding passing "int btf" to map_dump(). For plain text output, the btf_wtr is only created when the map has BTF (i.e. info->btf_id != 0). The nullness of "json_writer_t *wtr" in map_dump() alone can decide if dumping BTF output is needed. As long as wtr is not NULL, map_dump() will print out the BTF-described data whenever a map has BTF available (i.e. info->btf_id != 0) regardless of json or plain-text output. In do_dump(), the "int btf" is also renamed to "int do_plain_btf". Fixes: 99f9863a0c45 ("bpftool: Match maps by name") Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Cc: Paul Chaignon Link: https://lore.kernel.org/bpf/20200115230025.1101828-1-kafai@fb.com --- tools/bpf/bpftool/map.c | 44 ++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 23 deletions(-) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index e00e9e19d6b7..45c1eda6512c 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -933,7 +933,7 @@ static int maps_have_btf(int *fds, int nb_fds) static int map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, - bool enable_btf, bool show_header) + bool show_header) { void *key, *value, *prev_key; unsigned int num_elems = 0; @@ -950,18 +950,16 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, prev_key = NULL; - if (enable_btf) { - err = btf__get_from_id(info->btf_id, &btf); - if (err || !btf) { - /* enable_btf is true only if we've already checked - * that all maps have BTF information. - */ - p_err("failed to get btf"); - goto exit_free; - } - } - if (wtr) { + if (info->btf_id) { + err = btf__get_from_id(info->btf_id, &btf); + if (err || !btf) { + err = err ? : -ESRCH; + p_err("failed to get btf"); + goto exit_free; + } + } + if (show_header) { jsonw_start_object(wtr); /* map object */ show_map_header_json(info, wtr); @@ -1009,7 +1007,7 @@ static int do_dump(int argc, char **argv) { json_writer_t *wtr = NULL, *btf_wtr = NULL; struct bpf_map_info info = {}; - int nb_fds, i = 0, btf = 0; + int nb_fds, i = 0; __u32 len = sizeof(info); int *fds = NULL; int err = -1; @@ -1029,17 +1027,17 @@ static int do_dump(int argc, char **argv) if (json_output) { wtr = json_wtr; } else { - btf = maps_have_btf(fds, nb_fds); - if (btf < 0) + int do_plain_btf; + + do_plain_btf = maps_have_btf(fds, nb_fds); + if (do_plain_btf < 0) goto exit_close; - if (btf) { + + if (do_plain_btf) { btf_wtr = get_btf_writer(); - if (btf_wtr) { - wtr = btf_wtr; - } else { + wtr = btf_wtr; + if (!btf_wtr) p_info("failed to create json writer for btf. falling back to plain output"); - btf = 0; - } } } @@ -1050,7 +1048,7 @@ static int do_dump(int argc, char **argv) p_err("can't get map info: %s", strerror(errno)); break; } - err = map_dump(fds[i], &info, wtr, btf, nb_fds > 1); + err = map_dump(fds[i], &info, wtr, nb_fds > 1); if (!wtr && i != nb_fds - 1) printf("\n"); @@ -1061,7 +1059,7 @@ static int do_dump(int argc, char **argv) if (wtr && nb_fds > 1) jsonw_end_array(wtr); /* root array */ - if (btf) + if (btf_wtr) jsonw_destroy(&btf_wtr); exit_close: for (; i < nb_fds; i++) From fb2426ad00b136c88d57457504d1e843159a367a Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 15 Jan 2020 15:00:31 -0800 Subject: [PATCH 3/5] libbpf: Expose bpf_find_kernel_btf as a LIBBPF_API This patch exposes bpf_find_kernel_btf() as a LIBBPF_API. It will be used in 'bpftool map dump' in a following patch to dump a map with btf_vmlinux_value_type_id set. bpf_find_kernel_btf() is renamed to libbpf_find_kernel_btf() and moved to btf.c. As is included, some of the max/min type casting needs to be fixed. Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200115230031.1102305-1-kafai@fb.com --- tools/lib/bpf/btf.c | 102 ++++++++++++++++++++++++++++++++++++--- tools/lib/bpf/btf.h | 2 + tools/lib/bpf/libbpf.c | 93 ++--------------------------------- tools/lib/bpf/libbpf.map | 1 + 4 files changed, 102 insertions(+), 96 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index cfeb6a44480b..3d1c25fc97ae 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -8,6 +8,10 @@ #include #include #include +#include +#include +#include +#include #include #include #include @@ -20,8 +24,8 @@ /* make sure libbpf doesn't use kernel-only integer typedefs */ #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 -#define BTF_MAX_NR_TYPES 0x7fffffff -#define BTF_MAX_STR_OFFSET 0x7fffffff +#define BTF_MAX_NR_TYPES 0x7fffffffU +#define BTF_MAX_STR_OFFSET 0x7fffffffU static struct btf_type btf_void; @@ -53,7 +57,7 @@ static int btf_add_type(struct btf *btf, struct btf_type *t) if (btf->types_size == BTF_MAX_NR_TYPES) return -E2BIG; - expand_by = max(btf->types_size >> 2, 16); + expand_by = max(btf->types_size >> 2, 16U); new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by); new_types = realloc(btf->types, sizeof(*new_types) * new_size); @@ -289,7 +293,7 @@ int btf__align_of(const struct btf *btf, __u32 id) switch (kind) { case BTF_KIND_INT: case BTF_KIND_ENUM: - return min(sizeof(void *), t->size); + return min(sizeof(void *), (size_t)t->size); case BTF_KIND_PTR: return sizeof(void *); case BTF_KIND_TYPEDEF: @@ -1401,7 +1405,7 @@ static int btf_dedup_hypot_map_add(struct btf_dedup *d, if (d->hypot_cnt == d->hypot_cap) { __u32 *new_list; - d->hypot_cap += max(16, d->hypot_cap / 2); + d->hypot_cap += max((size_t)16, d->hypot_cap / 2); new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap); if (!new_list) return -ENOMEM; @@ -1697,7 +1701,7 @@ static int btf_dedup_strings(struct btf_dedup *d) if (strs.cnt + 1 > strs.cap) { struct btf_str_ptr *new_ptrs; - strs.cap += max(strs.cnt / 2, 16); + strs.cap += max(strs.cnt / 2, 16U); new_ptrs = realloc(strs.ptrs, sizeof(strs.ptrs[0]) * strs.cap); if (!new_ptrs) { @@ -2931,3 +2935,89 @@ static int btf_dedup_remap_types(struct btf_dedup *d) } return 0; } + +static struct btf *btf_load_raw(const char *path) +{ + struct btf *btf; + size_t read_cnt; + struct stat st; + void *data; + FILE *f; + + if (stat(path, &st)) + return ERR_PTR(-errno); + + data = malloc(st.st_size); + if (!data) + return ERR_PTR(-ENOMEM); + + f = fopen(path, "rb"); + if (!f) { + btf = ERR_PTR(-errno); + goto cleanup; + } + + read_cnt = fread(data, 1, st.st_size, f); + fclose(f); + if (read_cnt < st.st_size) { + btf = ERR_PTR(-EBADF); + goto cleanup; + } + + btf = btf__new(data, read_cnt); + +cleanup: + free(data); + return btf; +} + +/* + * Probe few well-known locations for vmlinux kernel image and try to load BTF + * data out of it to use for target BTF. + */ +struct btf *libbpf_find_kernel_btf(void) +{ + struct { + const char *path_fmt; + bool raw_btf; + } locations[] = { + /* try canonical vmlinux BTF through sysfs first */ + { "/sys/kernel/btf/vmlinux", true /* raw BTF */ }, + /* fall back to trying to find vmlinux ELF on disk otherwise */ + { "/boot/vmlinux-%1$s" }, + { "/lib/modules/%1$s/vmlinux-%1$s" }, + { "/lib/modules/%1$s/build/vmlinux" }, + { "/usr/lib/modules/%1$s/kernel/vmlinux" }, + { "/usr/lib/debug/boot/vmlinux-%1$s" }, + { "/usr/lib/debug/boot/vmlinux-%1$s.debug" }, + { "/usr/lib/debug/lib/modules/%1$s/vmlinux" }, + }; + char path[PATH_MAX + 1]; + struct utsname buf; + struct btf *btf; + int i; + + uname(&buf); + + for (i = 0; i < ARRAY_SIZE(locations); i++) { + snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release); + + if (access(path, R_OK)) + continue; + + if (locations[i].raw_btf) + btf = btf_load_raw(path); + else + btf = btf__parse_elf(path, NULL); + + pr_debug("loading kernel BTF '%s': %ld\n", + path, IS_ERR(btf) ? PTR_ERR(btf) : 0); + if (IS_ERR(btf)) + continue; + + return btf; + } + + pr_warn("failed to find valid kernel BTF\n"); + return ERR_PTR(-ESRCH); +} diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 8d73f7f5551f..70c1b7ec2bd0 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -102,6 +102,8 @@ LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf, LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); +LIBBPF_API struct btf *libbpf_find_kernel_btf(void); + struct btf_dedup_opts { unsigned int