At $WORK we hit a bug where ${var%/*} was not producing the correct
expansion. There are two patches to fix this. I prefer the first
as I feel it is cleaner from an API perspective. I've also added
a regression testcase that shows the problem.
Thoughts?
--
-- David (obr...@freebsd.org)
Commit log:
Do not assume in growstackstr() that a precious character will be
immediately written into the stack after the call. Instead let the
caller manage the space left.
Currently growstackstr()'s assumption causes problems with
STACKSTRNUL() where we want to be able to turn a stack into a C
string, and later pretend the NUL is not there.
This fixes a bug in STACKSTRNUL() (that grew the stack) where:
1. STADJUST() called after a STACKSTRNUL() results in an improper
adjust. This can be seen in ${var%pattern} and ${var%%pattern}
evaluation.
2. Memory leak in STPUTC() called after a STACKSTRNUL().
--%--%--%--%--%--
Index: bin/sh/memalloc.h
===
--- bin/sh/memalloc.h (revision 213714)
+++ bin/sh/memalloc.h (working copy)
@@ -67,9 +67,16 @@ void ungrabstackstr(char *, char *);
#define stackblock() stacknxt
#define stackblocksize() stacknleft
#define STARTSTACKSTR(p) p = stackblock(), sstrnleft = stackblocksize()
-#define STPUTC(c, p) (--sstrnleft = 0? (*p++ = (c)) : (p = growstackstr(),
*p++ = (c)))
+#define STPUTC(c, p) (--sstrnleft = 0? (*p++ = (c)) : (p = growstackstr(),
--sstrnleft, *p++ = (c)))
#define CHECKSTRSPACE(n, p){ if (sstrnleft n) p = makestrspace(); }
#define USTPUTC(c, p) (--sstrnleft, *p++ = (c))
+/*
+ * STACKSTRNUL's use is where we want to be able to turn a stack
+ * (non-sentinel, character counting string) into a C string,
+ * and later pretend the NUL is not there.
+ * Note: Because of STACKSTRNUL's semantics, STACKSTRNUL cannot be used
+ * on a stack that will grabstackstr()ed.
+ */
#define STACKSTRNUL(p) (sstrnleft == 0? (p = growstackstr(), *p = '\0') : (*p
= '\0'))
#define STUNPUTC(p)(++sstrnleft, --p)
#define STTOPC(p) p[-1]
Index: bin/sh/histedit.c
===
--- bin/sh/histedit.c (revision 213714)
+++ bin/sh/histedit.c (working copy)
@@ -418,7 +418,7 @@ fc_replace(const char *s, char *p, char
} else
STPUTC(*s++, dest);
}
- STACKSTRNUL(dest);
+ STPUTC('\0', dest);
dest = grabstackstr(dest);
return (dest);
Index: bin/sh/memalloc.c
===
--- bin/sh/memalloc.c (revision 213714)
+++ bin/sh/memalloc.c (working copy)
@@ -295,6 +295,12 @@ grabstackblock(int len)
* is space for at least one character.
*/
+static char *
+growstrstackblock(int n) {
+ growstackblock();
+ sstrnleft = stackblocksize() - n;
+ return stackblock() + n;
+}
char *
growstackstr(void)
@@ -304,12 +310,10 @@ growstackstr(void)
len = stackblocksize();
if (herefd = 0 len = 1024) {
xwrite(herefd, stackblock(), len);
- sstrnleft = len - 1;
+ sstrnleft = len;
return stackblock();
}
- growstackblock();
- sstrnleft = stackblocksize() - len - 1;
- return stackblock() + len;
+ return growstrstackblock(len);
}
@@ -323,9 +327,7 @@ makestrspace(void)
int len;
len = stackblocksize() - sstrnleft;
- growstackblock();
- sstrnleft = stackblocksize() - len;
- return stackblock() + len;
+ return growstrstackblock(len);
}
--%--%--%--%--%--
ALTERNATE PATCH:
Index: bin/sh-1/memalloc.h
===
--- bin/sh-1/memalloc.h (revision 213696)
+++ bin/sh-1/memalloc.h (working copy)
@@ -70,7 +70,17 @@ void ungrabstackstr(char *, char *);
#define STPUTC(c, p) (--sstrnleft = 0? (*p++ = (c)) : (p = growstackstr(),
*p++ = (c)))
#define CHECKSTRSPACE(n, p){ if (sstrnleft n) p = makestrspace(); }
#define USTPUTC(c, p) (--sstrnleft, *p++ = (c))
-#define STACKSTRNUL(p) (sstrnleft == 0? (p = growstackstr(), *p = '\0') : (*p
= '\0'))
+/*
+ * growstackstr() has the assumption that a precious character will be
+ * immediately written into it, so it sets up 'sstrnleft' appropriately.
+ * But that is not the case for STACKSTRNUL, where we want to be able to
+ * turn a stack (non-sentinel, character counting string) into a C string,
+ * and later pretend the NUL is not there (without adjusting 'sstrnleft').
+ * Note: because of STACKSTRNUL's semantics, STACKSTRNUL cannot be used on
+ * a stack that will grabstackstr()ed.
+ */
+#define STACKSTRNUL(p) (sstrnleft == 0? (p = growstackstr(), *p = '\0',
++sstrnleft) : (*p = '\0'))
+//#define STACKSTRNUL(p)
