diff options
author | Quentin Monnet <quentin.monnet@netronome.com> | 2017-10-23 09:24:10 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-10-24 01:25:08 +0100 |
commit | f05e2c32f715985f54265b1e237b5cce1b576c71 (patch) | |
tree | e2038a3c68b105bf6e58bb58d6c3d995a0bafe70 /tools | |
parent | 107f041212c1dfd3bf72b01c0d2013e98b6f32c2 (diff) | |
download | op-kernel-dev-f05e2c32f715985f54265b1e237b5cce1b576c71.zip op-kernel-dev-f05e2c32f715985f54265b1e237b5cce1b576c71.tar.gz |
tools: bpftool: add JSON output for `bpftool prog dump xlated *` command
Add a new printing function to dump translated eBPF instructions as
JSON. As for plain output, opcodes are printed only on request (when
`opcodes` is provided on the command line).
The disassembled output is generated by the same code that is used by
the kernel verifier.
Example output:
$ bpftool --json --pretty prog dump xlated id 1
[{
"disasm": "(bf) r6 = r1"
},{
"disasm": "(61) r7 = *(u32 *)(r6 +16)"
},{
"disasm": "(95) exit"
}
]
$ bpftool --json --pretty prog dump xlated id 1 opcodes
[{
"disasm": "(bf) r6 = r1",
"opcodes": {
"code": "0xbf",
"src_reg": "0x1",
"dst_reg": "0x6",
"off": ["0x00","0x00"
],
"imm": ["0x00","0x00","0x00","0x00"
]
}
},{
"disasm": "(61) r7 = *(u32 *)(r6 +16)",
"opcodes": {
"code": "0x61",
"src_reg": "0x6",
"dst_reg": "0x7",
"off": ["0x10","0x00"
],
"imm": ["0x00","0x00","0x00","0x00"
]
}
},{
"disasm": "(95) exit",
"opcodes": {
"code": "0x95",
"src_reg": "0x0",
"dst_reg": "0x0",
"off": ["0x00","0x00"
],
"imm": ["0x00","0x00","0x00","0x00"
]
}
}
]
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/bpf/bpftool/common.c | 10 | ||||
-rw-r--r-- | tools/bpf/bpftool/json_writer.c | 8 | ||||
-rw-r--r-- | tools/bpf/bpftool/json_writer.h | 2 | ||||
-rw-r--r-- | tools/bpf/bpftool/main.h | 1 | ||||
-rw-r--r-- | tools/bpf/bpftool/prog.c | 70 |
5 files changed, 89 insertions, 2 deletions
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index df8396a..e7a756b 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -214,3 +214,13 @@ char *get_fdinfo(int fd, const char *key) fclose(fdi); return NULL; } + +void print_hex_data_json(uint8_t *data, size_t len) +{ + unsigned int i; + + jsonw_start_array(json_wtr); + for (i = 0; i < len; i++) + jsonw_printf(json_wtr, "\"0x%02hhx\"", data[i]); + jsonw_end_array(json_wtr); +} diff --git a/tools/bpf/bpftool/json_writer.c b/tools/bpf/bpftool/json_writer.c index 6b77d28..c6eef76 100644 --- a/tools/bpf/bpftool/json_writer.c +++ b/tools/bpf/bpftool/json_writer.c @@ -156,6 +156,14 @@ void jsonw_name(json_writer_t *self, const char *name) putc(' ', self->out); } +void jsonw_vprintf_enquote(json_writer_t *self, const char *fmt, va_list ap) +{ + jsonw_eor(self); + putc('"', self->out); + vfprintf(self->out, fmt, ap); + putc('"', self->out); +} + void jsonw_printf(json_writer_t *self, const char *fmt, ...) { va_list ap; diff --git a/tools/bpf/bpftool/json_writer.h b/tools/bpf/bpftool/json_writer.h index 1516aaf..0fa2fb1 100644 --- a/tools/bpf/bpftool/json_writer.h +++ b/tools/bpf/bpftool/json_writer.h @@ -17,6 +17,7 @@ #include <stdbool.h> #include <stdint.h> +#include <stdarg.h> /* Opaque class structure */ typedef struct json_writer json_writer_t; @@ -33,6 +34,7 @@ void jsonw_pretty(json_writer_t *self, bool on); void jsonw_name(json_writer_t *self, const char *name); /* Add value */ +void jsonw_vprintf_enquote(json_writer_t *self, const char *fmt, va_list ap); void jsonw_printf(json_writer_t *self, const char *fmt, ...); void jsonw_string(json_writer_t *self, const char *value); void jsonw_bool(json_writer_t *self, bool value); diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index 15927fc..693fc97 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -95,5 +95,6 @@ int do_map(int argc, char **arg); int prog_parse_fd(int *argc, char ***argv); void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes); +void print_hex_data_json(uint8_t *data, size_t len); #endif diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index f373f2b..43e4979 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -385,7 +385,7 @@ static void print_insn(struct bpf_verifier_env *env, const char *fmt, ...) va_end(args); } -static void dump_xlated(void *buf, unsigned int len, bool opcodes) +static void dump_xlated_plain(void *buf, unsigned int len, bool opcodes) { struct bpf_insn *insn = buf; bool double_insn = false; @@ -414,6 +414,69 @@ static void dump_xlated(void *buf, unsigned int len, bool opcodes) } } +static void print_insn_json(struct bpf_verifier_env *env, const char *fmt, ...) +{ + unsigned int l = strlen(fmt); + char chomped_fmt[l]; + va_list args; + + va_start(args, fmt); + if (l > 0) { + strncpy(chomped_fmt, fmt, l - 1); + chomped_fmt[l - 1] = '\0'; + } + jsonw_vprintf_enquote(json_wtr, chomped_fmt, args); + va_end(args); +} + +static void dump_xlated_json(void *buf, unsigned int len, bool opcodes) +{ + struct bpf_insn *insn = buf; + bool double_insn = false; + unsigned int i; + + jsonw_start_array(json_wtr); + for (i = 0; i < len / sizeof(*insn); i++) { + if (double_insn) { + double_insn = false; + continue; + } + double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW); + + jsonw_start_object(json_wtr); + jsonw_name(json_wtr, "disasm"); + print_bpf_insn(print_insn_json, NULL, insn + i, true); + + if (opcodes) { + jsonw_name(json_wtr, "opcodes"); + jsonw_start_object(json_wtr); + + jsonw_name(json_wtr, "code"); + jsonw_printf(json_wtr, "\"0x%02hhx\"", insn[i].code); + + jsonw_name(json_wtr, "src_reg"); + jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].src_reg); + + jsonw_name(json_wtr, "dst_reg"); + jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].dst_reg); + + jsonw_name(json_wtr, "off"); + print_hex_data_json((uint8_t *)(&insn[i].off), 2); + + jsonw_name(json_wtr, "imm"); + if (double_insn && i < len - 1) + print_hex_data_json((uint8_t *)(&insn[i].imm), + 12); + else + print_hex_data_json((uint8_t *)(&insn[i].imm), + 4); + jsonw_end_object(json_wtr); + } + jsonw_end_object(json_wtr); + } + jsonw_end_array(json_wtr); +} + static int do_dump(int argc, char **argv) { struct bpf_prog_info info = {}; @@ -523,7 +586,10 @@ static int do_dump(int argc, char **argv) if (member_len == &info.jited_prog_len) disasm_print_insn(buf, *member_len, opcodes); else - dump_xlated(buf, *member_len, opcodes); + if (json_output) + dump_xlated_json(buf, *member_len, opcodes); + else + dump_xlated_plain(buf, *member_len, opcodes); } free(buf); |