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Commit 5f036ab8 authored by Yabin Cui's avatar Yabin Cui
Browse files

libprocinfo: return error msg instead of printing it. 

So users can decide whether to print error msg or not.

Bug: none
Test: run libprocinfo_test.
Change-Id: Ie1afcb58cb97493c7ffade6841b6eb7a800a3981
parent a54c2938

libprocinfo/include/procinfo/process.h

+17 −9
Original line number Diff line number Diff line
@@ -56,23 +56,25 @@ struct ProcessInfo { 
};



// Parse the contents of /proc/<tid>/status into |process_info|.

bool GetProcessInfo(pid_t tid, ProcessInfo* process_info);

bool GetProcessInfo(pid_t tid, ProcessInfo* process_info, std::string* error = nullptr);



// Parse the contents of <fd>/status into |process_info|.

// |fd| should be an fd pointing at a /proc/<pid> directory.

bool GetProcessInfoFromProcPidFd(int fd, ProcessInfo* process_info);

bool GetProcessInfoFromProcPidFd(int fd, ProcessInfo* process_info, std::string* error = nullptr);



// Fetch the list of threads from a given process's /proc/<pid> directory.

// |fd| should be an fd pointing at a /proc/<pid> directory.

template <typename Collection>

auto GetProcessTidsFromProcPidFd(int fd, Collection* out) ->

auto GetProcessTidsFromProcPidFd(int fd, Collection* out, std::string* error = nullptr) ->

    typename std::enable_if<sizeof(typename Collection::value_type) >= sizeof(pid_t), bool>::type {

  out->clear();



  int task_fd = openat(fd, "task", O_DIRECTORY | O_RDONLY | O_CLOEXEC);

  std::unique_ptr<DIR, int (*)(DIR*)> dir(fdopendir(task_fd), closedir);

  if (!dir) {

    PLOG(ERROR) << "failed to open task directory";

    if (error != nullptr) {

      *error = "failed to open task directory";

    }

    return false;

  }
@@ -81,7 +83,9 @@ auto GetProcessTidsFromProcPidFd(int fd, Collection* out) -> 
    if (strcmp(dent->d_name, ".") != 0 && strcmp(dent->d_name, "..") != 0) {

      pid_t tid;

      if (!android::base::ParseInt(dent->d_name, &tid, 1, std::numeric_limits<pid_t>::max())) {

        LOG(ERROR) << "failed to parse task id: " << dent->d_name;

        if (error != nullptr) {

          *error = std::string("failed to parse task id: ") + dent->d_name;

        }

        return false;

      }
@@ -93,21 +97,25 @@ auto GetProcessTidsFromProcPidFd(int fd, Collection* out) -> 
}



template <typename Collection>

auto GetProcessTids(pid_t pid, Collection* out) ->

auto GetProcessTids(pid_t pid, Collection* out, std::string* error = nullptr) ->

    typename std::enable_if<sizeof(typename Collection::value_type) >= sizeof(pid_t), bool>::type {

  char task_path[PATH_MAX];

  if (snprintf(task_path, PATH_MAX, "/proc/%d", pid) >= PATH_MAX) {

    LOG(ERROR) << "task path overflow (pid = " << pid << ")";

    if (error != nullptr) {

      *error = "task path overflow (pid = " + std::to_string(pid) + ")";

    }

    return false;

  }



  android::base::unique_fd fd(open(task_path, O_DIRECTORY | O_RDONLY | O_CLOEXEC));

  if (fd == -1) {

    PLOG(ERROR) << "failed to open " << task_path;

    if (error != nullptr) {

      *error = std::string("failed to open ") + task_path;

    }

    return false;

  }



  return GetProcessTidsFromProcPidFd(fd.get(), out);

  return GetProcessTidsFromProcPidFd(fd.get(), out, error);

}



#endif

libprocinfo/process.cpp

+12 −6
Original line number Diff line number Diff line
@@ -31,17 +31,19 @@ using android::base::unique_fd; 
namespace android {

namespace procinfo {



bool GetProcessInfo(pid_t tid, ProcessInfo* process_info) {

bool GetProcessInfo(pid_t tid, ProcessInfo* process_info, std::string* error) {

  char path[PATH_MAX];

  snprintf(path, sizeof(path), "/proc/%d", tid);



  unique_fd dirfd(open(path, O_DIRECTORY | O_RDONLY));

  if (dirfd == -1) {

    PLOG(ERROR) << "failed to open " << path;

    if (error != nullptr) {

      *error = std::string("failed to open ") + path;

    }

    return false;

  }



  return GetProcessInfoFromProcPidFd(dirfd.get(), process_info);

  return GetProcessInfoFromProcPidFd(dirfd.get(), process_info, error);

}



static ProcessState parse_state(const char* state) {
@@ -62,17 +64,21 @@ static ProcessState parse_state(const char* state) { 
  }

}



bool GetProcessInfoFromProcPidFd(int fd, ProcessInfo* process_info) {

bool GetProcessInfoFromProcPidFd(int fd, ProcessInfo* process_info, std::string* error) {

  int status_fd = openat(fd, "status", O_RDONLY | O_CLOEXEC);



  if (status_fd == -1) {

    PLOG(ERROR) << "failed to open status fd in GetProcessInfoFromProcPidFd";

    if (error != nullptr) {

      *error = "failed to open status fd in GetProcessInfoFromProcPidFd";

    }

    return false;

  }



  std::unique_ptr<FILE, decltype(&fclose)> fp(fdopen(status_fd, "r"), fclose);

  if (!fp) {

    PLOG(ERROR) << "failed to open status file in GetProcessInfoFromProcPidFd";

    if (error != nullptr) {

      *error = "failed to open status file in GetProcessInfoFromProcPidFd";

    }

    close(status_fd);

    return false;

  }