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#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/inotify.h>
#include <unistd.h>
#include "Clean.h"
/** The empty string, as a CleanString */
static struct {int length; char chars[1]; } empty_string = {0,""};
/**
* Poll an inotify file descriptor
*
* fd The inotify file descriptor to poll
* timeout The timeout (negative for no timeout)
* re_nrevents Will be set to the number of polled events
* re_fd Will be set to fd (needed for uniqueness)
*/
void clean_poll(int fd, int timeout, int *re_nrevents, int *re_fd) {
struct pollfd pfd = {fd, POLLIN, 0};
*re_nrevents = poll(&pfd, 1, timeout);
*re_fd = fd;
}
/**
* CleanStrings that are returned from clean_inotify_check (so that we don't
* have to malloc all the time.)
*/
static CleanStringVariable(wds_string, 1024);
static CleanStringVariable(masks_string, 1024);
static CleanStringVariable(names_string, 4096);
/**
* Check for events on an inotify file descriptor.
*
* fd The inotify file descriptor
* re_ok Will be set to 1 on success, 0 on failure
* re_wds An array of ints, the watch descriptors that had events
* re_masks An array of ints, the events
* re_fnames A list of strings, the filenames of the events (may be empty)
* re_fd Will be set to fd (needed for uniqueness)
*
* re_wds, re_masks and re_fnames are hacks because ccall doesn't allow
* returning {#Int} or {#String}. The int arrays can be read by taking 4 chars
* at a time and casting that to an int. The string array can be read by
* splitting on \0 (since they are filenames, \0 cannot occur).
*/
void clean_inotify_check(int fd,
int *re_ok, CleanString* re_wds, CleanString* re_masks,
CleanString* re_fnames, int *re_fd) {
char buf[4096] __attribute__((aligned(__alignof__(struct inotify_event))));
const struct inotify_event *ev;
ssize_t len;
char *ptr;
struct pollfd pfd = {fd, POLLIN, 0};
int poll_n;
char *wds_ptr = CleanStringCharacters(wds_string);
char *masks_ptr = CleanStringCharacters(masks_string);
char *names_ptr = CleanStringCharacters(names_string);
CleanStringLength(wds_string) = 0;
CleanStringLength(masks_string) = 0;
CleanStringLength(names_string) = 0;
*re_ok = 0;
*re_fd = fd;
*re_wds = (CleanString) &empty_string;
*re_masks = (CleanString) &empty_string;
*re_fnames = (CleanString) &empty_string;
for (;;) {
poll_n = poll(&pfd, 1, 0);
if (poll_n < 0) {
return;
} else if (poll_n == 0) {
break;
}
len = read(fd, buf, sizeof buf);
if (len == -1 && errno != EAGAIN) {
return;
}
if (len <= 0) {
break;
}
for (ptr = buf; ptr < buf + len;
ptr += sizeof(struct inotify_event) + ev->len) {
ev = (const struct inotify_event*) ptr;
memcpy(masks_ptr, &ev->mask, 4);
masks_ptr += 4;
CleanStringLength(masks_string) += 4;
memcpy(wds_ptr, &ev->wd, sizeof(int));
wds_ptr += sizeof(int);
CleanStringLength(wds_string) += sizeof(int);
int len = strlen(ev->name);
memcpy(names_ptr, &ev->name, len);
names_ptr += len + 1;
*(names_ptr - 1) = '\00';
CleanStringLength(names_string) += len + 1;
}
}
*re_wds = (CleanString) wds_string;
*re_masks = (CleanString) masks_string;
*re_fnames = (CleanString) names_string;
*re_ok = 1;
}
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