--- /dev/null
+// SPDX-License-Identifier: LGPL-2.1-or-later
+// SPDX-FileCopyrightText: 2021-2022 Bartosz Golaszewski <brgl@bgdev.pl>
+
+#include <errno.h>
+#include <libkmod.h>
+#include <libmount.h>
+#include <linux/version.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/random.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/utsname.h>
+#include <unistd.h>
+
+#include "gpiosim.h"
+
+#define GPIOSIM_API __attribute__((visibility("default")))
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
+/* FIXME Change the minimum version to v5.17.0 once released. */
+#define MIN_KERNEL_VERSION KERNEL_VERSION(5, 16, 0)
+
+struct refcount {
+ unsigned int cnt;
+ void (*release)(struct refcount *);
+};
+
+static void refcount_init(struct refcount *ref,
+ void (*release)(struct refcount *))
+{
+ ref->cnt = 1;
+ ref->release = release;
+}
+
+static void refcount_inc(struct refcount *ref)
+{
+ ref->cnt++;
+}
+
+static void refcount_dec(struct refcount *ref)
+{
+ ref->cnt--;
+
+ if (!ref->cnt)
+ ref->release(ref);
+}
+
+struct list_head {
+ struct list_head *prev;
+ struct list_head *next;
+};
+
+static void list_init(struct list_head *list)
+{
+ list->next = list;
+ list->prev = list;
+}
+
+static void list_add(struct list_head *new, struct list_head *head)
+{
+ struct list_head *prev = head->prev;
+
+ head->prev = new;
+ new->next = head;
+ new->prev = prev;
+ prev->next = new;
+}
+
+static void list_del(struct list_head *entry)
+{
+ struct list_head *prev = entry->prev, *next = entry->next;
+
+ prev->next = next;
+ next->prev = prev;
+}
+
+#define container_of(ptr, type, member) ({ \
+ void *__mptr = (void *)(ptr); \
+ ((type *)(__mptr - offsetof(type, member))); \
+})
+
+#define list_entry(ptr, type, member) \
+ container_of(ptr, type, member)
+
+#define list_first_entry(ptr, type, member) \
+ list_entry((ptr)->next, type, member)
+
+#define list_next_entry(pos, member) \
+ list_entry((pos)->member.next, typeof(*(pos)), member)
+
+#define list_entry_is_head(pos, head, member) \
+ (&pos->member == (head))
+
+#define list_for_each_entry(pos, head, member) \
+ for (pos = list_first_entry(head, typeof(*pos), member); \
+ !list_entry_is_head(pos, head, member); \
+ pos = list_next_entry(pos, member))
+
+static int open_write_close(int base_fd, const char *where, const char *what)
+{
+ ssize_t written, size;
+ int fd;
+
+ if (what)
+ size = strlen(what) + 1;
+ else
+ size = 1;
+
+ fd = openat(base_fd, where, O_WRONLY);
+ if (fd < 0)
+ return -1;
+
+ written = write(fd, what ?: "", size);
+ close(fd);
+ if (written < 0) {
+ return -1;
+ } else if (written != size) {
+ errno = EIO;
+ return -1;
+ }
+
+ return 0;
+}
+
+static int open_read_close(int base_fd, const char *where,
+ char *buf, size_t bufsize)
+{
+ ssize_t rd;
+ int fd;
+
+ fd = openat(base_fd, where, O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ memset(buf, 0, bufsize);
+ rd = read(fd, buf, bufsize);
+ close(fd);
+ if (rd < 0)
+ return -1;
+
+ if (buf[rd - 1] == '\n')
+ buf[rd - 1] = '\0';
+
+ return 0;
+}
+
+static int check_kernel_version(void)
+{
+ unsigned int major, minor, release;
+ struct utsname un;
+ int ret;
+
+ ret = uname(&un);
+ if (ret)
+ return -1;
+
+ ret = sscanf(un.release, "%u.%u.%u", &major, &minor, &release);
+ if (ret != 3) {
+ errno = EFAULT;
+ return -1;
+ }
+
+ if (KERNEL_VERSION(major, minor, release) < MIN_KERNEL_VERSION) {
+ errno = EOPNOTSUPP;
+ return -1;
+ }
+
+ return 0;
+}
+
+static int check_gpiosim_module(void)
+{
+ struct kmod_module *module;
+ struct kmod_ctx *kmod;
+ const char *modpath;
+ int ret, initstate;
+
+ kmod = kmod_new(NULL, NULL);
+ if (!kmod)
+ return -1;
+
+ ret = kmod_module_new_from_name(kmod, "gpio-sim", &module);
+ if (ret)
+ goto out_unref_kmod;
+
+again:
+ /* First check if the module is already loaded or built-in. */
+ initstate = kmod_module_get_initstate(module);
+ if (initstate < 0) {
+ if (errno == ENOENT) {
+ /*
+ * It's not loaded, let's see if we can do it manually.
