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2020-07-21tools/bpftool: Fix error handing in do_skeleton()YueHaibing1-1/+4
Fix pass 0 to PTR_ERR, also dump more err info using libbpf_strerror. Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200717123059.29624-1-yuehaibing@huawei.com
2020-07-14tools/bpftool: Strip away modifiers from global variablesAndrii Nakryiko1-13/+10
Reliably remove all the type modifiers from read-only (.rodata) global variable definitions, including cases of inner field const modifiers and arrays of const values. Also modify one of selftests to ensure that const volatile struct doesn't prevent user-space from modifying .rodata variable. Fixes: 985ead416df3 ("bpftool: Add skeleton codegen command") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200713232409.3062144-3-andriin@fb.com
2020-06-13tools/bpftool: Fix skeleton codegenAndrii Nakryiko1-2/+0
Remove unnecessary check at the end of codegen() routine which makes codegen() to always fail and exit bpftool with error code. Positive value of variable n is not an indicator of a failure. Fixes: 2c4779eff837 ("tools, bpftool: Exit on error in function codegen") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Tobias Klauser <tklauser@distanz.ch> Link: https://lore.kernel.org/bpf/20200612201603.680852-1-andriin@fb.com
2020-06-12tools, bpftool: Exit on error in function codegenTobias Klauser1-5/+6
Currently, the codegen function might fail and return an error. But its callers continue without checking its return value. Since codegen can fail only in the unlikely case of the system running out of memory or the static template being malformed, just exit(-1) directly from codegen and make it void-returning. Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200611103341.21532-1-tklauser@distanz.ch
2020-06-11tools, bpftool: Fix memory leak in codegen error casesTobias Klauser1-0/+2
Free the memory allocated for the template on error paths in function codegen. Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200610130804.21423-1-tklauser@distanz.ch
2020-06-02tools, bpftool: Clean subcommand help messagesQuentin Monnet1-3/+3
This is a clean-up for the formatting of the do_help functions for bpftool's subcommands. The following fixes are included: - Do not use argv[-2] for "iter" help message, as the help is shown by default if no "iter" action is selected, resulting in messages looking like "./bpftool bpftool pin...". - Do not print unused HELP_SPEC_PROGRAM in help message for "bpftool link". - Andrii used argument indexing to avoid having multiple occurrences of bin_name and argv[-2] in the fprintf() for the help message, for "bpftool gen" and "bpftool link". Let's reuse this for all other help functions. We can remove up to thirty arguments for the "bpftool map" help message. - Harmonise all functions, e.g. use ending quotes-comma on a separate line. Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200523010751.23465-1-quentin@isovalent.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-04-26tools/bpf/bpftool: Remove duplicate headersJagadeesh Pagadala1-1/+0
Code cleanup: Remove duplicate headers which are included twice. Signed-off-by: Jagadeesh Pagadala <jagdsh.linux@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/1587274757-14101-1-git-send-email-jagdsh.linux@gmail.com
2020-01-21bpftool: Use consistent include paths for libbpfToke Høiland-Jørgensen1-5/+5
Fix bpftool to include libbpf header files with the bpf/ prefix, to be consistent with external users of the library. Also ensure that all includes of exported libbpf header files (those that are exported on 'make install' of the library) use bracketed includes instead of quoted. To make sure no new files are introduced that doesn't include the bpf/ prefix in its include, remove tools/lib/bpf from the include path entirely, and use tools/lib instead. Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir") Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/157952560684.1683545.4765181397974997027.stgit@toke.dk
2019-12-27bpftool: Make skeleton C code compilable with C++ compilerAndrii Nakryiko1-5/+5
When auto-generated BPF skeleton C code is included from C++ application, it triggers compilation error due to void * being implicitly casted to whatever target pointer type. This is supported by C, but not C++. To solve this problem, add explicit casts, where necessary. To ensure issues like this are captured going forward, add skeleton usage in test_cpp test. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191226210253.3132060-1-andriin@fb.com
2019-12-19libbpf: Put Kconfig externs into .kconfig sectionAndrii Nakryiko1-4/+4
Move Kconfig-provided externs into custom .kconfig section. Add __kconfig into bpf_helpers.h for user convenience. Update selftests accordingly. Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191219002837.3074619-2-andriin@fb.com
2019-12-19bpftool: Simplify format string to not use positional argsAndrii Nakryiko1-2/+2
