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[ELFLOAER] Improved elfloader a bit (in sync with box64)
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@ptitSeb
ptitSeb committed Mar 29, 2024
1 parent 811c4fc commit ba01765
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Showing 2 changed files with 76 additions and 37 deletions.
111 changes: 74 additions & 37 deletions src/elfs/elfloader.c
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Original file line number Diff line number Diff line change
Expand Up @@ -183,8 +183,6 @@ int AllocLoadElfMemory(box86context_t* context, elfheader_t* head, int mainbin)
uintptr_t max_align = (box86_pagesize-1);
for (size_t i=0; i<head->numPHEntries; ++i)
if(head->PHEntries[i].p_type == PT_LOAD && head->PHEntries[i].p_flags) {
if(max_align < head->PHEntries[i].p_align-1)
max_align = head->PHEntries[i].p_align-1;
++head->multiblock_n;
}

Expand All @@ -195,16 +193,24 @@ int AllocLoadElfMemory(box86context_t* context, elfheader_t* head, int mainbin)
}
if(!offs && !head->vaddr)
offs = (uintptr_t)find32bitBlockElf(head->memsz, mainbin, max_align);

// prereserve the whole elf image, without populating
void* image = mmap64((void*)(head->vaddr?head->vaddr:offs), head->memsz, 0, MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
if(image!=MAP_FAILED && head->vaddr && image!=(void*)offs && (((uintptr_t)image)&max_align)) {
munmap(image, head->memsz);
image = mmap64(find32bitBlockElf(head->memsz, mainbin, max_align), head->memsz, 0, MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
size_t sz = head->memsz;
void* raw = NULL;
void* image = NULL;
if(!head->vaddr) {
sz += head->align;
raw = mmap64((void*)offs, sz, 0, MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
image = (void*)(((uintptr_t)raw+max_align)&~max_align);
} else {
image = raw = mmap64((void*)head->vaddr, sz, 0, MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
}
if(image!=MAP_FAILED && !head->vaddr && image!=(void*)offs) {
printf_log(LOG_INFO, "%s: Mmap64 for (@%p 0x%zx) for elf \"%s\" returned %p(%p/0x%zx) instead\n", (((uintptr_t)image)&max_align)?"Error":"Warning", (void*)(head->vaddr?head->vaddr:offs), head->memsz, head->name, image, raw, head->align);
offs = (uintptr_t)image;
printf_log(LOG_INFO, "Mamp64 for (@%p 0x%zx) for elf \"%s\" returned %p instead", (void*)(head->vaddr?head->vaddr:offs), head->memsz, head->name, image);
if(((uintptr_t)image)&max_align) {
munmap(raw, sz);
return 1; // that's an error, alocated memory is not aligned properly
}
}
if(image==MAP_FAILED || image!=(void*)(head->vaddr?head->vaddr:offs)) {
printf_log(LOG_NONE, "%s cannot create memory map (@%p 0x%zx) for elf \"%s\"", (image==MAP_FAILED)?"Error:":"Warning:", (void*)(head->vaddr?head->vaddr:offs), head->memsz, head->name);
Expand All @@ -217,12 +223,14 @@ int AllocLoadElfMemory(box86context_t* context, elfheader_t* head, int mainbin)
return 1;
offs = (uintptr_t)image-head->vaddr;
}
printf_log(log_level, "Pre-allocated 0x%zx byte at %p for %s\n", head->memsz, image, head->name);
printf_dump(log_level, "Pre-allocated 0x%zx byte at %p for %s\n", head->memsz, image, head->name);
head->delta = offs;
printf_log(log_level, "Delta of %p (vaddr=%p) for Elf \"%s\" (0x%zx bytes)\n", (void*)offs, (void*)head->vaddr, head->name, head->memsz);
printf_dump(log_level, "Delta of %p (vaddr=%p) for Elf \"%s\"\n", (void*)offs, (void*)head->vaddr, head->name);

