diff options
| -rw-r--r-- | elf/dl-load.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/elf/dl-load.c b/elf/dl-load.c index 0ed670d158..bba1c83ba0 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -50,15 +50,17 @@ overwritten. Some losing VM systems like Linux's lack MAP_COPY. All we get is MAP_PRIVATE, which copies each page when it is modified; this means if the file is overwritten, we may at some point get some pages - from the new version after starting with pages from the old version. */ -#ifndef MAP_COPY -# define MAP_COPY MAP_PRIVATE -#endif + from the new version after starting with pages from the old version. -/* We want to prevent people from modifying DSOs which are currently in - use. This is what MAP_DENYWRITE is for. */ -#ifndef MAP_DENYWRITE -# define MAP_DENYWRITE 0 + To make up for the lack and avoid the overwriting problem, + what Linux does have is MAP_DENYWRITE. This prevents anyone + from modifying the file while we have it mapped. */ +#ifndef MAP_COPY +# ifdef MAP_DENYWRITE +# define MAP_COPY (MAP_PRIVATE | MAP_DENYWRITE) +# else +# define MAP_COPY MAP_PRIVATE +# endif #endif /* Some systems link their relocatable objects for another base address @@ -1181,7 +1183,7 @@ cannot allocate TLS data structures for initial thread"); /* Remember which part of the address space this object uses. */ l->l_map_start = (ElfW(Addr)) __mmap ((void *) mappref, maplength, c->prot, - MAP_COPY|MAP_FILE|MAP_DENYWRITE, + MAP_COPY|MAP_FILE, fd, c->mapoff); if (__builtin_expect ((void *) l->l_map_start == MAP_FAILED, 0)) { @@ -1229,7 +1231,7 @@ cannot allocate TLS data structures for initial thread"); /* Map the segment contents from the file. */ && (__mmap ((void *) (l->l_addr + c->mapstart), c->mapend - c->mapstart, c->prot, - MAP_FIXED|MAP_COPY|MAP_FILE|MAP_DENYWRITE, + MAP_FIXED|MAP_COPY|MAP_FILE, fd, c->mapoff) == MAP_FAILED)) goto map_error; |