diff options
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c | 873 |
1 files changed, 873 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c b/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c new file mode 100644 index 000000000000..3b7c57fe55a5 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c @@ -0,0 +1,873 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <limits.h> +#include <stdio.h> +#include <string.h> +#include <ctype.h> +#include <regex.h> +#include <test_progs.h> + +#include "bpf/btf.h" +#include "bpf_util.h" +#include "linux/filter.h" +#include "disasm.h" + +#define MAX_PROG_TEXT_SZ (32 * 1024) + +/* The code in this file serves the sole purpose of executing test cases + * specified in the test_cases array. Each test case specifies a program + * type, context field offset, and disassembly patterns that correspond + * to read and write instructions generated by + * verifier.c:convert_ctx_access() for accessing that field. + * + * For each test case, up to three programs are created: + * - One that uses BPF_LDX_MEM to read the context field. + * - One that uses BPF_STX_MEM to write to the context field. + * - One that uses BPF_ST_MEM to write to the context field. + * + * The disassembly of each program is then compared with the pattern + * specified in the test case. + */ +struct test_case { + char *name; + enum bpf_prog_type prog_type; + enum bpf_attach_type expected_attach_type; + int field_offset; + int field_sz; + /* Program generated for BPF_ST_MEM uses value 42 by default, + * this field allows to specify custom value. + */ + struct { + bool use; + int value; + } st_value; + /* Pattern for BPF_LDX_MEM(field_sz, dst, ctx, field_offset) */ + char *read; + /* Pattern for BPF_STX_MEM(field_sz, ctx, src, field_offset) and + * BPF_ST_MEM (field_sz, ctx, src, field_offset) + */ + char *write; + /* Pattern for BPF_ST_MEM(field_sz, ctx, src, field_offset), + * takes priority over `write`. + */ + char *write_st; + /* Pattern for BPF_STX_MEM (field_sz, ctx, src, field_offset), + * takes priority over `write`. + */ + char *write_stx; +}; + +#define N(_prog_type, type, field, name_extra...) \ + .name = #_prog_type "." #field name_extra, \ + .prog_type = BPF_PROG_TYPE_##_prog_type, \ + .field_offset = offsetof(type, field), \ + .field_sz = sizeof(typeof(((type *)NULL)->field)) + +static struct test_case test_cases[] = { +/* Sign extension on s390 changes the pattern */ +#if defined(__x86_64__) || defined(__aarch64__) + { + N(SCHED_CLS, struct __sk_buff, tstamp), + .read = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);" + "w11 &= 3;" + "if w11 != 0x3 goto pc+2;" + "$dst = 0;" + "goto pc+1;" + "$dst = *(u64 *)($ctx + sk_buff::tstamp);", + .write = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);" + "if w11 & 0x2 goto pc+1;" + "goto pc+2;" + "w11 &= -2;" + "*(u8 *)($ctx + sk_buff::__mono_tc_offset) = r11;" + "*(u64 *)($ctx + sk_buff::tstamp) = $src;", + }, +#endif + { + N(SCHED_CLS, struct __sk_buff, priority), + .read = "$dst = *(u32 *)($ctx + sk_buff::priority);", + .write = "*(u32 *)($ctx + sk_buff::priority) = $src;", + }, + { + N(SCHED_CLS, struct __sk_buff, mark), + .read = "$dst = *(u32 *)($ctx + sk_buff::mark);", + .write = "*(u32 *)($ctx + sk_buff::mark) = $src;", + }, + { + N(SCHED_CLS, struct __sk_buff, cb[0]), + .read = "$dst = *(u32 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::data));", + .write = "*(u32 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::data)) = $src;", + }, + { + N(SCHED_CLS, struct __sk_buff, tc_classid), + .read = "$dst = *(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid));", + .write = "*(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid)) = $src;", + }, + { + N(SCHED_CLS, struct __sk_buff, tc_index), + .read = "$dst = *(u16 *)($ctx + sk_buff::tc_index);", + .write = "*(u16 *)($ctx + sk_buff::tc_index) = $src;", + }, + { + N(SCHED_CLS, struct __sk_buff, queue_mapping), + .read = "$dst = *(u16 *)($ctx + sk_buff::queue_mapping);", + .write_stx = "if $src >= 0xffff goto pc+1;" + "*(u16 *)($ctx + sk_buff::queue_mapping) = $src;", + .write_st = "*(u16 *)($ctx + sk_buff::queue_mapping) = $src;", + }, + { + /* This is a corner case in filter.c:bpf_convert_ctx_access() */ + N(SCHED_CLS, struct __sk_buff, queue_mapping, ".ushrt_max"), + .st_value = { true, USHRT_MAX }, + .write_st = "goto pc+0;", + }, + { + N(CGROUP_SOCK, struct bpf_sock, bound_dev_if), + .read = "$dst = *(u32 *)($ctx + sock_common::skc_bound_dev_if);", + .write = "*(u32 *)($ctx + sock_common::skc_bound_dev_if) = $src;", + }, + { + N(CGROUP_SOCK, struct bpf_sock, mark), + .read = "$dst = *(u32 *)($ctx + sock::sk_mark);", + .write = "*(u32 *)($ctx + sock::sk_mark) = $src;", + }, + { + N(CGROUP_SOCK, struct bpf_sock, priority), + .read = "$dst = *(u32 *)($ctx + sock::sk_priority);", + .write = "*(u32 *)($ctx + sock::sk_priority) = $src;", + }, + { + N(SOCK_OPS, struct bpf_sock_ops, replylong[0]), + .read = "$dst = *(u32 *)($ctx + bpf_sock_ops_kern::replylong);", + .write = "*(u32 *)($ctx + bpf_sock_ops_kern::replylong) = $src;", + }, + { + N(CGROUP_SYSCTL, struct bpf_sysctl, file_pos), +#if __BYTE_ORDER == __LITTLE_ENDIAN + .read = "$dst = *(u64 *)($ctx + bpf_sysctl_kern::ppos);" + "$dst = *(u32 *)($dst +0);", + .write = "*(u64 *)($ctx + bpf_sysctl_kern::tmp_reg) = r9;" + "r9 = *(u64 *)($ctx + bpf_sysctl_kern::ppos);" + "*(u32 *)(r9 +0) = $src;" + "r9 = *(u64 *)($ctx + bpf_sysctl_kern::tmp_reg);", +#else + .read = "$dst = *(u64 *)($ctx + bpf_sysctl_kern::ppos);" + "$dst = *(u32 *)($dst +4);", + .write = "*(u64 *)($ctx + bpf_sysctl_kern::tmp_reg) = r9;" + "r9 = *(u64 *)($ctx + bpf_sysctl_kern::ppos);" + "*(u32 *)(r9 +4) = $src;" + "r9 = *(u64 *)($ctx + bpf_sysctl_kern::tmp_reg);", +#endif + }, + { + N(CGROUP_SOCKOPT, struct bpf_sockopt, sk), + .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::sk);", + .expected_attach_type = BPF_CGROUP_GETSOCKOPT, + }, + { + N(CGROUP_SOCKOPT, struct bpf_sockopt, level), + .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::level);", + .write = "*(u32 *)($ctx + bpf_sockopt_kern::level) = $src;", + .expected_attach_type = BPF_CGROUP_SETSOCKOPT, + }, + { + N(CGROUP_SOCKOPT, struct bpf_sockopt, optname), + .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::optname);", + .write = "*(u32 *)($ctx + bpf_sockopt_kern::optname) = $src;", + .expected_attach_type = BPF_CGROUP_SETSOCKOPT, + }, + { + N(CGROUP_SOCKOPT, struct bpf_sockopt, optlen), + .read = "$dst = *(u32 *)($ctx + bpf_sockopt_kern::optlen);", + .write = "*(u32 *)($ctx + bpf_sockopt_kern::optlen) = $src;", + .expected_attach_type = BPF_CGROUP_SETSOCKOPT, + }, + { + N(CGROUP_SOCKOPT, struct bpf_sockopt, retval), + .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::current_task);" + "$dst = *(u64 *)($dst + task_struct::bpf_ctx);" + "$dst = *(u32 *)($dst + bpf_cg_run_ctx::retval);", + .write = "*(u64 *)($ctx + bpf_sockopt_kern::tmp_reg) = r9;" + "r9 = *(u64 *)($ctx + bpf_sockopt_kern::current_task);" + "r9 = *(u64 *)(r9 + task_struct::bpf_ctx);" + "*(u32 *)(r9 + bpf_cg_run_ctx::retval) = $src;" + "r9 = *(u64 *)($ctx + bpf_sockopt_kern::tmp_reg);", + .expected_attach_type = BPF_CGROUP_GETSOCKOPT, + }, + { + N(CGROUP_SOCKOPT, struct bpf_sockopt, optval), + .