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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/testing/selftests/bpf/trace_helpers.c | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/testing/selftests/bpf/trace_helpers.c')
-rw-r--r-- | tools/testing/selftests/bpf/trace_helpers.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c new file mode 100644 index 000000000..1bbd1d983 --- /dev/null +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <unistd.h> +#include <linux/perf_event.h> +#include <sys/mman.h> +#include "trace_helpers.h" + +#define DEBUGFS "/sys/kernel/debug/tracing/" + +#define MAX_SYMS 300000 +static struct ksym syms[MAX_SYMS]; +static int sym_cnt; + +static int ksym_cmp(const void *p1, const void *p2) +{ + return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr; +} + +int load_kallsyms(void) +{ + FILE *f = fopen("/proc/kallsyms", "r"); + char func[256], buf[256]; + char symbol; + void *addr; + int i = 0; + + if (!f) + return -ENOENT; + + while (fgets(buf, sizeof(buf), f)) { + if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3) + break; + if (!addr) + continue; + syms[i].addr = (long) addr; + syms[i].name = strdup(func); + i++; + } + fclose(f); + sym_cnt = i; + qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp); + return 0; +} + +struct ksym *ksym_search(long key) +{ + int start = 0, end = sym_cnt; + int result; + + /* kallsyms not loaded. return NULL */ + if (sym_cnt <= 0) + return NULL; + + while (start < end) { + size_t mid = start + (end - start) / 2; + + result = key - syms[mid].addr; + if (result < 0) + end = mid; + else if (result > 0) + start = mid + 1; + else + return &syms[mid]; + } + + if (start >= 1 && syms[start - 1].addr < key && + key < syms[start].addr) + /* valid ksym */ + return &syms[start - 1]; + + /* out of range. return _stext */ + return &syms[0]; +} + +long ksym_get_addr(const char *name) +{ + int i; + + for (i = 0; i < sym_cnt; i++) { + if (strcmp(syms[i].name, name) == 0) + return syms[i].addr; + } + + return 0; +} + +/* open kallsyms and read symbol addresses on the fly. Without caching all symbols, + * this is faster than load + find. + */ +int kallsyms_find(const char *sym, unsigned long long *addr) +{ + char type, name[500]; + unsigned long long value; + int err = 0; + FILE *f; + + f = fopen("/proc/kallsyms", "r"); + if (!f) + return -EINVAL; + + while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) { + if (strcmp(name, sym) == 0) { + *addr = value; + goto out; + } + } + err = -ENOENT; + +out: + fclose(f); + return err; +} + +void read_trace_pipe(void) +{ + int trace_fd; + + trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0); + if (trace_fd < 0) + return; + + while (1) { + static char buf[4096]; + ssize_t sz; + + sz = read(trace_fd, buf, sizeof(buf) - 1); + if (sz > 0) { + buf[sz] = 0; + puts(buf); + } + } +} |