ipsw: implemented file locking for on-demand downloading

4 files changed, 175 insertions, 1 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index c9f1313..53d2fda 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -18,7 +18,7 @@ AM_LDADD = $(AC_LDADD)
 
 bin_PROGRAMS = idevicerestore
 
-idevicerestore_SOURCES = idevicerestore.c common.c tss.c img3.c ipsw.c normal.c dfu.c recovery.c restore.c asr.c libirecovery.c limera1n.c download.c
+idevicerestore_SOURCES = idevicerestore.c common.c tss.c img3.c ipsw.c normal.c dfu.c recovery.c restore.c asr.c libirecovery.c limera1n.c download.c locking.c
 idevicerestore_CFLAGS = $(AM_CFLAGS)
 idevicerestore_LDFLAGS = $(AM_LDFLAGS)
 idevicerestore_LDADD = $(AM_LDADD)
diff --git a/src/ipsw.c b/src/ipsw.c
index 033b894..8e3d598 100644
--- a/src/ipsw.c
+++ b/src/ipsw.c
@@ -26,6 +26,7 @@
 #include <openssl/sha.h>
 
 #include "ipsw.h"
+#include "locking.h"
 #include "idevicerestore.h"
 
 #define BUFSIZE 0x100000
@@ -403,6 +404,15 @@ int ipsw_download_latest_fw(plist_t version_data, const char* product, const cha
 	char fwlfn[256];
 	sprintf(fwlfn, "%s/%s", todir, fwfn);
 
+	char fwlock[256];
+	sprintf(fwlock, "%s.lock", fwlfn);
+
+	lock_info_t lockinfo;
+
+	if (lock_file(fwlock, &lockinfo) != 0) {
+		error("WARNING: Could not lock file '%s'\n", fwlock);
+	}
+
 	int need_dl = 0;
 	unsigned char zsha1[20] = {0, };
 	FILE* f = fopen(fwlfn, "rb");
@@ -452,5 +462,10 @@ int ipsw_download_latest_fw(plist_t version_data, const char* product, const cha
 	if (res == 0) {
 		*ipswfile = strdup(fwlfn);
 	}
+
+	if (unlock_file(&lockinfo) != 0) {
+		error("WARNING: Could not unlock file '%s'\n", fwlock);
+	}
+
 	return res;
 }
diff --git a/src/locking.c b/src/locking.c
new file mode 100644
index 0000000..dbbbd7c
--- /dev/null
+++ b/src/locking.c
@@ -0,0 +1,116 @@
+/*
+ * locking.c
+ * locking extras
+ *
+ * Copyright (c) 2012 Nikias Bassen. All Rights Reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifdef WIN32
+#include <windows.h>
+#else
+#include <errno.h>
+#endif
+
+#include "locking.h"
+#include "common.h"
+
+int lock_file(const char* filename, lock_info_t* lockinfo)
+{
+	if (!lockinfo) {
+		return -1;
+	}
+#ifdef WIN32
+	lockinfo->fp = CreateFile(filename, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+	if (lockinfo->fp == INVALID_HANDLE_VALUE) {
+		debug("ERROR: could not open or create lockfile '%s'\n", filename);
+		return -1;
+	}
+
+	lockinfo->ldata.Offset = 0;
+	lockinfo->ldata.OffsetHigh = 0;
+
+	if (!LockFileEx(lockinfo->fp, LOCKFILE_EXCLUSIVE_LOCK, 0, 1, 0, &lockinfo->ldata)) {
+		debug("ERROR: can't lock file, error %d\n", GetLastError());
+		CloseHandle(lockinfo->fp);
+		lockinfo->fp = INVALID_HANDLE_VALUE;
+		return -1;
+	}
+#else
+	lockinfo->fp = fopen(filename, "a+");
+
+	if (!lockinfo->fp) {
+		debug("ERROR: could not open or create lockfile '%s'\n", filename);
+		return -1;
+	}
+
+	lockinfo->ldata.l_type = F_WRLCK;
+	lockinfo->ldata.l_whence = SEEK_SET;
+	lockinfo->ldata.l_start = 0;
+	lockinfo->ldata.l_len = 0;
+
+	if (fcntl(fileno(lockinfo->fp), F_SETLKW, &lockinfo->ldata) < 0) {
+		debug("ERROR: can't lock file, error %d\n", errno);
+		fclose(lockinfo->fp);
+		lockinfo->fp = NULL;
+		return -1;
+	}
+#endif
+	return 0;
+}
+
+int unlock_file(lock_info_t* lockinfo)
+{
+	if (!lockinfo) {
+		return -1;
+	}
+#ifdef WIN32
+	if (lockinfo->fp == INVALID_HANDLE_VALUE) {
+		return -1;
+	}
+
+	lockinfo->ldata.Offset = 0;
+	lockinfo->ldata.OffsetHigh = 0;
+
+	if (!UnlockFileEx(lockinfo->fp, 0, 1, 0, &lockinfo->ldata)) {
+		debug("ERROR: can't unlock file, error %d\n", GetLastError());
+		CloseHandle(lockinfo->fp);
+		lockinfo->fp = INVALID_HANDLE_VALUE;
+		return -1;
+	}
+	CloseHandle(lockinfo->fp);
+	lockinfo->fp = INVALID_HANDLE_VALUE;
+#else
+	if (!lockinfo->fp) {
+		return -1;
+	}
+
+	lockinfo->ldata.l_type = F_UNLCK;
+	lockinfo->ldata.l_whence = SEEK_SET;
+	lockinfo->ldata.l_start = 0;
+	lockinfo->ldata.l_len = 0;
+
+	if (fcntl(fileno(lockinfo->fp), F_SETLK, &lockinfo->ldata) < 0) {
+		debug("ERROR: can't unlock file, error %d\n", errno);
+		fclose(lockinfo->fp);
+		lockinfo->fp = NULL;
+		return -1;
+	}
+	fclose(lockinfo->fp);
+	lockinfo->fp = NULL;
+#endif
+	return 0;
+}
+
diff --git a/src/locking.h b/src/locking.h
new file mode 100644
index 0000000..9bde00b
--- /dev/null
+++ b/src/locking.h
@@ -0,0 +1,43 @@
+/*
+ * locking.h
+ * locking extras header file
+ *
+ * Copyright (c) 2012 Nikias Bassen. All Rights Reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef LOCKING_H
+#define LOCKING_H
+#ifdef WIN32
+#include <windows.h>
+#else
+#include <stdio.h>
+#include <fcntl.h>
+#endif
+
+typedef struct {
+#ifdef WIN32
+	HANDLE fp;
+	OVERLAPPED ldata;
+#else
+	FILE* fp;
+	struct flock ldata;
+#endif	
+} lock_info_t;
+
+int lock_file(const char* filename, lock_info_t* lockp);
+int unlock_file(lock_info_t* lockp);
+
+#endif