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::optval);", + .expected_attach_type = BPF_CGROUP_GETSOCKOPT, + }, + { + N(CGROUP_SOCKOPT, struct bpf_sockopt, optval_end), + .read = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::optval_end);", + .expected_attach_type = BPF_CGROUP_GETSOCKOPT, + }, +}; + +#undef N + +static regex_t *ident_regex; +static regex_t *field_regex; + +static char *skip_space(char *str) +{ + while (*str && isspace(*str)) + ++str; + return str; +} + +static char *skip_space_and_semi(char *str) +{ + while (*str && (isspace(*str) || *str == ';')) + ++str; + return str; +} + +static char *match_str(char *str, char *prefix) +{ + while (*str && *prefix && *str == *prefix) { + ++str; + ++prefix; + } + if (*prefix) + return NULL; + return str; +} + +static char *match_number(char *str, int num) +{ + char *next; + int snum = strtol(str, &next, 10); + + if (next - str == 0 || num != snum) + return NULL; + + return next; +} + +static int find_field_offset_aux(struct btf *btf, int btf_id, char *field_name, int off) +{ + const struct btf_type *type = btf__type_by_id(btf, btf_id); + const struct btf_member *m; + __u16 mnum; + int i; + + if (!type) { + PRINT_FAIL("Can't find btf_type for id %d\n", btf_id); + return -1; + } + + if (!btf_is_struct(type) && !btf_is_union(type)) { + PRINT_FAIL("BTF id %d is not struct or union\n", btf_id); + return -1; + } + + m = btf_members(type); + mnum = btf_vlen(type); + + for (i = 0; i < mnum; ++i, ++m) { + const char *mname = btf__name_by_offset(btf, m->name_off); + + if (strcmp(mname, "") == 0) { + int msize = find_field_offset_aux(btf, m->type, field_name, + off + m->offset); + if (msize >= 0) + return msize; + } + + if (strcmp(mname, field_name)) + continue; + + return (off + m->offset) / 8; + } + + return -1; +} + +static int find_field_offset(struct btf *btf, char *pattern, regmatch_t *matches) +{ + int type_sz = matches[1].rm_eo - matches[1].rm_so; + int field_sz = matches[2].rm_eo - matches[2].rm_so; + char *type = pattern + matches[1].rm_so; + char *field = pattern + matches[2].rm_so; + char field_str[128] = {}; + char type_str[128] = {}; + int btf_id, field_offset; + + if (type_sz >= sizeof(type_str)) { + PRINT_FAIL("Malformed pattern: type ident is too long: %d\n", type_sz); + return -1; + } + + if (field_sz >= sizeof(field_str)) { + PRINT_FAIL("Malformed pattern: field ident is too long: %d\n", field_sz); + return -1; + } + + strncpy(type_str, type, type_sz); + strncpy(field_str, field, field_sz); + btf_id = btf__find_by_name(btf, type_str); + if (btf_id < 0) { + PRINT_FAIL("No BTF info for type %s\n", type_str); + return -1; + } + + field_offset = find_field_offset_aux(btf, btf_id, field_str, 0); + if (field_offset < 0) { + PRINT_FAIL("No BTF info for field %s::%s\n", type_str, field_str); + return -1; + } + + return field_offset; +} + +static regex_t *compile_regex(char *pat) +{ + regex_t *re; + int err; + + re = malloc(sizeof(regex_t)); + if (!re) { + PRINT_FAIL("Can't alloc regex\n"); + return NULL; + } + + err = regcomp(re, pat, REG_EXTENDED); + if (err) { + char errbuf[512]; + + regerror(err, re, errbuf, sizeof(errbuf)); + PRINT_FAIL("Can't compile regex: %s\n", errbuf); + free(re); + return NULL; + } + + return re; +} + +static void free_regex(regex_t *re) +{ + if (!re) + return; + + regfree(re); + free(re); +} + +static u32 max_line_len(char *str) +{ + u32 max_line = 0; + char *next = str; + + while (next) { + next = strchr(str, '\n'); + if (next) { + max_line = max_t(u32, max_line, (next - str)); + str = next + 1; + } else { + max_line = max_t(u32, max_line, strlen(str)); + } + } + + return min(max_line, 60u); +} + +/* Print strings `pattern_origin` and `text_origin` side by side, + * assume `pattern_pos` and `text_pos` designate location within + * corresponding origin string where match diverges. + * The output should look like: + * + * Can't match disassembly(left) with pattern(right): + * r2 = *(u64 *)(r1 +0) ; $dst = *(u64 *)($ctx + bpf_sockopt_kern::sk1) + * ^ ^ + * r0 = 0 ; + * exit ; + */ +static void print_match_error(FILE *out, + char *pattern_origin, char *text_origin, + char *pattern_pos, char *text_pos) +{ + char *pattern = pattern_origin; + char *text = text_origin; + int middle = max_line_len(text) + 2; + + fprintf(out, "Can't match disassembly(left) with pattern(right):\n"); + while (*pattern || *text) { + int column = 0; + int mark1 = -1; + int mark2 = -1; + + /* Print one line from text */ + while (*text && *text != '\n') { + if (text == text_pos) + mark1 = column; + fputc(*text, out); + ++text; + ++column; + } + if (text == text_pos) + mark1 = column; + + /* Pad to the middle */ + while (column < middle) { + fputc(' ', out); + ++column; + } + fputs("; ", out); + column += 3; + + /* Print one line from pattern, pattern lines are terminated by ';' */ + while (*pattern && *pattern != ';') { + if (pattern == pattern_pos) + mark2 = column; + fputc(*pattern, out); + ++pattern; + ++column; + } + if (pattern == pattern_pos) + mark2 = column; + + fputc('\n', out); + if (*pattern) + ++pattern; + if (*text) + ++text; + + /* If pattern and text diverge at this line, print an + * additional line with '^' marks, highlighting + * positions where match fails. + */ + if (mark1 > 0 || mark2 > 0) { + for (column = 0; column <= max(mark1, mark2); ++column) { + if (column == mark1 || column == mark2) + fputc('^', out); + else + fputc(' ', out); + } + fputc('\n', out); + } + } +} + +/* Test if `text` matches `pattern`. Pattern consists of the following elements: + * + * - Field offset references: + * + * <type>::<field> + * + * When such reference is encountered BTF is used to compute numerical + * value for the offset of <field> in <type>. The `text` is expected to + * contain matching numerical value. + * + * - Field groups: + * + * $(<type>::<field> [+ <type>::<field>]*) + * + * Allows to specify an offset that is a sum of multiple field offsets. + * The `text` is expected to contain matching numerical value. + * + * - Variable references, e.g. `$src`, `$dst`, `$ctx`. + * These are substitutions specified in `reg_map` array. + * If a substring of pattern is equal to `reg_map[i][0]` the `text` is + * expected to contain `reg_map[i][1]` in the matching position. + * + * - Whitespace is ignored, ';' counts as whitespace for `pattern`. + * + * - Any other characters, `pattern` and `text` should match one-to-one. + * + * Example of a pattern: + * + * __________ fields group ________________ + * ' ' + * *(u16 *)($ctx + $(sk_buff::cb + qdisc_skb_cb::tc_classid)) = $src; + * ^^^^ '______________________' + * variable reference field offset reference + */ +static bool match_pattern(struct btf *btf, char *pattern, char *text, char *reg_map[][2]) +{ + char *pattern_origin = pattern; + char *text_origin = text; + regmatch_t matches[3]; + +_continue: + while (*pattern) { + if (!*text) + goto err; + + /* Skip whitespace */ + if (isspace(*pattern) || *pattern == ';') { + if (!isspace(*text) && text != text_origin && isalnum(text[-1])) + goto err; + pattern = skip_space_and_semi(pattern); + text = skip_space(text); + continue; + } + + /* Check for variable references */ + for (int i = 0; reg_map[i][0]; ++i) { + char *pattern_next, *text_next; + + pattern_next = match_str(pattern, reg_map[i][0]); + if (!pattern_next) + continue; + + text_next = match_str(text, reg_map[i][1]); + if (!text_next) + goto err; + + pattern = pattern_next; + text = text_next; + goto _continue; + } + + /* Match field group: + * $(sk_buff::cb + qdisc_skb_cb::tc_classid) + */ + if (strncmp(pattern, "$(", 2) == 0) { + char *group_start = pattern, *text_next; + int acc_offset = 0; + + pattern += 2; + + for (;;) { + int field_offset; + + pattern = skip_space(pattern); + if (!