static int write_sysfs_str(char *path, enum cxl_sysfs_attr attr, char *str)
{
char *attr_name;
char *attr_path;
int fd, count;
if (OUT_OF_RANGE(attr))
return -1;
if (path == NULL)
return -1;
attr_name = sysfs_attr_name(attr);
if (attr_name == NULL)
return -1;
attr_path = sysfs_get_path(path, attr_name);
if (attr_path == NULL)
return -1;
fd = open(attr_path, O_WRONLY);
free(attr_path);
if (fd == -1)
return -1;
count = write(fd, str, strlen(str));
close(fd);
if (count == -1)
return -1;
return 0;
}
static char *sysfs_get_path(char *path, enum cxl_sysfs_attr attr)
{
char *attr_path = NULL;
char *new_path;
struct stat sb;
char *attr_name;
attr_name = sysfs_attr_name(attr);
if (attr_name == NULL)
return NULL;
path = strdup(path);
if (path == NULL)
return NULL;
/*
* Try to open the attribute in sysfs. If it doesn't exist, keep
* following "device/" path down until we find it.
*/
while (stat(path, &sb) != -1) {
if (asprintf(&attr_path, "%s/%s", path, attr_name) == -1)
goto out;
if (stat(attr_path, &sb) == 0) {
free(path);
return attr_path;
}
if (errno != ENOENT)
/* Something unexpected beside it not existing */
goto enodev;
/* If it doesn't exist, walk down "device/" link */
if (asprintf(&new_path, "%s/device", path) == -1)
goto out;
free(path);
path = new_path;
free(attr_path);
}
/* Directory doesn't exist */
enodev:
errno = ENODEV;
out:
if (attr_path)
free(attr_path);
free(path);
return NULL;
}
static int read_sysfs(char *sysfs_path, enum cxl_sysfs_attr attr, long *majorp,
long *minorp)
{
char *attr_name;
char *attr_path;
char *buf;
int expected, ret;
if (OUT_OF_RANGE(attr))
return -1;
attr_name = sysfs_attr_name(attr);
if (attr_name == NULL)
return -1;
/*
* Hack:
* For configuration record attributes, attr_name is a printf
* format with one parameter, the configuration record number,
* pointed to by minorp.
*/
switch (attr) {
case CR_CLASS:
case CR_DEVICE:
case CR_VENDOR:
if (asprintf(&buf, attr_name, *minorp) == -1)
return -1;
attr_path = sysfs_get_path(sysfs_path, buf);
free(buf);
break;
default:
attr_path = sysfs_get_path(sysfs_path, attr_name);
}
if (attr_path == NULL)
return -1;
if ((buf = read_sysfs_str(attr_path)) == NULL)
return -1;
expected = sysfs_entry[attr].expected_num;
ret = scan_sysfs_str(attr, buf, majorp, minorp);
free(buf);
return (ret == expected) ? 0 : -1;
}