[PATCH v2 07/10] perf symbol: Use fallbacks for filename__read_debuglink

[Ian Rogers <irogers@google.com>]

Try libbfd and then libelf in symbol.c. Remove the non-existent
symbol-minimal version.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/perf-libelf.c    | 52 +++++++++++++++++++++++++++++
 tools/perf/util/perf-libelf.h    | 10 ++++++
 tools/perf/util/symbol-elf.c     | 56 --------------------------------
 tools/perf/util/symbol-minimal.c |  9 -----
 tools/perf/util/symbol.c         | 10 ++++++
 5 files changed, 72 insertions(+), 65 deletions(-)

diff --git a/tools/perf/util/perf-libelf.c b/tools/perf/util/perf-libelf.c
index c7fa08a177d0..a8a8c39056da 100644
--- a/tools/perf/util/perf-libelf.c
+++ b/tools/perf/util/perf-libelf.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "perf-libelf.h"
 
+#include <fcntl.h>
 #include <stddef.h>
 #include <string.h>
 #include <unistd.h>
@@ -143,3 +144,54 @@ int libelf__read_build_id(int _fd, const char *filename, struct build_id *bid)
 out:
 	return err;
 }
+
+int libelf_filename__read_debuglink(const char *filename, char *debuglink, size_t size)
+{
+	int fd, err = -1;
+	Elf *elf;
+	GElf_Ehdr ehdr;
+	GElf_Shdr shdr;
+	Elf_Data *data;
+	Elf_Scn *sec;
+	Elf_Kind ek;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		goto out;
+
+	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
+	if (elf == NULL) {
+		pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
+		goto out_close;
+	}
+
+	ek = elf_kind(elf);
+	if (ek != ELF_K_ELF)
+		goto out_elf_end;
+
+	if (gelf_getehdr(elf, &ehdr) == NULL) {
+		pr_err("%s: cannot get elf header.\n", __func__);
+		goto out_elf_end;
+	}
+
+	sec = elf_section_by_name(elf, &ehdr, &shdr,
+				  ".gnu_debuglink", NULL);
+	if (sec == NULL)
+		goto out_elf_end;
+
+	data = elf_getdata(sec, NULL);
+	if (data == NULL)
+		goto out_elf_end;
+
+	/* the start of this section is a zero-terminated string */
+	strncpy(debuglink, data->d_buf, size);
+
+	err = 0;
+
+out_elf_end:
+	elf_end(elf);
+out_close:
+	close(fd);
+out:
+	return err;
+}
diff --git a/tools/perf/util/perf-libelf.h b/tools/perf/util/perf-libelf.h
index 931597493b1f..167679f9fc9b 100644
--- a/tools/perf/util/perf-libelf.h
+++ b/tools/perf/util/perf-libelf.h
@@ -2,6 +2,8 @@
 #ifndef __PERF_LIBELF_H
 #define __PERF_LIBELF_H
 
+#include <stddef.h>
+
 struct build_id;
 
 #ifdef HAVE_LIBELF_SUPPORT
@@ -30,6 +32,7 @@ Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, GElf_Shdr *shp, const char
 int __libelf__read_build_id(Elf *elf, void *bf, size_t size);
 
 int libelf__read_build_id(int _fd, const char *filename, struct build_id *bid);
+int libelf_filename__read_debuglink(const char *filename, char *debuglink, size_t size);
 
 #else // !defined(HAVE_LIBELF_SUPPORT)
 
@@ -40,6 +43,13 @@ static inline int libelf__read_build_id(int fd __always_unused,
 	return -1;
 }
 
+static inline int libelf_filename__read_debuglink(const char *filename __always_unused,
+						  char *debuglink __always_unused,
+						  size_t size __always_unused)
+{
+	return -1;
+}
+
 #endif // defined(HAVE_LIBELF_SUPPORT)
 
 #endif /* __PERF_LIBELF_H */
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 8fb7bf743ca6..9ceb746b6c59 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -801,62 +801,6 @@ int sysfs__read_build_id(const char *filename, struct build_id *bid)
 	return err;
 }
 
-int filename__read_debuglink(const char *filename, char *debuglink,
-			     size_t size)
-{
-	int fd, err = -1;
-	Elf *elf;
-	GElf_Ehdr ehdr;
-	GElf_Shdr shdr;
-	Elf_Data *data;
-	Elf_Scn *sec;
-	Elf_Kind ek;
-
-	err = libbfd_filename__read_debuglink(filename, debuglink, size);
-	if (err >= 0)
-		goto out;
-
-	fd = open(filename, O_RDONLY);
-	if (fd < 0)
-		goto out;
-
-	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
-	if (elf == NULL) {
-		pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
-		goto out_close;
-	}
-
-	ek = elf_kind(elf);
-	if (ek != ELF_K_ELF)
-		goto out_elf_end;
-
-	if (gelf_getehdr(elf, &ehdr) == NULL) {
-		pr_err("%s: cannot get elf header.\n", __func__);
-		goto out_elf_end;
-	}
-
-	sec = elf_section_by_name(elf, &ehdr, &shdr,
-				  ".gnu_debuglink", NULL);
-	if (sec == NULL)
-		goto out_elf_end;
-
-	data = elf_getdata(sec, NULL);
-	if (data == NULL)
-		goto out_elf_end;
-
-	/* the start of this section is a zero-terminated string */
-	strncpy(debuglink, data->d_buf, size);
-
-	err = 0;
-
-out_elf_end:
-	elf_end(elf);
-out_close:
-	close(fd);
-out:
-	return err;
-}
-
 bool symsrc__possibly_runtime(struct symsrc *ss)
 {
 	return ss->dynsym || ss->opdsec;
diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c
index b71cf8caf282..445307f230af 100644
--- a/tools/perf/util/symbol-minimal.c
+++ b/tools/perf/util/symbol-minimal.c
@@ -77,15 +77,6 @@ static int read_build_id(void *note_data, size_t note_len, struct build_id *bid,
 	return -1;
 }
 
-#ifndef HAVE_LIBELF_SUPPORT
-int filename__read_debuglink(const char *filename __maybe_unused,
-			     char *debuglink __maybe_unused,
-			     size_t size __maybe_unused)
-{
-	return -1;
-}
-#endif
-
 /*
  * Just try PT_NOTE header otherwise fails
  */
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 8d461974a69f..da75a1c159f2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -2050,6 +2050,16 @@ int filename__read_build_id(const char *filename, struct build_id *bid)
 	return err;
 }
 
+int filename__read_debuglink(const char *filename, char *debuglink, size_t size)
+{
+	int err = libbfd_filename__read_debuglink(filename, debuglink, size);
+
+	if (err == 0)
+		return 0;
+
+	return libelf_filename__read_debuglink(filename, debuglink, size);
+}
+
 static char *dso__find_kallsyms(struct dso *dso, struct map *map)
 {
 	struct build_id bid = { .size = 0, };
-- 
2.52.0.158.g65b55ccf14-goog