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

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

diff --git a/printutils/lpr.c b/printutils/lpr.c
index 748879542302cb1dc8fd1ea0950b64db23639829..70cda7717f93cb502ba0723c633fc056d65d0380 100644 (file)
--- 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) {