完善基于ebpf观测用户态函数时延项目：利用ptrace机制解决短时间程序的观测

.github/workflows/user_function_tracer.yml

@@ -34,4 +34,12 @@ jobs:
           cmake -B build -S . -G Ninja
           cmake --build build
           gcc test/sleep.c -o test/sleep
-          sudo build/utrace test/sleep
+          gcc test/mmap.c -o test/mmap
+          gcc test/strcpy.c -o test/strcpy
+          gcc test/fib.c -o test/fib
+          gcc test/thread.c -o test/thread
+          sudo build/utrace -c test/sleep
+          sudo build/utrace -c test/mmap
+          sudo build/utrace -c test/strcpy
+          sudo build/utrace -c test/fib
+          sudo build/utrace -c test/thread

eBPF_Supermarket/User_Function_Tracer/.clang-format

@@ -5,8 +5,14 @@ ColumnLimit: 100
 PointerAlignment: Right
 IncludeCategories:  
   - Regex: '"vmlinux.h"' # let vmlinux.h come first
-    Priority: -1000
-  - Regex: '"utrace.h"'
-    Priority: -1001
-  - Regex: '"utrace.skel.h"'
-    Priority: -1000
+    Priority: -1
+  - Regex: '"utrace.*h"'    
+    Priority: 0
+  - Regex: '<getopt.h>'
+    Priority: -1
+  - Regex: '^"(llvm|llvm-c|clang|clang-c)/'
+    Priority: 2
+  - Regex: '^(<|"(gtest|isl|json)/)'
+    Priority: 2
+  - Regex: '.\*'
+    Priority: 1

eBPF_Supermarket/User_Function_Tracer/README.md

@@ -11,23 +11,35 @@ sudo apt install -y clang cmake ninja-build libelf1 libelf-dev zlib1g-dev libbpf
 
 ### 编译运行
 ```shell
-mkdir -p vmlinux
-bash tools/gen_vmlinux_h.sh > vmlinux/vmlinux.h
-cmake -B build -S . -G Ninja
-cmake --build build
+$ mkdir -p vmlinux
+$ bash tools/gen_vmlinux_h.sh > vmlinux/vmlinux.h
+$ cmake -B build -S . -G Ninja
+$ cmake --build build
+$ build/utrace -h
+Usage: build/utrace [$OPTIONS...]
 
-build/utrace PROGRAM|PID
+Options:
+  -c --command: the command to run the program to be traced.
+  -p --pid: the PID of the program to be traced.
+  -d --debug: enable debug mode.
+     --no-ASLR: disable Address Space Layout Randomization (ASLR).
+  -h --help: disaply this usage information.
+
+Examples:
+  sudo build/utrace -c "$PROGRAM $ARGS"
+  sudo build/utrace -p $PID
 ```
 
 ### 特点
+- 观测用户态函数调用流程以及调用时延
+- 非侵入式，不依赖任何编译选项
+- 支持多线程程序、已经运行的程序（输入进程PID号）
 + 不同于`ftrace`，`eBPF-utrace`用于观测用户态函数。
-+ 不同于`uftrace`，`eBPF-utrace`基于eBPF，不依赖于任何编译技术，但是需要内核的支持，需要root权限，且可能有更高的开销。
-+ 不同于`perf`, `gprof`等性能分析工具，`eBPF-utrace`输出准确的函数调用时延，而不是基于perf_event()的采样方式。
++ 不同于`uftrace`，`eBPF-utrace`基于eBPF，不依赖于任何编译技术，但是需要内核的支持，需要root权限。
++ 不同于`perf`, `gprof`等性能分析工具，`eBPF-utrace`输出准确的函数调用时延，而不是基于perf_event的采样方式。
 
 ### TODO
-- [] short live process
-- [] arg parser
-- [] input pid
-- [] more tests
-- [] colorful log
-- [] multithread
+- IFUNC符号的观测
+- 嵌套的共享库观测
+- 简化C++符号的展示
+- 更多的测试

eBPF_Supermarket/User_Function_Tracer/src/demangle.c

@@ -18,24 +18,36 @@
 
 #include "utrace.h"
 
-#include "demangle.h"
-
 #include <stdlib.h>
 #include <string.h>
 
+#include "demangle.h"
+
 char *demangle(const char *mangled_name) {
   char *original_name;
-  long len = MAX_SYMBOL_LEN;
+  long len = MAX_MANGLED_LEN;
+  long name_len;
   int status;
 
-  /** 确保只还原重整过的符号（以"_Z"起始）*/
-  if (mangled_name[0] != '_' || mangled_name[1] != 'Z') return strdup(mangled_name);
-
-  __cxa_demangle(mangled_name, NULL, &len, &status);
-  if (status < 0) return strdup(mangled_name);
-
-  original_name = malloc(len);
-  __cxa_demangle(mangled_name, original_name, &len, &status);
-
-  return original_name;
-}
+  if (strncmp(mangled_name, "_Z", 2) == 0) {
+    __cxa_demangle(mangled_name, NULL, &len, &status);
+    if (status < 0) {
+      return strdup(mangled_name);
+    }
+    original_name = malloc(len);
+    __cxa_demangle(mangled_name, original_name, &len, &status);
+
+    name_len = strlen(original_name);
+    if (original_name[name_len - 1] == ')') {
+      int cont = 1;
+      while (cont) {
+        --name_len;
+        if (original_name[name_len] == '(') cont = 0;
+        original_name[name_len] = 0;
+      }
+    }
+    return original_name;
+  }
+
+  return strdup(mangled_name);
+}

eBPF_Supermarket/User_Function_Tracer/src/demangle.h

@@ -31,4 +31,4 @@ extern char *__cxa_demangle(const char *name, char *output, long *len, int *stat
  */
 char *demangle(const char *mangled_name);
 
