linker: small code-cleanup
This patch adds to make the linker a little bit easier to understand
by making all functions that acts on a sofino object with a soinfo_
prefix.
This is to more easily distinguish functions that operate on global
state, and those that operate on individual libraries.
This should be purely stylistic, i.e. no feature/behaviour change.
Change-Id: Ie510d13d743aa4317644caefa9910b8af7e84f44
diff --git a/linker/dlfcn.c b/linker/dlfcn.c
index ac7e5d3..3d0384f 100644
--- a/linker/dlfcn.c
+++ b/linker/dlfcn.c
@@ -60,7 +60,7 @@
if (unlikely(ret == NULL)) {
set_dlerror(DL_ERR_CANNOT_LOAD_LIBRARY);
} else {
- call_constructors_recursive(ret);
+ soinfo_call_constructors(ret);
ret->refcount++;
}
pthread_mutex_unlock(&dl_lock);
@@ -103,7 +103,7 @@
}
} else {
found = (soinfo*)handle;
- sym = lookup_in_library(found, symbol);
+ sym = soinfo_lookup(found, symbol);
}
if(likely(sym != 0)) {
@@ -141,7 +141,7 @@
info->dli_fbase = (void*)si->base;
/* Determine if any symbol in the library contains the specified address */
- Elf32_Sym *sym = find_containing_symbol(addr, si);
+ Elf32_Sym *sym = soinfo_find_symbol(si, addr);
if(sym != NULL) {
info->dli_sname = si->strtab + sym->st_name;
@@ -159,7 +159,7 @@
int dlclose(void *handle)
{
pthread_mutex_lock(&dl_lock);
- (void)unload_library((soinfo*)handle);
+ (void)soinfo_unload((soinfo*)handle);
pthread_mutex_unlock(&dl_lock);
return 0;
}
diff --git a/linker/linker.c b/linker/linker.c
index be90fd7..d26272c 100644
--- a/linker/linker.c
+++ b/linker/linker.c
@@ -82,7 +82,7 @@
*/
-static int link_image(soinfo *si, unsigned wr_offset);
+static int soinfo_link_image(soinfo *si, unsigned wr_offset);
static int socount = 0;
static soinfo sopool[SO_MAX];
@@ -254,7 +254,7 @@
rtld_db_dlactivity();
}
-static soinfo *alloc_info(const char *name)
+static soinfo *soinfo_alloc(const char *name)
{
soinfo *si;
@@ -263,7 +263,7 @@
return NULL;
}
- /* The freelist is populated when we call free_info(), which in turn is
+ /* The freelist is populated when we call soinfo_free(), which in turn is
done only by dlclose(), which is not likely to be used.
*/
if (!freelist) {
@@ -290,7 +290,7 @@
return si;
}
-static void free_info(soinfo *si)
+static void soinfo_free(soinfo *si)
{
soinfo *prev = NULL, *trav;
@@ -377,7 +377,7 @@
}
#endif
-static Elf32_Sym *_elf_lookup(soinfo *si, unsigned hash, const char *name)
+static Elf32_Sym *soinfo_elf_lookup(soinfo *si, unsigned hash, const char *name)
{
Elf32_Sym *s;
Elf32_Sym *symtab = si->symtab;
@@ -423,7 +423,7 @@
}
static Elf32_Sym *
-_do_lookup(soinfo *si, const char *name, unsigned *base, Elf32_Addr *offset)
+soinfo_do_lookup(soinfo *si, const char *name, unsigned *base, Elf32_Addr *offset)
{
unsigned elf_hash = elfhash(name);
Elf32_Sym *s;
@@ -441,14 +441,14 @@
* and some the first non-weak definition. This is system dependent.
* Here we return the first definition found for simplicity. */
- s = _elf_lookup(si, elf_hash, name);
+ s = soinfo_elf_lookup(si, elf_hash, name);
if(s != NULL)
goto done;
/* Next, look for it in the preloads list */
for(i = 0; preloads[i] != NULL; i++) {
lsi = preloads[i];
- s = _elf_lookup(lsi, elf_hash, name);
+ s = soinfo_elf_lookup(lsi, elf_hash, name);
if(s != NULL)
goto done;
}
@@ -464,7 +464,7 @@
DEBUG("%5d %s: looking up %s in %s\n",
pid, si->name, name, lsi->name);
- s = _elf_lookup(lsi, elf_hash, name);
+ s = soinfo_elf_lookup(lsi, elf_hash, name);
if ((s != NULL) && (s->st_shndx != SHN_UNDEF))
goto done;
}
@@ -479,7 +479,7 @@
lsi = somain;
DEBUG("%5d %s: looking up %s in executable %s\n",
pid, si->name, name, lsi->name);
- s = _elf_lookup(lsi, elf_hash, name);
+ s = soinfo_elf_lookup(lsi, elf_hash, name);
}
#endif
@@ -500,9 +500,9 @@
/* This is used by dl_sym(). It performs symbol lookup only within the
specified soinfo object and not in any of its dependencies.
*/
-Elf32_Sym *lookup_in_library(soinfo *si, const char *name)
+Elf32_Sym *soinfo_lookup(soinfo *si, const char *name)
{
- return _elf_lookup(si, elfhash(name), name);
+ return soinfo_elf_lookup(si, elfhash(name), name);
}
/* This is used by dl_sym(). It performs a global symbol lookup.
@@ -521,7 +521,7 @@
{
if(si->flags & FLAG_ERROR)
continue;
- s = _elf_lookup(si, elf_hash, name);
+ s = soinfo_elf_lookup(si, elf_hash, name);
if (s != NULL) {
*found = si;
break;
@@ -551,7 +551,7 @@
return NULL;
}
-Elf32_Sym *find_containing_symbol(const void *addr, soinfo *si)
+Elf32_Sym *soinfo_find_symbol(soinfo* si, const void *addr)
{
unsigned int i;
unsigned soaddr = (unsigned)addr - si->base;
@@ -586,7 +586,7 @@
}
#endif
-static const char *sopaths[] = {
+static const char * const sopaths[] = {
"/vendor/lib",
"/system/lib",
0
@@ -598,7 +598,7 @@
struct stat filestat;
if ((stat(name, &filestat) >= 0) && S_ISREG(filestat.st_mode)) {
- if ((fd = open(name, O_RDONLY)) >= 0)
+ if ((fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY))) >= 0)
return fd;
}
@@ -609,7 +609,7 @@
{
int fd;
char buf[512];
- const char **path;
+ const char * const*path;
int n;
TRACE("[ %5d opening %s ]\n", pid, name);
@@ -661,12 +661,12 @@
return 0;
}
- if (read(fd, &info, sizeof(info)) != sizeof(info)) {
+ if (TEMP_FAILURE_RETRY(read(fd, &info, sizeof(info)) != sizeof(info))) {
WARN("Could not read prelink_info_t structure for `%s`\n", name);
return 0;
}
- if (strncmp(info.tag, "PRE ", 4)) {
+ if (memcmp(info.tag, "PRE ", 4)) {
WARN("`%s` is not a prelinked library\n", name);
return 0;
}
@@ -674,8 +674,8 @@
return (unsigned long)info.mmap_addr;
}
-/* verify_elf_object
- * