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2c2f6abeff
Selftests for typed ksyms. Tests two types of ksyms: one is a struct, the other is a plain int. This tests two paths in the kernel. Struct ksyms will be converted into PTR_TO_BTF_ID by the verifier while int typed ksyms will be converted into PTR_TO_MEM. Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200929235049.2533242-4-haoluo@google.com
138 lines
2.4 KiB
C
138 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <poll.h>
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#include <unistd.h>
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#include <linux/perf_event.h>
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#include <sys/mman.h>
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#include "trace_helpers.h"
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#define DEBUGFS "/sys/kernel/debug/tracing/"
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#define MAX_SYMS 300000
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static struct ksym syms[MAX_SYMS];
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static int sym_cnt;
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static int ksym_cmp(const void *p1, const void *p2)
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{
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return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
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}
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int load_kallsyms(void)
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{
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FILE *f = fopen("/proc/kallsyms", "r");
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char func[256], buf[256];
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char symbol;
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void *addr;
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int i = 0;
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if (!f)
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return -ENOENT;
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while (fgets(buf, sizeof(buf), f)) {
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if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
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break;
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if (!addr)
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continue;
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syms[i].addr = (long) addr;
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syms[i].name = strdup(func);
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i++;
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}
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fclose(f);
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sym_cnt = i;
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qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp);
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return 0;
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}
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struct ksym *ksym_search(long key)
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{
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int start = 0, end = sym_cnt;
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int result;
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/* kallsyms not loaded. return NULL */
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if (sym_cnt <= 0)
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return NULL;
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while (start < end) {
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size_t mid = start + (end - start) / 2;
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result = key - syms[mid].addr;
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if (result < 0)
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end = mid;
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else if (result > 0)
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start = mid + 1;
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else
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return &syms[mid];
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}
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if (start >= 1 && syms[start - 1].addr < key &&
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key < syms[start].addr)
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/* valid ksym */
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return &syms[start - 1];
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/* out of range. return _stext */
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return &syms[0];
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}
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long ksym_get_addr(const char *name)
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{
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int i;
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for (i = 0; i < sym_cnt; i++) {
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if (strcmp(syms[i].name, name) == 0)
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return syms[i].addr;
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}
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return 0;
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}
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/* open kallsyms and read symbol addresses on the fly. Without caching all symbols,
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* this is faster than load + find.
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*/
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int kallsyms_find(const char *sym, unsigned long long *addr)
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{
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char type, name[500];
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unsigned long long value;
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int err = 0;
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FILE *f;
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f = fopen("/proc/kallsyms", "r");
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if (!f)
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return -EINVAL;
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while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) {
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if (strcmp(name, sym) == 0) {
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*addr = value;
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goto out;
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}
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}
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err = -ENOENT;
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out:
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fclose(f);
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return err;
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}
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void read_trace_pipe(void)
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{
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int trace_fd;
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trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
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if (trace_fd < 0)
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return;
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while (1) {
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static char buf[4096];
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ssize_t sz;
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sz = read(trace_fd, buf, sizeof(buf) - 1);
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if (sz > 0) {
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buf[sz] = 0;
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puts(buf);
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}
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}
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}
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