Initial support for multiple UIs

Move the device discovery code from separate udev helpers to a single
process to listen on two sockets: one SOCK_DGRAM for incoming udev
events, and one SOCK_STREAM for UIs to connect.

Initial support for client/server infrastructure, still need to wire-up
the udev messages.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 141 insertions, 0 deletions

diff --git a/discover/paths.c b/discover/paths.c
new file mode 100644
index 0000000..2373c28
--- /dev/null
+++ b/discover/paths.c
@@ -0,0 +1,141 @@
+#define _GNU_SOURCE
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "paths.h"
+
+static char *mount_base;
+
+struct device_map {
+	char *dev, *mnt;
+};
+
+#define DEVICE_MAP_SIZE 32
+static struct device_map device_map[DEVICE_MAP_SIZE];
+
+char *encode_label(const char *label)
+{
+	char *str, *c;
+	int i;
+
+	/* the label can be expanded by up to four times */
+	str = malloc(strlen(label) * 4 + 1);
+	c = str;
+
+	for (i = 0; i < strlen(label); i++) {
+
+		if (label[i] == '/' || label[i] == '\\') {
+			sprintf(c, "\\x%02x", label[i]);
+			c += 4;
+			continue;
+		}
+
+		*(c++) = label[i];
+	}
+
+	*c = '\0';
+
+	return str;
+}
+
+char *parse_device_path(const char *dev_str, const char *cur_dev)
+{
+	char *dev, tmp[256], *enc;
+
+	if (!strncasecmp(dev_str, "uuid=", 5)) {
+		asprintf(&dev, "/dev/disk/by-uuid/%s", dev_str + 5);
+		return dev;
+	}
+
+	if (!strncasecmp(dev_str, "label=", 6)) {
+		enc = encode_label(dev_str + 6);
+		asprintf(&dev, "/dev/disk/by-label/%s", enc);
+		free(enc);
+		return dev;
+	}
+
+	/* normalise '/dev/foo' to 'foo' for easy comparisons, we'll expand
+	 * back before returning.
+	 */
+	if (!strncmp(dev_str, "/dev/", 5))
+		dev_str += 5;
+
+	/* PS3 hack: if we're reading from a ps3dx device, and we refer to
+	 * a sdx device, remap to ps3dx */
+	if (cur_dev && !strncmp(cur_dev, "/dev/ps3d", 9)
+			&& !strncmp(dev_str, "sd", 2)) {
+		snprintf(tmp, 255, "ps3d%s", dev_str + 2);
+		dev_str = tmp;
+	}
+
+	return join_paths("/dev", dev_str);
+}
+
+const char *mountpoint_for_device(const char *dev)
+{
+	int i;
+
+	if (!strncmp(dev, "/dev/", 5))
+		dev += 5;
+
+	/* check existing entries in the map */
+	for (i = 0; (i < DEVICE_MAP_SIZE) && device_map[i].dev; i++)
+		if (!strcmp(device_map[i].dev, dev))
+			return device_map[i].mnt;
+
+	if (i == DEVICE_MAP_SIZE)
+		return NULL;
+
+	device_map[i].dev = strdup(dev);
+	device_map[i].mnt = join_paths(mount_base, dev);
+	return device_map[i].mnt;
+}
+
+char *resolve_path(const char *path, const char *current_dev)
+{
+	char *ret;
+	const char *devpath, *sep;
+
+	sep = strchr(path, ':');
+	if (!sep) {
+		devpath = mountpoint_for_device(current_dev);
+		ret = join_paths(devpath, path);
+	} else {
+		/* parse just the device name into dev */
+		char *tmp, *dev;
+		tmp = strndup(path, sep - path);
+		dev = parse_device_path(tmp, current_dev);
+
+		devpath = mountpoint_for_device(dev);
+		ret = join_paths(devpath, sep + 1);
+
+		free(dev);
+		free(tmp);
+	}
+
+	return ret;
+}
+
+void set_mount_base(const char *path)
+{
+	if (mount_base)
+		free(mount_base);
+	mount_base = strdup(path);
+}
+
+char *join_paths(const char *a, const char *b)
+{
+	char *full_path;
+
+	full_path = malloc(strlen(a) + strlen(b) + 2);
+
+	strcpy(full_path, a);
+	if (b[0] != '/' && a[strlen(a) - 1] != '/')
+		strcat(full_path, "/");
+	strcat(full_path, b);
+
+	return full_path;
+}
+