+ * See if we can find the module.
+ */
+ modpath = kmod_module_get_path(module);
+ if (!modpath) {
+ /* libkmod doesn't set errno. */
+ errno = ENOENT;
+ ret = -1;
+ goto out_unref_module;
+ }
+
+ ret = kmod_module_probe_insert_module(module,
+ KMOD_PROBE_IGNORE_LOADED,
+ NULL, NULL, NULL, NULL);
+ if (ret)
+ goto out_unref_module;
+
+ goto again;
+ } else {
+ if (errno == 0)
+ errno = EOPNOTSUPP;
+
+ goto out_unref_module;
+ }
+ }
+
+ if (initstate != KMOD_MODULE_BUILTIN &&
+ initstate != KMOD_MODULE_LIVE &&
+ initstate != KMOD_MODULE_COMING) {
+ errno = EPERM;
+ goto out_unref_module;
+ }
+
+ ret = 0;
+
+out_unref_module:
+ kmod_module_unref(module);
+out_unref_kmod:
+ kmod_unref(kmod);
+ return ret;
+}
+
+/* We don't have mkdtempat()... :( */
+static char *make_random_dir_at(int at)
+{
+ static const char chars[] = "abcdefghijklmnoprstquvwxyz"
+ "ABCDEFGHIJKLMNOPRSTQUVWXYZ"
+ "0123456789";
+
+ char name[] = "XXXXXXXXXXXX\0";
+ unsigned int idx, i;
+ int ret;
+
+again:
+ for (i = 0; i < sizeof(name) - 1; i++) {
+ ret = getrandom(&idx, sizeof(idx), GRND_NONBLOCK);
+ if (ret != sizeof(idx)) {
+ if (ret >= 0)
+ errno = EAGAIN;
+
+ return NULL;
+ }
+
+ name[i] = chars[idx % (ARRAY_SIZE(chars) - 1)];
+ }
+
+ ret = mkdirat(at, name, 0600);
+ if (ret) {
+ if (errno == EEXIST)
+ goto again;
+
+ return NULL;
+ }
+
+ return strdup(name);
+}
+
+static char *configfs_make_item_name(int at, const char *name)
+{
+ char *item_name;
+ int ret;
+
+ if (name) {
+ item_name = strdup(name);
+ if (!item_name)
+ return NULL;
+
+ ret = mkdirat(at, item_name, 0600);
+ if (ret) {
+ free(item_name);
+ return NULL;
+ }
+ } else {
+ item_name = make_random_dir_at(at);
+ if (!item_name)
+ return NULL;
+ }
+
+ return item_name;
+}
+
+struct gpiosim_ctx {
+ struct refcount refcnt;
+ int cfs_dir_fd;
+ char *cfs_mnt_dir;
+};
+
+struct gpiosim_dev {
+ struct refcount refcnt;
+ struct gpiosim_ctx *ctx;
+ bool live;
+ char *item_name;
+ char *dev_name;
+ int cfs_dir_fd;
+ int sysfs_dir_fd;
+ struct list_head banks;
+};
+
+struct gpiosim_bank {
+ struct refcount refcnt;
+ struct gpiosim_dev *dev;
+ struct list_head siblings;
+ char *item_name;
+ char *chip_name;
+ char *dev_path;
+ int cfs_dir_fd;
+ int sysfs_dir_fd;
+ unsigned int num_lines;
+};
+
+static int ctx_open_configfs_dir(struct gpiosim_ctx *ctx, const char *cfs_path)
+{
+ char *path;
+ int ret;
+
+ ret = asprintf(&path, "%s/gpio-sim", cfs_path);
+ if (ret < 0)
+ return -1;
+
+ ctx->cfs_dir_fd = open(path, O_RDONLY);
+ free(path);
+ if (ctx->cfs_dir_fd < 0)
+ return -1;
+
+ return 0;
+}
+
+/*
+ * We don't need to check the configfs module as loading gpio-sim will pull it
+ * in but we need to find out if and where configfs was mounted. If it wasn't
+ * then as a last resort we'll try to mount it ourselves.
