[hackers] [sbase] Audit concat() in libutil || FRIGN

[git]

commit 268817de3526173124ee5268594c5f0c0a913393
Author: FRIGN <d...@frign.de>
Date:   Wed Mar 18 22:58:42 2015 +0100

    Audit concat() in libutil
    
    Be more pedantic about the error-checking, fread can also return
    values > 0 even though there has been a read-error.
    We want to write the last incoming data and then bail.

diff --git a/libutil/concat.c b/libutil/concat.c
index ef1e5b9..551b5b9 100644
--- a/libutil/concat.c
+++ b/libutil/concat.c
@@ -10,12 +10,13 @@ concat(FILE *fp1, const char *s1, FILE *fp2, const char *s2)
        char buf[BUFSIZ];
        size_t n;
 
-       while ((n = fread(buf, 1, sizeof(buf), fp1)) > 0) {
-               if (fwrite(buf, 1, n, fp2) != n)
-                       eprintf("%s: write error:", s2);
-               if (feof(fp1))
+       while ((n = fread(buf, 1, sizeof(buf), fp1))) {
+               fwrite(buf, 1, n, fp2);
+               if (ferror(fp2))
+                       eprintf("fwrite %s:", s2);
+               if (feof(fp1) || ferror(fp1))
                        break;
        }
        if (ferror(fp1))
-               eprintf("%s: read error:", s1);
+               eprintf("fread %s", s1);
 }