lpr: don't send 0-byte print jobs (compat)

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 17 insertions, 13 deletions

diff --git a/printutils/lpr.c b/printutils/lpr.c
index 748879542..70cda7717 100644
--- a/printutils/lpr.c
+++ b/printutils/lpr.c
@@ -89,6 +89,10 @@ int lpqr_main(int argc UNUSED_PARAM, char *argv[])
         unsigned opts;
         int fd;
 
+        queue = getenv("PRINTER");
+        if (!queue)
+                queue = "lp";
+
         // parse options
         // TODO: set opt_complementary: s,d,f are mutually exclusive
         opts = getopt32(argv,
@@ -98,16 +102,7 @@ int lpqr_main(int argc UNUSED_PARAM, char *argv[])
         );
         argv += optind;
 
-        // if queue is not specified -> use $PRINTER
-        if (!(opts & OPT_P))
-                queue = getenv("PRINTER");
-        // if queue is still not specified ->
-        if (!queue) {
-                // ... queue defaults to "lp"
-                // server defaults to "localhost"
-                queue = "lp";
-        // if queue is specified ->
-        } else {
+        {
                 // queue name is to the left of '@'
                 char *s = strchr(queue, '@');
                 if (s) {
@@ -186,6 +181,17 @@ int lpqr_main(int argc UNUSED_PARAM, char *argv[])
                         dfd = xopen(*argv, O_RDONLY);
                 }
 
+                st.st_size = 0; /* paranoia: fstat may theoretically fail */
+                fstat(dfd, &st);
+
+                /* Apparently, some servers are buggy and won't accept 0-sized jobs.
+                 * Standard lpr works around it by refusing to send such jobs:
+                 */
+                if (st.st_size == 0) {
+                        bb_error_msg("nothing to print");
+                        continue;
+                }
+
                 /* "The name ... should start with ASCII "cfA",
                  * followed by a three digit job number, followed
                  * by the host name which has constructed the file."
@@ -210,7 +216,7 @@ int lpqr_main(int argc UNUSED_PARAM, char *argv[])
                         , (opts & LPR_m) ? user : ""
                         , remote_filename
                 );
-                // delete possible "\nX\n" patterns
+                // delete possible "\nX\n" (that is, one-char) patterns
                 c = controlfile;
                 while ((c = strchr(c, '\n')) != NULL) {
                         if (c[1] && c[2] == '\n') {
@@ -239,8 +245,6 @@ int lpqr_main(int argc UNUSED_PARAM, char *argv[])
                 // send data file, with name "dfaXXX"
                 if (opts & LPR_V)
                         bb_error_msg("sending data file");
-                st.st_size = 0; /* paranoia: fstat may theoretically fail */
-                fstat(dfd, &st);
                 fdprintf(fd, "\x3" "%"OFF_FMT"u d%s\n", st.st_size, remote_filename);
                 get_response_or_say_and_die(fd, "sending data file");
                 if (bb_copyfd_size(dfd, fd, st.st_size) != st.st_size) {