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#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include "procfs.hpp"
#include "errno.hpp"
#include "fs_close.hpp"
#include "fs_open.hpp"
#include "fs_openat.hpp"
#include "fs_read.hpp"
#include "fmt/core.h"
#include <array>
#include <cassert>
#include <pthread.h>
static int g_PROCFS_DIR_FD = -1;
namespace procfs { int PROC_SELF_FD_FD = -1; }
static constexpr const char PROCFS_PATH[] = "/proc";
static constexpr const char PROC_SELF_FD[] = "/proc/self/fd";
// This is critical to the function of the app. abort if failed to
// open.
static
void
_open_proc_self_fd()
{
procfs::PROC_SELF_FD_FD = fs::open(PROC_SELF_FD,O_PATH|O_DIRECTORY);
assert(procfs::PROC_SELF_FD_FD >= 0);
}
int
procfs::init()
{
int rv;
if(g_PROCFS_DIR_FD >= 0)
return 0;
rv = fs::open(PROCFS_PATH,O_PATH|O_DIRECTORY);
if(rv < 0)
return rv;
g_PROCFS_DIR_FD = rv;
#if defined(__linux__)
::_open_proc_self_fd();
#endif
return 0;
}
std::string
procfs::get_name(const int tid_)
{
int fd;
int rv;
std::array<char,256> commpath;
fmt::format_to_n_result<char*> frv;
frv = fmt::format_to_n(commpath.data(),commpath.size()-1,"{}/comm",tid_);
frv.out[0] = '\0';
fd = fs::openat(g_PROCFS_DIR_FD,commpath.data(),O_RDONLY);
if(fd < 0)
return {};
rv = fs::read(fd,commpath.data(),commpath.size());
if(rv < 0)
return {};
// Overwrite the newline with NUL
commpath[rv-1] = '\0';
fs::close(fd);
return commpath.data();
}