From 328bafc9a373da5f268d82533dd8f2e66526d168 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 31 Mar 2023 11:31:55 +0200 Subject: [PATCH 1/3] selftests/bpf: Add err.h header Moving error macros from profiler.inc.h to new err.h header. It will be used in following changes. Also adding PTR_ERR macro that will be used in following changes. Acked-by: Andrii Nakryiko Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20230331093157.1749137-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/progs/err.h | 18 ++++++++++++++++++ .../testing/selftests/bpf/progs/profiler.inc.h | 3 +-- 2 files changed, 19 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/err.h diff --git a/tools/testing/selftests/bpf/progs/err.h b/tools/testing/selftests/bpf/progs/err.h new file mode 100644 index 000000000000..d66d283d9e59 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/err.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ERR_H__ +#define __ERR_H__ + +#define MAX_ERRNO 4095 +#define IS_ERR_VALUE(x) (unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO + +static inline int IS_ERR_OR_NULL(const void *ptr) +{ + return !ptr || IS_ERR_VALUE((unsigned long)ptr); +} + +static inline long PTR_ERR(const void *ptr) +{ + return (long) ptr; +} + +#endif /* __ERR_H__ */ diff --git a/tools/testing/selftests/bpf/progs/profiler.inc.h b/tools/testing/selftests/bpf/progs/profiler.inc.h index 875513866032..f799d87e8700 100644 --- a/tools/testing/selftests/bpf/progs/profiler.inc.h +++ b/tools/testing/selftests/bpf/progs/profiler.inc.h @@ -6,6 +6,7 @@ #include #include "profiler.h" +#include "err.h" #ifndef NULL #define NULL 0 @@ -16,7 +17,6 @@ #define O_DIRECTORY 00200000 #define __O_TMPFILE 020000000 #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY) -#define MAX_ERRNO 4095 #define S_IFMT 00170000 #define S_IFSOCK 0140000 #define S_IFLNK 0120000 @@ -34,7 +34,6 @@ #define S_ISBLK(m) (((m)&S_IFMT) == S_IFBLK) #define S_ISFIFO(m) (((m)&S_IFMT) == S_IFIFO) #define S_ISSOCK(m) (((m)&S_IFMT) == S_IFSOCK) -#define IS_ERR_VALUE(x) (unsigned long)(void*)(x) >= (unsigned long)-MAX_ERRNO #define KILL_DATA_ARRAY_SIZE 8 From 88dc8b3605b38a440fba45edcc53a6c7a98eee3b Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 31 Mar 2023 11:31:56 +0200 Subject: [PATCH 2/3] selftests/bpf: Add read_build_id function Adding read_build_id function that parses out build id from specified binary. It will replace extract_build_id and also be used in following changes. Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20230331093157.1749137-3-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/trace_helpers.c | 82 +++++++++++++++++++++ tools/testing/selftests/bpf/trace_helpers.h | 5 ++ 2 files changed, 87 insertions(+) diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index 934bf28fc888..9b070cdf44ac 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -11,6 +11,9 @@ #include #include #include "trace_helpers.h" +#include +#include +#include #define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" #define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" @@ -234,3 +237,82 @@ ssize_t get_rel_offset(uintptr_t addr) fclose(f); return -EINVAL; } + +static int +parse_build_id_buf(const void *note_start, Elf32_Word note_size, char *build_id) +{ + Elf32_Word note_offs = 0; + + while (note_offs + sizeof(Elf32_Nhdr) < note_size) { + Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs); + + if (nhdr->n_type == 3 && nhdr->n_namesz == sizeof("GNU") && + !strcmp((char *)(nhdr + 1), "GNU") && nhdr->n_descsz > 0 && + nhdr->n_descsz <= BPF_BUILD_ID_SIZE) { + memcpy(build_id, note_start + note_offs + + ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr), nhdr->n_descsz); + memset(build_id + nhdr->n_descsz, 0, BPF_BUILD_ID_SIZE - nhdr->n_descsz); + return (int) nhdr->n_descsz; + } + + note_offs = note_offs + sizeof(Elf32_Nhdr) + + ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4); + } + + return -ENOENT; +} + +/* Reads binary from *path* file and returns it in the *build_id* buffer + * with *size* which is expected to be at least BPF_BUILD_ID_SIZE bytes. + * Returns size of build id on success. On error the error value is + * returned. + */ +int read_build_id(const char *path, char *build_id, size_t size) +{ + int fd, err = -EINVAL; + Elf *elf = NULL; + GElf_Ehdr ehdr; + size_t max, i; + + if (size < BPF_BUILD_ID_SIZE) + return -EINVAL; + + fd = open(path, O_RDONLY | O_CLOEXEC); + if (fd < 0) + return -errno; + + (void)elf_version(EV_CURRENT); + + elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + if (!elf) + goto out; + if (elf_kind(elf) != ELF_K_ELF) + goto out; + if (!gelf_getehdr(elf, &ehdr)) + goto out; + + for (i = 0; i < ehdr.e_phnum; i++) { + GElf_Phdr mem, *phdr; + char *data; + + phdr = gelf_getphdr(elf, i, &mem); + if (!phdr) + goto out; + if (phdr->p_type != PT_NOTE) + continue; + data = elf_rawfile(elf, &max); + if (!data) + goto out; + if (phdr->p_offset + phdr->p_memsz > max) + goto out; + err = parse_build_id_buf(data + phdr->p_offset, phdr->p_memsz, build_id); + if (err > 0) + break; + } + +out: + if (elf) + elf_end(elf); + close(fd); + return err; +} diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h index 53efde0e2998..876f3e711df6 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -4,6 +4,9 @@ #include +#define __ALIGN_MASK(x, mask) (((x)+(mask))&~(mask)) +#define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a)-1) + struct ksym { long addr; char *name; @@ -23,4 +26,6 @@ void