1 files changed, 80 insertions, 31 deletions

diff --git a/coreutils/dd.c b/coreutils/dd.c
index b5f3cbec5..24d7f0b84 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -59,7 +59,7 @@
 //usage:       "[if=FILE] [of=FILE] [" IF_FEATURE_DD_IBS_OBS("ibs=N obs=N/") "bs=N] [count=N] [skip=N] [seek=N]\n"
 //usage:        IF_FEATURE_DD_IBS_OBS(
 //usage:       "        [conv=notrunc|noerror|sync|fsync]\n"
-//usage:       "        [iflag=skip_bytes|fullblock] [oflag=seek_bytes|append]"
+//usage:       "        [iflag=skip_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]"
 //usage:        )
 //usage:#define dd_full_usage "\n\n"
 //usage:       "Copy a file with converting and formatting\n"
@@ -82,9 +82,11 @@
 //usage:     "\n        conv=fsync      Physically write data out before finishing"
 //usage:     "\n        conv=swab       Swap every pair of bytes"
 //usage:     "\n        iflag=skip_bytes        skip=N is in bytes"
-//usage:     "\n        iflag=fullblock Read full blocks"
 //usage:     "\n        oflag=seek_bytes        seek=N is in bytes"
-//usage:     "\n        oflag=append    Open output file in append mode"
+//usage:     "\n        iflag=direct    O_DIRECT input"
+//usage:     "\n        oflag=direct    O_DIRECT output"
+//usage:     "\n        iflag=fullblock Read full blocks"
+//usage:     "\n        oflag=append    Open output in append mode"
 //usage:        )
 //usage:        IF_FEATURE_DD_STATUS(
 //usage:     "\n        status=noxfer   Suppress rate output"
@@ -137,16 +139,18 @@ enum {
         FLAG_IFLAG_SHIFT = 5,
         FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
         FLAG_FULLBLOCK = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
+        FLAG_IDIRECT = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
         /* end of input flags */
         /* start of output flags */
-        FLAG_OFLAG_SHIFT = 7,
-        FLAG_SEEK_BYTES = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
-        FLAG_APPEND = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
+        FLAG_OFLAG_SHIFT = 8,
+        FLAG_SEEK_BYTES = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
+        FLAG_APPEND = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
+        FLAG_ODIRECT = (1 << 10) * ENABLE_FEATURE_DD_IBS_OBS,
         /* end of output flags */
-        FLAG_TWOBUFS = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
-        FLAG_COUNT   = 1 << 10,
-        FLAG_STATUS_NONE = 1 << 11,
-        FLAG_STATUS_NOXFER = 1 << 12,
+        FLAG_TWOBUFS = (1 << 11) * ENABLE_FEATURE_DD_IBS_OBS,
+        FLAG_COUNT   = 1 << 12,
+        FLAG_STATUS_NONE = 1 << 13,
+        FLAG_STATUS_NOXFER = 1 << 14,
 };
 
 static void dd_output_status(int UNUSED_PARAM cur_signal)
@@ -192,12 +196,50 @@ static void dd_output_status(int UNUSED_PARAM cur_signal)
 #endif
 }
 
+#if ENABLE_FEATURE_DD_IBS_OBS
+static int clear_O_DIRECT(int fd)
+{
+        if (errno == EINVAL) {
+                int fl = fcntl(fd, F_GETFL);
+                if (fl & O_DIRECT) {
+                        fcntl(fd, F_SETFL, fl & ~O_DIRECT);
+                        return 1;
+                }
+        }
+        return 0;
+}
+#endif
+
+static ssize_t dd_read(void *ibuf, size_t ibs)
+{
+        ssize_t n;
+
+#if ENABLE_FEATURE_DD_IBS_OBS
+ read_again:
+        if (G.flags & FLAG_FULLBLOCK)
+                n = full_read(ifd, ibuf, ibs);
+        else
+#endif
+                n = safe_read(ifd, ibuf, ibs);
+#if ENABLE_FEATURE_DD_IBS_OBS
+        if (n < 0 && (G.flags & FLAG_IDIRECT) && clear_O_DIRECT(ifd))
+                goto read_again;
+#endif
+        return n;
+}
+
 static bool write_and_stats(const void *buf, size_t len, size_t obs,
         const char *filename)
 {
         ssize_t n;
 
