From 438d2542e4bb731c65d10f908cd0519cf502750c Mon Sep 17 00:00:00 2001 From: Wolfgang Corcoran-Mathe Date: Fri, 28 Aug 2015 00:10:02 -0400 Subject: [PATCH] tail: Don't print garbage when input contains no newlines. getline(3) expects newline-terminated input. While glibc's implementation seems to catch unterminated input and zero the buffer, other versions (notably musl's) do not. This is a workaround. Garbage will still be read, but not printed. --- tail.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tail.c b/tail.c index 306bbc1..417289f 100644 --- a/tail.c +++ b/tail.c @@ -39,6 +39,7 @@ taketail(FILE *fp, const char *str, size_t n) Rune *r = NULL; char **ring = NULL; size_t i, j, *size = NULL; + int seenln = 0; if (!n) return; @@ -47,7 +48,7 @@ taketail(FILE *fp, const char *str, size_t n) ring = ecalloc(n, sizeof(*ring)); size = ecalloc(n, sizeof(*size)); - for (i = j = 0; getline(ring + i, size + i, fp) > 0; ) + for (i = j = 0; getline(ring + i, size + i, fp) > 0; seenln = 1) i = j = (i + 1) % n; } else { r = ecalloc(n, sizeof(*r)); @@ -59,7 +60,7 @@ taketail(FILE *fp, const char *str, size_t n) eprintf("%s: read error:", str); do { - if (ring && ring[j]) { + if (seenln && ring && ring[j]) { fputs(ring[j], stdout); free(ring[j]); } else if (r) {