Adding elf_find_patern_func_offset function that looks up
offsets for symbols specified by pattern argument.
The 'pattern' argument allows wildcards (*?' supported).
Offsets are returned in allocated array together with its
size and needs to be released by the caller.
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/lib/bpf/libbpf.c | 121 +++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 7 +++
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 129 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0b15609d4573..7eb7035f7b73 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -11052,6 +11052,127 @@ elf_find_multi_func_offset(const char *binary_path, int cnt,
return ret;
}
+struct match_pattern_data {
+ const char *pattern;
+ struct elf_func_offset *func_offs;
+ size_t func_offs_cnt;
+ size_t func_offs_cap;
+};
+
+static int pattern_done(void *_data)
+{
+ struct match_pattern_data *data = _data;
+
+ // If we found anything in the first symbol section, do not search others
+ // to avoid duplicates.
+ return data->func_offs_cnt;
+}
+
+static int pattern_match(Elf *elf, const char *binary_path, const char *sname,
+ GElf_Sym *sym, void *_data)
+{
+ struct match_pattern_data *data = _data;
+ unsigned long offset;
+ Elf_Scn *sym_scn;
+ GElf_Shdr sym_sh;
+ int err;
+
+ if (!glob_match(sname, data->pattern))
+ return 0;
+ sym_scn = elf_getscn(elf, sym->st_shndx);
+ if (!sym_scn)
+ return 0;
+ if (!gelf_getshdr(sym_scn, &sym_sh))
+ return 0;
+
+ err = libbpf_ensure_mem((void **) &data->func_offs, &data->func_offs_cap,
+ sizeof(*data->func_offs), data->func_offs_cnt + 1);
+ if (err)
+ return err;
+
+ offset = sym->st_value - sym_sh.sh_addr + sym_sh.sh_offset;
+ data->func_offs[data->func_offs_cnt].offset = offset;
+ data->func_offs[data->func_offs_cnt].name = strdup(sname);
+ data->func_offs_cnt++;
+ return 0;
+}
+
+static int
+__elf_find_patern_func_offset(Elf *elf, const char *binary_path, const char *pattern,
+ const char ***pnames, unsigned long **poffsets, size_t *pcnt)
+{
+ struct match_pattern_data data = {
+ .pattern = pattern,
+ };
+ unsigned long *offsets = NULL;
+ const char **names = NULL;
+ size_t cnt = 0;
+ int err, i;
+
+ err = elf_for_each_symbol(elf, binary_path, pattern_match, pattern_done, &data);
+ if (err)
+ goto out;
+
+ cnt = data.func_offs_cnt;
+ if (!cnt) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ offsets = calloc(cnt, sizeof(*offsets));
+ names = calloc(cnt, sizeof(*names));
+ if (!offsets || !names) {
+ free(offsets);
+ free(names);
+ err = -ENOMEM;
+ goto out;
+ }
+
+ for (i = 0; i < cnt; i++) {
+ offsets[i] = data.func_offs[i].offset;
+ names[i] = data.func_offs[i].name;
+ }
+
+out:
+ *pnames = names;
+ *poffsets = offsets;
+ *pcnt = cnt;
+ free(data.func_offs);
+ return err;
+}
+
+LIBBPF_API int
+elf_find_patern_func_offset(const char *binary_path, const char *pattern,
+ const char ***pnames, unsigned long **poffsets, size_t *pcnt)
+{
+ char errmsg[STRERR_BUFSIZE];
+ long ret = -ENOENT;
+ Elf *elf;
+ int fd;
+
+ fd = open(binary_path, O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ ret = -errno;
+ pr_warn("failed to open %s: %s\n", binary_path,
+ libbpf_strerror_r(ret, errmsg, sizeof(errmsg)));
+ return ret;
+ }
+ if (elf_version(EV_CURRENT) == EV_NONE) {
+ pr_warn("failed to init libelf for %s\n", binary_path);
+ return -LIBBPF_ERRNO__LIBELF;
+ }
+ elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+ if (!elf) {
+ pr_warn("elf: could not read elf from %s: %s\n", binary_path, elf_errmsg(-1));
+ close(fd);
+ return -LIBBPF_ERRNO__FORMAT;
+ }
+ ret = __elf_find_patern_func_offset(elf, binary_path, pattern, pnames, poffsets, pcnt);
+ elf_end(elf);
+ close(fd);
+ return ret;
+}
+
/* Find offset of function name in ELF object specified by path. "name" matches
* symbol name or name@@LIB for library functions.
*/
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index b1b159263d47..96ed109ae011 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1655,6 +1655,13 @@ LIBBPF_API int libbpf_unregister_prog_handler(int handler_id);
LIBBPF_API int elf_find_multi_func_offset(const char *binary_path, int cnt,
const char **syms, unsigned long **poffsets);
+/**
+ * @brief *elf_find_patern_func_offset()* return symbols and offsets for given *pattern*
+ */
+LIBBPF_API int
+elf_find_patern_func_offset(const char *binary_path, const char *pattern,
+ const char ***pnames, unsigned long **poffsets, size_t *pcnt);
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7b1bf3f9ce4f..2f091a0f093b 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -391,4 +391,5 @@ LIBBPF_1.2.0 {
bpf_map_get_info_by_fd;
bpf_prog_get_info_by_fd;
elf_find_multi_func_offset;
+ elf_find_patern_func_offset;
} LIBBPF_1.1.0;
--
2.40.0
