Resolve device paths in kernel and initrd locations.

Instead of mounting in random locations, create a fixed mapping between
device and mountpoint. This allows the parsers to refer to files
outside the current partition.

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

8 files changed, 144 insertions, 50 deletions

diff --git a/devices/kboot-parser.c b/devices/kboot-parser.c
index d449ef6..b70d5fc 100644
--- a/devices/kboot-parser.c
+++ b/devices/kboot-parser.c
@@ -138,13 +138,13 @@ static int parse_option(struct boot_option *opt, char *config)
 
 	/* if there's no space, it's only a kernel image with no params */
 	if (!pos) {
-		opt->boot_image_file = join_paths(mountpoint, config);
+		opt->boot_image_file = resolve_path(config, mountpoint);
 		opt->description = strdup(config);
 		return 1;
 	}
 
 	*pos = 0;
-	opt->boot_image_file = join_paths(mountpoint, config);
+	opt->boot_image_file = resolve_path(config, mountpoint);
 
 	cmdline = malloc(buf_size);
 	*cmdline = 0;
@@ -179,7 +179,7 @@ static int parse_option(struct boot_option *opt, char *config)
 		free(cmdline);
 		cmdline = tmp;
 
-		opt->initrd_file = join_paths(mountpoint, initrd);
+		opt->initrd_file = resolve_path(initrd, mountpoint);
 	}
 
 	if (root) {
@@ -197,7 +197,8 @@ static int parse_option(struct boot_option *opt, char *config)
 	pb_log("kboot cmdline: %s\n", cmdline);
 	opt->boot_args = cmdline;
 
-	asprintf(&opt->description, "%s %s", config, cmdline);
+	asprintf(&opt->description, "%s %s",
+			config, opt->boot_args);
 
 	return 1;
 }
diff --git a/devices/parser-test.c b/devices/parser-test.c
index 4b134d0..9622d4d 100644
--- a/devices/parser-test.c
+++ b/devices/parser-test.c
@@ -1,8 +1,10 @@
+#define _GNU_SOURCE
 
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <unistd.h>
+#include <string.h>
 
 #include "parser.h"
 
@@ -16,10 +18,10 @@ void pb_log(const char *fmt, ...)
 }
 
 
-int mount_device(const char *dev_path, char *mount_path)
+int mount_device(const char *dev_path)
 {
 	pb_log("attempt to mount device (%s) not supported\n", dev_path);
-	return -1;
+	return 0;
 }
 
 int add_device(const struct device *dev)
@@ -48,16 +50,49 @@ enum generic_icon_type guess_device_type(void)
 	return ICON_TYPE_UNKNOWN;
 }
 
+static char *mountpoint;
+
+const char *mountpoint_for_device(const char *dev_path)
+{
+	char *tmp, *dev;
+	dev = strrchr(dev_path, '/');
+	if (dev)
+		dev_path = dev + 1;
+	asprintf(&tmp, "%s/%s", mountpoint, dev_path);
+	return tmp;
+}
+
+char *resolve_path(const char *path, const char *default_mountpoint)
+{
+	char *sep, *ret;
+	const char *devpath;
+
+	sep = strchr(path, ':');
+	if (!sep) {
+		devpath = default_mountpoint;
+		asprintf(&ret, "%s/%s", devpath, path);
+	} else {
+		char *tmp = strndup(path, sep - path);
+		devpath = mountpoint_for_device(path);
+		asprintf(&ret, "%s/%s", devpath, sep + 1);
+		free(tmp);
+	}
+
+	return ret;
+}
+
 int main(int argc, char **argv)
 {
-	const char *dev = "/dev/null";
+	const char *dev = "sda1";
 
 	if (argc != 2) {
 		fprintf(stderr, "usage: %s <fake-mountpoint>\n", argv[0]);
 		return EXIT_FAILURE;
 	}
 
-	iterate_parsers(dev, argv[1]);
+	mountpoint = argv[1];
+
+	iterate_parsers(dev, mountpoint);
 
 	return EXIT_SUCCESS;
 }
diff --git a/devices/parser.c b/devices/parser.c
index d1cdb43..00f3659 100644
--- a/devices/parser.c
+++ b/devices/parser.c
@@ -21,12 +21,12 @@ void iterate_parsers(const char *devpath, const char *mountpoint)
 {
 	int i;
 