+ */
+static int ctx_get_configfs_fd(struct gpiosim_ctx *ctx)
+{
+ struct libmnt_context *mntctx;
+ struct libmnt_iter *iter;
+ struct libmnt_table *tb;
+ struct libmnt_fs *fs;
+ const char *type;
+ int ret;
+
+ /* Try to find out if and where configfs is mounted. */
+ mntctx = mnt_new_context();
+ if (!mntctx)
+ return -1;
+
+ ret = mnt_context_get_mtab(mntctx, &tb);
+ if (ret)
+ goto out_free_ctx;
+
+ iter = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!iter)
+ goto out_free_ctx;
+
+ while (mnt_table_next_fs(tb, iter, &fs) == 0) {
+ type = mnt_fs_get_fstype(fs);
+
+ if (strcmp(type, "configfs") == 0) {
+ ret = ctx_open_configfs_dir(ctx, mnt_fs_get_target(fs));
+ if (ret)
+ goto out_free_iter;
+
+ ret = 0;
+ goto out_free_iter;
+ }
+ }
+
+ /* Didn't find any configfs mounts - let's try to do it ourselves. */
+ ctx->cfs_mnt_dir = strdup("/tmp/gpiosim-configfs-XXXXXX");
+ if (!ctx->cfs_mnt_dir)
+ goto out_free_iter;
+
+ ctx->cfs_mnt_dir = mkdtemp(ctx->cfs_mnt_dir);
+ if (!ctx->cfs_mnt_dir)
+ goto out_free_tmpdir;
+
+ ret = mount(NULL, ctx->cfs_mnt_dir, "configfs", MS_RELATIME, NULL);
+ if (ret)
+ goto out_rm_tmpdir;
+
+ ret = ctx_open_configfs_dir(ctx, ctx->cfs_mnt_dir);
+ if (ret == 0)
+ /* Skip unmounting & deleting the tmp directory on success. */
+ goto out_free_iter;
+
+ umount(ctx->cfs_mnt_dir);
+out_rm_tmpdir:
+ rmdir(ctx->cfs_mnt_dir);
+out_free_tmpdir:
+ free(ctx->cfs_mnt_dir);
+ ctx->cfs_mnt_dir = NULL;
+out_free_iter:
+ mnt_free_iter(iter);
+out_free_ctx:
+ mnt_free_context(mntctx);
+
+ return ret;
+}
+
+static void ctx_release(struct refcount *ref)
+{
+ struct gpiosim_ctx *ctx = container_of(ref, struct gpiosim_ctx, refcnt);
+
+ close(ctx->cfs_dir_fd);
+
+ if (ctx->cfs_mnt_dir) {
+ umount(ctx->cfs_mnt_dir);
+ rmdir(ctx->cfs_mnt_dir);
+ free(ctx->cfs_mnt_dir);
+ }
+
+ free(ctx);
+}
+
+GPIOSIM_API struct gpiosim_ctx *gpiosim_ctx_new(void)
+{
+ struct gpiosim_ctx *ctx;
+ int ret;
+
+ ret = check_kernel_version();
+ if (ret)
+ return NULL;
+
+ ret = check_gpiosim_module();
+ if (ret)
+ return NULL;
+
+ ctx = malloc(sizeof(*ctx));
+ if (!ctx)
+ return NULL;
+
+ memset(ctx, 0, sizeof(*ctx));
+ refcount_init(&ctx->refcnt, ctx_release);
+
+ ret = ctx_get_configfs_fd(ctx);
+ if (ret) {
+ free(ctx);
+ return NULL;
+ }
+
+ return ctx;
+}
+
+GPIOSIM_API struct gpiosim_ctx *gpiosim_ctx_ref(struct gpiosim_ctx *ctx)
+{
+ refcount_inc(&ctx->refcnt);
+
+ return ctx;
+}
+
+GPIOSIM_API void gpiosim_ctx_unref(struct gpiosim_ctx *ctx)
+{
+ refcount_dec(&ctx->refcnt);
+}
+
+static void dev_release(struct refcount *ref)
+{
