coreutils/dd: support /dev/zero

1 files changed, 11 insertions, 3 deletions

diff --git a/coreutils/dd.c b/coreutils/dd.c
index ba3afeae8..5b0119d25 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -109,6 +109,7 @@ int dd_main(int argc, char **argv)
         ssize_t n, w;
         off_t seek = 0, skip = 0, count = OFF_T_MAX;
         int ifd, ofd;
+        int devzero = 0;
         const char *infile = NULL, *outfile = NULL;
         char *ibuf, *obuf;
 
@@ -211,7 +212,13 @@ int dd_main(int argc, char **argv)
                 obuf = xmalloc(obs);
         }
         if (infile != NULL)
-                ifd = xopen(infile, O_RDONLY);
+                if (!strcmp(infile, "/dev/zero")) {
+                        flags |= NOERROR;
+                        devzero = 1;
+                        ifd = -1;
+                }
+                else
+                        ifd = xopen(infile, O_RDONLY);
         else {
                 ifd = STDIN_FILENO;
                 infile = bb_msg_standard_input;
@@ -262,7 +269,8 @@ int dd_main(int argc, char **argv)
                 if (n < 0) {
                         if (flags & NOERROR) {
                                 n = ibs;
-                                bb_perror_msg("%s", infile);
+                                if (!devzero)
+                                        bb_perror_msg("%s", infile);
                         } else
                                 goto die_infile;
                 }
@@ -302,7 +310,7 @@ int dd_main(int argc, char **argv)
                 if (w > 0)
                         G.out_part++;
         }
-        if (close(ifd) < 0) {
+        if (!devzero && close(ifd) < 0) {
 die_infile:
                 bb_perror_msg_and_die("%s", infile);
         }