head->image = image;
setProtection_elf((uintptr_t)image, head->memsz, 0);
head->raw = raw;
head->raw_size = sz;
setProtection_elf((uintptr_t)raw, sz, 0);

head->multiblocks = (multiblock_t*)box_calloc(head->multiblock_n, sizeof(multiblock_t));
head->tlsbase = AddTLSPartition(context, head->tlssize);
Expand All @@ -241,37 +249,34 @@ int AllocLoadElfMemory(box86context_t* context, elfheader_t* head, int mainbin)
uint8_t prot = PROT_READ|PROT_WRITE|((e->p_flags & PF_X)?PROT_EXEC:0);
// check if alignment is correct
uintptr_t balign = head->multiblocks[n].align-1;
if(balign<(box86_pagesize-1)) balign = (box86_pagesize-1);
head->multiblocks[n].asize = ALIGN(e->p_memsz+(e->p_paddr&balign));
if(balign<4095) balign = 4095;
head->multiblocks[n].asize = (e->p_memsz+(e->p_paddr&balign)+4095)&~4095;
int try_mmap = 1;
if(e->p_paddr&balign)
try_mmap = 0;
if(e->p_offset&(box86_pagesize-1))
try_mmap = 0;
if(e->p_memsz-e->p_filesz>(box86_pagesize-1))
if(ALIGN(e->p_memsz)!=ALIGN(e->p_filesz))
try_mmap = 0;
if(!e->p_filesz)
try_mmap = 0;
if(e->p_align<box86_pagesize)
try_mmap = 0;
if(try_mmap) {
printf_log(log_level, "Mmaping 0x%zx memory @%p for Elf \"%s\"\n", head->multiblocks[n].size, (void*)head->multiblocks[n].paddr, head->name);
printf_dump(log_level, "Mmaping 0x%lx(0x%lx) bytes @%p for Elf \"%s\"\n", head->multiblocks[n].size, head->multiblocks[n].asize, (void*)head->multiblocks[n].paddr, head->name);
void* p = mmap64(
(void*)head->multiblocks[n].paddr,
head->multiblocks[n].size,
prot,
MAP_PRIVATE|MAP_FIXED,
MAP_PRIVATE|MAP_FIXED, //((prot&PROT_WRITE)?MAP_SHARED:MAP_PRIVATE)|MAP_FIXED,
head->fileno,
e->p_offset
);
if(p==MAP_FAILED || p!=(void*)head->multiblocks[n].paddr) {
try_mmap = 0;
printf_log(log_level, "Mapping failed, using regular mmap+read");
if(p==MAP_FAILED) {
printf_log(log_level, " err=%d/%s\n", errno, strerror(errno));
} else {
printf_log(log_level, " got %p instead\n", p);
}
printf_dump(log_level, "Mapping failed, using regular mmap+read");
} else {
if(e->p_memsz>e->p_filesz)
if(e->p_memsz>e->p_filesz && (prot&PROT_WRITE))
memset((void*)((uintptr_t)p + e->p_filesz), 0, e->p_memsz-e->p_filesz);
setProtection_elf((uintptr_t)p, head->multiblocks[n].asize, prot);
head->multiblocks[n].p = p;
Expand All @@ -281,15 +286,43 @@ int AllocLoadElfMemory(box86context_t* context, elfheader_t* head, int mainbin)
if(!try_mmap) {
uintptr_t paddr = head->multiblocks[n].paddr&~balign;
size_t asize = head->multiblocks[n].asize;
printf_log(log_level, "Allocating 0x%zx (0x%zx) bytes @%p, will read 0x%zx @%p for Elf \"%s\"\n", asize, e->p_memsz, (void*)paddr, e->p_filesz, (void*)head->multiblocks[n].paddr, head->name);
void* p = mmap64(
(void*)paddr,
asize,
prot,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
-1,
0
);
void* p = MAP_FAILED;
if(paddr==(paddr&~(box86_pagesize-1)) && (asize==ALIGN(asize))) {
printf_dump(log_level, "Allocating 0x%zx (0x%zx) bytes @%p, will read 0x%zx @%p for Elf \"%s\"\n", asize, e->p_memsz, (void*)paddr, e->p_filesz, (void*)head->multiblocks[n].paddr, head->name);
