Messages in this thread | | | Date | Mon, 18 May 2015 10:35:23 -0700 | From | Alexei Starovoitov <> | Subject | Re: [RFC PATCH v3 06/37] bpf tools: Introduce 'bpf' library to tools |
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On 5/17/15 3:56 AM, Wang Nan wrote: > This is the first patch of libbpf. The goal of libbpf is to create a > standard way for accessing eBPF object files. This patch creates > Makefile and Build for it, allows 'make' to build libbpf.a and > libbpf.so, 'make install' to put them into proper directories. > Most part of Makefile is borrowed from traceevent. Before building, > it checks the existance of libelf in Makefile, and deny to build if > not found. Instead of throw an error if libelf not found, the error > raises in a phony target "elfdep". This design is to ensure > 'make clean' still workable even if libelf is not found. > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > --- ... > + > +# Version of eBPF elf file > +FILE_VERSION = 1
what that comment suppose to mean?
> +# Makefiles suck: This macro sets a default value of $(2) for the > +# variable named by $(1), unless the variable has been set by > +# environment or command line. This is necessary for CC and AR > +# because make sets default values, so the simpler ?= approach > +# won't work as expected.
what this for? copy-paste?
> +# Allow setting CC and AR, or setting CROSS_COMPILE as a prefix. > +$(call allow-override,CC,$(CROSS_COMPILE)gcc) > +$(call allow-override,AR,$(CROSS_COMPILE)ar)
was cross-compile tested or just copy-pasted?
> +EXT = -std=gnu99
I guess it was copy-pasted from libtraceevent, but please double check that it's actually needed.
> +# Append required CFLAGS > +override CFLAGS += -fPIC > +override CFLAGS += $(INCLUDES) > +override CFLAGS += -D_GNU_SOURCE
_GNU_SOURCE actually needed? Please sanitize the file.
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > new file mode 100644 > index 0000000..bebe99a > --- /dev/null > +++ b/tools/lib/bpf/libbpf.c > @@ -0,0 +1,15 @@ > +/* > + * common eBPF ELF loading operations. > + * > + * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com> > + * Copyright (C) 2015, Huawei Inc.
since it borrows heavily from samples/bpf/bpf_load.c, libbpf.h would be nice if you mention the source and/or copyright in the header.
> + * > + * Released under the GPL v2. (and only v2, not any later version) > + */
are you sure about this restriction? libtracevent is LGPL, for example.
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