diff options
| author | Sergey Bugaev <bugaevc@gmail.com> | 2021-05-21 13:21:15 +0300 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2022-08-10 22:04:35 +0200 |
| commit | 7c3323a25bc1d5844feb7f9ed241fdbdb4819739 (patch) | |
| tree | 26348f5485ccba70458b69be6662680236a0b162 /tmpfs | |
| parent | 1ed64a8674d3359822831d4ac9a016c04d3e8b14 (diff) | |
tmpfs: Return read-only memory objects when appropriate
Diffstat (limited to 'tmpfs')
| -rw-r--r-- | tmpfs/node.c | 37 | ||||
| -rw-r--r-- | tmpfs/tmpfs.h | 2 |
2 files changed, 32 insertions, 7 deletions
diff --git a/tmpfs/node.c b/tmpfs/node.c index 02d213ed..1a73a164 100644 --- a/tmpfs/node.c +++ b/tmpfs/node.c @@ -21,6 +21,7 @@ #include <stddef.h> #include <stdlib.h> #include <fcntl.h> +#include <mach/mach4.h> #include <hurd/hurd_types.h> #include <hurd/store.h> #include "default_pager_U.h" @@ -72,9 +73,11 @@ diskfs_free_node (struct node *np, mode_t mode) switch (np->dn->type) { case DT_REG: + /* XXX GNU Mach will terminate the object, and thus existing mappings + * will get SIGBUS. */ + if (np->dn->u.reg.ro_memobj != MACH_PORT_NULL) + mach_port_deallocate (mach_task_self (), np->dn->u.reg.ro_memobj); if (np->dn->u.reg.memobj != MACH_PORT_NULL) { - /* XXX GNU Mach will terminate the object, and thus existing mappings - * will get SIGBUS. */ vm_deallocate (mach_task_self (), np->dn->u.reg.memref, 4096); mach_port_deallocate (mach_task_self (), np->dn->u.reg.memobj); } @@ -520,6 +523,7 @@ mach_port_t diskfs_get_filemap (struct node *np, vm_prot_t prot) { error_t err; + mach_port_t right; if (np->dn->type != DT_REG) { @@ -561,14 +565,35 @@ diskfs_get_filemap (struct node *np, vm_prot_t prot) assert_perror_backtrace (err); } - /* XXX always writable */ + if (prot & VM_PROT_WRITE) + right = np->dn->u.reg.memobj; + else if (np->dn->u.reg.ro_memobj == MACH_PORT_NULL) + { + vm_offset_t offset = 0; + vm_offset_t start = 0; + vm_size_t len = ~0; + err = memory_object_create_proxy (mach_task_self (), + VM_PROT_READ | VM_PROT_EXECUTE, + &np->dn->u.reg.memobj, 1, + &offset, 1, &start, 1, &len, 1, + &np->dn->u.reg.ro_memobj); + if (err) + { + errno = err; + return MACH_PORT_NULL; + } + + right = np->dn->u.reg.ro_memobj; + } + else + right = np->dn->u.reg.ro_memobj; /* Add a reference for each call, the caller will deallocate it. */ - err = mach_port_mod_refs (mach_task_self (), np->dn->u.reg.memobj, - MACH_PORT_RIGHT_SEND, +1); + err = mach_port_mod_refs (mach_task_self (), right, + MACH_PORT_RIGHT_SEND, +1); assert_perror_backtrace (err); - return np->dn->u.reg.memobj; + return right; } /* The user must define this function. Return a `struct pager *' suitable diff --git a/tmpfs/tmpfs.h b/tmpfs/tmpfs.h index ad472009..40554557 100644 --- a/tmpfs/tmpfs.h +++ b/tmpfs/tmpfs.h @@ -46,7 +46,7 @@ struct disknode char *lnk; /* malloc'd symlink target */ struct { - mach_port_t memobj; + mach_port_t memobj, ro_memobj; vm_address_t memref; unsigned int allocpages; /* largest size while memobj was live */ } reg; |