mirror of
https://github.com/trapexit/mergerfs.git
synced 2026-10-26 10:51:52 -04:00
107 lines
2.7 KiB
C++
107 lines
2.7 KiB
C++
/*
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ISC License
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Copyright (c) 2026, Antonio SJ Musumeci <trapexit@spawn.link>
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef _GNU_SOURCE
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#define _GNU_SOURCE
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#endif
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#include "procfs.hpp"
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#include "fatal.hpp"
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#include "fs_close.hpp"
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#include "fs_open.hpp"
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#include "fs_openat.hpp"
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#include "fs_read.hpp"
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#include "fmt/core.h"
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#include "scope_guard/scope_guard.hpp"
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#include <array>
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#include <cstring>
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static int g_PROCFS_DIR_FD = -1;
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namespace procfs { int PROC_SELF_FD_FD = -1; }
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static constexpr const char PROCFS_PATH[] = "/proc";
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void
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procfs::init()
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{
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if(g_PROCFS_DIR_FD >= 0)
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return;
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g_PROCFS_DIR_FD = fs::open(PROCFS_PATH,O_PATH|O_DIRECTORY);
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if(g_PROCFS_DIR_FD < 0)
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fatal::abort("failed to open {}: {}",PROCFS_PATH,strerror(-g_PROCFS_DIR_FD));
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#if defined(__linux__)
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static constexpr const char PROC_SELF_FD[] = "/proc/self/fd";
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procfs::PROC_SELF_FD_FD = fs::open(PROC_SELF_FD,O_PATH|O_DIRECTORY);
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if(procfs::PROC_SELF_FD_FD < 0)
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fatal::abort("failed to open /proc/self/fd: {}",strerror(-procfs::PROC_SELF_FD_FD));
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#endif
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}
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void
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procfs::shutdown()
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{
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if(g_PROCFS_DIR_FD >= 0)
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{
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fs::close(g_PROCFS_DIR_FD);
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g_PROCFS_DIR_FD = -1;
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}
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#if defined(__linux__)
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if(procfs::PROC_SELF_FD_FD >= 0)
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{
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fs::close(procfs::PROC_SELF_FD_FD);
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procfs::PROC_SELF_FD_FD = -1;
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}
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#endif
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}
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std::string
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procfs::get_name(const int tid_)
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{
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int fd;
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int rv;
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std::array<char,256> commpath;
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fmt::format_to_n_result<char*> frv;
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if(g_PROCFS_DIR_FD < 0)
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fatal::abort("procfs::get_name called before procfs::init()");
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// Reserve 1 byte for the NUL terminator that format_to_n does not write.
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frv = fmt::format_to_n(commpath.data(),commpath.size()-1,"{}/comm",tid_);
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frv.out[0] = '\0';
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fd = fs::openat(g_PROCFS_DIR_FD,commpath.data(),O_RDONLY);
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if(fd < 0)
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return {};
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DEFER { fs::close(fd); };
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rv = fs::read(fd,commpath.data(),commpath.size()-1);
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if(rv <= 0)
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return {};
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if(commpath[rv-1] == '\n')
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commpath[rv-1] = '\0';
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else
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commpath[rv] = '\0';
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return commpath.data();
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}
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