p = mmap64(
(void*)paddr,
asize,
prot|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
-1,
0
);
} else {
// difference in pagesize, so need to mmap only what needed to be...
//check startint point
uintptr_t new_addr = paddr;
ssize_t new_size = asize;
while(getProtection(new_addr) && (new_size>0)) {
new_size -= ALIGN(new_addr) - new_addr;
new_addr = ALIGN(new_addr);
}
if(new_size>0) {
printf_dump(log_level, "Allocating 0x%zx (0x%zx) bytes @%p, will read 0x%zx @%p for Elf \"%s\"\n", ALIGN(new_size), e->p_memsz, (void*)new_addr, e->p_filesz, (void*)head->multiblocks[n].paddr, head->name);
p = mmap64(
(void*)new_addr,
ALIGN(new_size),
prot|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
-1,
0
);
if(p==(void*)new_addr)
p = (void*)paddr;
} else {
p = (void*)paddr;
printf_dump(log_level, "Will read 0x%zx @%p for Elf \"%s\"\n", e->p_filesz, (void*)head->multiblocks[n].paddr, head->name);
}
}
if(p==MAP_FAILED || p!=(void*)paddr) {
printf_log(LOG_NONE, "Cannot create memory map (@%p 0x%zx/0x%zx) for elf \"%s\"", (void*)paddr, asize, balign, head->name);
if(p==MAP_FAILED) {
Expand All @@ -308,6 +341,8 @@ int AllocLoadElfMemory(box86context_t* context, elfheader_t* head, int mainbin)
return 1;
}
}
if(!(prot&PROT_WRITE) && (paddr==(paddr&(box86_pagesize-1)) && (asize==ALIGN(asize))))
mprotect((void*)paddr, asize, prot);
}
#ifdef DYNAREC
if(box86_dynarec && (e->p_flags & PF_X)) {
Expand Down Expand Up @@ -349,18 +384,20 @@ void FreeElfMemory(elfheader_t* head)
if(head->multiblock_n) {
#ifdef DYNAREC
for(int i=0; i<head->multiblock_n; ++i) {
dynarec_log(LOG_INFO, "Free DynaBlocks for %s\n", head->path);
dynarec_log(LOG_INFO, "Free DynaBlocks %p-%p for %s\n", head->multiblocks[i].p, head->multiblocks[i].p+head->multiblocks[i].asize, head->path);
if(box86_dynarec)
cleanDBFromAddressRange((uintptr_t)head->multiblocks[i].p, head->multiblocks[i].size, 1);
cleanDBFromAddressRange((uintptr_t)head->multiblocks[i].p, head->multiblocks[i].asize, 1);
freeProtection((uintptr_t)head->multiblocks[i].p, head->multiblocks[i].asize);
}
#endif
box_free(head->multiblocks);
}
// we only need to free the overall mmap, no need to free individual part as they are inside the big one
if(head->image && head->memsz)
munmap(head->image, head->memsz);
freeProtection((uintptr_t)head->image, head->memsz);
if(head->raw && head->raw_size) {
dynarec_log(LOG_INFO, "Unmap elf memory %p-%p for %s\n", head->raw, head->raw+head->raw_size, head->path);
munmap(head->raw, head->raw_size);
}
freeProtection((uintptr_t)head->raw, head->raw_size);
}

int isElfHasNeededVer(elfheader_t* head, const char* libname, elfheader_t* verneeded)
Expand Down
2 changes: 2 additions & 0 deletions src/elfs/elfloader_private.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,8 @@ typedef struct elfheader_s {

intptr_t delta; // should be 0
void* image;
void* raw; // raw pointer (might be unaligned vs image and max_align of elf)
size_t raw_size;

uintptr_t entrypoint;
uintptr_t initentry;
Expand Down

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