--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_inject - trace event injection
+ *
+ * Copyright (C) 2019 Cong Wang <cwang@twitter.com>
+ */
+
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+
+#include "trace.h"
+
+static int
+trace_inject_entry(struct trace_event_file *file, void *rec, int len)
+{
+ struct trace_event_buffer fbuffer;
+ struct ring_buffer *buffer;
+ int written = 0;
+ void *entry;
+
+ rcu_read_lock_sched();
+ buffer = file->tr->trace_buffer.buffer;
+ entry = trace_event_buffer_reserve(&fbuffer, file, len);
+ if (entry) {
+ memcpy(entry, rec, len);
+ written = len;
+ trace_event_buffer_commit(&fbuffer);
+ }
+ rcu_read_unlock_sched();
+
+ return written;
+}
+
+static int
+parse_field(char *str, struct trace_event_call *call,
+ struct ftrace_event_field **pf, u64 *pv)
+{
+ struct ftrace_event_field *field;
+ char *field_name;
+ int s, i = 0;
+ int len;
+ u64 val;
+
+ if (!str[i])
+ return 0;
+ /* First find the field to associate to */
+ while (isspace(str[i]))
+ i++;
+ s = i;
+ while (isalnum(str[i]) || str[i] == '_')
+ i++;
+ len = i - s;
+ if (!len)
+ return -EINVAL;
+
+ field_name = kmemdup_nul(str + s, len, GFP_KERNEL);
+ if (!field_name)
+ return -ENOMEM;
+ field = trace_find_event_field(call, field_name);
+ kfree(field_name);
+ if (!field)
+ return -ENOENT;
+
+ *pf = field;
+ while (isspace(str[i]))
+ i++;
+ if (str[i] != '=')
+ return -EINVAL;
+ i++;
+ while (isspace(str[i]))
+ i++;
+ s = i;
+ if (isdigit(str[i]) || str[i] == '-') {
+ char *num, c;
+ int ret;
+
+ /* Make sure the field is not a string */
+ if (is_string_field(field))
+ return -EINVAL;
+
+ if (str[i] == '-')
+ i++;
+
+ /* We allow 0xDEADBEEF */
+ while (isalnum(str[i]))
+ i++;
+ num = str + s;
+ c = str[i];
+ if (c != '\0' && !isspace(c))
+ return -EINVAL;
+ str[i] = '\0';
+ /* Make sure it is a value */
+ if (field->is_signed)
+ ret = kstrtoll(num, 0, &val);
+ else
+ ret = kstrtoull(num, 0, &val);
+ str[i] = c;
+ if (ret)
+ return ret;
+
+ *pv = val;
+ return i;
+ } else if (str[i] == '\'' || str[i] == '"') {
+ char q = str[i];
+
+ /* Make sure the field is OK for strings */
+ if (!is_string_field(field))
+ return -EINVAL;
+
+ for (i++; str[i]; i++) {
+ if (str[i] == '\\' && str[i + 1]) {
+ i++;
+ continue;
+ }
+ if (str[i] == q)
+ break;
+ }
+ if (!str[i])
+ return -EINVAL;
+
+ /* Skip quotes */
+ s++;
+ len = i - s;
+ if (len >= MAX_FILTER_STR_VAL)
+ return -EINVAL;
+
+ *pv = (unsigned long)(str + s);
+ str[i] = 0;
+ /* go past the last quote */
+ i++;
+ return i;
+ }
+
+ return -EINVAL;
+}
+
+static int trace_get_entry_size(struct trace_event_call *call)
+{
+ struct ftrace_event_field *field;
+ struct list_head *head;
+ int size = 0;
+
+ head = trace_get_fields(call);
+ list_for_each_entry(field, head, link) {
+ if (field->size + field->offset > size)
+ size = field->size + field->offset;
+ }
+
+ return size;
+}
+
+static void *trace_alloc_entry(struct trace_event_call *call, int *size)
+{
+ int entry_size = trace_get_entry_size(call);
+ struct ftrace_event_field *field;
+ struct list_head *head;
+ void *entry = NULL;
+
+ /* We need an extra '\0' at the end. */
+ entry = kzalloc(entry_size + 1, GFP_KERNEL);
+ if (!entry)
+ return NULL;
+
+ head = trace_get_fields(call);
+ list_for_each_entry(field, head, link) {
+ if (!is_string_field(field))
+ continue;
