54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
/*
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* Copyright (c) 2024 Alexey Dobriyan <adobriyan@gmail.com>
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*
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* Permission to use, copy, modify, and 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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*
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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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/* Test that kernel thread is reported as such. */
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#undef NDEBUG
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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int main(void)
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{
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/*
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* The following solutions don't really work:
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*
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* 1) jit kernel module which creates kernel thread:
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* test becomes arch-specific,
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* problems with mandatory module signing,
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* problems with lockdown mode,
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* doesn't work with CONFIG_MODULES=n at all,
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* kthread creation API is formally unstable internal kernel API,
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* need a mechanism to report test kernel thread's PID back,
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*
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* 2) ksoftirqd/0 and kswapd0 look like stable enough kernel threads,
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* but their PIDs are unstable.
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*
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* Check against kthreadd which always seem to exist under pid 2.
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*/
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int fd = open("/proc/2/status", O_RDONLY);
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assert(fd >= 0);
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char buf[4096];
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ssize_t rv = read(fd, buf, sizeof(buf));
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assert(0 <= rv && rv < sizeof(buf));
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buf[rv] = '\0';
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assert(strstr(buf, "Kthread:\t1\n"));
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return 0;
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}
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