From bf0a010cf705d21c75d2c6ba8de38cec038f9aa1 Mon Sep 17 00:00:00 2001
From: Matt Kraai <kraai@debian.org>
Date: Mon, 11 Jun 2001 13:58:02 +0000
Subject: [PATCH] Copy files until EOF, not the reported file size, to deal
 with bad sizes in the proc filesystem.

---
 libbb/copy_file.c       |  7 ++--
 libbb/copy_file_chunk.c | 72 +++++++++++++++++++++++------------------
 2 files changed, 44 insertions(+), 35 deletions(-)

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index 22684be74..24bdf9002 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -94,7 +94,7 @@ int copy_file(const char *source, const char *dest, int flags)
 
 			umask(saved_umask);
 		}
-		
+
 		/* Recursively copy files in SOURCE.  */
 		if ((dp = opendir(source)) == NULL) {
 			perror_msg("unable to open directory `%s'", source);
@@ -116,7 +116,7 @@ int copy_file(const char *source, const char *dest, int flags)
 			free(new_source);
 			free(new_dest);
 		}
-		
+
 		/* ??? What if an error occurs in readdir?  */
 
 		if (closedir(dp) < 0) {
@@ -173,7 +173,8 @@ int copy_file(const char *source, const char *dest, int flags)
 			goto end;
 		}
 
-		copy_file_chunk(sfp, dfp, source_stat.st_size);
+		if (copy_file_chunk(sfp, dfp, -1) < 0)
+			status = -1;
 
 		if (fclose(dfp) < 0) {
 			perror_msg("unable to close `%s'", dest);
diff --git a/libbb/copy_file_chunk.c b/libbb/copy_file_chunk.c
index e9663c354..c440a6102 100644
--- a/libbb/copy_file_chunk.c
+++ b/libbb/copy_file_chunk.c
@@ -29,38 +29,46 @@
 #include <sys/stat.h>
 #include "libbb.h"
 
-/*
- * Copy chunksize bytes between two file descriptors
- *
- * unsigned long is used so that if -1 is passed as chunksize it will read as
- * much as possible, and it will work with off_t or off64_t
- */
+/* Copy CHUNKSIZE bytes (or until EOF if CHUNKSIZE equals -1) from SRC_FILE
+ * to DST_FILE.  */
 extern int copy_file_chunk(FILE *src_file, FILE *dst_file, unsigned long long chunksize)
 {
-	off_t size, amount_written;
-	char buffer[BUFSIZ]; /* BUFSIZ is declared in stdio.h */
-	
-	while (chunksize > 0) {
-		if (chunksize > BUFSIZ) {
-			size = BUFSIZ;
-		} else {
-			size = chunksize;
-		}
-		amount_written = fwrite(buffer, 1, fread(buffer, 1, size, src_file), dst_file);
-		if (amount_written != size) {
-			error_msg("Couldnt write correct amount");
-			return(FALSE);
-		}
-		chunksize -= amount_written;
-	}
-	return (TRUE);
-}
+	size_t nread, nwritten, size;
+	char buffer[BUFSIZ];
 
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/
+	while (chunksize != 0) {
+		if (chunksize > BUFSIZ)
+			size = BUFSIZ;
+		else
+			size = chunksize;
+
+		nread = fread (buffer, 1, size, src_file);
+
+		if (nread != size && ferror (src_file)) {
+			perror_msg ("read");
+			return -1;
+		} else if (nread == 0) {
+			if (chunksize != -1) {
+				error_msg ("Unable to read all data");
+				return -1;
+			}
+
+			return 0;
+		}
+
+		nwritten = fwrite (buffer, 1, nread, dst_file);
+
+		if (nwritten != nread) {
+			if (ferror (dst_file))
+				perror_msg ("write");
+			else
+				error_msg ("Unable to write all data");
+			return -1;
+		}
+
+		if (chunksize != -1)
+			chunksize -= nwritten;
+	}
+
+	return 0;
+}