-#endif  // UTRACE_DEMANGLE_H
+#endif  // UTRACE_DEMANGLE_H

eBPF_Supermarket/User_Function_Tracer/src/gdb.c

@@ -0,0 +1,55 @@
+// Copyright 2023 The LMP Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://github.com/linuxkerneltravel/lmp/blob/develop/LICENSE
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// author: jinyufeng2000@gmail.com
+//
+// 设置断点，为探针提供时间
+
+#include "gdb.h"
+
+#include <stdlib.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+
+struct gdb* new_gdb(pid_t pid) {
+  struct gdb* gdb = (struct gdb*)malloc(sizeof(struct gdb));
+  gdb->pid = pid;
+  return gdb;
+}
+
+void enable_breakpoint(struct gdb* gdb, uint64_t addr) {
+  long data = ptrace(PTRACE_PEEKDATA, gdb->pid, addr, NULL);
+  gdb->inst = (uint8_t)data & 0xFF;
+
+  uint64_t int3 = 0xCC;
+  ptrace(PTRACE_POKEDATA, gdb->pid, addr, (data & ~0xFF) | int3);
+}
+
+void disable_breakpoint(struct gdb* gdb, uint64_t addr) {
+  long data = ptrace(PTRACE_PEEKDATA, gdb->pid, addr, NULL);
+  ptrace(PTRACE_POKEDATA, gdb->pid, (data & ~0xFF) | gdb->inst);
+}
+
+long continue_execution(struct gdb* gdb) { return ptrace(PTRACE_CONT, gdb->pid, NULL, NULL); }
+
+long wait_for_signal(struct gdb* gdb) {
+  int wstatus;
+  int options = 0;
+  return waitpid(gdb->pid, &wstatus, options);
+}
+
+void delete_gdb(struct gdb* gdb) {
+  ptrace(PTRACE_DETACH, gdb->pid, NULL, NULL);
+  free(gdb);
+}

eBPF_Supermarket/User_Function_Tracer/src/gdb.h

@@ -0,0 +1,74 @@
+// Copyright 2023 The LMP Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://github.com/linuxkerneltravel/lmp/blob/develop/LICENSE
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// author: jinyufeng2000@gmail.com
+//
+// 设置断点，为探针提供时间
+
+#ifndef UTRACE_GDB_H
+#define UTRACE_GDB_H
+
+#include <stdint.h>
+#include <unistd.h>
+
+/*
+ * @brief 记录跨函数传递的信息
+ */
+struct gdb {
+  pid_t pid;    /**< gdb附加到的进程的编号 */
+  uint8_t inst; /**< 被int3覆盖的单字节指令 */
+};
+
+/*
+ * @brief 创建一个gdb结构体
+ * @param[in] pid 进程号
+ * @return 指向gdb结构体的指针
+ * @note 从堆中申请空间
+ */
+struct gdb* new_gdb(pid_t pid);
+
+/*
+ * @brief 设置一个断点
+ * @param[in] gdb 指向一个gdb结构体
+ * @param[in] addr 物理地址
+ */
+void enable_breakpoint(struct gdb* gdb, uint64_t addr);
+
+/*
+ * @brief 取消一个断点
+ * @param[in] gdb 指向一个gdb结构体
+ * @param[in] addr 物理地址
+ * @note 需要保证之前调用过enable_breakpoint(gdb, pid, addr)
+ */
+void disable_breakpoint(struct gdb* gdb, uint64_t addr);
+
+/*
+ * @brief 继续执行
+ * @param[in] gdb 指向一个gdb结构体
+ */
+long continue_execution(struct gdb* gdb);
+
+/*
+ * @brief 等待进程收到信号
+ * @param[in] gdb 指向一个gdb结构体
+ */
+long wait_for_signal(struct gdb* gdb);
+
+/*
+ * @brief 取消ptrace并释放gdb结构体的空间
+ * @param[in] gdb 指向要释放的gdb结构体
+ */
+void delete_gdb(struct gdb* gdb);
+
+#endif  // UTRACE_GDB_H

eBPF_Supermarket/User_Function_Tracer/src/log.c

@@ -18,21 +18,36 @@
 
 #include "log.h"
 
-#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
-void print_char(char c, int cnt) {
+int debug;
+
+void log_color(const char* color) {
+  char* term = getenv("TERM");
+  if (isatty(fileno(stderr)) && !(term && !strcmp(term, "dumb"))) {
+    LOG("%s", color);
+  }
+}
+
+void log_char(char c, int cnt) {
   while (cnt > 0) {
-    printf("%c", c);
+    LOG("%c", c);
     --cnt;
   }
 }
 
-void print_header() { printf("# DURATION     TID     FUNCTION\n"); }
+void log_header() { LOG(" CPU |   TID  |   DURATION  |   FUNCTION CALLS\n"); }
 
-void print_tid(int tid) { printf("[%6d]", tid); }
+void log_tid(int tid) { LOG("%6d", tid); }
 
-void print_time_unit(size_t ns) {
-  static char *units[] = {
+void log_cpuid(int cpuid) { LOG("%4d", cpuid); }
+
+void log_split() { LOG(" | "); }
+
+void log_time(size_t ns) {
+  static char* units[] = {
       "ns", "us", "ms", " s", " m", " h",
   };
   static size_t limit[] = {
@@ -48,5 +63,5 @@ void print_time_unit(size_t ns) {
     ++i;
   }
 
-  printf("%3zu.%03zu %s", t, t_mod, units[i]);
-}
+  LOG("%4zu.%03zu %s", t, t_mod, units[i]);
+}