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Merge "Use mmap to read an initial ELF header of library"

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Elliott Hughes 2012-05-25 15:11:35 -07:00 committed by Android (Google) Code Review
commit 1dd9efc541
1 changed files with 17 additions and 18 deletions
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35
linker/linker.c
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@ -640,10 +640,6 @@ static int open_library(const char *name)
return -1;
}
/* temporary space for holding the first page of the shared lib
* which contains the elf header (with the pht). */
static unsigned char __header[PAGE_SIZE];
typedef struct {
long mmap_addr;
char tag[4]; /* 'P', 'R', 'E', ' ' */
@ -1086,29 +1082,34 @@ load_library(const char *name)
unsigned ext_sz;
unsigned req_base;
const char *bname;
struct stat sb;
soinfo *si = NULL;
Elf32_Ehdr *hdr;
Elf32_Ehdr *hdr = MAP_FAILED;
if(fd == -1) {
if (fd == -1) {
DL_ERR("Library '%s' not found", name);
return NULL;
}
/* We have to read the ELF header to figure out what to do with this image
/* We have to read the ELF header to figure out what to do with this image.
* Map entire file for this. There won't be much difference in physical
* memory usage or performance.
*/
if (lseek(fd, 0, SEEK_SET) < 0) {
DL_ERR("lseek() failed!");
if (fstat(fd, &sb) < 0) {
DL_ERR("%5d fstat() failed! (%s)", pid, strerror(errno));
goto fail;
}
if ((cnt = read(fd, &__header[0], PAGE_SIZE)) < 0) {
DL_ERR("read() failed!");
hdr = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (hdr == MAP_FAILED) {
DL_ERR("%5d failed to mmap() header of '%s' (%s)",
pid, name, strerror(errno));
goto fail;
}
/* Parse the ELF header and get the size of the memory footprint for
* the library */
req_base = get_lib_extents(fd, name, &__header[0], &ext_sz);
req_base = get_lib_extents(fd, name, hdr, &ext_sz);
if (req_base == (unsigned)-1)
goto fail;
TRACE("[ %5d - '%s' (%s) wants base=0x%08x sz=0x%08x ]\n", pid, name,
@ -1138,22 +1139,20 @@ load_library(const char *name)
pid, name, (void *)si->base, (unsigned) ext_sz);
/* Now actually load the library's segments into right places in memory */
if (load_segments(fd, &__header[0], si) < 0) {
if (load_segments(fd, hdr, si) < 0) {
goto fail;
}
/* this might not be right. Technically, we don't even need this info
* once we go through 'load_segments'. */
hdr = (Elf32_Ehdr *)si->base;
si->phdr = (Elf32_Phdr *)((unsigned char *)si->base + hdr->e_phoff);
si->phnum = hdr->e_phnum;
/**/
munmap(hdr, sb.st_size);
close(fd);
return si;
fail:
if (si) free_info(si);
if (hdr != MAP_FAILED) munmap(hdr, sb.st_size);
close(fd);
return NULL;
}
@ -1678,7 +1677,7 @@ static int link_image(soinfo *si, unsigned wr_offset)
if (si->flags & (FLAG_EXE | FLAG_LINKER)) {
/* Locate the needed program segments (DYNAMIC/ARM_EXIDX) for
* linkage info if this is the executable or the linker itself.
* linkage info if this is the executable or the linker itself.
* If this was a dynamic lib, that would have been done at load time.
*
* TODO: It's unfortunate that small pieces of this are