nandwrite: Add Support for Reading from Standard Input

Added suppport for reading in band data from standard input based on a
patch originally generated by Richard Titmuss <titmuss@slimdevices.com>
at <http://lists.slimdevices.com/pipermail/jive-checkins/2008-May/001918.html>.

Signed-off-by: Grant Erickson <gerickson@nuovations.com>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>

diff --git a/nandwrite.c b/nandwrite.c
index b7cd72e261806f9ba1ae364f1e56b2dd54da1a17..fc23e8522b7c6da926fd889302e813f7e566b456 100644 (file)
--- a/nandwrite.c
+++ b/nandwrite.c
@@ -24,6 +24,8 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -74,7 +76,7 @@ static struct nand_oobinfo autoplace_oobinfo = {
 static void display_help (void)
 {
        printf(
-"Usage: nandwrite [OPTION] MTD_DEVICE INPUTFILE\n"
+"Usage: nandwrite [OPTION] MTD_DEVICE [INPUTFILE|-]\n"
 "Writes to the specified MTD device.\n"
 "\n"
 "  -a, --autoplace         Use auto oob layout\n"
@@ -110,6 +112,7 @@ static void display_version (void)
        exit (EXIT_SUCCESS);
 }
 
+static const char      *standard_input = "-";
 static const char      *mtd_device, *img;
 static int             mtdoffset = 0;
 static bool            quiet = false;
@@ -198,16 +201,46 @@ static void process_options (int argc, char * const argv[])
                                blockalign = atoi (optarg);
                                break;
                        case '?':
-                               error = 1;
+                               error++;
                                break;
                }
        }
 
-       if ((argc - optind) != 2 || error)
+       if (mtdoffset < 0) {
+               fprintf(stderr, "Can't specify a negative device offset `%d'\n",
+                               mtdoffset);
+               exit (EXIT_FAILURE);
+       }
+
+       argc -= optind;
+       argv += optind;
+
+       /*
+        * There must be at least the MTD device node positional
+        * argument remaining and, optionally, the input file.
+        */
+
+       if (argc < 1 || argc > 2 || error)
                display_help ();
 
-       mtd_device = argv[optind++];
-       img = argv[optind];
+       mtd_device = argv[0];
+
+       /*
+        * Standard input may be specified either explictly as "-" or
+        * implicity by simply omitting the second of the two
+        * positional arguments.
+        */
+
+       img = ((argc == 2) ? argv[1] : standard_input);
+}
+
+static void erase_buffer(void *buffer, size_t size)
+{
+       const uint8_t kEraseByte = 0xff;
+
+       if (buffer != NULL && size > 0) {
+               memset(buffer, kEraseByte, size);
+       }
 }
 
 /*
@@ -215,8 +248,12 @@ static void process_options (int argc, char * const argv[])
  */
 int main(int argc, char * const argv[])
 {
-       int cnt, fd, ifd, imglen = 0, pagelen, blockstart = -1;
+       int cnt = 0;
+       int fd = -1;
+       int ifd = -1;
+       int imglen = 0, pagelen;
        bool baderaseblock = false;
+       int blockstart = -1;
        struct mtd_info_user meminfo;
        struct mtd_oob_buf oob;
        loff_t offs;
@@ -226,7 +263,7 @@ int main(int argc, char * const argv[])
 
        process_options(argc, argv);
 
-       memset(oobbuf, 0xff, sizeof(oobbuf));
+       erase_buffer(oobbuf, sizeof(oobbuf));
 
        if (pad && writeoob) {
                fprintf(stderr, "Can't pad when oob data is present.\n");
@@ -340,21 +377,48 @@ int main(int argc, char * const argv[])
        oob.length = meminfo.oobsize;
        oob.ptr = noecc ? oobreadbuf : oobbuf;
 
-       /* Open the input file */
-       if ((ifd = open(img, O_RDONLY)) == -1) {
+       /* Determine if we are reading from standard input or from a file. */
+       if (strcmp(img, standard_input) == 0) {
+               ifd = STDIN_FILENO;
+       } else {
+               ifd = open(img, O_RDONLY);
+       }
+
+       if (ifd == -1) {
                perror(img);
                goto restoreoob;
        }
 
-       // get image length
-       imglen = lseek(ifd, 0, SEEK_END);
-       lseek (ifd, 0, SEEK_SET);
+       /* For now, don't allow writing oob when reading from standard input. */
+       if (ifd == STDIN_FILENO && writeoob) {
+               fprintf(stderr, "Can't write oob when reading from standard input.\n");
+               goto closeall;
+       }
 
        pagelen = meminfo.writesize + ((writeoob) ? meminfo.oobsize : 0);
 