+ IF_FEATURE_DD_IBS_OBS(write_again:)
         n = full_write(ofd, buf, len);
+#if ENABLE_FEATURE_DD_IBS_OBS
+        if (n < 0 && (G.flags & FLAG_ODIRECT) && clear_O_DIRECT(ofd))
+                goto write_again;
+#endif
+
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
         if (n > 0)
                 G.total_bytes += n;
@@ -254,6 +296,14 @@ static int parse_comma_flags(char *val, const char *words, const char *error_in)
 }
 #endif
 
+static void *alloc_buf(size_t size)
+{
+        /* Important for "{i,o}flag=direct" - buffers must be page aligned */
+        if (size >= bb_getpagesize())
+                return xmmap_anon(size);
+        return xmalloc(size);
+}
+
 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int dd_main(int argc UNUSED_PARAM, char **argv)
 {
@@ -267,9 +317,9 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
         static const char conv_words[] ALIGN1 =
                 "notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
         static const char iflag_words[] ALIGN1 =
-                "skip_bytes\0""fullblock\0";
+                "skip_bytes\0""fullblock\0""direct\0";
         static const char oflag_words[] ALIGN1 =
-                "seek_bytes\0append\0";
+                "seek_bytes\0append\0""direct\0";
 #endif
 #if ENABLE_FEATURE_DD_STATUS
         static const char status_words[] ALIGN1 =
@@ -310,7 +360,9 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
         //swab          swap every pair of input bytes: will abort on non-even reads
                 OP_iflag_skip_bytes,
                 OP_iflag_fullblock,
+                OP_iflag_direct,
                 OP_oflag_seek_bytes,
+                OP_oflag_direct,
 #endif
         };
         smallint exitcode = EXIT_FAILURE;
@@ -426,13 +478,12 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
 #endif
         } /* end of "for (argv[i])" */
 
-//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
-        ibuf = xmalloc(ibs);
+        ibuf = alloc_buf(ibs);
         obuf = ibuf;
 #if ENABLE_FEATURE_DD_IBS_OBS
         if (ibs != obs) {
                 G.flags |= FLAG_TWOBUFS;
-                obuf = xmalloc(obs);
+                obuf = alloc_buf(obs);
         }
 #endif
 
@@ -444,7 +495,12 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
 #endif
 
         if (infile) {
-                xmove_fd(xopen(infile, O_RDONLY), ifd);
+                int iflag = O_RDONLY;
+#if ENABLE_FEATURE_DD_IBS_OBS
+                if (G.flags & FLAG_IDIRECT)
+                        iflag |= O_DIRECT;
+#endif
+                xmove_fd(xopen(infile, iflag), ifd);
         } else {
                 infile = bb_msg_standard_input;
         }
@@ -455,7 +511,10 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                         oflag |= O_TRUNC;
                 if (G.flags & FLAG_APPEND)
                         oflag |= O_APPEND;
-
+#if ENABLE_FEATURE_DD_IBS_OBS
+                if (G.flags & FLAG_ODIRECT)
+                        oflag |= O_DIRECT;
+#endif
                 xmove_fd(xopen(outfile, oflag), ofd);
 
                 if (seek && !(G.flags & FLAG_NOTRUNC)) {
@@ -478,13 +537,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                 size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
                 if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
                         do {
-                                ssize_t n;
-#if ENABLE_FEATURE_DD_IBS_OBS
-                                if (G.flags & FLAG_FULLBLOCK)
-                                        n = full_read(ifd, ibuf, blocksz);
-                                else
-#endif
-                                        n = safe_read(ifd, ibuf, blocksz);
+                                ssize_t n = dd_read(ibuf, blocksz);
                                 if (n < 0)
                                         goto die_infile;
                                 if (n == 0)
@@ -499,13 +552,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
         }
 
         while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
-                ssize_t n;
-#if ENABLE_FEATURE_DD_IBS_OBS
-                if (G.flags & FLAG_FULLBLOCK)
-                        n = full_read(ifd, ibuf, ibs);
-                else
-#endif
-                        n = safe_read(ifd, ibuf, ibs);
+                ssize_t n = dd_read(ibuf, ibs);
                 if (n == 0)
                         break;
                 if (n < 0) {
@@ -600,11 +647,13 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
         if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
                 dd_output_status(0);
 
+#if 0 /* can't just free(), they can be mmap()ed */
         if (ENABLE_FEATURE_CLEAN_UP) {
                 free(obuf);
                 if (G.flags & FLAG_TWOBUFS)
                         free(ibuf);
         }
+#endif
 
         return exitcode;
 }