read_trace_pipe(void); ssize_t get_uprobe_offset(const void *addr); ssize_t get_rel_offset(uintptr_t addr); +int read_build_id(const char *path, char *build_id, size_t size); + #endif From dcc46f51d770bde625e4845cac42e808b3302b62 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 31 Mar 2023 11:31:57 +0200 Subject: [PATCH 3/3] selftests/bpf: Replace extract_build_id with read_build_id Replacing extract_build_id with read_build_id that parses out build id directly from elf without using readelf tool. Acked-by: Andrii Nakryiko Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20230331093157.1749137-4-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- .../bpf/prog_tests/stacktrace_build_id.c | 19 ++++++-------- .../bpf/prog_tests/stacktrace_build_id_nmi.c | 17 +++++-------- tools/testing/selftests/bpf/test_progs.c | 25 ------------------- tools/testing/selftests/bpf/test_progs.h | 1 - 4 files changed, 13 insertions(+), 49 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c index 9ad09a6c538a..b7ba5cd47d96 100644 --- a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c +++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c @@ -7,13 +7,12 @@ void test_stacktrace_build_id(void) int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd; struct test_stacktrace_build_id *skel; - int err, stack_trace_len; + int err, stack_trace_len, build_id_size; __u32 key, prev_key, val, duration = 0; - char buf[256]; - int i, j; + char buf[BPF_BUILD_ID_SIZE]; struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH]; int build_id_matches = 0; - int retry = 1; + int i, retry = 1; retry: skel = test_stacktrace_build_id__open_and_load(); @@ -52,9 +51,10 @@ retry: "err %d errno %d\n", err, errno)) goto cleanup; - err = extract_build_id(buf, 256); + build_id_size = read_build_id("urandom_read", buf, sizeof(buf)); + err = build_id_size < 0 ? build_id_size : 0; - if (CHECK(err, "get build_id with readelf", + if (CHECK(err, "read_build_id", "err %d errno %d\n", err, errno)) goto cleanup; @@ -64,8 +64,6 @@ retry: goto cleanup; do { - char build_id[64]; - err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs); if (CHECK(err, "lookup_elem from stackmap", "err %d, errno %d\n", err, errno)) @@ -73,10 +71,7 @@ retry: for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i) if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID && id_offs[i].offset != 0) { - for (j = 0; j < 20; ++j) - sprintf(build_id + 2 * j, "%02x", - id_offs[i].build_id[j] & 0xff); - if (strstr(buf, build_id) != NULL) + if (memcmp(buf, id_offs[i].build_id, build_id_size) == 0) build_id_matches = 1; } prev_key = key; diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c index f4ea1a215ce4..47558b0d7f66 100644 --- a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c +++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c @@ -28,11 +28,10 @@ void test_stacktrace_build_id_nmi(void) .config = PERF_COUNT_HW_CPU_CYCLES, }; __u32 key, prev_key, val, duration = 0; - char buf[256]; - int i, j; + char buf[BPF_BUILD_ID_SIZE]; struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH]; - int build_id_matches = 0; - int retry = 1; + int build_id_matches = 0, build_id_size; + int i, retry = 1; attr.sample_freq = read_perf_max_sample_freq(); @@ -94,7 +93,8 @@ retry: "err %d errno %d\n", err, errno)) goto cleanup; - err = extract_build_id(buf, 256); + build_id_size = read_build_id("urandom_read", buf, sizeof(buf)); + err = build_id_size < 0 ? build_id_size : 0; if (CHECK(err, "get build_id with readelf", "err %d errno %d\n", err, errno)) @@ -106,8 +106,6 @@ retry: goto cleanup; do { - char build_id[64]; - err = bpf_map__lookup_elem(skel->maps.stackmap, &key, sizeof(key), id_offs, sizeof(id_offs), 0); if (CHECK(err, "lookup_elem from stackmap", @@ -116,10 +114,7 @@ retry: for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i) if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID && id_offs[i].offset != 0) { - for (j = 0; j < 20; ++j) - sprintf(build_id + 2 * j, "%02x", - id_offs[i].build_id[j] & 0xff); - if (strstr(buf, build_id) != NULL) + if (memcmp(buf, id_offs[i].build_id, build_id_size) == 0) build_id_matches = 1; } prev_key = key; diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index d903e6a72a96..ea82921110da 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -629,31 +629,6 @@ out: return err; } -int extract_build_id(char *build_id, size_t size) -{ - FILE *fp; - char *line = NULL; - size_t len = 0; - - fp = popen("readelf -n ./urandom_read | grep 'Build ID'", "r"); - if (fp == NULL) - return -1; - - if (getline(&line, &len, fp) == -1) - goto err; - pclose(fp); - - if (len > size) - len = size; - memcpy(build_id, line, len); - build_id[len] = '\0'; - free(line); - return 0; -err: - pclose(fp); - return -1; -} - static int finit_module(int fd, const char *param_values, int flags) { return syscall(__NR_finit_module, fd, param_values, flags); diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h index 4b06b8347cd4..10ba43250668 100644 --- a/tools/testing/selftests/bpf/test_progs.h +++ b/tools/testing/selftests/bpf/test_progs.h @@ -405,7 +405,6 @@ static inline void *u64_to_ptr(__u64 ptr) int bpf_find_map(const char *test, struct bpf_object *obj, const char *name); int compare_map_keys(int map1_fd, int map2_fd); int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len); -int extract_build_id(char *build_id, size_t size); int kern_sync_rcu(void); int trigger_module_test_read(int read_sz); int trigger_module_test_write(int write_sz);