Author: kib
Date: Tue Dec 22 14:13:13 2009
New Revision: 200839
URL: http://svn.freebsd.org/changeset/base/200839
Log:
MFC r190883:
Update comment, fix spacing.
MFC r190885:
Change the way the mapping of the ELF objects is constructed, by first
mapping PROT_NONE anonymous memory over the whole range, and then
mapping the segments of the object over it.
MFC r195743:
Only perform .bss mapping and cleaning operations when segment file size
is not equal to its memory size.
Tested by: Mykola Dzham <freebsd levsha org ua>
Modified:
stable/7/libexec/rtld-elf/map_object.c
Directory Properties:
stable/7/libexec/rtld-elf/ (props changed)
Modified: stable/7/libexec/rtld-elf/map_object.c
==============================================================================
--- stable/7/libexec/rtld-elf/map_object.c Tue Dec 22 13:53:34 2009
(r200838)
+++ stable/7/libexec/rtld-elf/map_object.c Tue Dec 22 14:13:13 2009
(r200839)
@@ -91,8 +91,7 @@ map_object(int fd, const char *path, con
/*
* Scan the program header entries, and save key information.
*
- * We rely on there being exactly two load segments, text and data,
- * in that order.
+ * We expect that the loadable segments are ordered by load address.
*/
phdr = (Elf_Phdr *) ((char *)hdr + hdr->e_phoff);
phsize = hdr->e_phnum * sizeof (phdr[0]);
@@ -153,8 +152,8 @@ map_object(int fd, const char *path, con
mapsize = base_vlimit - base_vaddr;
base_addr = hdr->e_type == ET_EXEC ? (caddr_t) base_vaddr : NULL;
- mapbase = mmap(base_addr, mapsize, convert_prot(segs[0]->p_flags),
- convert_flags(segs[0]->p_flags), fd, base_offset);
+ mapbase = mmap(base_addr, mapsize, PROT_NONE, MAP_ANON | MAP_PRIVATE |
+ MAP_NOCORE, -1, 0);
if (mapbase == (caddr_t) -1) {
_rtld_error("%s: mmap of entire address space failed: %s",
path, strerror(errno));
@@ -167,7 +166,7 @@ map_object(int fd, const char *path, con
return NULL;
}
- for (i = 0; i <= nsegs; i++) {
+ for (i = 0; i <= nsegs; i++) {
/* Overlay the segment onto the proper region. */
data_offset = trunc_page(segs[i]->p_offset);
data_vaddr = trunc_page(segs[i]->p_vaddr);
@@ -175,45 +174,49 @@ map_object(int fd, const char *path, con
data_addr = mapbase + (data_vaddr - base_vaddr);
data_prot = convert_prot(segs[i]->p_flags);
data_flags = convert_flags(segs[i]->p_flags) | MAP_FIXED;
- /* Do not call mmap on the first segment - this is redundant */
- if (i && mmap(data_addr, data_vlimit - data_vaddr, data_prot,
+ if (mmap(data_addr, data_vlimit - data_vaddr, data_prot,
data_flags, fd, data_offset) == (caddr_t) -1) {
_rtld_error("%s: mmap of data failed: %s", path, strerror(errno));
return NULL;
}
- /* Clear any BSS in the last page of the segment. */
- clear_vaddr = segs[i]->p_vaddr + segs[i]->p_filesz;
- clear_addr = mapbase + (clear_vaddr - base_vaddr);
- clear_page = mapbase + (trunc_page(clear_vaddr) - base_vaddr);
- if ((nclear = data_vlimit - clear_vaddr) > 0) {
- /* Make sure the end of the segment is writable */
- if ((data_prot & PROT_WRITE) == 0 &&
- -1 == mprotect(clear_page, PAGE_SIZE, data_prot|PROT_WRITE)) {
+ /* Do BSS setup */
+ if (segs[i]->p_filesz != segs[i]->p_memsz) {
+
+ /* Clear any BSS in the last page of the segment. */
+ clear_vaddr = segs[i]->p_vaddr + segs[i]->p_filesz;
+ clear_addr = mapbase + (clear_vaddr - base_vaddr);
+ clear_page = mapbase + (trunc_page(clear_vaddr) - base_vaddr);
+
+ if ((nclear = data_vlimit - clear_vaddr) > 0) {
+ /* Make sure the end of the segment is writable */
+ if ((data_prot & PROT_WRITE) == 0 && -1 ==
+ mprotect(clear_page, PAGE_SIZE, data_prot|PROT_WRITE)) {
_rtld_error("%s: mprotect failed: %s", path,
strerror(errno));
return NULL;
- }
+ }
- memset(clear_addr, 0, nclear);
+ memset(clear_addr, 0, nclear);
- /* Reset the data protection back */
- if ((data_prot & PROT_WRITE) == 0)
- mprotect(clear_page, PAGE_SIZE, data_prot);
- }
+ /* Reset the data protection back */
+ if ((data_prot & PROT_WRITE) == 0)
+ mprotect(clear_page, PAGE_SIZE, data_prot);
+ }
- /* Overlay the BSS segment onto the proper region. */
- bss_vaddr = data_vlimit;
- bss_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_memsz);
- bss_addr = mapbase + (bss_vaddr - base_vaddr);
- if (bss_vlimit > bss_vaddr) { /* There is something to do */
- if (mmap(bss_addr, bss_vlimit - bss_vaddr, data_prot,
- MAP_PRIVATE|MAP_FIXED|MAP_ANON, -1, 0) == (caddr_t) -1) {
- _rtld_error("%s: mmap of bss failed: %s", path,
+ /* Overlay the BSS segment onto the proper region. */
+ bss_vaddr = data_vlimit;
+ bss_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_memsz);
+ bss_addr = mapbase + (bss_vaddr - base_vaddr);
+ if (bss_vlimit > bss_vaddr) { /* There is something to do */
+ if (mprotect(bss_addr, bss_vlimit - bss_vaddr, data_prot) ==
-1) {
+ _rtld_error("%s: mprotect of bss failed: %s", path,
strerror(errno));
- return NULL;
+ return NULL;
+ }
}
}
+
if (phdr_vaddr == 0 && data_offset <= hdr->e_phoff &&
(data_vlimit - data_vaddr + data_offset) >=
(hdr->e_phoff + hdr->e_phnum * sizeof (Elf_Phdr))) {
_______________________________________________
[email protected] mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "[email protected]"