-	pb_log("trying parsers for %s@%s\n", devpath, mountpoint);
+	pb_log("trying parsers for %s\n", devpath);
 
 	for (i = 0; parsers[i]; i++) {
 		pb_log("\ttrying parser '%s'\n", parsers[i]->name);
 		/* just use a dummy device path for now */
-		if (parsers[i]->parse(devpath, mountpoint))
+		if (parsers[i]->parse(devpath, mountpoint_for_device(devpath)))
 			return;
 	}
 	pb_log("\tno boot_options found\n");
diff --git a/devices/parser.h b/devices/parser.h
index 2034cf1..840ca1b 100644
--- a/devices/parser.h
+++ b/devices/parser.h
@@ -35,7 +35,10 @@ const char *generic_icon_file(enum generic_icon_type type);
 /* functions provided by udev-helper or the test wrapper */
 void pb_log(const char *fmt, ...);
 
-int mount_device(const char *dev_path, char *mount_path);
+int mount_device(const char *dev_path);
+
+char *resolve_path(const char *path, const char *default_mountpoint);
+const char *mountpoint_for_device(const char *dev_path);
 
 enum generic_icon_type guess_device_type(void);
 
diff --git a/devices/udev-helper.c b/devices/udev-helper.c
index 4ec054b..661fb08 100644
--- a/devices/udev-helper.c
+++ b/devices/udev-helper.c
@@ -1,4 +1,6 @@
 
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
@@ -181,28 +183,92 @@ int connect_to_socket()
 #endif
 }
 
-int mount_device(const char *dev_path, char *mount_path)
+struct device_map {
+	char *dev, *mnt;
+};
+
+#define DEVICE_MAP_SIZE 32
+static struct device_map device_map[DEVICE_MAP_SIZE];
+
+const char *mountpoint_for_device(const char *dev_path)
 {
-	char *dir;
+	int i;
 	const char *basename;
-	int pid, status, rc = -1;
 
- 	basename = strrchr(dev_path, '/');
- 	if (basename)
- 		basename++;
- 	else
+	/* shorten '/dev/foo' to 'foo' */
+	basename = strrchr(dev_path, '/');
+	if (basename)
+		basename++;
+	else
 		basename = dev_path;
- 
- 	/* create a unique mountpoint */
- 	dir = malloc(strlen(TMP_DIR) + 13 + strlen(basename));
- 	sprintf(dir, "%s/mnt-%s-XXXXXX", TMP_DIR, basename);
-
-	if (!mkdtemp(dir)) {
-		pb_log("failed to create temporary directory in %s: %s",
-				TMP_DIR, strerror(errno));
-		goto out;
+
+	/* check existing entries in the map */
+	for (i = 0; (i < DEVICE_MAP_SIZE) && device_map[i].dev; i++)
+		if (!strcmp(device_map[i].dev, basename))
+			return device_map[i].mnt;
+
+	if (i == DEVICE_MAP_SIZE)
+		return NULL;
+
+	device_map[i].dev = strdup(dev_path);
+	asprintf(&device_map[i].mnt, "%s/%s", TMP_DIR, basename);
+	return device_map[i].mnt;
+}
+
+/**
+ * Resolve a path given in a config file, to a path in the local filesystem.
+ * Paths may be of the form:
+ *  device:path (eg /dev/sda:/boot/vmlinux)
+ *
+ * or just a path:
+ *  /boot/vmlinux
+ * - in this case, the default mountpoint is used.
+ *
+ * Returns a newly-allocated string containing a full path to the file in path
+ */
+char *resolve_path(const char *path, const char *default_mountpoint)
+{
+	char *ret;
+	const char *devpath, *sep;
+
+	sep = strchr(path, ':');
+	if (!sep) {
+		devpath = default_mountpoint;
+		asprintf(&ret, "%s/%s", devpath, path);
+	} else {
+		/* copy just the device name into tmp */
+		char *dev = strndup(path, sep - path);
+		devpath = mountpoint_for_device(dev);
+		asprintf(&ret, "%s/%s", devpath, sep + 1);
+		free(dev);
 	}
 
+	return ret;
+}
+
+int mount_device(const char *dev_path)
+{
+	const char *dir;
+	int pid, status, rc = -1;
+	struct stat statbuf;
+
+	dir = mountpoint_for_device(dev_path);
+
+	if (stat(dir, &statbuf)) {
+		if (mkdir(dir, 0755)) {
+			pb_log("couldn't create directory %s: %s\n",
+					dir, strerror(errno));
+			goto out;
+		}
+	} else {
+		if (!S_ISDIR(statbuf.st_mode)) {
+			pb_log("mountpoint %s exists, "
+					"but isn't a directory\n", dir);
+			goto out;
+		}
+	}
+
+
 	pid = fork();
 	if (pid == -1) {
 		pb_log("%s: fork failed: %s\n", __FUNCTION__, strerror(errno));
@@ -220,13 +286,10 @@ int mount_device(const char *dev_path, char *mount_path)
 		goto out;
 	}
 
