Cleaup read() and write() variants, plus a couple of new functions like

xlseek and fdlength() for the new mkswap.

libbb/change_identity.c

@@ -46,10 +46,8 @@ const char *change_identity_e2str ( const struct passwd *pw )
 		return "cannot set groups";
 	endgrent ( );
 
-	if ( setgid ( pw-> pw_gid ))
-		return "cannot set group id";
-	if ( setuid ( pw->pw_uid ))
-		return "cannot set user id";
+	xsetgid(pw-> pw_gid);
+	xsetuid(pw->pw_uid);
 	return NULL;
 }
 

libbb/copyfd.c

@@ -30,24 +30,24 @@ static ssize_t bb_full_fd_action(int src_fd, int dst_fd, size_t size)
 	if (src_fd < 0) goto out;
 	while (!size || total < size)
 	{
-		ssize_t wrote, xread;
+		ssize_t wr, rd;
 
-		xread = safe_read(src_fd, buffer,
+		rd = safe_read(src_fd, buffer,
 				(!size || size - total > BUFSIZ) ? BUFSIZ : size - total);
 
-		if (xread > 0) {
+		if (rd > 0) {
 			/* A -1 dst_fd means we need to fake it... */
-			wrote = (dst_fd < 0) ? xread : bb_full_write(dst_fd, buffer, xread);
-			if (wrote < xread) {
+			wr = (dst_fd < 0) ? rd : full_write(dst_fd, buffer, rd);
+			if (wr < rd) {
 				bb_perror_msg(bb_msg_write_error);
 				break;
 			}
-			total += wrote;
+			total += wr;
 			if (total == size) status = 0;
-		} else if (xread < 0) {
+		} else if (rd < 0) {
 			bb_perror_msg(bb_msg_read_error);
 			break;
-		} else if (xread == 0) {
+		} else if (rd == 0) {
 			/* All done. */
 			status = 0;
 			break;

libbb/create_icmp6_socket.c

@@ -32,7 +32,7 @@ int create_icmp6_socket(void)
 	}
 
 	/* drop root privs if running setuid */
-	setuid(getuid());
+	xsetuid(getuid());
 
 	return sock;
 }

libbb/create_icmp_socket.c

@@ -31,7 +31,7 @@ int create_icmp_socket(void)
 	}
 
 	/* drop root privs if running setuid */
-	setuid(getuid());
+	xsetuid(getuid());
 
 	return sock;
 }

libbb/full_read.c

@@ -17,7 +17,7 @@
  * Returns the amount read, or -1 on an error.
  * A short read is returned on an end of file.
  */
-ssize_t bb_full_read(int fd, void *buf, size_t len)
+ssize_t full_read(int fd, void *buf, size_t len)
 {
 	ssize_t cc;
 	ssize_t total;

libbb/full_write.c

@@ -16,7 +16,7 @@
  * This does multiple writes as necessary.
  * Returns the amount written, or -1 on an error.
  */
-ssize_t bb_full_write(int fd, const void *buf, size_t len)
+ssize_t full_write(int fd, const void *buf, size_t len)
 {
 	ssize_t cc;
 	ssize_t total;

libbb/loop.c

@@ -3,6 +3,7 @@
  * Utility routines.
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2005 by Rob Landley <rob@landley.net>
  *
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */

libbb/xfuncs.c

@@ -120,40 +120,55 @@ int bb_xopen3(const char *pathname, int flags, int mode)
 #endif
 
 #ifdef L_xread
-ssize_t bb_xread(int fd, void *buf, size_t count)
+
+// Die with an error message if we can't read the entire buffer.
+
+void xread(int fd, void *buf, size_t count)
 {
-	ssize_t size;
-
-	size = read(fd, buf, count);
-	if (size < 0) {
-		bb_perror_msg_and_die(bb_msg_read_error);
-	}
-	return(size);
-}
-#endif
-
-#ifdef L_xread_all
-void bb_xread_all(int fd, void *buf, size_t count)
-{
-	ssize_t size;
-
 	while (count) {
-		if ((size = bb_xread(fd, buf, count)) == 0) {	/* EOF */
+		ssize_t size;
+
+		if ((size = safe_read(fd, buf, count)) < 1)
 			bb_error_msg_and_die("Short read");
-		}
 		count -= size;
 		buf = ((char *) buf) + size;
 	}
-	return;
+}
+#endif
+
+#ifdef L_xwrite
+
+// Die with an error message if we can't write the entire buffer.
+
+void xwrite(int fd, void *buf, size_t count)
+{
+	while (count) {
+		ssize_t size;
+
+		if ((size = safe_write(fd, buf, count)) < 1)
+			bb_error_msg_and_die("Short write");
+		count -= size;
+		buf = ((char *) buf) + size;
+	}
+}
+#endif
+
+#ifdef L_xlseek
+
+// Die if we can't lseek to the right spot.
+
+void xlseek(int fd, off_t offset, int whence)
+{
+	if (whence != lseek(fd, offset, whence)) bb_error_msg_and_die("lseek");
 }
 #endif
 
 #ifdef L_xread_char
-unsigned char bb_xread_char(int fd)
+unsigned char xread_char(int fd)
 {
 	char tmp;
 
-	bb_xread_all(fd, &tmp, 1);
+	xread(fd, &tmp, 1);
 
 	return(tmp);
 }
@@ -294,3 +309,41 @@ void xsetuid(uid_t uid)
 	if (setuid(uid)) bb_error_msg_and_die("setuid");
 }
 #endif
+
+#ifdef L_fdlength
+off_t fdlength(int fd)
+{
+	off_t bottom = 0, top = 0, pos;
+	long size;
+
+	// If the ioctl works for this, return it.
+
+	if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;
+
+	// If not, do a binary search for the last location we can read.
+
+	do {
+		char temp;
+
+		pos = bottom + (top - bottom) / 2;;
+
+		// If we can read from the current location, it's bigger.
+
+		if (lseek(fd, pos, 0)>=0 && safe_read(fd, &temp, 1)==1) {
+			if (bottom == top) bottom = top = (top+1) * 2;
+			else bottom = pos;
+
+		// If we can't, it's smaller.
+
+		} else {
+			if (bottom == top) {
+				if (!top) return 0;
+				bottom = top/2;
+			}
+			else top = pos;
+		}
+	} while (bottom + 1 != top);
+
+	return pos + 1;
+}
+#endif