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#endif
/* The module's file functions ********************** */
/* Here we keep the last message received, to prove
* that we can process our input */
#define MESSAGE_LENGTH 80
static char Message[MESSAGE_LENGTH];
/* Since we use the file operations struct, we can't use
* the special proc output provisions - we have to use
* a standard read function, which is this function */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
static size_t module_output(
struct file *file, /* The file read */
char *buf, /* The buffer to put data to (in the user segment) */
size_t len, /* The length of the buffer */
loff_t *offset) /* Offset in the file - ignore */
#else
static int module_output(
struct inode *inode, /* The inode read */
struct file *file, /* The file read */
char *buf, /* The buffer to put data to (in the user segment) */
int len) /* The length of the buffer */
#endif
{
static int finished = 0;
int i;
char message[MESSAGE_LENGTH+30];
/* Return 0 to signify end of file - that we have
* nothing more to say at this point. */
if (finished) {
finished = 0;
return 0;
}
/* If you don't understand this by now, you're
* hopeless as a kernel programmer. */
sprintf(message, "Last input:%s\n", Message);
for(i=0; i<len && message[i]; i++) put_user(message[i], buf+i);
finished = 1;
return i; /* Return the number of bytes "read" */
}
/* This function receives input from the user when
* the user writes to the /proc file. */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
static ssize_t module_input(
struct file *file, /* The file itself */
const char *buf, /* The buffer with input */
size_t length, /* The buffer's length */
loff_t *offset) /* offset to file - ignore */
#else
static int module_input(
struct inode *inode, /* The file's inode */
struct file *file, /* The file itself */
const char *buf, /* The buffer with the input */
int length) /* The buffer's length */
#endif
{
int i;
/* Put the input into Message, where module_output
* will later be able to use it */
for(i=0; i<MESSAGE_LENGTH-1 && i<length; i++)
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
get_user(Message[i], buf+i);
#else
Message[i] = get_user(buf+i);
#endif
/* we want a standard, zero terminated string */
Message[i] = '\0';
/* We need to return the number of input characters used */
return i;
}
/* 1 if the file is currently open by somebody */
int Already_Open = 0;
/* Queue of processes who want our file */
static struct wait_queue *WaitQ = NULL;
/* Called when the /proc file is opened */
static int module_open(struct inode *inode, struct file *file) {
/* If the file's flags include O_NONBLOCK, it means