Document and work around a BeOS snprintf() bug.

diff --git a/ChangeLog b/ChangeLog
index 727651c8867c33cdf23740349adae8b1f8a3f918..09587c1c71b58d3498a27a397ee4b8f50c7a4ed5 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2007-11-09  Bruno Haible  <bruno@clisp.org>
+
+       * doc/functions/snprintf.texi: Mention BeOS deficiency.
+       * doc/functions/vsnprintf.texi: Likewise.
+       * lib/vasnprintf.c (VASNPRINTF): Ensure that we never call snprintf
+       with a size argument < 2.
+
 2007-11-09  Bruno Haible  <bruno@clisp.org>
 
        * lib/vasnprintf.c (VASNPRINTF): Increase reallocation of snprintf

diff --git a/doc/functions/snprintf.texi b/doc/functions/snprintf.texi
index 7e5f2f8ac429c985edf01dd4795b190d44de59b6..43ca802dbaf7dfbbee47f7e333117b383f989ffb 100644 (file)
--- a/doc/functions/snprintf.texi
+++ b/doc/functions/snprintf.texi
@@ -61,6 +61,10 @@ HP-UX 11, IRIX 6.5, OSF/1 5.1, mingw.
 This function does not fully support the @samp{n} directive on some platforms:
 HP-UX 11, mingw.
 @item
+This function overwrites memory when a size = 1 argument is passed on some
+platforms:
+BeOS.
+@item
 This function overwrites memory even when a zero size argument is passed on some
 platforms:
 OSF/1 5.1.

diff --git a/doc/functions/vsnprintf.texi b/doc/functions/vsnprintf.texi
index 13c009cf97d6a939ce281308e02abb63080bae2a..645ae70209ea168735d23cd62371fb4d92cc700c 100644 (file)
--- a/doc/functions/vsnprintf.texi
+++ b/doc/functions/vsnprintf.texi
@@ -61,6 +61,10 @@ HP-UX 11, IRIX 6.5, OSF/1 5.1, mingw.
 This function does not fully support the @samp{n} directive on some platforms:
 HP-UX 11, mingw.
 @item
+This function overwrites memory when a size = 1 argument is passed on some
+platforms:
+BeOS.
+@item
 This function overwrites memory even when a zero size argument is passed on some
 platforms:
 HP-UX 11, OSF/1 5.1.

diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c
index ccc531b57be9a2428645d6e396207eeb95b4eac4..d6b012a4ac255b889bae71cfc48bc584636219ce 100644 (file)
--- a/lib/vasnprintf.c
+++ b/lib/vasnprintf.c
@@ -4046,9 +4046,13 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                   sizeof (TCHAR_T) divides sizeof (DCHAR_T) and
                   alignof (TCHAR_T) <= alignof (DCHAR_T).  */
 # define TCHARS_PER_DCHAR (sizeof (DCHAR_T) / sizeof (TCHAR_T))
+               /* Ensure that maxlen below will be >= 2.  Needed on BeOS,
+                  where an snprintf() with maxlen==1 acts like sprintf().  */
+               ENSURE_ALLOCATION (xsum (length,
+                                        (2 + TCHARS_PER_DCHAR - 1)
+                                        / TCHARS_PER_DCHAR));
                /* Prepare checking whether snprintf returns the count
                   via %n.  */
-               ENSURE_ALLOCATION (xsum (length, 1));
                *(TCHAR_T *) (result + length) = '\0';
 #endif