Initial device handler code

Mount discovered devices, and set up symlinks for UUID and LABELs

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

1 files changed, 60 insertions, 46 deletions

diff --git a/discover/paths.c b/discover/paths.c
index 2373c28..72d07b2 100644
--- a/discover/paths.c
+++ b/discover/paths.c
@@ -4,24 +4,41 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <talloc/talloc.h>
+
 #include "paths.h"
 
-static char *mount_base;
+#define DEVICE_MOUNT_BASE (LOCAL_STATE_DIR "/petitboot/mnt")
 
-struct device_map {
+struct mount_map {
 	char *dev, *mnt;
 };
 
-#define DEVICE_MAP_SIZE 32
-static struct device_map device_map[DEVICE_MAP_SIZE];
+static struct mount_map *mount_map;
+static int mount_map_size;
+
+static int is_prefix(const char *str, const char *prefix)
+{
+	return !strncmp(str, prefix, strlen(prefix));
+}
+
+static int is_prefix_ignorecase(const char *str, const char *prefix)
+{
+	return !strncasecmp(str, prefix, strlen(prefix));
+}
 
-char *encode_label(const char *label)
+const char *mount_base(void)
+{
+	return DEVICE_MOUNT_BASE;
+}
+
+char *encode_label(void *alloc_ctx, const char *label)
 {
 	char *str, *c;
 	int i;
 
 	/* the label can be expanded by up to four times */
-	str = malloc(strlen(label) * 4 + 1);
+	str = talloc_size(alloc_ctx, strlen(label) * 4 + 1);
 	c = str;
 
 	for (i = 0; i < strlen(label); i++) {
@@ -40,60 +57,64 @@ char *encode_label(const char *label)
 	return str;
 }
 
-char *parse_device_path(const char *dev_str, const char *cur_dev)
+char *parse_device_path(void *alloc_ctx,
+		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);
+	if (is_prefix_ignorecase(dev_str, "uuid=")) {
+		dev = talloc_asprintf(alloc_ctx, "/dev/disk/by-uuid/%s",
+				dev_str + strlen("uuid="));
 		return dev;
 	}
 
-	if (!strncasecmp(dev_str, "label=", 6)) {
-		enc = encode_label(dev_str + 6);
-		asprintf(&dev, "/dev/disk/by-label/%s", enc);
-		free(enc);
+	if (is_prefix_ignorecase(dev_str, "label=")) {
+		enc = encode_label(NULL, dev_str + strlen("label="));
+		dev = talloc_asprintf(alloc_ctx, "/dev/disk/by-label/%s", enc);
+		talloc_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;
+	if (is_prefix(dev_str, "/dev/"))
+		dev_str += strlen("/dev/");
 
 	/* 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)) {
+	if (cur_dev && is_prefix(cur_dev, "/dev/ps3d")
+			&& is_prefix(dev_str, "sd")) {
 		snprintf(tmp, 255, "ps3d%s", dev_str + 2);
 		dev_str = tmp;
 	}
 
-	return join_paths("/dev", dev_str);
+	return join_paths(alloc_ctx, "/dev", dev_str);
 }
 
 const char *mountpoint_for_device(const char *dev)
 {
 	int i;
 
-	if (!strncmp(dev, "/dev/", 5))
-		dev += 5;
+	if (is_prefix(dev, "/dev/"))
+		dev += strlen("/dev/");
 
 	/* 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;
+	for (i = 0; i < mount_map_size; i++)
+		if (!strcmp(mount_map[i].dev, dev))
+			return mount_map[i].mnt;
+
+	/* no existing entry, create a new one */
+	i = mount_map_size++;
+	mount_map = talloc_realloc(NULL, mount_map,
+			struct mount_map, mount_map_size);
+
+	mount_map[i].dev = talloc_strdup(mount_map, dev);
+	mount_map[i].mnt = join_paths(mount_map, DEVICE_MOUNT_BASE, dev);
+	return mount_map[i].mnt;
 }
 
-char *resolve_path(const char *path, const char *current_dev)
+char *resolve_path(void *alloc_ctx, const char *path, const char *current_dev)
 {
 	char *ret;
 	const char *devpath, *sep;
@@ -101,35 +122,28 @@ char *resolve_path(const char *path, const char *current_dev)
 	sep = strchr(path, ':');
 	if (!sep) {
 		devpath = mountpoint_for_device(current_dev);
-		ret = join_paths(devpath, path);
+		ret = join_paths(alloc_ctx, 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);
+		tmp = talloc_strndup(NULL, path, sep - path);
+		dev = parse_device_path(NULL, tmp, current_dev);
 
 		devpath = mountpoint_for_device(dev);
-		ret = join_paths(devpath, sep + 1);
+		ret = join_paths(alloc_ctx, devpath, sep + 1);
 
-		free(dev);
-		free(tmp);
+		talloc_free(dev);
+		talloc_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 *join_paths(void *alloc_ctx, const char *a, const char *b)
 {
 	char *full_path;
 
-	full_path = malloc(strlen(a) + strlen(b) + 2);
+	full_path = talloc_array(alloc_ctx, char, strlen(a) + strlen(b) + 2);
 
 	strcpy(full_path, a);
 	if (b[0] != '/' && a[strlen(a) - 1] != '/')