*pattern) { + PRINT_FAIL("Unexpected end of pattern\n"); + goto err; + } + + if (*pattern == ')') { + ++pattern; + break; + } + + if (*pattern == '+') { + ++pattern; + continue; + } + + printf("pattern: %s\n", pattern); + if (regexec(field_regex, pattern, 3, matches, 0) != 0) { + PRINT_FAIL("Field reference expected\n"); + goto err; + } + + field_offset = find_field_offset(btf, pattern, matches); + if (field_offset < 0) + goto err; + + pattern += matches[0].rm_eo; + acc_offset += field_offset; + } + + text_next = match_number(text, acc_offset); + if (!text_next) { + PRINT_FAIL("No match for group offset %.*s (%d)\n", + (int)(pattern - group_start), + group_start, + acc_offset); + goto err; + } + text = text_next; + } + + /* Match field reference: + * sk_buff::cb + */ + if (regexec(field_regex, pattern, 3, matches, 0) == 0) { + int field_offset; + char *text_next; + + field_offset = find_field_offset(btf, pattern, matches); + if (field_offset < 0) + goto err; + + text_next = match_number(text, field_offset); + if (!text_next) { + PRINT_FAIL("No match for field offset %.*s (%d)\n", + (int)matches[0].rm_eo, pattern, field_offset); + goto err; + } + + pattern += matches[0].rm_eo; + text = text_next; + continue; + } + + /* If pattern points to identifier not followed by '::' + * skip the identifier to avoid n^2 application of the + * field reference rule. + */ + if (regexec(ident_regex, pattern, 1, matches, 0) == 0) { + if (strncmp(pattern, text, matches[0].rm_eo) != 0) + goto err; + + pattern += matches[0].rm_eo; + text += matches[0].rm_eo; + continue; + } + + /* Match literally */ + if (*pattern != *text) + goto err; + + ++pattern; + ++text; + } + + return true; + +err: + test__fail(); + print_match_error(stdout, pattern_origin, text_origin, pattern, text); + return false; +} + +static void print_insn(void *private_data, const char *fmt, ...) +{ + va_list args; + + va_start(args, fmt); + vfprintf((FILE *)private_data, fmt, args); + va_end(args); +} + +/* Disassemble instructions to a stream */ +static void print_xlated(FILE *out, struct bpf_insn *insn, __u32 len) +{ + const struct bpf_insn_cbs cbs = { + .cb_print = print_insn, + .cb_call = NULL, + .cb_imm = NULL, + .private_data = out, + }; + bool double_insn = false; + int i; + + for (i = 0; i < len; i++) { + if (double_insn) { + double_insn = false; + continue; + } + + double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW); + print_bpf_insn(&cbs, insn + i, true); + } +} + +/* We share code with kernel BPF disassembler, it adds '(FF) ' prefix + * for each instruction (FF stands for instruction `code` byte). + * This function removes the prefix inplace for each line in `str`. + */ +static void remove_insn_prefix(char *str, int size) +{ + const int prefix_size = 5; + + int write_pos = 0, read_pos = prefix_size; + int len = strlen(str); + char c; + + size = min(size, len); + + while (read_pos < size) { + c = str[read_pos++]; + if (c == 0) + break; + str[write_pos++] = c; + if (c == '\n') + read_pos += prefix_size; + } + str[write_pos] = 0; +} + +struct prog_info { + char *prog_kind; + enum bpf_prog_type prog_type; + enum bpf_attach_type expected_attach_type; + struct bpf_insn *prog; + u32 prog_len; +}; + +static void match_program(struct btf *btf, + struct prog_info *pinfo, + char *pattern, + char *reg_map[][2], + bool skip_first_insn) +{ + struct bpf_insn *buf = NULL; + int err = 0, prog_fd = 0; + FILE *prog_out = NULL; + char *text = NULL; + __u32 cnt = 0; + + text = calloc(MAX_PROG_TEXT_SZ, 1); + if (!text) { + PRINT_FAIL("Can't allocate %d bytes\n", MAX_PROG_TEXT_SZ); + goto out; + } + + // TODO: log level + LIBBPF_OPTS(bpf_prog_load_opts, opts); + opts.log_buf = text; + opts.log_size = MAX_PROG_TEXT_SZ; + opts.log_level = 1 | 2 | 4; + opts.expected_attach_type = pinfo->expected_attach_type; + + prog_fd = bpf_prog_load(pinfo->prog_type, NULL, "GPL", + pinfo->prog, pinfo->prog_len, &opts); + if (prog_fd < 0) { + PRINT_FAIL("Can't load program, errno %d (%s), verifier log:\n%s\n", + errno, strerror(errno), text); + goto out; + } + + memset(text, 0, MAX_PROG_TEXT_SZ); + + err = get_xlated_program(prog_fd, &buf, &cnt); + if (err) { + PRINT_FAIL("Can't load back BPF program\n"); + goto out; + } + + prog_out = fmemopen(text, MAX_PROG_TEXT_SZ - 1, "w"); + if (!prog_out) { + PRINT_FAIL("Can't open memory stream\n"); + goto out; + } + if (skip_first_insn) + print_xlated(prog_out, buf + 1, cnt - 1); + else + print_xlated(prog_out, buf, cnt); + fclose(prog_out); + remove_insn_prefix(text, MAX_PROG_TEXT_SZ); + + ASSERT_TRUE(match_pattern(btf, pattern, text, reg_map), + pinfo->prog_kind); + +out: + if (prog_fd) + close(prog_fd); + free(buf); + free(text); +} + +static void run_one_testcase(struct btf *btf, struct test_case *test) +{ + struct prog_info pinfo = {}; + int bpf_sz; + + if (!test__start_subtest(test->name)) + return; + + switch (test->field_sz) { + case 8: + bpf_sz = BPF_DW; + break; + case 4: + bpf_sz = BPF_W; + break; + case 2: + bpf_sz = BPF_H; + break; + case 1: + bpf_sz = BPF_B; + break; + default: + PRINT_FAIL("Unexpected field size: %d, want 8,4,2 or 1\n", test->field_sz); + return; + } + + pinfo.prog_type = test->prog_type; + pinfo.expected_attach_type = test->expected_attach_type; + + if (test->read) { + struct bpf_insn ldx_prog[] = { + BPF_LDX_MEM(bpf_sz, BPF_REG_2, BPF_REG_1, test->field_offset), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + char *reg_map[][2] = { + { "$ctx", "r1" }, + { "$dst", "r2" }, + {} + }; + + pinfo.prog_kind = "LDX"; + pinfo.prog = ldx_prog; + pinfo.prog_len = ARRAY_SIZE(ldx_prog); + match_program(btf, &pinfo, test->read, reg_map, false); + } + + if (test->write || test->write_st || test->write_stx) { + struct bpf_insn stx_prog[] = { + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_STX_MEM(bpf_sz, BPF_REG_1, BPF_REG_2, test->field_offset), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + char *stx_reg_map[][2] = { + { "$ctx", "r1" }, + { "$src", "r2" }, + {} + }; + struct bpf_insn st_prog[] = { + BPF_ST_MEM(bpf_sz, BPF_REG_1, test->field_offset, + test->st_value.use ? test->st_value.value : 42), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + char *st_reg_map[][2] = { + { "$ctx", "r1" }, + { "$src", "42" }, + {} + }; + + if (test->write || test->write_stx) { + char *pattern = test->write_stx ? test->write_stx : test->write; + + pinfo.prog_kind = "STX"; + pinfo.prog = stx_prog; + pinfo.prog_len = ARRAY_SIZE(stx_prog); + match_program(btf, &pinfo, pattern, stx_reg_map, true); + } + + if (test->write || test->write_st) { + char *pattern = test->write_st ? test->write_st : test->write; + + pinfo.prog_kind = "ST"; + pinfo.prog = st_prog; + pinfo.prog_len = ARRAY_SIZE(st_prog); + match_program(btf, &pinfo, pattern, st_reg_map, false); + } + } + + test__end_subtest(); +} + +void test_ctx_rewrite(void) +{ + struct btf *btf; + int i; + + field_regex = compile_regex("^([[:alpha:]_][[:alnum:]_]+)::([[:alpha:]_][[:alnum:]_]+)"); + ident_regex = compile_regex("^[[:alpha:]_][[:alnum:]_]+"); + if (!field_regex || !ident_regex) + return; + + btf = btf__load_vmlinux_btf(); + if (!btf) { + PRINT_FAIL("Can't load vmlinux BTF, errno %d (%s)\n", errno, strerror(errno)); + goto out; + } + + for (i = 0; i < ARRAY_SIZE(test_cases); ++i) + run_one_testcase(btf, &test_cases[i]); + +out: + btf__free(btf); + free_regex(field_regex); + free_regex(ident_regex); +} |