static int get_dev_mtd(const char *fdt_flash_path, char **mtd_path)
{
struct dirent **namelist;
char fdt_node_path[PATH_MAX];
int count, i, rc, fd;
bool done;
if (!fdt_flash_path)
return -1;
fd = open(fdt_flash_path, O_RDONLY);
if (fd == -1) {
fprintf(stderr, "Couldn't open '%s' FDT attribute to determine which flash device to use\n",
fdt_flash_path);
fprintf(stderr, "Does your skiboot new enough to expose the flash through the device tree?\n");
hint_root();
return -1;
}
rc = read(fd, fdt_node_path, sizeof(fdt_node_path));
close(fd);
if (rc == -1) {
fprintf(stderr, "Couldn't read flash FDT node from '%s'\n", fdt_flash_path);
hint_root();
return -1;
}
count = scandir(SYSFS_MTD_PATH, &namelist, NULL, alphasort);
if (count == -1) {
fprintf(stderr, "Couldn't scan '%s' for MTD\n", SYSFS_MTD_PATH);
hint_root();
return -1;
}
rc = 0;
done = false;
for (i = 0; i < count; i++) {
struct dirent *dirent;
char *dev_path;
char fdt_node_path_tmp[PATH_MAX];
dirent = namelist[i];
/*
* The call to asprintf must happen last as when it succeeds it
* will allocate dev_path
*/
if (dirent->d_name[0] == '.' || rc || done ||
asprintf(&dev_path, "%s/%s/device/of_node", SYSFS_MTD_PATH, dirent->d_name) < 0) {
free(namelist[i]);
continue;
}
rc = readlink(dev_path, fdt_node_path_tmp, sizeof(fdt_node_path_tmp) - 1);
free(dev_path);
if (rc == -1) {
/*
* This might fail because it could not exist if the system has flash
* devices that present as mtd but don't have corresponding FDT
* nodes, just continue silently.
*/
free(namelist[i]);
/* Should still try the next dir so reset rc */
rc = 0;
continue;
}
fdt_node_path_tmp[rc] = '\0';
if (strstr(fdt_node_path_tmp, fdt_node_path)) {
uint32_t flags, size;
/*
* size and flags could perhaps have be gotten another way but this
* method is super unlikely to fail so it will do.
*/
/* Check to see if device is writeable */
rc = get_dev_attr(dirent->d_name, "flags", &flags);
if (rc) {
free(namelist[i]);
continue;
}
/* Get the size of the mtd device while we're at it */
rc = get_dev_attr(dirent->d_name, "size", &size);
if (rc) {
free(namelist[i]);
continue;
}
rc = asprintf(&dev_path, "/dev/%s", dirent->d_name);
if (rc < 0) {
free(namelist[i]);
continue;
}
rc = 0;
*mtd_path = dev_path;
done = true;
}
free(namelist[i]);
}
free(namelist);
if (!done) {
fprintf(stderr, "Couldn't find '%s' corresponding MTD\n", fdt_flash_path);
fprintf(stderr, "Is your kernel new enough to expose MTD?\n");
}
/* explicit negative value so as to not return a libflash code */
return done ? rc : -1;
}
static int open_from_dev(struct gard_ctx *ctx, const char *fdt_flash_path)
{
struct dirent **namelist;
char fdt_node_path[PATH_MAX];
int count, i, rc, fd;
bool done;
if (!fdt_flash_path)
return -1;
fd = open(fdt_flash_path, O_RDONLY);
if (fd == -1) {
fprintf(stderr, "Couldn't open '%s' FDT attribute to determine which flash device to use\n",
fdt_flash_path);
return -1;
}
rc = read(fd, fdt_node_path, sizeof(fdt_node_path));
close(fd);
if (rc == -1) {
fprintf(stderr, "Couldn't read flash FDT node from '%s'\n", fdt_flash_path);
return -1;
}
count = scandir(SYSFS_MTD_PATH, &namelist, NULL, alphasort);
if (count == -1) {
fprintf(stderr, "Couldn't scan '%s' for MTD devices\n", SYSFS_MTD_PATH);
return -1;
}
rc = 0;
done = false;
for (i = 0; i < count; i++) {
struct dirent *dirent;
char dev_path[PATH_MAX] = SYSFS_MTD_PATH;
char fdt_node_path_tmp[PATH_MAX];
dirent = namelist[i];
if (dirent->d_name[0] == '.' || rc || done) {
free(namelist[i]);
continue;
}
strncat(dev_path, dirent->d_name, sizeof(dev_path) - strlen(dev_path) - 2);
strncat(dev_path, "/device/of_node", sizeof(dev_path) - strlen(dev_path) - 2);
rc = readlink(dev_path, fdt_node_path_tmp, sizeof(fdt_node_path_tmp) - 1);
if (rc == -1) {
/*
* This might fail because it could not exist if the system has flash
* devices that present as mtd but don't have corresponding FDT
* nodes, just continue silently.
*/
free(namelist[i]);
/* Should still try the next dir so reset rc */
rc = 0;
continue;
}
fdt_node_path_tmp[rc] = '\0';
if (strstr(fdt_node_path_tmp, fdt_node_path)) {
uint32_t flags, size;
/*
* size and flags could perhaps have be gotten another way but this
* method is super unlikely to fail so it will do.
*/
/* Check to see if device is writeable */
rc = get_dev_attr(dirent->d_name, "flags", &flags);
if (rc) {
free(namelist[i]);
continue;
}
/* Get the size of the mtd device while we're at it */
rc = get_dev_attr(dirent->d_name, "size", &size);
if (rc) {
free(namelist[i]);
continue;
}
strcpy(dev_path, "/dev/");
strncat(dev_path, dirent->d_name, sizeof(dev_path) - strlen(dev_path) - 2);
ctx->readonly = !(flags && MTD_WRITEABLE);
ctx->f_size = size;
ctx->fd = open(dev_path, ctx->readonly ? O_RDONLY : O_RDWR);
if (ctx->fd == -1) {
fprintf(stderr, "Couldn't open MTD device '%s' for %s as the system flash device\n",
dev_path, ctx->readonly ? "reading" : "read/write");
rc = -1;
}
done = true;
}
free(namelist[i]);
}
free(namelist);
if (!done)
fprintf(stderr, "Couldn't find '%s' corresponding MTD\n", fdt_flash_path);
/* explicit negative value so as to not return a libflash code */
return done ? rc : -1;
}
