Unified reading from standard input and from file

Nandwrite tries to use lseek() when failing to write on a page. lseek() will fail when used on the standard input so nandwrite fails. This code replaces lseek with a buffer.

When the data is read, it is put in a buffer (filebuf). This buffer is reset at each block boundary. So a "seek" just means reading from the beginning of the buffer. writebuf and oobreadbuf are now just pointers to locations in filebuf.

@@ -45,13 +45,6 @@

#define MAX_PAGE_SIZE 4096
#define MAX_OOB_SIZE 128

-/*
- * Buffer array used for writing data
- */
-static unsigned char writebuf[MAX_PAGE_SIZE]; -static unsigned char oobbuf[MAX_OOB_SIZE];
-static unsigned char oobreadbuf[MAX_OOB_SIZE];
-
// oob layouts to pass into the kernel as default static struct nand_oobinfo none_oobinfo = {
.useecc = MTD_NANDECC_OFF,
@@ -257,10 +250,19 @@ int main(int argc, char * const argv[])

	struct mtd_info_user meminfo;
	struct mtd_oob_buf oob;
	loff_t offs;
-	int ret, readlen;
+	int ret;
	int oobinfochanged = 0;
	struct nand_oobinfo old_oobinfo;
	bool failed = true;

+ // contains all the data read from the file so far for the current eraseblock
+ unsigned char *filebuf = NULL;
+ size_t filebuf_max = 0;
+ size_t filebuf_len = 0; + // points to the current page inside filebuf
+ unsigned char *writebuf = NULL;
+ // points to the OOB for the current page in filebuf
+ unsigned char *oobreadbuf = NULL;
+ unsigned char oobbuf[MAX_OOB_SIZE];

	process_options(argc, argv);

@@ -431,6 +433,16 @@ int main(int argc, char * const argv[])

		goto closeall;
	}

+ // Allocate a buffer big enough to contain all the data (OOB included) for one eraseblock
+ filebuf_max = pagelen * meminfo.erasesize / meminfo.writesize;
+ filebuf = (unsigned char*)malloc(filebuf_max);
+ if (!filebuf) {
+ fprintf(stderr, "Failed to allocate memory for file buffer (%d bytes)\n",
+ pagelen * meminfo.erasesize / meminfo.writesize);
+ goto closeall;
+ }
+ erase_buffer(filebuf, filebuf_max);
+
/*
* Get data from input and write to the device while there is
* still input to read and we are still within the device
@@ -438,7 +450,9 @@ int main(int argc, char * const argv[])
* length is simply a quasi-boolean flag whose values are page
* length or zero.
*/
- while (imglen && (mtdoffset < meminfo.size)) {
+ while (((imglen > 0) || (writebuf < (filebuf + filebuf_len)))
+ && (mtdoffset < meminfo.size))

+	{
		// new eraseblock , check for bad block(s)
		// Stay in the loop to be sure if the mtdoffset changes because
		// of a bad block, that the next block that will be written to
@@ -448,6 +462,15 @@ int main(int argc, char * const argv[])
		while (blockstart != (mtdoffset & (~meminfo.erasesize + 1))) {
			blockstart = mtdoffset & (~meminfo.erasesize + 1);
			offs = blockstart;

+
+ // if writebuf == filebuf, we are rewinding so we must not
+ // reset the buffer but just replay it
+ if (writebuf != filebuf) {
+ erase_buffer(filebuf, filebuf_len);
+ filebuf_len = 0;
+ writebuf = filebuf;
+ }
+

			baderaseblock = false;
			if (!quiet)
				fprintf (stdout, "Writing data to block %d at offset 0x%x\n",

@@ -475,10 +498,12 @@ int main(int argc, char * const argv[])

		}

- {
- readlen = meminfo.writesize;
+ // Read more data from the input if there isn't enough in the buffer
+ if ((writebuf + meminfo.writesize) > (filebuf + filebuf_len)) {
+ int readlen = meminfo.writesize;