dedup_table_size; bool dont_resolve_fwds; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 23868883477f..3afaca9bce1d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -73,7 +73,6 @@ #define __printf(a, b) __attribute__((format(printf, a, b))) -static struct btf *bpf_find_kernel_btf(void); static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); static struct bpf_program *bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx); @@ -848,7 +847,7 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) continue; if (!kern_btf) { - kern_btf = bpf_find_kernel_btf(); + kern_btf = libbpf_find_kernel_btf(); if (IS_ERR(kern_btf)) return PTR_ERR(kern_btf); } @@ -4300,92 +4299,6 @@ static int bpf_core_reloc_insn(struct bpf_program *prog, return 0; } -static struct btf *btf_load_raw(const char *path) -{ - struct btf *btf; - size_t read_cnt; - struct stat st; - void *data; - FILE *f; - - if (stat(path, &st)) - return ERR_PTR(-errno); - - data = malloc(st.st_size); - if (!data) - return ERR_PTR(-ENOMEM); - - f = fopen(path, "rb"); - if (!f) { - btf = ERR_PTR(-errno); - goto cleanup; - } - - read_cnt = fread(data, 1, st.st_size, f); - fclose(f); - if (read_cnt < st.st_size) { - btf = ERR_PTR(-EBADF); - goto cleanup; - } - - btf = btf__new(data, read_cnt); - -cleanup: - free(data); - return btf; -} - -/* - * Probe few well-known locations for vmlinux kernel image and try to load BTF - * data out of it to use for target BTF. - */ -static struct btf *bpf_find_kernel_btf(void) -{ - struct { - const char *path_fmt; - bool raw_btf; - } locations[] = { - /* try canonical vmlinux BTF through sysfs first */ - { "/sys/kernel/btf/vmlinux", true /* raw BTF */ }, - /* fall back to trying to find vmlinux ELF on disk otherwise */ - { "/boot/vmlinux-%1$s" }, - { "/lib/modules/%1$s/vmlinux-%1$s" }, - { "/lib/modules/%1$s/build/vmlinux" }, - { "/usr/lib/modules/%1$s/kernel/vmlinux" }, - { "/usr/lib/debug/boot/vmlinux-%1$s" }, - { "/usr/lib/debug/boot/vmlinux-%1$s.debug" }, - { "/usr/lib/debug/lib/modules/%1$s/vmlinux" }, - }; - char path[PATH_MAX + 1]; - struct utsname buf; - struct btf *btf; - int i; - - uname(&buf); - - for (i = 0; i < ARRAY_SIZE(locations); i++) { - snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release); - - if (access(path, R_OK)) - continue; - - if (locations[i].raw_btf) - btf = btf_load_raw(path); - else - btf = btf__parse_elf(path, NULL); - - pr_debug("loading kernel BTF '%s': %ld\n", - path, IS_ERR(btf) ? PTR_ERR(btf) : 0); - if (IS_ERR(btf)) - continue; - - return btf; - } - - pr_warn("failed to find valid kernel BTF\n"); - return ERR_PTR(-ESRCH); -} - /* Output spec definition in the format: * [] () + => @, * where is a C-syntax view of recorded field access, e.g.: x.a[3].b @@ -4620,7 +4533,7 @@ bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path) if (targ_btf_path) targ_btf = btf__parse_elf(targ_btf_path, NULL); else - targ_btf = bpf_find_kernel_btf(); + targ_btf = libbpf_find_kernel_btf(); if (IS_ERR(targ_btf)) { pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf)); return PTR_ERR(targ_btf); @@ -6595,7 +6508,7 @@ invalid_prog: int libbpf_find_vmlinux_btf_id(const char *name, enum bpf_attach_type attach_type) { - struct btf *btf = bpf_find_kernel_btf(); + struct btf *btf = libbpf_find_kernel_btf(); char raw_tp_btf[128] = BTF_PREFIX; char *dst = raw_tp_btf + sizeof(BTF_PREFIX) - 1; const char *btf_name; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 1902a0fc6afc..64ec71ba41f1 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -231,4 +231,5 @@ LIBBPF_0.0.7 { bpf_program__is_struct_ops; bpf_program__set_struct_ops; btf__align_of; + libbpf_find_kernel_btf; } LIBBPF_0.0.6; From 84c72ceee91c166e19b506d618dbe9df6eacce97 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 15 Jan 2020 15:00:37 -0800 Subject: [PATCH 4/5] bpftool: Add struct_ops map name This patch adds BPF_MAP_TYPE_STRUCT_OPS to "struct_ops" name mapping so that "bpftool map show" can print the "struct_ops" map type properly. [root@arch-fb-vm1 bpf]# ~/devshare/fb-kernel/linux/tools/bpf/bpftool/bpftool map show id 8 8: struct_ops name dctcp flags 0x0 key 4B value 256B max_entries 1 memlock 4096B btf_id 7 Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200115230037.1102674-1-kafai@fb.com --- tools/bpf/bpftool/map.