Change format string referring to just single argument out of two available. Some versions of libc can reject such format string. Reported-by: Nikita Shirokov <tehnerd@tehnerd.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20191218214314.2403729-1-andriin@fb.com
2019-12-18bpftool, selftests/bpf: Embed object file inside skeletonAndrii Nakryiko1-89/+143
Embed contents of BPF object file used for BPF skeleton generation inside skeleton itself. This allows to keep BPF object file and its skeleton in sync at all times, and simpifies skeleton instantiation. Also switch existing selftests to not require BPF_EMBED_OBJ anymore. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20191218052552.2915188-2-andriin@fb.com
2019-12-16bpftool: Fix compilation warning on shadowed variablePaul Chaignon1-1/+1
The ident variable has already been declared at the top of the function and doesn't need to be re-declared. Fixes: 985ead416df39 ("bpftool: Add skeleton codegen command") Signed-off-by: Paul Chaignon <paul.chaignon@orange.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191216112733.GA28366@Omicron
2019-12-16bpftool: Generate externs datasec in BPF skeletonAndrii Nakryiko1-0/+4
Add support for generation of mmap()-ed read-only view of libbpf-provided extern variables. As externs are not supposed to be provided by user code (that's what .data, .bss, and .rodata is for), don't mmap() it initially. Only after skeleton load is performed, map .extern contents as read-only memory. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191214014710.3449601-4-andriin@fb.com
2019-12-16bpftool: Add skeleton codegen commandAndrii Nakryiko1-0/+551
Add `bpftool gen skeleton` command, which takes in compiled BPF .o object file and dumps a BPF skeleton struct and related code to work with that skeleton. Skeleton itself is tailored to a specific structure of provided BPF object file, containing accessors (just plain struct fields) for every map and program, as well as dedicated space for bpf_links. If BPF program is using global variables, corresponding structure definitions of compatible memory layout are emitted as well, making it possible to initialize and subsequently read/update global variables values using simple and clear C syntax for accessing fields. This skeleton majorly improves usability of opening/loading/attaching of BPF object, as well as interacting with it throughout the lifetime of loaded BPF object. Generated skeleton struct has the following structure: struct <object-name> { /* used by libbpf's skeleton API */ struct bpf_object_skeleton *skeleton; /* bpf_object for libbpf APIs */ struct bpf_object *obj; struct { /* for every defined map in BPF object: */ struct bpf_map *<map-name>; } maps; struct { /* for every program in BPF object: */ struct bpf_program *<program-name>; } progs; struct { /* for every program in BPF object: */ struct bpf_link *<program-name>; } links; /* for every present global data section: */ struct <object-name>__<one of bss, data, or rodata> { /* memory layout of corresponding data section, * with every defined variable represented as a struct field * with exactly the same type, but without const/volatile * modifiers, e.g.: */ int *my_var_1; ... } *<one of bss, data, or rodata>; }; This provides great usability improvements: - no need to look up maps and programs by name, instead just my_obj->maps.my_map or my_obj->progs.my_prog would give necessary bpf_map/bpf_program pointers, which user can pass to existing libbpf APIs; - pre-defined places for bpf_links, which will be automatically populated for program types that libbpf knows how to attach automatically (currently tracepoints, kprobe/kretprobe, raw tracepoint and tracing programs). On tearing down skeleton, all active bpf_links will be destroyed (meaning BPF programs will be detached, if they are attached). For cases in which libbpf doesn't know how to auto-attach BPF program, user can manually create link after loading skeleton and they will be auto-detached on skeleton destruction: my_obj->links.my_fancy_prog = bpf_program__attach_cgroup_whatever( my_obj->progs.my_fancy_prog, <whatever extra param); - it's extremely easy and convenient to work with global data from userspace now. Both for read-only and read/write variables, it's possible to pre-initialize them before skeleton is loaded: skel = my_obj__open(raw_embed_data); my_obj->rodata->my_var = 123; my_obj__load(skel); /* 123 will be initialization value for my_var */ After load, if kernel supports mmap() for BPF arrays, user can still read (and write for .bss and .data) variables values, but at that point it will be directly mmap()-ed to BPF array, backing global variables. This allows to seamlessly exchange data with BPF side. From userspace program's POV, all the pointers and memory contents stay the same, but mapped kernel memory changes to point to created map. If kernel doesn't yet support mmap() for BPF arrays, it's still possible to use those data section structs to pre-initialize .bss, .data, and .rodata, but after load their pointers will be reset to NULL, allowing user code to gracefully handle this condition, if necessary. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20191214014341.3442258-14-andriin@fb.com