libinstaller: introduce syslxrw library

Due to size constraints on DOS systems, do not include whole syslxcom
into DOS-based installer for using xpread() and xpwrite() functions,
instead make them part of another separate library and include it only.

Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>

extlinux/Makefile

@@ -27,6 +27,7 @@ SRCS     = main.c \
 	   ../libinstaller/syslxmod.c \
 	   ../libinstaller/syslxopt.c \
 	   ../libinstaller/syslxcom.c \
+	   ../libinstaller/syslxrw.c \
 	   ../libinstaller/setadv.c \
 	   ../libinstaller/advio.c \
 	   ../libinstaller/bootsect_bin.c \

extlinux/main.c

@@ -56,6 +56,7 @@
 #include "version.h"
 #include "syslxint.h"
 #include "syslxcom.h" /* common functions shared with extlinux and syslinux */
+#include "syslxrw.h"
 #include "syslxfs.h"
 #include "setadv.h"
 #include "syslxopt.h" /* unified options */

libinstaller/advio.c

@@ -32,6 +32,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include "syslxint.h"
+#include "syslxrw.h"
 #include "syslxcom.h"
 
 /*

libinstaller/syslxcom.c

@@ -32,6 +32,7 @@
 #include <sys/vfs.h>
 
 #include "linuxioctl.h"
+#include "syslxrw.h"
 #include "syslxcom.h"
 #include "syslxfs.h"
 
@@ -47,69 +48,6 @@ int fs_type;
 
 #define SECTOR_SHIFT	9
 
-static void die(const char *msg)
-{
-    fputs(msg, stderr);
-    exit(1);
-}
-
-/*
- * read/write wrapper functions
- */
-ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
-{
-    char *bufp = (char *)buf;
-    ssize_t rv;
-    ssize_t done = 0;
-
-    while (count) {
-	rv = pread(fd, bufp, count, offset);
-	if (rv == 0) {
-	    die("short read");
-	} else if (rv == -1) {
-	    if (errno == EINTR) {
-		continue;
-	    } else {
-		die(strerror(errno));
-	    }
-	} else {
-	    bufp += rv;
-	    offset += rv;
-	    done += rv;
-	    count -= rv;
-	}
-    }
-
-    return done;
-}
-
-ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
-{
-    const char *bufp = (const char *)buf;
-    ssize_t rv;
-    ssize_t done = 0;
-
-    while (count) {
-	rv = pwrite(fd, bufp, count, offset);
-	if (rv == 0) {
-	    die("short write");
-	} else if (rv == -1) {
-	    if (errno == EINTR) {
-		continue;
-	    } else {
-		die(strerror(errno));
-	    }
-	} else {
-	    bufp += rv;
-	    offset += rv;
-	    done += rv;
-	    count -= rv;
-	}
-    }
-
-    return done;
-}
-
 /*
  * Set and clear file attributes
  */

libinstaller/syslxcom.h

@@ -4,8 +4,6 @@
 #include "syslinux.h"
 
 extern const char *program;
-ssize_t xpread(int fd, void *buf, size_t count, off_t offset);
-ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset);
 void clear_attributes(int fd);
 void set_attributes(int fd);
 int sectmap(int fd, sector_t *sectors, int nsectors);

libinstaller/syslxrw.c

@@ -0,0 +1,84 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2010 Intel Corp. - All Rights Reserved
+ *   Copyright 2015 Paulo Alcantara <pcacjr@zytor.com>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "syslxrw.h"
+
+static void die(const char *msg)
+{
+    fputs(msg, stderr);
+    exit(1);
+}
+
+/*
+ * read/write wrapper functions
+ */
+ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
+{
+    char *bufp = (char *)buf;
+    ssize_t rv;
+    ssize_t done = 0;
+
+    while (count) {
+	rv = pread(fd, bufp, count, offset);
+	if (rv == 0) {
+	    die("short read");
+	} else if (rv == -1) {
+	    if (errno == EINTR) {
+		continue;
+	    } else {
+		die(strerror(errno));
+	    }
+	} else {
+	    bufp += rv;
+	    offset += rv;
+	    done += rv;
+	    count -= rv;
+	}
+    }
+
+    return done;
+}
+
+ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
+{
+    const char *bufp = (const char *)buf;
+    ssize_t rv;
+    ssize_t done = 0;
+
+    while (count) {
+	rv = pwrite(fd, bufp, count, offset);
+	if (rv == 0) {
+	    die("short write");
+	} else if (rv == -1) {
+	    if (errno == EINTR) {
+		continue;
+	    } else {
+		die(strerror(errno));
+	    }
+	} else {
+	    bufp += rv;
+	    offset += rv;
+	    done += rv;
+	    count -= rv;
+	}
+    }
+
+    return done;
+}

libinstaller/syslxrw.h

@@ -0,0 +1,20 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2010 Intel Corp. - All Rights Reserved
+ *   Copyright 2015 Paulo Alcantara <pcacjr@zytor.com>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#ifndef _H_SYSLXRW_
+#define _H_SYSLXRW_
+
+ssize_t xpread(int fd, void *buf, size_t count, off_t offset);
+ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset);
+
+#endif /* _H_SYSLXRW_ */

linux/Makefile

@@ -23,6 +23,7 @@ LDFLAGS	 =
 
 SRCS     = syslinux.c \
 	   ../libinstaller/syslxopt.c \
+	   ../libinstaller/syslxrw.c \
 	   ../libinstaller/syslxcom.c \
 	   ../libinstaller/setadv.c \
 	   ../libinstaller/advio.c \

linux/syslinux.c

@@ -68,6 +68,7 @@
 
 #include <getopt.h>
 #include <sysexits.h>
+#include "syslxrw.h"
 #include "syslxcom.h"
 #include "syslxfs.h"
 #include "setadv.h"

mtools/Makefile

@@ -9,7 +9,7 @@ SRCS     = syslinux.c \
 	   ../libinstaller/fs.c \
 	   ../libinstaller/syslxmod.c \
 	   ../libinstaller/syslxopt.c \
-	   ../libinstaller/syslxcom.c \
+	   ../libinstaller/syslxrw.c \
 	   ../libinstaller/setadv.c \
 	   ../libinstaller/bootsect_bin.c \
 	   ../libinstaller/ldlinux_bin.c \

mtools/syslinux.c

@@ -42,8 +42,9 @@
 #include "setadv.h"
 #include "syslxopt.h"
 #include "syslxfs.h"
-#include "syslxcom.h"
+#include "syslxrw.h"
 
+const char *program;
 pid_t mypid;
 
 void __attribute__ ((noreturn)) die(const char *msg)