+ struct gpiosim_dev *dev = container_of(ref, struct gpiosim_dev, refcnt);
+ struct gpiosim_ctx *ctx = dev->ctx;
+
+ if (dev->live)
+ gpiosim_dev_disable(dev);
+
+ unlinkat(ctx->cfs_dir_fd, dev->item_name, AT_REMOVEDIR);
+ close(dev->cfs_dir_fd);
+ free(dev->dev_name);
+ free(dev->item_name);
+ gpiosim_ctx_unref(ctx);
+ free(dev);
+}
+
+GPIOSIM_API struct gpiosim_dev *
+gpiosim_dev_new(struct gpiosim_ctx *ctx, const char *name)
+{
+ struct gpiosim_dev *dev;
+ int configfs_fd, ret;
+ char devname[128];
+ char *item_name;
+
+ item_name = configfs_make_item_name(ctx->cfs_dir_fd, name);
+ if (!item_name)
+ return NULL;
+
+ configfs_fd = openat(ctx->cfs_dir_fd, item_name, O_RDONLY);
+ if (configfs_fd < 0)
+ goto err_unlink;
+
+ dev = malloc(sizeof(*dev));
+ if (!dev)
+ goto err_close_fd;
+
+ ret = open_read_close(configfs_fd, "dev_name",
+ devname, sizeof(devname));
+ if (ret)
+ goto err_free_dev;
+
+ memset(dev, 0, sizeof(*dev));
+ refcount_init(&dev->refcnt, dev_release);
+ list_init(&dev->banks);
+ dev->cfs_dir_fd = configfs_fd;
+ dev->sysfs_dir_fd = -1;
+ dev->item_name = item_name;
+
+ dev->dev_name = strdup(devname);
+ if (!dev->dev_name)
+ goto err_free_dev;
+
+ dev->ctx = gpiosim_ctx_ref(ctx);
+
+ return dev;
+
+err_free_dev:
+ free(dev);
+err_close_fd:
+ close(configfs_fd);
+err_unlink:
+ unlinkat(ctx->cfs_dir_fd, item_name, AT_REMOVEDIR);
+ free(item_name);
+
+ return NULL;
+}
+
+GPIOSIM_API struct gpiosim_dev *gpiosim_dev_ref(struct gpiosim_dev *dev)
+{
+ refcount_inc(&dev->refcnt);
+
+ return dev;
+}
+
+GPIOSIM_API void gpiosim_dev_unref(struct gpiosim_dev *dev)
+{
+ refcount_dec(&dev->refcnt);
+}
+
+GPIOSIM_API struct gpiosim_ctx *gpiosim_dev_get_ctx(struct gpiosim_dev *dev)
+{
+ return gpiosim_ctx_ref(dev->ctx);
+}
+
+GPIOSIM_API const char *gpiosim_dev_get_name(struct gpiosim_dev *dev)
+{
+ return dev->dev_name;
+}
+
+static bool dev_check_pending(struct gpiosim_dev *dev)
+{
+ if (dev->live)
+ errno = EBUSY;
+
+ return !dev->live;
+}
+
+static bool dev_check_live(struct gpiosim_dev *dev)
+{
+ if (!dev->live)
+ errno = ENODEV;
+
+ return dev->live;
+}
+
+static int bank_set_chip_name(struct gpiosim_bank *bank)
+{
+ char chip_name[32];
+ int ret;
+
+ ret = open_read_close(bank->cfs_dir_fd, "chip_name",
+ chip_name, sizeof(chip_name));
+ if (ret)
+ return -1;
+
+ bank->chip_name = strdup(chip_name);
+ if (!bank->chip_name)
+ return -1;
+
+ return 0;
+}
+
+static int bank_set_dev_path(struct gpiosim_bank *bank)
+{
+ char dev_path[64];
+
+ snprintf(dev_path, sizeof(dev_path), "/dev/%s", bank->chip_name);
+
+ bank->dev_path = strdup(dev_path);
