checked in first draft of "Dynamic Uml Mesh Modeler"

src/dumm/guest.c

@@ -0,0 +1,240 @@
+#define _GNU_SOURCE
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/uio.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <signal.h>
+
+#include <debug.h>
+
+#include "dumm.h"
+#include "guest.h"
+
+typedef struct private_guest_t private_guest_t;
+
+struct private_guest_t {
+	guest_t public;
+	char *name;
+	char *kernel;
+	char *master;
+	int mem;
+	int pid;
+	int bootlog;
+};
+
+static char* get_name(private_guest_t *this)
+{
+	return this->name;
+}
+
+static char* write_arg(char **pos, size_t *left, char *format, ...)
+{
+	size_t len;
+	char *res = NULL;
+	va_list args;
+
+	va_start(args, format);
+	len = vsnprintf(*pos, *left, format, args);
+	va_end(args);
+	if (len < *left)
+	{
+		res = *pos;
+		len++;
+		*pos += len + 1;
+		*left -= len + 1;
+	}
+	return res;
+}
+
+static bool start(private_guest_t *this)
+{
+	char buf[1024];
+	char cwd[512];
+	char *pos = buf;
+	char *args[16];
+	int i = 0;
+	size_t left = sizeof(buf);
+
+	args[i++] = this->kernel;
+	args[i++] = write_arg(&pos, &left, "root=/dev/root");
+	args[i++] = write_arg(&pos, &left, "rootfstype=hostfs");
+	args[i++] = write_arg(&pos, &left, "rootflags=%s/%s/%s",
+						  getcwd(cwd, sizeof(cwd)), MOUNT_DIR, this->name);
+	args[i++] = write_arg(&pos, &left, "uml_dir=%s/%s", RUN_DIR, this->name);
+	args[i++] = write_arg(&pos, &left, "umid=%s", this->name);
+	args[i++] = write_arg(&pos, &left, "mem=%dM", this->mem);
+	//args[i++] = write_arg(&pos, &left, "con=pts");
+	args[i++] = write_arg(&pos, &left, "con0=null,fd:%d", this->bootlog);
+	args[i++] = write_arg(&pos, &left, "con1=fd:0,fd:1");
+	args[i++] = write_arg(&pos, &left, "con3=null,null");
+	args[i++] = write_arg(&pos, &left, "con4=null,null");
+	args[i++] = write_arg(&pos, &left, "con5=null,null");
+	args[i++] = write_arg(&pos, &left, "con6=null,null");
+	args[i++] = NULL;
+	  
+	this->pid = fork();
+	switch (this->pid)
+	{
+		case 0: /* child,  */
+			dup2(open("/dev/null", 0), 0);
+			dup2(open("/dev/null", 0), 1);
+			dup2(open("/dev/null", 0), 2);
+			execvp(args[0], args);
+			exit(1);
+		case -1:
+			this->pid = 0;
+			return FALSE;
+		default:
+			return TRUE;
+	}
+}
+
+static void stop(private_guest_t *this)
+{
+	if (this->pid)
+	{
+		kill(this->pid, SIGINT);
+		this->pid = 0;
+	}
+}
+
+/**
+ * create a directory
+ */
+static bool makedir(char *dir, char *name)
+{
+	struct stat st;
+	char buf[256];
+	size_t len;
+	
+	len = snprintf(buf, sizeof(buf), "%s/%s", dir, name);
+	if (len < 0 || len >= sizeof(buf))
+	{
+		return FALSE;
+	}
+	if (stat(buf, &st) != 0)
+	{
+		return mkdir(buf, S_IRWXU) == 0;
+	}
+	return S_ISDIR(st.st_mode);
+}
+
+/**
+ * umount the union filesystem
+ */
+static bool umount_unionfs(char *name)
+{
+	char cmd[128];
+	size_t len;
+	
+	len = snprintf(cmd, sizeof(cmd), "fusermount -u %s/%s", MOUNT_DIR, name);
+	if (len < 0 || len >= sizeof(cmd))
+	{
+		return FALSE;
+	}
+	if (system(cmd) != 0)
+	{
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * mount the union filesystem
+ */
+static bool mount_unionfs(char *name, char *master)
+{
+	char cmd[256];
+	size_t len;
+	
+	/* mount unionfs */
+	len = snprintf(cmd, sizeof(cmd), "unionfs %s/%s:%s %s/%s",
+				   HOST_DIR, name, master, MOUNT_DIR, name);
+	if (len < 0 || len >= sizeof(cmd))
+	{
+		return FALSE;
+	}
+	if (system(cmd) != 0)
+	{
+		DBG1("mounting unionfs using '%s' failed.", cmd);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * open logfile for boot messages
+ */
+static int open_bootlog(char *name)
+{
+	char blg[256];
+	size_t len;
+	int fd;
+	
+	len = snprintf(blg, sizeof(blg), "%s/%s/boot.log", RUN_DIR, name);
+	if (len < 0 || len >= sizeof(blg))
+	{
+		return 1;
+	}
+	fd = open(blg, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
+	if (fd == -1)
+	{
+		return 1;
+	}
+	return fd;
+}
+
+/**
+ * stop guest, unmount mounts
+ */
+static void destroy(private_guest_t *this)
+{
+	stop(this);
+	umount_unionfs(this->name);
+	free(this->name);
+	free(this->kernel);
+	free(this->master);
+	free(this);
+}
+
+/**
+ * create the guest instance, including required dirs and mounts 
+ */
+guest_t *guest_create(char *name, char *kernel, char *master, int mem)
+{
+	private_guest_t *this = malloc_thing(private_guest_t);
+	
+	this->public.get_name = (void*)get_name;
+	this->public.start = (void*)start;
+	this->public.stop = (void*)stop;
+	this->public.destroy = (void*)destroy;
+	
+	if (!makedir(HOST_DIR, name) || !makedir(MOUNT_DIR, name) ||
+		!makedir(RUN_DIR, name))
+	{
+		DBG1("creating guest directories for %s failed failed.", name);
+		free(this);
+		return NULL;
+	}
+	
+	if (!mount_unionfs(name, master))
+	{
+		DBG1("mounting guest unionfs for %s failed.", name);
+		free(this);
+		return NULL;
+	}
+	
+	this->name = strdup(name);
+	this->kernel = strdup(kernel);
+	this->master = strdup(master);
+	this->mem = mem;
+	this->pid = 0;
+	this->bootlog = open_bootlog(name);
+
+	return &this->public;
+}
+