- int tinycnt = 0;
+ int alreadyread = (filebuf + filebuf_len) - writebuf;
+ int tinycnt = alreadyread;

			while (tinycnt < readlen) {
				cnt = read(ifd, writebuf + tinycnt, readlen - tinycnt);
@@ -513,17 +538,25 @@ int main(int argc, char * const argv[])
				erase_buffer(writebuf + tinycnt, readlen - tinycnt);
			}

- if ((ifd == STDIN_FILENO) && (cnt == 0)) {
+ filebuf_len += readlen - alreadyread;
+ if (ifd != STDIN_FILENO) {
+ imglen -= tinycnt - alreadyread;
+ }

+			else if (cnt == 0) {
				/* No more bytes - we are done after writing the remaining bytes */
				imglen = 0;
			}
		}

		if (writeoob) {

- {
+ oobreadbuf = writebuf + meminfo.writesize;
+
+ // Read more data for the OOB from the input if there isn't enough in the buffer

+			if ((oobreadbuf + meminfo.oobsize) > (filebuf + filebuf_len)) {
				int readlen = meminfo.oobsize;

- int tinycnt = 0;
+ int alreadyread = (filebuf + filebuf_len) - oobreadbuf;
+ int tinycnt = alreadyread;

				while (tinycnt < readlen) {
					cnt = read(ifd, oobreadbuf + tinycnt, readlen - tinycnt);
@@ -542,13 +575,19 @@ int main(int argc, char * const argv[])
					goto closeall;
				}

- if ((ifd == STDIN_FILENO) && (cnt == 0)) {
+ filebuf_len += readlen - alreadyread;
+ if (ifd != STDIN_FILENO) {
+ imglen -= tinycnt - alreadyread;
+ }

+				else if (cnt == 0) {
					/* No more bytes - we are done after writing the remaining bytes */
					imglen = 0;
				}
			}

- if (!noecc) {
+ if (noecc) {
+ oob.ptr = oobreadbuf;

+			} else {
				int i, start, len;
				/*
				 *  We use autoplacement and have the oobinfo with the autoplacement
@@ -581,13 +620,10 @@ int main(int argc, char * const argv[])
				perror ("ioctl(MEMWRITEOOB)");
				goto closeall;
			}
-			imglen -= meminfo.oobsize;
		}

		/* Write out the Page data */
		if (pwrite(fd, writebuf, meminfo.writesize, mtdoffset) != meminfo.writesize) {
-			int rewind_blocks;
-			off_t rewind_bytes;
			erase_info_t erase;

			perror ("pwrite");
@@ -596,15 +632,8 @@ int main(int argc, char * const argv[])
			}

			/* Must rewind to blockstart if we can */

- rewind_blocks = (mtdoffset - blockstart) / meminfo.writesize; /* Not including the one we just attempted */
- rewind_bytes = (rewind_blocks * meminfo.writesize) + readlen;
- if (writeoob)
- rewind_bytes += (rewind_blocks + 1) * meminfo.oobsize;
- if (lseek(ifd, -rewind_bytes, SEEK_CUR) == -1) {
- perror("lseek");
- fprintf(stderr, "Failed to seek backwards to recover from write error\n");
- goto closeall;
- }
+ writebuf = filebuf;
+

			erase.start = blockstart;
			erase.length = meminfo.erasesize;
			fprintf(stderr, "Erasing failed write from %08lx-%08lx\n",
@@ -625,19 +654,20 @@ int main(int argc, char * const argv[])
				}
			}
			mtdoffset = blockstart + meminfo.erasesize;

- imglen += rewind_blocks * meminfo.writesize;

			continue;
		}
-		if (ifd != STDIN_FILENO) {
-			imglen -= readlen;
-		}
		mtdoffset += meminfo.writesize;
+		writebuf += pagelen;
	}

	failed = false;

closeall:
+ if (filebuf) {
+ free(filebuf);
+ }
+

	close(ifd);

restoreoob:
@@ -651,7 +681,10 @@ restoreoob:

	close(fd);

- if (failed || ((ifd != STDIN_FILENO) && (imglen > 0))) {
+ if (failed

+		|| ((ifd != STDIN_FILENO) && (imglen > 0))
+		|| (writebuf < (filebuf + filebuf_len)))
+	{
		perror ("Data was only partially written due to error\n");
		exit (EXIT_FAILURE);
	}