+ if (!bank->dev_path)
+ return -1;
+
+ return 0;
+}
+
+static int bank_open_sysfs_dir(struct gpiosim_bank *bank)
+{
+ struct gpiosim_dev *dev = bank->dev;
+ int fd;
+
+ fd = openat(dev->sysfs_dir_fd, bank->chip_name, O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ bank->sysfs_dir_fd = fd;
+
+ return 0;
+}
+
+static int bank_enable(struct gpiosim_bank *bank)
+{
+ int ret;
+
+ ret = bank_set_chip_name(bank);
+ if (ret)
+ return -1;
+
+ ret = bank_set_dev_path(bank);
+ if (ret)
+ return -1;
+
+ return bank_open_sysfs_dir(bank);
+}
+
+static int dev_open_sysfs_dir(struct gpiosim_dev *dev)
+{
+ int ret, fd;
+ char *sysp;
+
+ ret = asprintf(&sysp, "/sys/devices/platform/%s", dev->dev_name);
+ if (ret < 0)
+ return -1;
+
+ fd = open(sysp, O_RDONLY);
+ free(sysp);
+ if (fd < 0)
+ return -1;
+
+ dev->sysfs_dir_fd = fd;
+
+ return 0;
+}
+
+/* Closes the sysfs dir for this device and all its child banks. */
+static void dev_close_sysfs_dirs(struct gpiosim_dev *dev)
+{
+ struct gpiosim_bank *bank;
+
+ list_for_each_entry(bank, &dev->banks, siblings) {
+ free(bank->chip_name);
+ free(bank->dev_path);
+ bank->chip_name = bank->dev_path = NULL;
+
+ if (bank->sysfs_dir_fd < 0)
+ break;
+
+ close(bank->sysfs_dir_fd);
+ bank->sysfs_dir_fd = -1;
+ }
+
+ close(dev->sysfs_dir_fd);
+ dev->sysfs_dir_fd = -1;
+}
+
+GPIOSIM_API int gpiosim_dev_enable(struct gpiosim_dev *dev)
+{
+ struct gpiosim_bank *bank;
+ int ret;
+
+ if (!dev_check_pending(dev))
+ return -1;
+
+ ret = open_write_close(dev->cfs_dir_fd, "live", "1");
+ if (ret)
+ return -1;
+
+ ret = dev_open_sysfs_dir(dev);
+ if (ret) {
+ open_write_close(dev->cfs_dir_fd, "live", "0");
+ return -1;
+ }
+
+ bank = container_of(&dev->banks, struct gpiosim_bank, siblings);
+
+ list_for_each_entry(bank, &dev->banks, siblings) {
+ ret = bank_enable(bank);
+ if (ret) {
+ dev_close_sysfs_dirs(dev);
+ open_write_close(dev->cfs_dir_fd, "live", "0");
+ return -1;
+ }
+ }
+
+ dev->live = true;
+
+ return 0;
+}
+
+GPIOSIM_API int gpiosim_dev_disable(struct gpiosim_dev *dev)
+{
+ int ret;
+
+ if (!dev_check_live(dev))
+ return -1;
+
+ ret = open_write_close(dev->cfs_dir_fd, "live", "0");
+ if (ret)
+ return ret;
+
+ dev_close_sysfs_dirs(dev);
+
+ dev->live = false;
+
+ return 0;
+}
+
+GPIOSIM_API bool gpiosim_dev_is_live(struct gpiosim_dev *dev)
+{
+ return dev->live;
+}
+
+static void bank_release(struct refcount *ref)
+{
+ struct gpiosim_bank *bank = container_of(ref, struct gpiosim_bank,
+ refcnt);
+ struct gpiosim_dev *dev = bank->dev;
+ unsigned int i;
+ char buf[64];
+
