awk: next_input_file can return NULL, don't SEGV in this case.

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

diff --git a/editors/awk.c b/editors/awk.c
index 7685546e5596bad989d6b443899d1fda2b2b8d90..0918026d7339add22c6c192a818e1a4322bc9421 100644 (file)
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -2627,7 +2627,7 @@ static var *evaluate(node *op, var *res)
                                rsm = iF;
                        }
 
-                       if (!rsm->F) {
+                       if (!rsm || !rsm->F) {
                                setvar_i(intvar[ERRNO], errno);
                                setvar_i(res, -1);
                                break;
@@ -2961,7 +2961,7 @@ static rstream *next_input_file(void)
 #define rsm          (G.next_input_file__rsm)
 #define files_happen (G.next_input_file__files_happen)
 
-       FILE *F = NULL;
+       FILE *F;
        const char *fname, *ind;
 
        if (rsm.F)
@@ -2969,19 +2969,21 @@ static rstream *next_input_file(void)
        rsm.F = NULL;
        rsm.pos = rsm.adv = 0;
 
-       do {
+       for (;;) {
                if (getvar_i(intvar[ARGIND])+1 >= getvar_i(intvar[ARGC])) {
                        if (files_happen)
                                return NULL;
                        fname = "-";
                        F = stdin;
-               } else {
-                       ind = getvar_s(incvar(intvar[ARGIND]));
-                       fname = getvar_s(findvar(iamarray(intvar[ARGV]), ind));
-                       if (fname && *fname && !is_assignment(fname))
-                               F = xfopen_stdin(fname);
+                       break;
                }
-       } while (!F);
+               ind = getvar_s(incvar(intvar[ARGIND]));
+               fname = getvar_s(findvar(iamarray(intvar[ARGV]), ind));
+               if (fname && *fname && !is_assignment(fname)) {
+                       F = xfopen_stdin(fname);
+                       break;
+               }
+       }
 
        files_happen = TRUE;
        setvar_s(intvar[FILENAME], fname);