Server restart get other process command line for linux

ProcessArgvLinux.cc

#include <string>
#include <climits>
#include <cstring>
#include <unistd.h>
#include <vector>
#include <fcntl.h>

//// Support Restart
class ProcessArgv {
public:
  ProcessArgv() = default;
  ProcessArgv(const ProcessArgv &) = delete;
  ProcessArgv &operator=(const ProcessArgv &) = delete;
  ~ProcessArgv() {
    if (Argv_) {
      free(Argv_);
    }
    if (Args) {
      free(Args);
    }
  }
  bool Initialize(int pid);
  char **Argv() { return Argv_; }
  size_t Argc() const { return Argc_; }
  const std::string &AbsolutePath() const { return absolutePath; }

private:
  std::string absolutePath;
  char **Argv_{nullptr};
  char *Args{nullptr};
  size_t Argc_{0};
};

bool ProcessArgv::Initialize(int pid) {
  absolutePath.resize(PATH_MAX);
  auto N = readlink("/proc/self/exe", &absolutePath[0], PATH_MAX);
  if (N <= 0) {
    return false;
  }
  char filename[32];
  snprintf(filename, sizeof(filename), "/proc/%d/cmdline", pid);
  auto fd = open(filename, O_RDONLY);
  if (fd <= 0) {
    perror("cannot open /proc/pid/cmdline");
    return false;
  }
  Args = (char *)malloc(sizeof(char) * PATH_MAX);
  if (Args == nullptr) {
    perror("malloc error");
    close(fd);
    return false;
  }
  auto ret = read(fd, Args, PATH_MAX);
  std::vector<char *> Argvv;
  Argvv.push_back(Args);
  for (auto i = 0; i < ret; i++) {
    if (Args[i] == 0 && i + 1 < ret) {
      Argvv.push_back(&Args[++i]);
    }
  }
  Argvv.push_back(nullptr);
  close(fd);
  size_t i = 0;
  Argv_ = (char **)malloc(sizeof(char *) * (Argvv.size() + 1));
  for (auto &p : Argvv) {
    Argv_[i++] = p;
  }
  Argc_ = Argvv.size() - 1;
  return true;
}

int main() {
  /* code */
  auto pid = getpid();
  ProcessArgv argvX;
  if (argvX.Initialize(pid)) {
    fprintf(stderr, "Path %s\n", argvX.AbsolutePath().c_str());
    for (size_t i = 0; i < argvX.Argc(); i++) {
      fprintf(stderr, "%zu %s\n", i, argvX.Argv()[i]);
    }
  }
  return 0;
}