when using -o, we may restart a match in the middle of the line.

set NOTBOL so that anchored patterns don't match.
from a patch by Daniël de Kok in freebsd bug 201650
ok martijn

diff --git a/usr.bin/grep/util.c b/usr.bin/grep/util.c
index 617a684..1093b09 100644 (file)
--- a/usr.bin/grep/util.c
+++ b/usr.bin/grep/util.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: util.c,v 1.55 2016/04/04 05:49:47 otto Exp $  */
+/*     $OpenBSD: util.c,v 1.56 2016/08/25 15:11:05 tedu Exp $  */
 
 /*-
  * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
@@ -49,7 +49,7 @@
 
 static int     linesqueued;
 static int     procline(str_t *l, int);
-static int     grep_search(fastgrep_t *, char *, size_t, regmatch_t *pmatch);
+static int     grep_search(fastgrep_t *, char *, size_t, regmatch_t *pmatch, int);
 #ifndef SMALL
 static bool    grep_cmp(const char *, const char *, size_t);
 static void    grep_revstr(unsigned char *, int);
@@ -192,14 +192,20 @@ procline(str_t *l, int nottext)
                offset = 0;
 redo:
                if (fg_pattern[i].pattern) {
+                       int flags = 0;
+                       if (offset)
+                               flags |= REG_NOTBOL;
                        r = grep_search(&fg_pattern[i], l->dat + offset,
-                           l->len - offset, &pmatch);
+                           l->len - offset, &pmatch, flags);
                        pmatch.rm_so += offset;
                        pmatch.rm_eo += offset;
                } else {
+                       int flags = eflags;
+                       if (offset)
+                               flags |= REG_NOTBOL;
                        pmatch.rm_so = offset;
                        pmatch.rm_eo = l->len;
-                       r = regexec(&r_pattern[i], l->dat, 1, &pmatch, eflags);
+                       r = regexec(&r_pattern[i], l->dat, 1, &pmatch, flags);
                }
                if (r == 0 && xflag) {
                        if (pmatch.rm_so != 0 || pmatch.rm_eo != l->len)
@@ -459,7 +465,8 @@ nonspecial:
          e > s && isword(d[s]) && isword(d[e-1]))
 
 static int
-grep_search(fastgrep_t *fg, char *data, size_t dataLen, regmatch_t *pmatch)
+grep_search(fastgrep_t *fg, char *data, size_t dataLen, regmatch_t *pmatch,
+    int flags)
 {
 #ifdef SMALL
        return 0;
@@ -476,6 +483,8 @@ grep_search(fastgrep_t *fg, char *data, size_t dataLen, regmatch_t *pmatch)
 
        /* Only try once at the beginning or ending of the line. */
        if (fg->bol || fg->eol) {
+               if (fg->bol && (flags & REG_NOTBOL))
+                       return 0;
                /* Simple text comparison. */
                /* Verify data is >= pattern length before searching on it. */
                if (dataLen >= fg->patternLen) {