[PATCH dwarves v3 2/5] btf_encoder: Do not use both structs and pointers for the same data
From: Giuliano Procida <hidden>
Date: 2021-02-05 22:44:19
Subsystem:
the rest · Maintainer:
Linus Torvalds
Many operations in the libelf API return a pointer to a user-provided struct (on success) or NULL (on failure). There are a couple of places in btf_elf__write where both structs and pointers to the same structs are used. Holding on to the pointers raises ownership and lifetime issues unncessarily and the code is cleaner with only a single access path for these data. The code now treats the returned pointers as booleans. Signed-off-by: Giuliano Procida <redacted> --- libbtf.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/libbtf.c b/libbtf.c
index 7bc49ba..ace8896 100644
--- a/libbtf.c
+++ b/libbtf.c@@ -698,8 +698,7 @@ int32_t btf_elf__add_datasec_type(struct btf_elf *btfe, const char *section_name static int btf_elf__write(const char *filename, struct btf *btf) { - GElf_Shdr shdr_mem, *shdr; - GElf_Ehdr ehdr_mem, *ehdr; + GElf_Ehdr ehdr; Elf_Data *btf_data = NULL; Elf_Scn *scn = NULL; Elf *elf = NULL;
@@ -727,13 +726,12 @@ static int btf_elf__write(const char *filename, struct btf *btf) elf_flagelf(elf, ELF_C_SET, ELF_F_DIRTY); - ehdr = gelf_getehdr(elf, &ehdr_mem); - if (ehdr == NULL) { + if (!gelf_getehdr(elf, &ehdr)) { elf_error("elf_getehdr failed"); goto out; } - switch (ehdr_mem.e_ident[EI_DATA]) { + switch (ehdr.e_ident[EI_DATA]) { case ELFDATA2LSB: btf__set_endianness(btf, BTF_LITTLE_ENDIAN); break;
@@ -751,10 +749,10 @@ static int btf_elf__write(const char *filename, struct btf *btf) elf_getshdrstrndx(elf, &strndx); while ((scn = elf_nextscn(elf, scn)) != NULL) { - shdr = gelf_getshdr(scn, &shdr_mem); - if (shdr == NULL) + GElf_Shdr shdr; + if (!gelf_getshdr(scn, &shdr)) continue; - char *secname = elf_strptr(elf, strndx, shdr->sh_name); + char *secname = elf_strptr(elf, strndx, shdr.sh_name); if (strcmp(secname, ".BTF") == 0) { btf_data = elf_getdata(scn, btf_data); break;
--
2.30.0.478.g8a0d178c01-goog