什么是系统调用我就不赘述了，不清楚的可以去参考我的另外一篇博客用户态 内核态

本文主要是带大家看看怎样去查看 进程对于内核的系统调用

linux 进程即文件

• 在 linux 中，一切皆为文件，socket 是文件，进程也是文件
• 那么进程的文件在哪呢？
  • 每个进程都有一个进程号（eg ：pid = 3645）
  • 那么进程的相关文件就在 /proc/3645 目录下
  • 重点关注几个文件夹：
    • ask 目录下就有所有 线程 的信息
    • fd 文件描述符（一般用数字代表），每个进程都有io，至少三个（标准输入 0，标准输出 1，错误输出 2）
      • 比如一个tcp服务程序，必定至少有一个 listen 的 socket，就对多出一个文件
      • 又比如这个 tcp server 使用了 epoll，使用 epoll_create系统调用 会创建一个fd，也会在这个目录之下
• 如果出现某个服务（进程）比较卡的时候，就可以进入 task 目录查看是否是进程太多，进行问题排查

例子

• 一个简单的 echo tcpserver，监听在 0.0.0.0:9999 上

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  package main import ( "bufio" "fmt" "io" "log" "net" ) func main() { addr := "0.0.0.0:9999" tcpAddr, err := net.ResolveTCPAddr("tcp", addr) if err != nil { log.Fatalf("net.ResovleTCPAddr fail:%s", addr) } listener, err := net.ListenTCP("tcp", tcpAddr) if err != nil { log.Fatalf("listen %s fail: %s", addr, err) } else { log.Println("tcp listening", addr) } for { conn, err := listener.Accept() if err != nil { log.Println("listener.Accept error:", err) continue } go handleConnection(conn) } } func handleConnection(conn net.Conn) { defer conn.Close() reader := bufio.NewReader(conn) for { // read client request data bytes, err := reader.ReadBytes(byte('\n')) if err != nil { if err != io.EOF { fmt.Println("failed to read data, err:", err) } else { fmt.Println("connection closed") } return } fmt.Printf("request: %s", bytes) // prepend prefix and send as response line := fmt.Sprintf("%s", bytes) fmt.Printf("response: %s", line) conn.Write([]byte(line)) } }

• 编译成linux版本

  1	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o ./tcp-echo-server-linux ./main.go

• 上面的终端中启动 echo tcpserver
• 下面的终端中依次：
  • 获取 echo server 进程号
  • 进入进程对于的目录
  • 进入 fd 目录，可以看到有三个基础的fd（0，1，2）以及一个 socket fd & epoll fd
  • 进入 task 目录

