mirror of
https://github.com/trapexit/mergerfs.git
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97 lines
2.5 KiB
C++
97 lines
2.5 KiB
C++
/*
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The MIT License (MIT)
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Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <grp.h>
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#include <pwd.h>
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#include <map>
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#include <vector>
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namespace mergerfs
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{
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namespace ugid
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{
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extern __thread uid_t currentuid;
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extern __thread gid_t currentgid;
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extern __thread bool initialized;
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struct Set
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{
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Set(const uid_t newuid,
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const gid_t newgid)
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{
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if(!initialized)
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{
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currentuid = ::syscall(SYS_geteuid);
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currentgid = ::syscall(SYS_getegid);
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initialized = true;
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}
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if(newuid == currentuid && newgid == currentgid)
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return;
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if(currentuid != 0)
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{
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::syscall(SYS_setreuid,-1,0);
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::syscall(SYS_setregid,-1,0);
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}
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if(newgid)
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{
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::syscall(SYS_setregid,-1,newgid);
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initgroups(newuid,newgid);
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}
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if(newuid)
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::syscall(SYS_setreuid,-1,newuid);
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currentuid = newuid;
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currentgid = newgid;
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}
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};
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struct SetRootGuard
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{
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SetRootGuard() :
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prevuid(currentuid),
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prevgid(currentgid)
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{
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Set(0,0);
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}
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~SetRootGuard()
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{
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Set(prevuid,prevgid);
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}
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const uid_t prevuid;
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const gid_t prevgid;
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};
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}
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}
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