From b98442bbfaa0b61963c23c6079055c94515e38dd Mon Sep 17 00:00:00 2001
From: Joey Hewitt <joey@joeyhewitt.com>
Date: Mon, 9 Oct 2017 21:41:43 -0700
Subject: [PATCH] add uio dev support

diff --git a/sharedmem.c b/sharedmem.c
index f788b8a..eead258 100644
--- a/sharedmem.c
+++ b/sharedmem.c
@@ -44,6 +44,37 @@ static int parse_hex_sysattr(struct udev_device *dev, const char *name,
 	return 0;
 }
 
+static int parse_hex_sysfsfile(int dir_fd, const char *name,
+			     unsigned long *value)
+{
+	unsigned long val;
+	char buf[32];
+	char *endptr;
+	int fd;
+
+	fd = openat(dir_fd, name, O_RDONLY);
+	if (fd < 0) {
+		return -errno;
+	}
+
+	if (read(fd, buf, sizeof(buf)) < 0) {
+		close(fd);
+		return -errno;
+	}
+
+	close(fd);
+
+	errno = 0;
+	val = strtoul(buf, &endptr, 16);
+	if ((val == LONG_MAX && errno == ERANGE) || endptr == buf) {
+		return -errno;
+	}
+
+	*value = val;
+
+	return 0;
+}
+
 static int rmtfs_mem_open_rfsa(struct rmtfs_mem *rmem, int client_id)
 {
 	struct udev_device *dev;
@@ -114,6 +145,88 @@ err_close_fd:
 	return -saved_errno;
 }
 
+static int rmtfs_mem_open_uio(struct rmtfs_mem *rmem)
+{
+	int saved_errno;
+	char path[64];
+	char buf[32];
+	int ret;
+	int dir_fd;
+	int fd;
+
+	for (int uio_index = 0; uio_index < 8; uio_index++) {
+		snprintf(path, sizeof(path), "/sys/class/uio/uio%d", uio_index);
+		dir_fd = open(path, O_DIRECTORY);
+		if (dir_fd < 0) {
+			saved_errno = errno;
+			if (errno != ENOENT) {
+				fprintf(stderr, "failed to open %s: %s\n", path, strerror(errno));
+			}
+			goto ret;
+		}
+
+		fd = openat(dir_fd, "name", O_RDONLY);
+		if (fd < 0) {
+			saved_errno = errno;
+			fprintf(stderr, "failed to open %s/name: %s\n", path, strerror(errno));
+			goto close_dirfd;
+		}
+
+		if (read(fd, buf, sizeof(buf)) < 0) {
+			saved_errno = errno;
+			fprintf(stderr, "failed to read %s/name: %s\n", path, strerror(errno));
+			close(fd);
+			goto close_dirfd;
+		}
+
+		close(fd);
+
+		if (strncmp(buf, "rmtfs\n", 6)) {
+			continue;
+		}
+
+		ret = parse_hex_sysfsfile(dir_fd, "maps/map0/addr", &rmem->address);
+		if (ret < 0) {
+			fprintf(stderr, "failed to parse addr of %s\n", path);
+			saved_errno = -ret;
+			goto close_dirfd;
+		}
+
+		ret = parse_hex_sysfsfile(dir_fd, "maps/map0/size", &rmem->size);
+		if (ret < 0) {
+			fprintf(stderr, "failed to parse size of %s\n", path);
+			saved_errno = -ret;
+			goto close_dirfd;
+		}
+
+		snprintf(path, sizeof(path), "/dev/uio%d", uio_index);
+		rmem->fd = open(path, O_RDWR);
+		if (rmem->fd < 0) {
+			saved_errno = errno;
+			fprintf(stderr, "failed to open %s: %s\n", path, strerror(errno));
+			goto close_dirfd;
+		}
+
+		rmem->base = mmap(0, rmem->size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+		if (rmem->base == MAP_FAILED) {
+			saved_errno = errno;
+			fprintf(stderr, "failed to mmap: %s\n", strerror(errno));
+			close(rmem->fd);
+			goto close_dirfd;
+		}
+
+		saved_errno = 0;
+		goto close_dirfd;
+	}
+
+	saved_errno = ENOENT;
+
+close_dirfd:
+	close(dir_fd);
+ret:
+	return -saved_errno;
+}
+
 struct rmtfs_mem *rmtfs_mem_open(void)
 {
 	struct rmtfs_mem *rmem;
@@ -131,26 +244,31 @@ struct rmtfs_mem *rmtfs_mem_open(void)
 	if (ret < 0 && ret != -ENOENT) {
 		goto err;
 	} else if (ret < 0) {
-		fprintf(stderr, "falling back to /dev/mem access\n");
-
-		ret = rmtfs_mem_enumerate(rmem);
-		if (ret < 0)
-			goto err;
-
-		fd = open("/dev/mem", O_RDWR|O_SYNC);
-		if (fd < 0) {
-			fprintf(stderr, "failed to open /dev/mem\n");
+		ret = rmtfs_mem_open_uio(rmem);
+		if (ret < 0 && ret != -ENOENT) {
 			goto err;
+		} else if (ret < 0) {
+			fprintf(stderr, "falling back to /dev/mem access\n");
+
+			ret = rmtfs_mem_enumerate(rmem);
+			if (ret < 0)
+				goto err;
+
+			fd = open("/dev/mem", O_RDWR|O_SYNC);
+			if (fd < 0) {
+				fprintf(stderr, "failed to open /dev/mem\n");
+				goto err;
+			}
+
+			base = mmap(0, rmem->size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, rmem->address);
+			if (base == MAP_FAILED) {
+				fprintf(stderr, "failed to mmap: %s\n", strerror(errno));
+				goto err_close_fd;
+			}
+
+			rmem->base = base;
+			rmem->fd = fd;
 		}
-
-		base = mmap(0, rmem->size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, rmem->address);
-		if (base == MAP_FAILED) {
-			fprintf(stderr, "failed to mmap: %s\n", strerror(errno));
-			goto err_close_fd;
-		}
-
-		rmem->base = base;
-		rmem->fd = fd;
 	}
 
 	return rmem;