+ if (field->filter_type == FILTER_STATIC_STRING)
+ continue;
+ if (field->filter_type == FILTER_DYN_STRING) {
+ u32 *str_item;
+ int str_loc = entry_size & 0xffff;
+
+ str_item = (u32 *)(entry + field->offset);
+ *str_item = str_loc; /* string length is 0. */
+ } else {
+ char **paddr;
+
+ paddr = (char **)(entry + field->offset);
+ *paddr = "";
+ }
+ }
+
+ *size = entry_size + 1;
+ return entry;
+}
+
+#define INJECT_STRING "STATIC STRING CAN NOT BE INJECTED"
+
+/* Caller is responsible to free the *pentry. */
+static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
+{
+ struct ftrace_event_field *field;
+ unsigned long irq_flags;
+ void *entry = NULL;
+ int entry_size;
+ u64 val;
+ int len;
+
+ entry = trace_alloc_entry(call, &entry_size);
+ *pentry = entry;
+ if (!entry)
+ return -ENOMEM;
+
+ local_save_flags(irq_flags);
+ tracing_generic_entry_update(entry, call->event.type, irq_flags,
+ preempt_count());
+
+ while ((len = parse_field(str, call, &field, &val)) > 0) {
+ if (is_function_field(field))
+ return -EINVAL;
+
+ if (is_string_field(field)) {
+ char *addr = (char *)(unsigned long) val;
+
+ if (field->filter_type == FILTER_STATIC_STRING) {
+ strlcpy(entry + field->offset, addr, field->size);
+ } else if (field->filter_type == FILTER_DYN_STRING) {
+ int str_len = strlen(addr) + 1;
+ int str_loc = entry_size & 0xffff;
+ u32 *str_item;
+
+ entry_size += str_len;
+ *pentry = krealloc(entry, entry_size, GFP_KERNEL);
+ if (!*pentry) {
+ kfree(entry);
+ return -ENOMEM;
+ }
+ entry = *pentry;
+
+ strlcpy(entry + (entry_size - str_len), addr, str_len);
+ str_item = (u32 *)(entry + field->offset);
+ *str_item = (str_len << 16) | str_loc;
+ } else {
+ char **paddr;
+
+ paddr = (char **)(entry + field->offset);
+ *paddr = INJECT_STRING;
+ }
+ } else {
+ switch (field->size) {
+ case 1: {
+ u8 tmp = (u8) val;
+
+ memcpy(entry + field->offset, &tmp, 1);
+ break;
+ }
+ case 2: {
+ u16 tmp = (u16) val;
+
+ memcpy(entry + field->offset, &tmp, 2);
+ break;
+ }
+ case 4: {
+ u32 tmp = (u32) val;
+
+ memcpy(entry + field->offset, &tmp, 4);
+ break;
+ }
+ case 8:
+ memcpy(entry + field->offset, &val, 8);
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ str += len;
+ }
+
+ if (len < 0)
+ return len;
+
+ return entry_size;
+}
+
+static ssize_t
+event_inject_write(struct file *filp, const char __user *ubuf, size_t cnt,
+ loff_t *ppos)
+{
+ struct trace_event_call *call;
+ struct trace_event_file *file;
+ int err = -ENODEV, size;
+ void *entry = NULL;
+ char *buf;
+
+ if (cnt >= PAGE_SIZE)
+ return -EINVAL;
+
+ buf = memdup_user_nul(ubuf, cnt);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+ strim(buf);
+
+ mutex_lock(&event_mutex);
+ file = event_file_data(filp);
+ if (file) {
+ call = file->event_call;
+ size = parse_entry(buf, call, &entry);
+ if (size < 0)
+ err = size;
+ else
+ err = trace_inject_entry(file, entry, size);
+ }
+ mutex_unlock(&event_mutex);
+
+ kfree(entry);
+ kfree(buf);
+
+ if (err < 0)
+ return err;
+
+ *ppos += err;
+ return cnt;
+}
+
+static ssize_t
+event_inject_read(struct file *file, char __user *buf, size_t size,
+ loff_t *ppos)
+{
+ return -EPERM;
+}
+
+const struct file_operations event_inject_fops = {
+ .open = tracing_open_generic,
+ .read = event_inject_read,
+ .write = event_inject_write,
+};
projects / openwrt / staging / blogic.git / commitdiff