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author | Florian Weimer <fweimer@redhat.com> | 2021-02-03 08:55:13 -0300 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-02-08 14:10:42 -0300 |
commit | e9fed2438a1ff475821864f906286dc58907f06b (patch) | |
tree | 185b4a49e256ef312e65eafebf836ba17ea2ccef /sysdeps/posix/shm_unlink.c | |
parent | 7f61f785f16d22f185de77086c44a88218436cfb (diff) | |
download | glibc-e9fed2438a1ff475821864f906286dc58907f06b.tar.gz glibc-e9fed2438a1ff475821864f906286dc58907f06b.tar.xz glibc-e9fed2438a1ff475821864f906286dc58907f06b.zip |
linux: Require /dev/shm as the shared memory file system
Previously, glibc would pick an arbitrary tmpfs file system from /proc/mounts if /dev/shm was not available. This could lead to an unsuitable file system being picked for the backing storage for shm_open, sem_open, and related functions. This patch introduces a new function, __shm_get_name, which builds the file name under the appropriate (now hard-coded) directory. It is called from the various shm_* and sem_* function. Unlike the SHM_GET_NAME macro it replaces, the callers handle the return values and errno updates. shm-directory.c is moved directly into the posix subdirectory because it can be implemented directly using POSIX functionality. It resides in libc because it is needed by both librt and nptl/htl. In the sem_open implementation, tmpfname is initialized directly from a string constant. This happens to remove one alloca call. Checked on x86_64-linux-gnu.
Diffstat (limited to 'sysdeps/posix/shm_unlink.c')
-rw-r--r-- | sysdeps/posix/shm_unlink.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/sysdeps/posix/shm_unlink.c b/sysdeps/posix/shm_unlink.c index f3258a0f5a..c90b854c78 100644 --- a/sysdeps/posix/shm_unlink.c +++ b/sysdeps/posix/shm_unlink.c @@ -25,16 +25,21 @@ #include <errno.h> #include <string.h> -#include "shm-directory.h" +#include <shm-directory.h> /* Remove shared memory object. */ int shm_unlink (const char *name) { - SHM_GET_NAME (ENOENT, -1, ""); - - int result = unlink (shm_name); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, false) != 0) + { + __set_errno (ENOENT); + return -1; + } + + int result = unlink (dirname.name); if (result < 0 && errno == EPERM) __set_errno (EACCES); return result; |