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author | Marc-André Lureau <marcandre.lureau@redhat.com> | 2017-10-23 15:18:07 +0100 |
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committer | Eduardo Habkost <ehabkost@redhat.com> | 2018-01-19 11:18:51 -0200 |
commit | dcff1035dfdfb4c76634df64a5359ac18749f7ca (patch) | |
tree | 719e554270c95335c019003d20c64047cd68a61f /util | |
parent | 3e5bdc6573edf0585e4085e6a4e349b135abf3b4 (diff) | |
download | qemu-dcff1035dfdfb4c76634df64a5359ac18749f7ca.zip qemu-dcff1035dfdfb4c76634df64a5359ac18749f7ca.tar.gz qemu-dcff1035dfdfb4c76634df64a5359ac18749f7ca.tar.bz2 |
memfd: split qemu_memfd_alloc()
Add a function to only create a memfd, without mmap. The function is
used in the following memory backend.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20171023141815.17709-2-marcandre.lureau@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Diffstat (limited to 'util')
-rw-r--r-- | util/memfd.c | 61 |
1 files changed, 36 insertions, 25 deletions
diff --git a/util/memfd.c b/util/memfd.c index 412e94a..3a82505 100644 --- a/util/memfd.c +++ b/util/memfd.c @@ -53,6 +53,38 @@ static int memfd_create(const char *name, unsigned int flags) #define MFD_ALLOW_SEALING 0x0002U #endif +int qemu_memfd_create(const char *name, size_t size, unsigned int seals) +{ + int mfd = -1; + +#ifdef CONFIG_LINUX + unsigned int flags = MFD_CLOEXEC; + + if (seals) { + flags |= MFD_ALLOW_SEALING; + } + + mfd = memfd_create(name, flags); + if (mfd < 0) { + return -1; + } + + if (ftruncate(mfd, size) == -1) { + perror("ftruncate"); + close(mfd); + return -1; + } + + if (seals && fcntl(mfd, F_ADD_SEALS, seals) == -1) { + perror("fcntl"); + close(mfd); + return -1; + } +#endif + + return mfd; +} + /* * This is a best-effort helper for shared memory allocation, with * optional sealing. The helper will do his best to allocate using @@ -63,35 +95,14 @@ void *qemu_memfd_alloc(const char *name, size_t size, unsigned int seals, int *fd) { void *ptr; - int mfd = -1; - - *fd = -1; - -#ifdef CONFIG_LINUX - if (seals) { - mfd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC); - } + int mfd = qemu_memfd_create(name, size, seals); + /* some systems have memfd without sealing */ if (mfd == -1) { - /* some systems have memfd without sealing */ - mfd = memfd_create(name, MFD_CLOEXEC); - seals = 0; + mfd = qemu_memfd_create(name, size, 0); } -#endif - - if (mfd != -1) { - if (ftruncate(mfd, size) == -1) { - perror("ftruncate"); - close(mfd); - return NULL; - } - if (seals && fcntl(mfd, F_ADD_SEALS, seals) == -1) { - perror("fcntl"); - close(mfd); - return NULL; - } - } else { + if (mfd == -1) { const char *tmpdir = g_get_tmp_dir(); gchar *fname; |