72 lines
2.1 KiB
C
72 lines
2.1 KiB
C
/* midmesg - Display Linux kernel log information
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*
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* MIT License
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*
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* Copyright (c) 2021 Alinur Songül
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*
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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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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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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 THE
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* SOFTWARE. */
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#include <sys/klog.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <stdarg.h>
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#define PROGRAM "midmesg"
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#define eprintf(...) fprintf(stderr, __VA_ARGS__)
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int main()
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{
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int kbuf_unread_size;
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/* Get the number of all unread bytes in
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* the kernel ring buffer */
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kbuf_unread_size = klogctl(9, NULL, 0);
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if (kbuf_unread_size < 0)
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{
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eprintf("%s: unable to read log buffer: %s\n",
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PROGRAM, strerror(errno));
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exit(errno);
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}
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/* allocate memory for kernel log to be stored in memory */
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char* kbuf = (char*)malloc(kbuf_unread_size);
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printf("Waiting for klogctl...");
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int read_bytes = klogctl(2, kbuf, kbuf_unread_size);
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if (read_bytes != -1)
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printf("Read %d bytes\n\n", read_bytes);
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else {
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eprintf("%s\n", strerror(errno));
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free(kbuf); /* free up leftover allocated memory */
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exit(errno);
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}
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printf("%s\n", kbuf);
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free(kbuf);
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return 0;
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}
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