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| author | Cupertino Miranda <cupertino.miranda@oracle.com> | 2025-08-22 11:37:00 +0100 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-08-27 10:45:45 -0300 |
| commit | 3b2b88cceeb79f73a72367800d91599e2af4bb39 (patch) | |
| tree | a4f7c0efe8d6c2a49ac448c977a639e609c3f45c /sysdeps/unix | |
| parent | 921e251e8f364d00fc753274095007275381ae65 (diff) | |
| download | glibc-3b2b88cceeb79f73a72367800d91599e2af4bb39.zip glibc-3b2b88cceeb79f73a72367800d91599e2af4bb39.tar.gz glibc-3b2b88cceeb79f73a72367800d91599e2af4bb39.tar.bz2 | |
elf: early conversion of elf p_flags to mprotect flags
This patch replaces _dl_stack_flags global variable by
_dl_stack_prot_flags.
The advantage is that any convertion from p_flags to final used mprotect
flags occurs at loading of p_flags. It avoids repeated spurious
convertions of _dl_stack_flags, for example in allocate_thread_stack.
This modification was suggested in:
https://sourceware.org/pipermail/libc-alpha/2025-March/165537.html
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/unix')
| -rw-r--r-- | sysdeps/unix/sysv/linux/dl-execstack.c | 3 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/machine-sp.h | 2 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/spawni.c | 5 |
3 files changed, 5 insertions, 5 deletions
diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c index 6db9601..a59bd56 100644 --- a/sysdeps/unix/sysv/linux/dl-execstack.c +++ b/sysdeps/unix/sysv/linux/dl-execstack.c @@ -17,6 +17,7 @@ <https://www.gnu.org/licenses/>. */ #include <ldsodefs.h> +#include <stackinfo.h> int _dl_make_stack_executable (const void *stack_endp) @@ -36,7 +37,7 @@ _dl_make_stack_executable (const void *stack_endp) return errno; /* Remember that we changed the permission. */ - GL(dl_stack_flags) |= PF_X; + GL(dl_stack_prot_flags) |= PROT_EXEC; return 0; } diff --git a/sysdeps/unix/sysv/linux/machine-sp.h b/sysdeps/unix/sysv/linux/machine-sp.h index 6ab3ca6..bda90fe 100644 --- a/sysdeps/unix/sysv/linux/machine-sp.h +++ b/sysdeps/unix/sysv/linux/machine-sp.h @@ -19,6 +19,8 @@ #ifndef _MACHINE_SP_H #define _MACHINE_SP_H +#include <stackinfo.h> + /* Return the current stack pointer. */ static inline uintptr_t __thread_stack_pointer (void) diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c index eca1a84..bc8476f 100644 --- a/sysdeps/unix/sysv/linux/spawni.c +++ b/sysdeps/unix/sysv/linux/spawni.c @@ -348,9 +348,6 @@ __spawnix (int *pid, const char *file, return errno; } - int prot = (PROT_READ | PROT_WRITE - | ((GL (dl_stack_flags) & PF_X) ? PROT_EXEC : 0)); - /* Add a slack area for child's stack. */ size_t argv_size = (argc * sizeof (void *)) + 512; /* We need at least a few pages in case the compiler's stack checking is @@ -361,7 +358,7 @@ __spawnix (int *pid, const char *file, where it might use about 1k extra stack space). */ argv_size += (32 * 1024); size_t stack_size = ALIGN_UP (argv_size, GLRO(dl_pagesize)); - void *stack = __mmap (NULL, stack_size, prot, + void *stack = __mmap (NULL, stack_size, GL (dl_stack_prot_flags), MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); if (__glibc_unlikely (stack == MAP_FAILED)) return errno; |