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/*
* Append some random characters to a file
*
* Just a small tool to debug inotify
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#define DEFAULT_N_CHARS 1024
static char get_random_printable_char(void)
{
int fd;
char ret;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
perror("open");
exit(EXIT_FAILURE);
}
do {
read(fd, &ret, sizeof(ret));
} while (ret < 0x20 || ret > 0x7e);
close(fd);
return ret;
}
int main(int argc, char *argv[])
{
int fd, n_chars, i;
char *str;
if (argc < 3) {
fprintf(stderr, "Usage: %s <file> <n_chars>\n", argv[0]);
exit(EXIT_FAILURE);
}
/* Open the file, create it in case it doesn't exist */
if ((fd = open(argv[1], O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)) < 0) {
perror("open");
exit(EXIT_FAILURE);
}
if (lseek(fd, 0, SEEK_END) < 0) {
perror("lseek");
exit(EXIT_FAILURE);
}
n_chars = strtoul(argv[2], NULL, 0);
if (n_chars <= 0) {
fprintf(stderr, "Invalid number of characters: %d\n", n_chars);
n_chars = DEFAULT_N_CHARS;
}
str = malloc(n_chars * sizeof(char));
if (!str) {
perror("malloc");
exit(EXIT_FAILURE);
}
for (i = 0; i < n_chars; i++)
str[i] = get_random_printable_char();
write(fd, str, n_chars);
free(str);
close(fd);
exit(EXIT_SUCCESS);
}
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