| Message ID | 9c2fe5de-be23-3e66-6edf-3c2edfb804f3@web.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | compat: let git_mmap use malloc(3) directly | expand |
On Sat, Aug 21, 2021 at 02:52:40PM +0200, René Scharfe wrote: > xmalloc() dies on error, allows zero-sized allocations and enforces > GIT_ALLOC_LIMIT for testing. Our mmap replacement doesn't need any of > that. Let's cut out the wrapper, reject zero-sized requests as required > by POSIX and use malloc(3) directly. Allocation errors were needlessly > handled by git_mmap() before; this code becomes reachable now. Thanks, this is a good idea. As you note, the function was already expecting a possible NULL return. And I think in general it's good for our compat/ wrappers to stay as close to the OS-level functions they're emulating as possible. -Peff
Hi René, On Sat, 21 Aug 2021, René Scharfe wrote: > xmalloc() dies on error, allows zero-sized allocations and enforces > GIT_ALLOC_LIMIT for testing. Our mmap replacement doesn't need any of > that. Let's cut out the wrapper, reject zero-sized requests as required > by POSIX and use malloc(3) directly. Allocation errors were needlessly > handled by git_mmap() before; this code becomes reachable now. Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de> Thanks! Dscho > > Signed-off-by: René Scharfe <l.s.r@web.de> > --- > compat/mmap.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/compat/mmap.c b/compat/mmap.c > index 14d31010df..8d6c02d4bc 100644 > --- a/compat/mmap.c > +++ b/compat/mmap.c > @@ -7,7 +7,12 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of > if (start != NULL || flags != MAP_PRIVATE || prot != PROT_READ) > die("Invalid usage of mmap when built with NO_MMAP"); > > - start = xmalloc(length); > + if (length == 0) { > + errno = EINVAL; > + return MAP_FAILED; > + } > + > + start = malloc(length); > if (start == NULL) { > errno = ENOMEM; > return MAP_FAILED; > -- > 2.33.0 >
diff --git a/compat/mmap.c b/compat/mmap.c index 14d31010df..8d6c02d4bc 100644 --- a/compat/mmap.c +++ b/compat/mmap.c @@ -7,7 +7,12 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of if (start != NULL || flags != MAP_PRIVATE || prot != PROT_READ) die("Invalid usage of mmap when built with NO_MMAP"); - start = xmalloc(length); + if (length == 0) { + errno = EINVAL; + return MAP_FAILED; + } + + start = malloc(length); if (start == NULL) { errno = ENOMEM; return MAP_FAILED;
xmalloc() dies on error, allows zero-sized allocations and enforces GIT_ALLOC_LIMIT for testing. Our mmap replacement doesn't need any of that. Let's cut out the wrapper, reject zero-sized requests as required by POSIX and use malloc(3) directly. Allocation errors were needlessly handled by git_mmap() before; this code becomes reachable now. Signed-off-by: René Scharfe <l.s.r@web.de> --- compat/mmap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) -- 2.33.0