shared: use memdup over stdndupa

The stdndupa has a couple of gotchas:
 - allocates memory on stack via alloca(3)... where we pass it a
   user-provided string in at least one instance
 - it's a GNU extension missing on musl and bionic

The mkdir_p() function is not a hot path, so using heap allocation is
perfectly fine. Swap the stdndupa for our local helper memdup.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/92
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>

diff --git a/configure.ac b/configure.ac
index 5396436da734e43742a82bf4a17113c725bba6cc..d179159a777b8f753c3ce8fc4be3afcc4bedd9e8 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -50,10 +50,9 @@ CC_CHECK_FUNC_BUILTIN([__builtin_uaddll_overflow], [ ], [ ])
 # dietlibc doesn't have st.st_mtim struct member
 AC_CHECK_MEMBERS([struct stat.st_mtim], [], [], [#include <sys/stat.h>])
 
-# musl 1.0 and bionic 4.4 don't have strndupa
 # basename may be only available in libgen.h with the POSIX behavior,
 # not desired here
-AC_CHECK_DECLS_ONCE([[strndupa], [basename]], [], [], [[#include <string.h>]])
+AC_CHECK_DECLS_ONCE([[basename]], [], [], [[#include <string.h>]])
 
 AC_MSG_CHECKING([whether _Static_assert() is supported])
 AC_COMPILE_IFELSE(

diff --git a/shared/missing.h b/shared/missing.h
index 86caf80ae17525eaf93b289fa0327d31348acf29..9dbbd70737f4190edfe352b652561ec542959000 100644 (file)
--- a/shared/missing.h
+++ b/shared/missing.h
@@ -34,18 +34,6 @@ static inline int finit_module(int fd, const char *uargs, int flags)
 }
 #endif
 
-#if !HAVE_DECL_STRNDUPA
-#include <string.h>
-#define strndupa(s, n)                                                 \
-       ({                                                              \
-               const char *__old = (s);                                \
-               size_t __len = strnlen(__old, (n));                     \
-               char *__new = alloca(__len + 1);                        \
-               __new[__len] = '\0';                                    \
-               memcpy(__new, __old, __len);                            \
-        })
-#endif
-
 #if !HAVE_DECL_BASENAME
 #include <string.h>
 static inline const char *basename(const char *s)

diff --git a/shared/util.c b/shared/util.c
index d7db5d4f2f35b1a5849eed286d903c3a6c847131..1dfb218f7a3bf14cb3c43333aa9d765f36be0fa1 100644 (file)
--- a/shared/util.c
+++ b/shared/util.c
@@ -387,9 +387,14 @@ static inline int is_dir(const char *path)
 
 int mkdir_p(const char *path, int len, mode_t mode)
 {
-       char *start, *end;
+       _cleanup_free_ char *start;
+       char *end;
 
-       start = strndupa(path, len);
+       start = memdup(path, len + 1);
+       if (!start)
+               return -ENOMEM;
+
+       start[len] = '\0';
        end = start + len;
 
        /*