core: rework line handle & event requests

In order to correctly handle bulk requests create a separate,
refcounted structure for handle data.

Put the handle and event fields of struct gpiod_line into a union as
they can't be shared.

Add relevant helpers and use them in appropriate places.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

diff --git a/core.c b/core.c
index bb45e294715c2d0d757a73f2334638e5fc5e5989..8056e9fdaa771292316a12f6d1d1b67cdd885544 100644 (file)
--- a/core.c
+++ b/core.c
@@ -36,13 +36,20 @@ enum {
        LINE_EVENT,
 };
 
+struct handle_data {
+       struct gpiohandle_request request;
+       int refcount;
+};
+
 struct gpiod_line {
        int state;
        bool up_to_date;
        struct gpiod_chip *chip;
        struct gpioline_info info;
-       struct gpiohandle_request *request;
-       struct gpioevent_request event;
+       union {
+               struct handle_data *handle;
+               struct gpioevent_request event;
+       };
 };
 
 struct gpiod_chip_iter
@@ -242,6 +249,45 @@ static void line_set_state(struct gpiod_line *line, int state)
        line->state = state;
 }
 
+static int line_get_handle_fd(struct gpiod_line *line)
+{
+       if (line_get_state(line) != LINE_TAKEN)
+               return -1;
+       else
+               return line->handle->request.fd;
+}
+
+static int line_get_event_fd(struct gpiod_line *line)
+{
+       if (line_get_state(line) != LINE_EVENT)
+               return -1;
+       else
+               return line->event.fd;
+}
+
+static void line_set_handle(struct gpiod_line *line,
+                           struct handle_data *handle)
+{
+       line->handle = handle;
+       handle->refcount++;
+}
+
+static void line_remove_handle(struct gpiod_line *line)
+{
+       struct handle_data *handle;
+
+       if (!line->handle)
+               return;
+
+       handle = line->handle;
+       line->handle = NULL;
+       handle->refcount--;
+       if (handle->refcount <= 0) {
+               close(handle->request.fd);
+               free(handle);
+       }
+}
+
 unsigned int gpiod_line_offset(struct gpiod_line *line)
 {
        return (unsigned int)line->info.line_offset;
@@ -360,6 +406,7 @@ int gpiod_line_request_bulk(struct gpiod_line_bulk *line_bulk,
                            int *default_vals)
 {
        struct gpiohandle_request *req;
+       struct handle_data *handle;
        struct gpiod_chip *chip;
        struct gpiod_line *line;
        int status, fd;
@@ -368,10 +415,12 @@ int gpiod_line_request_bulk(struct gpiod_line_bulk *line_bulk,
        if (!verify_line_bulk(line_bulk))
                return -1;
 
-       req = zalloc(sizeof(*req));
-       if (!req)
+       handle = zalloc(sizeof(*handle));
+       if (!handle)
                return -1;
 
+       req = &handle->request;
+
        if (config->flags & GPIOD_REQUEST_OPEN_DRAIN)
                req->flags |= GPIOHANDLE_REQUEST_OPEN_DRAIN;
        if (config->flags & GPIOD_REQUEST_OPEN_SOURCE)
@@ -406,7 +455,7 @@ int gpiod_line_request_bulk(struct gpiod_line_bulk *line_bulk,
        for (i = 0; i < line_bulk->num_lines; i++) {
                line = line_bulk->lines[i];
 
-               line->request = req;
+               line_set_handle(line, handle);
                line_set_state(line, LINE_TAKEN);
                /*
                 * Update line info to include the changes after the
@@ -436,13 +485,10 @@ void gpiod_line_release_bulk(struct gpiod_line_bulk *line_bulk)
        unsigned int i;
        int status;
 
-       close(line_bulk->lines[0]->request->fd);
-       free(line_bulk->lines[0]->request);
-
        for (i = 0; i < line_bulk->num_lines; i++) {
                line = line_bulk->lines[i];
 
-               line->request = NULL;
+               line_remove_handle(line);
                line_set_state(line, LINE_FREE);
 
                status = gpiod_line_update(line);
@@ -501,7 +547,7 @@ int gpiod_line_get_value_bulk(struct gpiod_line_bulk *line_bulk, int *values)
 
        memset(&data, 0, sizeof(data));
 
-       status = gpio_ioctl(line_bulk->lines[0]->request->fd,
+       status = gpio_ioctl(line_get_handle_fd(line_bulk->lines[0]),
                            GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);
        if (status < 0)
                return -1;
@@ -538,7 +584,7 @@ int gpiod_line_set_value_bulk(struct gpiod_line_bulk *line_bulk, int *values)
        for (i = 0; i < line_bulk->num_lines; i++)
                data.values[i] = (__u8)!!values[i];
 
-       status = gpio_ioctl(line_bulk->lines[0]->request->fd,
+       status = gpio_ioctl(line_get_handle_fd(line_bulk->lines[0]),
                            GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data);
        if (status < 0)
                return -1;
@@ -628,7 +674,7 @@ int gpiod_line_event_request(struct gpiod_line *line,
 
 void gpiod_line_event_release(struct gpiod_line *line)
 {
-       close(line->event.fd);
+       close(line_get_event_fd(line));
        line_set_state(line, LINE_FREE);
 }
 
@@ -679,7 +725,7 @@ int gpiod_line_event_wait_bulk(struct gpiod_line_bulk *bulk,
        for (i = 0; i < bulk->num_lines; i++) {
                linetmp = bulk->lines[i];
 
-               fds[i].fd = linetmp->event.fd;
+               fds[i].fd = line_get_event_fd(linetmp);
                fds[i].events = POLLIN | POLLPRI;
        }
 
@@ -711,7 +757,7 @@ int gpiod_line_event_read(struct gpiod_line *line,
 
        memset(&evdata, 0, sizeof(evdata));
 
-       rd = read(line->event.fd, &evdata, sizeof(evdata));
+       rd = read(line_get_event_fd(line), &evdata, sizeof(evdata));
        if (rd < 0) {
                last_error_from_errno();
                return -1;
@@ -730,7 +776,8 @@ int gpiod_line_event_read(struct gpiod_line *line,
 
 int gpiod_line_event_get_fd(struct gpiod_line *line)
 {
-       return line_get_state(line) == LINE_EVENT ? line->event.fd : -1;
+       return line_get_state(line) == LINE_EVENT
+                               ? line_get_event_fd(line) : -1;
 }
 
 struct gpiod_chip * gpiod_chip_open(const char *path)