121 lines
2.0 KiB
C
121 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright (c) 2010 Mohamed Naufal Basheer
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// Author: Mohamed Naufal Basheer
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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/*
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* Named pipe to act as a communication channel between
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* shell script & this process
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*/
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#define STATUS_PIPE "status_pipe"
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int flag_exit;
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int flag_allocated;
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unsigned long memsize;
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/*
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* process_options: process user specified options
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*/
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void process_options(int argc, char **argv)
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{
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int c;
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char *end;
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opterr = 0;
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while ((c = getopt(argc, argv, "pm:")) != -1) {
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switch (c) {
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case 'm':
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memsize = strtoul(optarg, &end, 10);
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if (*end != '\0')
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errx(2, "invalid -m usage");
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break;
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default:
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errx(2, "invalid option specified");
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}
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}
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if (memsize <= 0)
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errx(3, "invalid usage");
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}
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/*
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* touch_memory: force physical memory allocation
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*/
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void touch_memory(char *p)
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{
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int i;
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int pagesize = getpagesize();
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for (i = 0; i < (int)memsize; i += pagesize)
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p[i] = 0xef;
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}
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void mem_map(void)
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{
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static char *p;
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if (flag_allocated) {
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if (munmap(p, memsize) == -1)
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err(5, "munmap failed");
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} else {
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p = mmap(NULL, memsize, PROT_READ | PROT_WRITE,
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MAP_SHARED | MAP_ANONYMOUS, 0, 0);
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if (p == MAP_FAILED)
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err(4, "mmap failed");
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touch_memory(p);
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}
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flag_allocated = !flag_allocated;
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}
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/*
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* done: retrieve instructions from the named pipe
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*/
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char action(int fd)
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{
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char ch;
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if (read(fd, &ch, 1) == -1)
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err(7, "Error reading named pipe");
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return ch;
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}
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int main(int argc, char **argv)
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{
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int ret;
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int fd;
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char ch;
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process_options(argc, argv);
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ret = mkfifo(STATUS_PIPE, 0666);
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if (ret == -1 && errno != EEXIST)
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errx(1, "Error creating named pipe");
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if ((fd = open(STATUS_PIPE, O_RDONLY)) == -1)
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err(6, "Error opening named pipe");
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do {
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ch = action(fd);
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if (ch == 'm')
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mem_map();
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} while (ch != 'x');
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close(fd);
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remove(STATUS_PIPE);
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return 0;
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}
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