Ok idk how i can use it… but…
Mknode Console Example
mknod [params] filename filetype [major number] [minor number]
params - you can see all in man ( in this example -m 0777 - set file permission bits)
filename - it filename=)
filetype - type can be 3 types:
p
for a FIFO
b
for a block special file
c
for a character special file\
Major number - devices accordantly doc devices
Minor number - idk…
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mknod -m 0777 /dev/loop10 b 7 10
Decribe:
Create - /dev/loop10
Type - b (its mean block)
Major number (Device) - 7 (“block Loopback”)
Minor number - 10 (idk how to use it, i think its will be equval loop number) \
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mount -o loop=/dev/loop8 openSUSE-Leap-15.4-DVD-x86_64-Build243.2-Media.iso /mnt
#mount: /mnt: WARNING: source write-protected, mounted read-only
Ok its work.. Also with mknod we can create FIFO
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mknod -m 777 /home/peter/fifo p
Same:
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mkfifo /home/peter/fifo
Type - p mean its pipe
We can check it do:
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tail -f /home/peter/fifo > /tmp/testfifo.log
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echo "OLOLOL" >> /home/peter/fifo
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cat /tmp/testfifo.log
We can see - OLOLOL
Remove fifo
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unlink /home/peter/fifo
Mknode C Example
Ok there we need client and server:
client.c
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#include <stdio.h>
#include <stdlib.h>
#define FIFO_FILE "myFifo"
int main(int argc, char *argv[])
{
FILE *fp;
if ( argc != 2 ) {
printf("USAGE: fifoclient [string]\n");
exit(1);
}
if((fp = fopen(FIFO_FILE, "w")) == NULL) {
perror("fopen");
exit(1);
}
fputs(argv[1], fp);
fclose(fp);
return(0);
}
server.c
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#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>
#define FIFO_FILE "myFifo"
int main(void)
{
FILE *fp;
char readbuf[80];
/* Create the FIFO if it does not exist */
umask(0);
mknod(FIFO_FILE, S_IFIFO|0667, 0);
while(1)
{
fp = fopen(FIFO_FILE, "r");
fgets(readbuf, 80, fp);
printf("Received string: %s\n", readbuf);
fclose(fp);
}
return(0);
}
Start Server
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gcc server.c -o server
./server
Start Client
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gcc client.c -o client
./client ololol
In server terminal we can se ololol
Links
- how-to-add-more-dev-loop-devices-on-fedora-19
- komanda-mknod
- creating-fifo-in-c-using-mknod-system-call