+ for (i = 0; i < bank->num_lines; i++) {
+ snprintf(buf, sizeof(buf), "line%u/hog", i);
+ unlinkat(bank->cfs_dir_fd, buf, AT_REMOVEDIR);
+ snprintf(buf, sizeof(buf), "line%u", i);
+ unlinkat(bank->cfs_dir_fd, buf, AT_REMOVEDIR);
+ }
+
+ list_del(&bank->siblings);
+ unlinkat(dev->cfs_dir_fd, bank->item_name, AT_REMOVEDIR);
+ gpiosim_dev_unref(dev);
+ close(bank->cfs_dir_fd);
+ free(bank->item_name);
+ free(bank);
+}
+
+GPIOSIM_API struct gpiosim_bank*
+gpiosim_bank_new(struct gpiosim_dev *dev, const char *name)
+{
+ struct gpiosim_bank *bank;
+ int configfs_fd;
+ char *item_name;
+
+ if (!dev_check_pending(dev))
+ return NULL;
+
+ item_name = configfs_make_item_name(dev->cfs_dir_fd, name);
+ if (!item_name)
+ return NULL;
+
+ configfs_fd = openat(dev->cfs_dir_fd, item_name, O_RDONLY);
+ if (configfs_fd < 0)
+ goto err_unlink;
+
+ bank = malloc(sizeof(*bank));
+ if (!bank)
+ goto err_close_cfs;
+
+ memset(bank, 0, sizeof(*bank));
+
+ refcount_init(&bank->refcnt, bank_release);
+ list_add(&bank->siblings, &dev->banks);
+ bank->cfs_dir_fd = configfs_fd;
+ bank->dev = gpiosim_dev_ref(dev);
+ bank->item_name = item_name;
+
+ return bank;
+
+err_close_cfs:
+ close(configfs_fd);
+err_unlink:
+ unlinkat(dev->cfs_dir_fd, item_name, AT_REMOVEDIR);
+
+ return NULL;
+}
+
+GPIOSIM_API struct gpiosim_bank *gpiosim_bank_ref(struct gpiosim_bank *bank)
+{
+ refcount_inc(&bank->refcnt);
+
+ return bank;
+}
+
+GPIOSIM_API void gpiosim_bank_unref(struct gpiosim_bank *bank)
+{
+ refcount_dec(&bank->refcnt);
+}
+
+GPIOSIM_API struct gpiosim_dev *gpiosim_bank_get_dev(struct gpiosim_bank *bank)
+{
+ return gpiosim_dev_ref(bank->dev);
+}
+
+GPIOSIM_API const char *gpiosim_bank_get_chip_name(struct gpiosim_bank *bank)
+{
+ return bank->chip_name;
+}
+
+GPIOSIM_API const char *gpiosim_bank_get_dev_path(struct gpiosim_bank *bank)
+{
+ return bank->dev_path;
+}
+
+GPIOSIM_API int gpiosim_bank_set_label(struct gpiosim_bank *bank,
+ const char *label)
+{
+ if (!dev_check_pending(bank->dev))
+ return -1;
+
+ return open_write_close(bank->cfs_dir_fd, "label", label);
+}
+
+GPIOSIM_API int gpiosim_bank_set_num_lines(struct gpiosim_bank *bank,
+ unsigned int num_lines)
+{
+ char buf[32];
+ int ret;
+
+ if (!dev_check_pending(bank->dev))
+ return -1;
+
+ snprintf(buf, sizeof(buf), "%u", num_lines);
+
+ ret = open_write_close(bank->cfs_dir_fd, "num_lines", buf);
+ if (ret)
+ return -1;
+
+ bank->num_lines = num_lines;
+
+ return 0;
+}
+
+/*
+ * Create a sub-directory under given bank's configfs directory. Do nothing
+ * if the directory exists and is writable. Mode is O_RDONLY.
