When working with sparse data buffers that may be larger than the address space, it is convenient to work with files instead. Add a function to create temporary files of a certain size.
Signed-off-by: Sean Anderson seanga2@gmail.com ---
(no changes since v1)
arch/sandbox/cpu/os.c | 17 +++++++++++++++++ include/os.h | 13 +++++++++++++ 2 files changed, 30 insertions(+)
diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c index 85d0d6a1703..8847c4cd0a8 100644 --- a/arch/sandbox/cpu/os.c +++ b/arch/sandbox/cpu/os.c @@ -282,6 +282,23 @@ int os_persistent_file(char *buf, int maxsize, const char *fname) return 0; }
+int os_mktemp(char *fname, off_t size) +{ + int fd; + + fd = mkostemp(fname, O_CLOEXEC); + if (fd < 0) + return -errno; + + if (unlink(fname) < 0) + return -errno; + + if (ftruncate(fd, size)) + return -errno; + + return fd; +} + /* Restore tty state when we exit */ static struct termios orig_term; static bool term_setup; diff --git a/include/os.h b/include/os.h index fc8a1b15cbf..877404a6c13 100644 --- a/include/os.h +++ b/include/os.h @@ -108,6 +108,19 @@ int os_unlink(const char *pathname); */ int os_persistent_file(char *buf, int maxsize, const char *fname);
+/** + * os_mktemp() - Create a temporary file + * @fname: The template to use for the file name. This must end with 6 Xs. It + * will be modified to the opened filename on success. + * @size: The size of the file + * + * Create a temporary file using @fname as a template, unlink it, and truncate + * it to @size. + * + * Return: A file descriptor, or negative errno on error + */ +int os_mktemp(char *fname, off_t size); + /** * os_exit() - access to the OS exit() system call *