-	if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
-		strcpy(mount_path, dir);
+	if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
 		rc = 0;
-	}
 
 out:
-	free(dir);
 	return rc;
 }
 
@@ -348,9 +411,9 @@ static int is_ignored_device(const char *devname)
 
 static int found_new_device(const char *dev_path)
 {
-	char mountpoint[PATH_MAX];
+	const char *mountpoint = mountpoint_for_device(dev_path);
 
-	if (mount_device(dev_path, mountpoint)) {
+	if (mount_device(dev_path)) {
 		pb_log("failed to mount %s\n", dev_path);
 		return EXIT_FAILURE;
 	}
diff --git a/devices/yaboot-parser.c b/devices/yaboot-parser.c
index 2324950..fc55047 100644
--- a/devices/yaboot-parser.c
+++ b/devices/yaboot-parser.c
@@ -15,7 +15,6 @@
 
 static struct device *dev;
 static const char *mountpoint;
-static char partition_mntpoint[PATH_MAX];
 static char *defimage;
 
 char *
@@ -103,13 +102,13 @@ void process_image(char *label)
 
 	opt.name = label;
 	cfgopt = cfg_get_strg(label, "image");
-	opt.boot_image_file = join_paths(mountpoint, cfgopt);
+	opt.boot_image_file = resolve_path(cfgopt, mountpoint);
 	if (cfgopt == defimage)
 		pb_log("This one is default. What do we do about it?\n");
 
 	cfgopt = cfg_get_strg(label, "initrd");
 	if (cfgopt)
-		opt.initrd_file = join_paths(mountpoint, cfgopt);
+		opt.initrd_file = resolve_path(cfgopt, mountpoint);
 
 	opt.boot_args = make_params(label, NULL);
 
@@ -182,8 +181,8 @@ static int yaboot_parse(const char *devicepath, const char *_mountpoint)
 	}
 	dev->icon_file = strdup(generic_icon_file(guess_device_type()));
 
-	/* Mount the 'partition' which is what all the image filenames
-	   are relative to */
+	/* If we have a 'partiton=' directive, update the default mountpoint
+	 * to use that instead of the current mountpoint */
 	tmpstr = cfg_get_strg(0, "partition");
 	if (tmpstr) {
 		char *endp;
@@ -203,16 +202,9 @@ static int yaboot_parse(const char *devicepath, const char *_mountpoint)
 			/* and add our own... */
 			sprintf(endp+1, "%d", partnr);
 
-			/* FIXME: udev may not have created the device node
-			   yet. And on removal, unmount_device() only unmounts
-			   it once, while in fact it may be mounted twice. */
-			if (mount_device(new_dev, partition_mntpoint)) {
-				pb_log("Error mounting image partition\n");
-				return 0;
-			}
-			mountpoint = partition_mntpoint;
+			mountpoint = mountpoint_for_device(new_dev);
 			dev->id = new_dev;
-		}				
+		}
 	}
 
 	defimage = cfg_get_default();
diff --git a/petitboot-paths.h b/petitboot-paths.h
index 114d0b2..f8c5964 100644
--- a/petitboot-paths.h
+++ b/petitboot-paths.h
@@ -10,7 +10,7 @@
 #endif
 
 #ifndef TMP_DIR
-#define TMP_DIR "/var/tmp"
+#define TMP_DIR "/var/tmp/mnt/"
 #endif
 
 #define PBOOT_DEVICE_SOCKET "/var/tmp/petitboot-dev"
diff --git a/utils/ps3-kboot-0.1-petitboot.patch b/utils/ps3-kboot-0.1-petitboot.patch
index 651f548..a33fa24 100644
--- a/utils/ps3-kboot-0.1-petitboot.patch
+++ b/utils/ps3-kboot-0.1-petitboot.patch
@@ -50,7 +50,7 @@ More info at http://ozlabs.org/~jk/projects/petitboot/
 +	find root/ -name '*.a' -o -name '*.la' -exec rm {} \;
  	mkdir -p root/etc root/tmp root/proc root/dev root/sys
  	mkdir -p root/mnt/tmp root/mnt/root root/bin root/sbin
-+	mkdir -p root/var/tmp
++	mkdir -p root/var/tmp/mnt
 +	mkdir -p root/etc/udev/rules.d
  	[ -e root/dev/console ] || mknod root/dev/console c 5 1
  	[ -e root/dev/null ] || mknod root/dev/null c 1 3
@@ -283,7 +283,7 @@ diff -urN ps3-kboot.orig/ps3-kboot-0.1/scripts/petitboot-init ps3-kboot/ps3-kboo
 +	/sbin/petitboot -u
 +
 +	# clean up after petitboot
-+	for dir in /var/tmp/mnt-*;
++	for dir in /var/tmp/mnt/*;
 +	do
 +		umount "$dir"
 +		rmdir "$dir"