如何查看进程的系统调用

• strace -ff -o ./ooxx ./tcp-echo-server-linux

• 上述命令会运行 tcp-echo-server-linux，并且对它进行系统调用的抓取，并放到当前目录下
  

• 执行上述命令之后，多出来很多 xxoo* 的文件，这些文件就记录来每个线程的系统调用

• 我将 ooxx.30927 中的内容贴出来

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  execve("./tcp-echo-server-linux", ["./tcp-echo-server-linux"], 0x7ffcc5d16c08 /* 24 vars */) = 0 arch_prctl(ARCH_SET_FS, 0x60c1f0) = 0 sched_getaffinity(0, 8192, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]) = 8 openat(AT_FDCWD, "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", O_RDONLY) = 3 read(3, "2097152\n", 20) = 8 close(3) = 0 mmap(NULL, 262144, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff92955b000 mmap(0xc000000000, 67108864, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc000000000 mmap(0xc000000000, 67108864, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xc000000000 mmap(NULL, 33554432, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff92755b000 mmap(NULL, 2164736, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff92734a000 mmap(NULL, 65536, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff92733a000 mmap(NULL, 65536, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff92732a000 rt_sigprocmask(SIG_SETMASK, NULL, [], 8) = 0 sigaltstack(NULL, {ss_sp=NULL, ss_flags=SS_DISABLE, ss_size=0}) = 0 sigaltstack({ss_sp=0xc000002000, ss_flags=0, ss_size=32768}, NULL) = 0 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 gettid() = 30927 rt_sigaction(SIGHUP, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGHUP, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGINT, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGQUIT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGQUIT, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGILL, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGILL, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGTRAP, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGTRAP, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGABRT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGABRT, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGBUS, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGBUS, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGFPE, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGFPE, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGUSR1, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGUSR1, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGSEGV, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGSEGV, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGUSR2, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGUSR2, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGPIPE, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGPIPE, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGALRM, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGALRM, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGTERM, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGTERM, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGSTKFLT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGSTKFLT, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGCHLD, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGCHLD, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGURG, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGURG, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGXCPU, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGXCPU, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGXFSZ, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGXFSZ, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGVTALRM, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGVTALRM, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGPROF, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGPROF, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGWINCH, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGWINCH, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGIO, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGIO, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGPWR, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGPWR, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGSYS, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGSYS, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRTMIN, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_1, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_2, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_2, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_3, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_3, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_4, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_4, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_5, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_5, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_6, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_6, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_7, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_7, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_8, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_8, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_9, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_9, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_10, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_10, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_11, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_11, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_12, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_12, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_13, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_13, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_14, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_14, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_15, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_15, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_16, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_16, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_17, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_17, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_18, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_18, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_19, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_19, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_20, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_20, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_21, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_21, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_22, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_22, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_23, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_23, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_24, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_24, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_25, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_25, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_26, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_26, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_27, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_27, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_28, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_28, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_29, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_29, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_30, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_30, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_31, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_31, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigaction(SIGRT_32, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0 rt_sigaction(SIGRT_32, {sa_handler=0x459560, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x459690}, NULL, 8) = 0 rt_sigprocmask(SIG_SETMASK, ~[], [], 8) = 0 clone(child_stack=0xc000062000, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM) = 30928 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 rt_sigprocmask(SIG_SETMASK, ~[], [], 8) = 0 clone(child_stack=0xc000064000, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM) = 30929 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 rt_sigprocmask(SIG_SETMASK, ~[], [], 8) = 0 clone(child_stack=0xc00005e000, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM) = 30930 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 futex(0x60c2a8, FUTEX_WAIT_PRIVATE, 0, NULL) = 0 rt_sigprocmask(SIG_SETMASK, ~[], [], 8) = 0 clone(child_stack=0xc000060000, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM) = 30932 rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 futex(0x60c2a8, FUTEX_WAIT_PRIVATE, 0, NULL) = 0 readlinkat(AT_FDCWD, "/proc/self/exe", "/root/temp/temp/tcp-echo-server-"..., 128) = 37 fcntl(0, F_GETFL) = 0x2 (flags O_RDWR) futex(0xc0000524c8, FUTEX_WAKE_PRIVATE, 1) = 1 mmap(NULL, 262144, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff9272ea000 fcntl(1, F_GETFL) = 0x2 (flags O_RDWR) fcntl(2, F_GETFL) = 0x2 (flags O_RDWR) socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_TCP) = 3 close(3) = 0 socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_TCP) = 3 setsockopt(3, SOL_IPV6, IPV6_V6ONLY, [1], 4) = 0 bind(3, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, 28) = -1 EADDRNOTAVAIL (Cannot assign requested address) socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_TCP) = 4 setsockopt(4, SOL_IPV6, IPV6_V6ONLY, [0], 4) = 0 bind(4, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "::ffff:127.0.0.1", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, 28) = 0 close(4) = 0 close(3) = 0 socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3 setsockopt(3, SOL_IPV6, IPV6_V6ONLY, [0], 4) = 0 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0 openat(AT_FDCWD, "/proc/sys/net/core/somaxconn", O_RDONLY|O_CLOEXEC) = 4 epoll_create1(EPOLL_CLOEXEC) = 5 epoll_ctl(5, EPOLL_CTL_ADD, 4, {EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLET, {u32=657387272, u64=140708080971528}}) = 0 fcntl(4, F_GETFL) = 0x8000 (flags O_RDONLY|O_LARGEFILE) fcntl(4, F_SETFL, O_RDONLY|O_NONBLOCK|O_LARGEFILE) = 0 read(4, "128\n", 65536) = 4 read(4, "", 65532) = 0 epoll_ctl(5, EPOLL_CTL_DEL, 4, 0xc0000a49a4) = 0 close(4) = 0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 bind(3, {sa_family=AF_INET6, sin6_port=htons(9999), inet_pton(AF_INET6, "::", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, 28) = 0 listen(3, 128) = 0 epoll_ctl(5, EPOLL_CTL_ADD, 3, {EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLET, {u32=657387272, u64=140708080971528}}) = 0 getsockname(3, {sa_family=AF_INET6, sin6_port=htons(9999), inet_pton(AF_INET6, "::", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, [112->28]) = 0 openat(AT_FDCWD, "/etc//localtime", O_RDONLY) = 4 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\3\0\0\0\3\0\0\0\0"..., 4096) = 554 read(4, "", 4096) = 0 close(4) = 0 write(2, "2020/04/15 10:30:01 tcp listenin"..., 47) = 47 accept4(3, 0xc000085bc0, [112], SOCK_CLOEXEC|SOCK_NONBLOCK) = -1 EAGAIN (Resource temporarily unavailable) epoll_pwait(5, [], 128, 0, NULL, 0) = 0 epoll_pwait(5, 0x7fffa12415e0, 128, -1, NULL, 0) = -1 EINTR (Interrupted system call) --- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} --- rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call) epoll_pwait(5, 0x7fffa12415e0, 128, -1, NULL, 0) = -1 EINTR (Interrupted system call) --- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} --- rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call) epoll_pwait(5, 0x7fffa12415e0, 128, -1, NULL, 0) = -1 EINTR (Interrupted system call) --- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} --- rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call) epoll_pwait(5, 0x7fffa12415e0, 128, -1, NULL, 0) = -1 EINTR (Interrupted system call) --- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} --- rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call) epoll_pwait(5, 0x7fffa12415e0, 128, -1, NULL, 0) = -1 EINTR (Interrupted system call) --- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} --- rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call) epoll_pwait(5, 0x7fffa12415e0, 128, -1, NULL, 0) = -1 EINTR (Interrupted system call) --- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} --- rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call) epoll_pwait(5, root

• 可以看到 134，137，140，144 行通过 clone 系统调用 创建新的线程

• 153，155 行分别调用 socket系统调用 创建了 socket，用于后续的 listen

  • 一个是ipv4（fd=3）
  • 一个是ipv6 (fd=4)

• 157，160 行分别调用了 bind系统调用 绑定监听的地址

• 167 行调用了 epoll_create系统调用 创建了 epoll 实例（fd = 5）

• 168，173，178 行分别调用 epoll_ctl系统调用

• 176 行调用了 bind系统调用 绑定9999端口

• 最后一行也可以看到调用了 epoll_wait 系统调用 等待连接