+ */
+static int bank_mkdirat(struct gpiosim_bank *bank, const char *path)
+{
+ int ret;
+
+ ret = faccessat(bank->cfs_dir_fd, path, W_OK, 0);
+ if (ret) {
+ if (errno == ENOENT) {
+ ret = mkdirat(bank->cfs_dir_fd, path, O_RDONLY);
+ if (ret)
+ return -1;
+ } else {
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+GPIOSIM_API int gpiosim_bank_set_line_name(struct gpiosim_bank *bank,
+ unsigned int offset,
+ const char *name)
+{
+ char buf[32];
+ int ret, fd;
+
+ if (!dev_check_pending(bank->dev))
+ return -1;
+
+ snprintf(buf, sizeof(buf), "line%u", offset);
+
+ ret = bank_mkdirat(bank, buf);
+ if (ret)
+ return -1;
+
+ fd = openat(bank->cfs_dir_fd, buf, O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ ret = open_write_close(fd, "name", name ?: "");
+ close(fd);
+ return ret;
+}
+
+GPIOSIM_API int gpiosim_bank_hog_line(struct gpiosim_bank *bank,
+ unsigned int offset,
+ const char *name, int direction)
+{
+ char buf[64], *dir;
+ int ret, fd;
+
+ switch (direction) {
+ case GPIOSIM_HOG_DIR_INPUT:
+ dir = "input";
+ break;
+ case GPIOSIM_HOG_DIR_OUTPUT_HIGH:
+ dir = "output-high";
+ break;
+ case GPIOSIM_HOG_DIR_OUTPUT_LOW:
+ dir = "output-low";
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (!dev_check_pending(bank->dev))
+ return -1;
+
+ snprintf(buf, sizeof(buf), "line%u", offset);
+
+ ret = bank_mkdirat(bank, buf);
+ if (ret)
+ return -1;
+
+ snprintf(buf, sizeof(buf), "line%u/hog", offset);
+
+ ret = bank_mkdirat(bank, buf);
+ if (ret)
+ return -1;
+
+ fd = openat(bank->cfs_dir_fd, buf, O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ ret = open_write_close(fd, "name", name ?: "");
+ if (ret) {
+ close(fd);
+ return -1;
+ }
+
+ ret = open_write_close(fd, "direction", dir);
+ close(fd);
+ return ret;
+}
+
+GPIOSIM_API int gpiosim_bank_clear_hog(struct gpiosim_bank *bank,
+ unsigned int offset)
+{
+ char buf[64];
+
+ snprintf(buf, sizeof(buf), "line%u/hog", offset);
+
+ return unlinkat(bank->cfs_dir_fd, buf, AT_REMOVEDIR);
+}
+
+static int sysfs_read_bank_attr(struct gpiosim_bank *bank, unsigned int offset,
+ const char *attr, char *buf,
+ unsigned int bufsize)
+{
+ struct gpiosim_dev *dev = bank->dev;
+ char where[32];
+
+ if (!dev_check_live(dev))
+ return -1;
+
+ snprintf(where, sizeof(where), "sim_gpio%u/%s", offset, attr);
+
+ return open_read_close(bank->sysfs_dir_fd, where, buf, bufsize);
+}
+
+GPIOSIM_API int gpiosim_bank_get_value(struct gpiosim_bank *bank,
+ unsigned int offset)
+{
+ char what[3];
+ int ret;
+
+ ret = sysfs_read_bank_attr(bank, offset, "value", what, sizeof(what));
+ if (ret)
+ return ret;
+
+ if (what[0] == '0')
+ return 0;
+ if (what[0] == '1')
+ return 1;
+
+ errno = EIO;
+ return -1;
+}
+
+GPIOSIM_API int gpiosim_bank_get_pull(struct gpiosim_bank *bank,
+ unsigned int offset)
+{
+ char what[16];
+ int ret;
+
+ ret = sysfs_read_bank_attr(bank, offset, "pull", what, sizeof(what));
+ if (ret)
+ return ret;
+
+ if (strcmp(what, "pull-down") == 0)
+ return GPIOSIM_PULL_DOWN;
+ if (strcmp(what, "pull-up") == 0)
+ return GPIOSIM_PULL_UP;
+
+ errno = EIO;
+ return -1;
+}
+
+GPIOSIM_API int gpiosim_bank_set_pull(struct gpiosim_bank *bank,
+ unsigned int offset, int pull)
+{
+ struct gpiosim_dev *dev = bank->dev;
+ char where[32], what[16];
+
+ if (!dev_check_live(dev))
+ return -1;
+
+ if (pull != GPIOSIM_PULL_DOWN && pull != GPIOSIM_PULL_UP) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ snprintf(where, sizeof(where), "sim_gpio%u/pull", offset);
+ snprintf(what, sizeof(what),
+ pull == GPIOSIM_PULL_DOWN ? "pull-down" : "pull-up");
+
+ return open_write_close(bank->sysfs_dir_fd, where, what);
+}
projects / qemu-gpiodev / libgpiod.git / commitdiff