cat,nl: fix handling of open errors

$ cat -n does_not_exist; echo $?
cat: does_not_exist: No such file or directory
1

function                                             old     new   delta
print_numbered_lines                                 118     129     +11
nl_main                                              196     201      +5
cat_main                                             421     425      +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 20/0)               Total: 20 bytes

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

4 files changed, 18 insertions, 7 deletions

diff --git a/coreutils/cat.c b/coreutils/cat.c
index fb735f994..65f0648f9 100644
--- a/coreutils/cat.c
+++ b/coreutils/cat.c
@@ -195,6 +195,7 @@ int cat_main(int argc UNUSED_PARAM, char **argv)
 # define CAT_OPT_b (1<<1)
         if (opts & (CAT_OPT_n|CAT_OPT_b)) { /* -n or -b */
                 struct number_state ns;
+                int exitcode;
 
                 ns.width = 6;
                 ns.start = 1;
@@ -203,10 +204,11 @@ int cat_main(int argc UNUSED_PARAM, char **argv)
                 ns.empty_str = "\n";
                 ns.all = !(opts & CAT_OPT_b); /* -n without -b */
                 ns.nonempty = (opts & CAT_OPT_b); /* -b (with or without -n) */
+                exitcode = EXIT_SUCCESS;
                 do {
-                        print_numbered_lines(&ns, *argv);
+                        exitcode |= print_numbered_lines(&ns, *argv);
                 } while (*++argv);
-                fflush_stdout_and_exit(EXIT_SUCCESS);
+                fflush_stdout_and_exit(exitcode);
         }
         /*opts >>= 2;*/
 #endif
diff --git a/coreutils/nl.c b/coreutils/nl.c
index c2f8b1042..2fdc9d85e 100644
--- a/coreutils/nl.c
+++ b/coreutils/nl.c
@@ -58,6 +58,8 @@ int nl_main(int argc UNUSED_PARAM, char **argv)
                 "number-width\0"        Required_argument "w"
         ;
 #endif
+        int exitcode;
+
         ns.width = 6;
         ns.start = 1;
         ns.inc = 1;
@@ -72,9 +74,10 @@ int nl_main(int argc UNUSED_PARAM, char **argv)
         if (!*argv)
                 *--argv = (char*)"-";
 
+        exitcode = EXIT_SUCCESS;
         do {
-                print_numbered_lines(&ns, *argv);
+                exitcode |= print_numbered_lines(&ns, *argv);
         } while (*++argv);
 
-        fflush_stdout_and_exit(EXIT_SUCCESS);
+        fflush_stdout_and_exit(exitcode);
 }
diff --git a/include/libbb.h b/include/libbb.h
index b560cc2eb..df3c2d3c9 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1386,7 +1386,7 @@ struct number_state {
         const char *empty_str;
         smallint all, nonempty;
 };
-void print_numbered_lines(struct number_state *ns, const char *filename) FAST_FUNC;
+int print_numbered_lines(struct number_state *ns, const char *filename) FAST_FUNC;
 
 
 /* Networking */
diff --git a/libbb/print_numbered_lines.c b/libbb/print_numbered_lines.c
index 9a8a51440..d6459d7c3 100644
--- a/libbb/print_numbered_lines.c
+++ b/libbb/print_numbered_lines.c
@@ -8,12 +8,16 @@
 
 #include "libbb.h"
 
-void FAST_FUNC print_numbered_lines(struct number_state *ns, const char *filename)
+int FAST_FUNC print_numbered_lines(struct number_state *ns, const char *filename)
 {
         FILE *fp = fopen_or_warn_stdin(filename);
-        unsigned N = ns->start;
+        unsigned N;
         char *line;
 
+        if (!fp)
+                return EXIT_FAILURE;
+
+        N = ns->start;
         while ((line = xmalloc_fgetline(fp)) != NULL) {
                 if (ns->all
                  || (ns->nonempty && line[0])
@@ -27,4 +31,6 @@ void FAST_FUNC print_numbered_lines(struct number_state *ns, const char *filenam
         ns->start = N;
 
         fclose(fp);
+
+        return EXIT_SUCCESS;
 }