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 45c1eda6512c..4c5b15d736b6 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -48,6 +48,7 @@ const char * const map_type_name[] = { [BPF_MAP_TYPE_QUEUE] = "queue", [BPF_MAP_TYPE_STACK] = "stack", [BPF_MAP_TYPE_SK_STORAGE] = "sk_storage", + [BPF_MAP_TYPE_STRUCT_OPS] = "struct_ops", }; const size_t map_type_name_size = ARRAY_SIZE(map_type_name); From 4e1ea33292ff2ea0a82f52b2600abb4aba752094 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 15 Jan 2020 15:00:44 -0800 Subject: [PATCH 5/5] bpftool: Support dumping a map with btf_vmlinux_value_type_id This patch makes bpftool support dumping a map's value properly when the map's value type is a type of the running kernel's btf. (i.e. map_info.btf_vmlinux_value_type_id is set instead of map_info.btf_value_type_id). The first usecase is for the BPF_MAP_TYPE_STRUCT_OPS. Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200115230044.1103008-1-kafai@fb.com --- tools/bpf/bpftool/map.c | 61 +++++++++++++++++++++++++++++++++-------- 1 file changed, 50 insertions(+), 11 deletions(-) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 4c5b15d736b6..86f8ab0b7e63 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -252,6 +252,7 @@ static int do_dump_btf(const struct btf_dumper *d, struct bpf_map_info *map_info, void *key, void *value) { + __u32 value_id; int ret; /* start of key-value pair */ @@ -265,9 +266,12 @@ static int do_dump_btf(const struct btf_dumper *d, goto err_end_obj; } + value_id = map_info->btf_vmlinux_value_type_id ? + : map_info->btf_value_type_id; + if (!map_is_per_cpu(map_info->type)) { jsonw_name(d->jw, "value"); - ret = btf_dumper_type(d, map_info->btf_value_type_id, value); + ret = btf_dumper_type(d, value_id, value); } else { unsigned int i, n, step; @@ -279,8 +283,7 @@ static int do_dump_btf(const struct btf_dumper *d, jsonw_start_object(d->jw); jsonw_int_field(d->jw, "cpu", i); jsonw_name(d->jw, "value"); - ret = btf_dumper_type(d, map_info->btf_value_type_id, - value + i * step); + ret = btf_dumper_type(d, value_id, value + i * step); jsonw_end_object(d->jw); if (ret) break; @@ -932,6 +935,44 @@ static int maps_have_btf(int *fds, int nb_fds) return 1; } +static struct btf *btf_vmlinux; + +static struct btf *get_map_kv_btf(const struct bpf_map_info *info) +{ + struct btf *btf = NULL; + + if (info->btf_vmlinux_value_type_id) { + if (!btf_vmlinux) { + btf_vmlinux = libbpf_find_kernel_btf(); + if (IS_ERR(btf_vmlinux)) + p_err("failed to get kernel btf"); + } + return btf_vmlinux; + } else if (info->btf_value_type_id) { + int err; + + err = btf__get_from_id(info->btf_id, &btf); + if (err || !btf) { + p_err("failed to get btf"); + btf = err ? ERR_PTR(err) : ERR_PTR(-ESRCH); + } + } + + return btf; +} + +static void free_map_kv_btf(struct btf *btf) +{ + if (!IS_ERR(btf) && btf != btf_vmlinux) + btf__free(btf); +} + +static void free_btf_vmlinux(void) +{ + if (!IS_ERR(btf_vmlinux)) + btf__free(btf_vmlinux); +} + static int map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, bool show_header) @@ -952,13 +993,10 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr, prev_key = NULL; if (wtr) { - if (info->btf_id) { - err = btf__get_from_id(info->btf_id, &btf); - if (err || !btf) { - err = err ? : -ESRCH; - p_err("failed to get btf"); - goto exit_free; - } + btf = get_map_kv_btf(info); + if (IS_ERR(btf)) { + err = PTR_ERR(btf); + goto exit_free; } if (show_header) { @@ -999,7 +1037,7 @@ exit_free: free(key); free(value); close(fd); - btf__free(btf); + free_map_kv_btf(btf); return err; } @@ -1067,6 +1105,7 @@ exit_close: close(fds[i]); exit_free: free(fds); + free_btf_vmlinux(); return err; }