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shared: guard all the seal logic behind HAVE_MEMFD_CREATE

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The initial version of os_ro_anonymous_file missed two guards around the
seal logic which leads to a compilation error on older systems.

Also make the check for a read-only file symmetric in
os_ro_anonymous_file_get_fd and os_ro_anonymous_file_put_fd.

Signed-off-by: Sebastian Wick <sebastian@sebastianwick.net>
This commit is contained in:
Sebastian Wick
2020-02-05 10:27:23 +01:00
parent 7bce28b543
commit f0d3a61491
1 changed files with 9 additions and 6 deletions
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shared/os-compatibility.c
+9 -6
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@@ -340,6 +340,7 @@ os_ro_anonymous_file_get_fd(struct ro_anonymous_file *file,
void *src, *dst; void *src, *dst;
int seals, fd; int seals, fd;
#ifdef HAVE_MEMFD_CREATE
seals = fcntl(file->fd, F_GET_SEALS); seals = fcntl(file->fd, F_GET_SEALS);
/* file was sealed for read-only and we don't have to support MAP_SHARED /* file was sealed for read-only and we don't have to support MAP_SHARED
@@ -348,6 +349,7 @@ os_ro_anonymous_file_get_fd(struct ro_anonymous_file *file,
if (seals != -1 && mapmode == RO_ANONYMOUS_FILE_MAPMODE_PRIVATE && if (seals != -1 && mapmode == RO_ANONYMOUS_FILE_MAPMODE_PRIVATE &&
(seals & READONLY_SEALS) == READONLY_SEALS) (seals & READONLY_SEALS) == READONLY_SEALS)
return file->fd; return file->fd;
#endif
/* for all other cases we create a new anonymous file that can be mapped /* for all other cases we create a new anonymous file that can be mapped
* with MAP_SHARED and copy the contents to it and return that instead * with MAP_SHARED and copy the contents to it and return that instead
@@ -388,17 +390,18 @@ os_ro_anonymous_file_get_fd(struct ro_anonymous_file *file,
int int
os_ro_anonymous_file_put_fd(int fd) os_ro_anonymous_file_put_fd(int fd)
{ {
#ifdef HAVE_MEMFD_CREATE
int seals = fcntl(fd, F_GET_SEALS); int seals = fcntl(fd, F_GET_SEALS);
if (seals == -1 && errno != EINVAL) if (seals == -1 && errno != EINVAL)
return -1; return -1;
/* If the fd cannot be sealed seals is -1 at this point /* The only case in which we do NOT have to close the file is when the file
* or the file can be sealed but has not been sealed for writing. * was sealed for read-only
* In both cases we created a new anonymous file that we have to
* close.
*/ */
if (seals == -1 || !(seals & F_SEAL_WRITE)) if (seals != -1 && (seals & READONLY_SEALS) == READONLY_SEALS)
close(fd); return 0;
#endif
close(fd);
return 0; return 0;
} }