Read /proc/interrupts

read_procfs.c

/**
 * Read /proc/interrupts and collect resulting current irq information into a list
 * filtered by a pattern adapted from irqbalance
 *
 * @param teb		Pointer to our teb
 * @param pattern	Pointer to const pattern to check in /proc/interrupts for
 * @param irq_head	Pointer to bl_pal_irq_info linked_list (initially empty)
 *
 * @retval		BL_OK on success, BL_ERR otherwise
 */
__BL_STATIC int
bl_pal_linux_collect_filtered_irq_list(bl_teb_t *teb,
                                       const char *pattern,
                                       bl_pal_irq_info_t **irq_head)
{
	FILE *file;
	char *line  = NULL;
	size_t size = 0;

	bl_assert(teb != NULL);
	bl_assert(!bl_empty(pattern));
	bl_assert(irq_head != NULL);

	file = fopen("/proc/interrupts", "r");
	if (!file)
	{
		bl_error_set_aux(
		    teb, BL_ERR_PAL_UNABLE_TO_OPEN_INTERRUPTS, errno, "/proc/interrupts");
		return BL_ERR;
	}

	/* first line is the header we don't need; nuke it */

	if (getline(&line, &size, file) <= 0)
	{
		bl_error_set_aux(
		    teb, BL_ERR_PAL_UNABLE_TO_READ_INTERRUPTS, errno, "getline()");

		/* we use free instead of bl_free as getline contains an internal realloc
		 * which we do not track */
		free(line);
		fclose(file);

		return BL_ERR;
	}

	while (!feof(file))
	{
		int irq_number;
		char *c;
		char *savedline = NULL;

		if (getline(&line, &size, file) <= 0)
			break;

		/* lines with letters in front are special, like NMI count. Ignore */
		c = line;
		while (bl_char_space(*c))
			c++;

		if (!bl_char_digit(*c))
			break;

		c = strchr(line, ':');
		if (!c)
			continue;

		/* skip if line doesn't contain pattern */
		if (strstr(line, pattern) == NULL)
			continue;

		/* remove trailing CR */
		bl_string_trim(line);

		savedline = bl_string_strdup(teb, line);

		*c         = '\0';
		irq_number = bl_strtoul(line);

		bl_pal_irq_info_t *irq_info = bl_malloc(teb, sizeof(bl_pal_irq_info_t));
		bl_pal_linux_init_irq_class_and_type(
		    teb, savedline, irq_info, irq_number);

		if (*irq_head != NULL)
			irq_info->next = *(irq_head);

		*irq_head = irq_info;

		/* we must bl_free the savedline as it was created via bl_string_dup which
		 * uses bl_malloc */

		bl_free(savedline);
	}

	fclose(file);

	/* we use free instead of bl_free as getline contains an internal realloc which we
	 * do not track */

	free(line);

	return BL_OK;
}