| Message ID | 20191024133025.10691-1-jolsa@kernel.org |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpftool: Allow to read btf as raw data | expand |
On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote: > The bpftool interface stays the same, but now it's possible > to run it over BTF raw data, like: > > $ bpftool btf dump file /sys/kernel/btf/vmlinux > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > [3] CONST '(anon)' type_id=2 > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > --- > v3 changes: > - fix title > > v2 changes: > - added is_btf_raw to find out which btf__parse_* function to call > - changed labels and error propagation in btf__parse_raw > - drop the err initialization, which is not needed under this change Aw, this is v3? Looks like I replied to the older now, such confusion :)
On 10/24/19 6:30 AM, Jiri Olsa wrote: > The bpftool interface stays the same, but now it's possible > to run it over BTF raw data, like: > > $ bpftool btf dump file /sys/kernel/btf/vmlinux > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > [3] CONST '(anon)' type_id=2 > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > --- > v3 changes: > - fix title The subject (by now) should be "[PATCH v3 bpf-next] ...". Include both version and intended tree (bpf-next usually). > > v2 changes: > - added is_btf_raw to find out which btf__parse_* function to call > - changed labels and error propagation in btf__parse_raw > - drop the err initialization, which is not needed under this change > > tools/bpf/bpftool/btf.c | 57 ++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 56 insertions(+), 1 deletion(-) > Overall looks good. It's kind of sad that we re-open that file twice, but we can optimize that later, if it ever is a problem. We should probably eventually implement btf__parse_raw as libbpf API with mmap2(). But perfect is the enemy of the good, so: Acked-by: Andrii Nakryiko <andriin@fb.com> > diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c > index 9a9376d1d3df..a7b8bf233cf5 100644 > --- a/tools/bpf/bpftool/btf.c > +++ b/tools/bpf/bpftool/btf.c > @@ -12,6 +12,9 @@ [...]
On Thu, Oct 24, 2019 at 10:55:37AM -0700, Jakub Kicinski wrote: > On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote: > > The bpftool interface stays the same, but now it's possible > > to run it over BTF raw data, like: > > > > $ bpftool btf dump file /sys/kernel/btf/vmlinux > > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > > [3] CONST '(anon)' type_id=2 > > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > --- > > v3 changes: > > - fix title > > > > v2 changes: > > - added is_btf_raw to find out which btf__parse_* function to call > > - changed labels and error propagation in btf__parse_raw > > - drop the err initialization, which is not needed under this change > > > Aw, this is v3? Looks like I replied to the older now, such confusion :) yea, that went well.. sry, missed the v3 in title jirka
On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote: > The bpftool interface stays the same, but now it's possible > to run it over BTF raw data, like: > > $ bpftool btf dump file /sys/kernel/btf/vmlinux > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > [3] CONST '(anon)' type_id=2 > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
On Fri, Oct 25, 2019 at 11:39:01AM -0700, Jakub Kicinski wrote: > On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote: > > The bpftool interface stays the same, but now it's possible > > to run it over BTF raw data, like: > > > > $ bpftool btf dump file /sys/kernel/btf/vmlinux > > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > > [3] CONST '(anon)' type_id=2 > > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> [root@ibm-z-107 bpftool]# ./bpftool btf dump file /sys/kernel/btf/vmlinux | head -3 [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) [3] CONST '(anon)' type_id=2 [root@ibm-z-107 bpftool]# lscpu | grep Endian Byte Order: Big Endian thanks, jirka
On Thu, Oct 24, 2019 at 03:30:25PM +0200, Jiri Olsa wrote: > The bpftool interface stays the same, but now it's possible > to run it over BTF raw data, like: > > $ bpftool btf dump file /sys/kernel/btf/vmlinux > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > [3] CONST '(anon)' type_id=2 > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> Applied, thanks!
On Fri, 25 Oct 2019 22:03:51 +0200, Jiri Olsa wrote: > On Fri, Oct 25, 2019 at 11:39:01AM -0700, Jakub Kicinski wrote: > > On Thu, 24 Oct 2019 15:30:25 +0200, Jiri Olsa wrote: > > > The bpftool interface stays the same, but now it's possible > > > to run it over BTF raw data, like: > > > > > > $ bpftool btf dump file /sys/kernel/btf/vmlinux > > > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > > > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > > > [3] CONST '(anon)' type_id=2 > > > > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > > > Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> > > [root@ibm-z-107 bpftool]# ./bpftool btf dump file /sys/kernel/btf/vmlinux | head -3 > [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) > [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > [3] CONST '(anon)' type_id=2 > [root@ibm-z-107 bpftool]# lscpu | grep Endian > Byte Order: Big Endian Thanks for checking! I thought the on-disk format is fixed like the ELF magic number. But if two bads make a right then all is good ☺️
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 9a9376d1d3df..a7b8bf233cf5 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -12,6 +12,9 @@ #include <libbpf.h> #include <linux/btf.h> #include <linux/hashtable.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> #include "btf.h" #include "json_writer.h" @@ -388,6 +391,54 @@ static int dump_btf_c(const struct btf *btf, return err; } +static struct btf *btf__parse_raw(const char *file) +{ + struct btf *btf; + struct stat st; + __u8 *buf; + FILE *f; + + if (stat(file, &st)) + return NULL; + + f = fopen(file, "rb"); + if (!f) + return NULL; + + buf = malloc(st.st_size); + if (!buf) { + btf = ERR_PTR(-ENOMEM); + goto exit_close; + } + + if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) { + btf = ERR_PTR(-EINVAL); + goto exit_free; + } + + btf = btf__new(buf, st.st_size); + +exit_free: + free(buf); +exit_close: + fclose(f); + return btf; +} + +static bool is_btf_raw(const char *file) +{ + __u16 magic = 0; + int fd; + + fd = open(file, O_RDONLY); + if (fd < 0) + return false; + + read(fd, &magic, sizeof(magic)); + close(fd); + return magic == BTF_MAGIC; +} + static int do_dump(int argc, char **argv) { struct btf *btf = NULL; @@ -465,7 +516,11 @@ static int do_dump(int argc, char **argv) } NEXT_ARG(); } else if (is_prefix(src, "file")) { - btf = btf__parse_elf(*argv, NULL); + if (is_btf_raw(*argv)) + btf = btf__parse_raw(*argv); + else + btf = btf__parse_elf(*argv, NULL); + if (IS_ERR(btf)) { err = PTR_ERR(btf); btf = NULL;
The bpftool interface stays the same, but now it's possible to run it over BTF raw data, like: $ bpftool btf dump file /sys/kernel/btf/vmlinux [1] INT '(anon)' size=4 bits_offset=0 nr_bits=32 encoding=(none) [2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) [3] CONST '(anon)' type_id=2 Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- v3 changes: - fix title v2 changes: - added is_btf_raw to find out which btf__parse_* function to call - changed labels and error propagation in btf__parse_raw - drop the err initialization, which is not needed under this change tools/bpf/bpftool/btf.c | 57 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 56 insertions(+), 1 deletion(-)