Implement a generic helper to escape a given set of characters with a
leading '\'. Generalizes virBufferEscapeSexpr().
Signed-off-by: Sage Weil <sage@newdream.net>
It's unlikely that we'll ever want to escape a string as long as
INT_MAX/6, but adding this check can't hurt.
* src/util/buf.c (virBufferEscapeSexpr, virBufferEscapeString):
Check for (unlikely) overflow.
Match the fact that we have virAsprintf and virVasprintf.
* src/util/buf.h (virBufferVasprintf): New prototype.
* src/util/buf.c (virBufferAsprintf): Move guts...
(virBufferVasprintf): ...to new function.
* src/libvirt_private.syms (buf.h): Export it.
* bootstrap.conf (gnulib_modules): Add stdarg, for va_copy.
We already have virAsprintf, so picking a similar name helps for
seeing a similar purpose. Furthermore, the prefix V before printf
generally implies 'va_list', even though this variant was '...', and
the old name got in the way of adding a new va_list version.
global rename performed with:
$ git grep -l virBufferVSprintf \
| xargs -L1 sed -i 's/virBufferVSprintf/virBufferAsprintf/g'
then revert the changes in ChangeLog-old.
When buf->error is 1, we do not return buf->content in the function
virBufferContentAndReset(). So we should free buf->content when
vsnprintf() failed.
The current code will go into an infinite loop if the printf generated
string is >= 1000, AND exactly 1 character smaller than the amount of free
space in the buffer. When this happens, we are dropped into the loop body,
but nothing will actually change, because count == (buf->size - buf->use - 1),
and virBufferGrow returns unchanged if count < (buf->size - buf->use)
Fix this by removing the '- 1' bit from 'size'. The *nprintf functions handle
the NULL byte for us anyways, so we shouldn't need to manually accommodate
for it.
Here's a bug where we are actually hitting this issue:
https://bugzilla.redhat.com/show_bug.cgi?id=602772
v2: Eric's improvements: while -> if (), remove extra va_list variable,
make sure we report buffer error if snprintf fails
v3: Add tests/virbuftest which reproduces the infinite loop before this
patch, works correctly after
Replace free(virBufferContentAndReset()) with virBufferFreeAndReset().
Update documentation and replace all remaining calls to free() with
calls to VIR_FREE(). Also add missing calls to virBufferFreeAndReset()
and virReportOOMError() in OOM error cases.
* src/util/buf.c: if virBufferEscapeString was called on a buffer that
had 0 bytes of space, a size of -1 will be passed to snprintf, resulting
in a segmentation fault, this preallocate some space.
