[hackers] [sbase] libutil/getlines: fix crash with no lines || Hiltjo Posthuma

[git]

commit 9f974301438f0063637e1330cdb829df12cd5081
Author: Hiltjo Posthuma <hil...@codemadness.org>
Date:   Sun Mar 29 21:48:49 2015 +0200

    libutil/getlines: fix crash with no lines
    
    because b->lines and b->nlines would be 0 with no lines read.
    
    reproduce: printf '' | sort or cols
    
    bug was introduced by commit: 66a5ea722d18fc76ce7c5c4323e8cfebe58e7517

diff --git a/libutil/getlines.c b/libutil/getlines.c
index 6746c0f..942232d 100644
--- a/libutil/getlines.c
+++ b/libutil/getlines.c
@@ -9,20 +9,21 @@
 void
 getlines(FILE *fp, struct linebuf *b)
 {
-       char *line = NULL, **nline;
+       char *line = NULL;
        size_t size = 0, linelen;
        ssize_t len;
 
        while ((len = getline(&line, &size, fp)) > 0) {
                if (++b->nlines > b->capacity) {
                        b->capacity += 512;
-                       nline = erealloc(b->lines, b->capacity * 
sizeof(*b->lines));
-                       b->lines = nline;
+                       b->lines = erealloc(b->lines, b->capacity * 
sizeof(*b->lines));
                }
                linelen = len + 1;
                b->lines[b->nlines - 1] = memcpy(emalloc(linelen), line, 
linelen);
        }
        free(line);
+       if(!b->nlines || !b->lines)
+               return;
        if (!strchr(b->lines[b->nlines - 1], '\n')) {
                b->lines[b->nlines - 1] = erealloc(b->lines[b->nlines - 1], 
linelen + 1);
                b->lines[b->nlines - 1][linelen - 1] = '\n';