On Fri, Jun 30, 2023 at 1:35 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding elf_open/elf_close functions and using it in
> elf_find_func_offset_from_file function. It will be
> used in following changes to save some common code.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> tools/lib/bpf/elf.c | 59 +++++++++++++++++++++++++-------------
> tools/lib/bpf/libbpf_elf.h | 8 ++++++
> tools/lib/bpf/usdt.c | 31 ++++++--------------
> 3 files changed, 56 insertions(+), 42 deletions(-)
>
one nit below
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> diff --git a/tools/lib/bpf/elf.c b/tools/lib/bpf/elf.c
> index 2b62b4af28ce..74e35071d22e 100644
> --- a/tools/lib/bpf/elf.c
> +++ b/tools/lib/bpf/elf.c
> @@ -11,6 +11,40 @@
>
> #define STRERR_BUFSIZE 128
>
> +int elf_open(const char *binary_path, struct elf_fd *elf_fd)
> +{
> + char errmsg[STRERR_BUFSIZE];
> + int fd, ret;
> + Elf *elf;
> +
> + if (elf_version(EV_CURRENT) == EV_NONE) {
> + pr_warn("elf: failed to init libelf for %s\n", binary_path);
> + return -LIBBPF_ERRNO__LIBELF;
> + }
> + fd = open(binary_path, O_RDONLY | O_CLOEXEC);
> + if (fd < 0) {
> + ret = -errno;
> + pr_warn("elf: failed to open %s: %s\n", binary_path,
> + libbpf_strerror_r(ret, errmsg, sizeof(errmsg)));
> + return ret;
> + }
> + 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;
> + }
> + elf_fd->fd = fd;
> + elf_fd->elf = elf;
> + return 0;
> +}
> +
> +void elf_close(struct elf_fd *elf_fd)
> +{
> + elf_end(elf_fd->elf);
> + close(elf_fd->fd);
nit: I'd make elf_close() work correctly with a) NULL elf_fd and b)
NULL elf_fd->elf, just to never have to think about this
> +}
> +
> /* Return next ELF section of sh_type after scn, or first of that type if scn is NULL. */
> static Elf_Scn *elf_find_next_scn_by_type(Elf *elf, int sh_type, Elf_Scn *scn)
> {
[...]