-       // Check, if file is pagealigned
+       /*
+        * For the standard input case, the input size is merely an
+        * invariant placeholder and is set to the write page
+        * size. Otherwise, just use the input file size.
+        *
+        * TODO: Add support for the -l,--length=length option (see
+        * previous discussion by Tommi Airikka <tommi.airikka@ericsson.com> at
+        * <http://lists.infradead.org/pipermail/linux-mtd/2008-September/
+        * 022913.html>
+        */
+
+       if (ifd == STDIN_FILENO) {
+           imglen = pagelen;
+       } else {
+           imglen = lseek(ifd, 0, SEEK_END);
+           lseek (ifd, 0, SEEK_SET);
+       }
+
+       // Check, if file is page-aligned
        if ((!pad) && ((imglen % pagelen) != 0)) {
-               fprintf (stderr, "Input file is not page aligned\n");
+               fprintf (stderr, "Input file is not page-aligned. Use the padding "
+                                "option.\n");
                goto closeall;
        }
 
@@ -366,7 +430,13 @@ int main(int argc, char * const argv[])
                goto closeall;
        }
 
-       /* Get data from input and write to the device */
+       /*
+        * Get data from input and write to the device while there is
+        * still input to read and we are still within the device
+        * bounds. Note that in the case of standard input, the input
+        * length is simply a quasi-boolean flag whose values are page
+        * length or zero.
+        */
        while (imglen && (mtdoffset < meminfo.size)) {
                // new eraseblock , check for bad block(s)
                // Stay in the loop to be sure if the mtdoffset changes because
@@ -379,7 +449,8 @@ int main(int argc, char * const argv[])
                        offs = blockstart;
                        baderaseblock = false;
                        if (!quiet)
-                               fprintf (stdout, "Writing data to block %x\n", blockstart);
+                               fprintf (stdout, "Writing data to block %d at offset 0x%x\n",
+                                                blockstart / meminfo.erasesize, blockstart);
 
                        /* Check all the blocks in an erase block for bad blocks */
                        do {
@@ -404,18 +475,50 @@ int main(int argc, char * const argv[])
                }
 
                readlen = meminfo.writesize;
-               if (pad && (imglen < readlen))
-               {
-                       readlen = imglen;
-                       memset(writebuf + readlen, 0xff, meminfo.writesize - readlen);
-               }
 
-               /* Read Page Data from input file */
-               if ((cnt = read(ifd, writebuf, readlen)) != readlen) {
-                       if (cnt == 0)   // EOF
+               if (ifd != STDIN_FILENO) {
+                       if (pad && (imglen < readlen))
+                       {
+                               readlen = imglen;
+                               erase_buffer(writebuf + readlen, meminfo.writesize - readlen);
+                       }
+
+                       /* Read Page Data from input file */
+                       if ((cnt = read(ifd, writebuf, readlen)) != readlen) {
+                               if (cnt == 0)   // EOF
+                                       break;
+                               perror ("File I/O error on input file");
+                               goto closeall;
+                       }
+               } else {
+                       int tinycnt = 0;
+
+                       while(tinycnt < readlen) {
+                               cnt = read(ifd, writebuf + tinycnt, readlen - tinycnt);
+                               if (cnt == 0) { // EOF
+                                       break;
+                               } else if (cnt < 0) {
+                                       perror ("File I/O error on stdin");
+                                       goto closeall;
+                               }
+                               tinycnt += cnt;
+                       }
+
+                       /* No padding needed - we are done */
+                       if (tinycnt == 0) {
+                               imglen = 0;
                                break;
-                       perror ("File I/O error on input file");
-                       goto closeall;
+                       }
+
+                       /* No more bytes - we are done after writing the remaining bytes */
+                       if (cnt == 0) {
+                               imglen = 0;
+                       }
+
+                       /* Padding */
+                       if (pad && (tinycnt < readlen)) {
+                               erase_buffer(writebuf + tinycnt, meminfo.writesize - tinycnt);
+                       }
                }
 
                if (writeoob) {
@@ -499,7 +602,9 @@ int main(int argc, char * const argv[])
 
                        continue;
                }
-               imglen -= readlen;
+               if (ifd != STDIN_FILENO) {
+                       imglen -= readlen;
+               }
                mtdoffset += meminfo.writesize;
        }
 
@@ -517,7 +622,7 @@ restoreoob:
 
        close(fd);
 
-       if (imglen > 0) {
+       if ((ifd != STDIN_FILENO) && (imglen > 0)) {
                perror ("Data was only partially written due to error\n");
                exit (EXIT_FAILURE);
        }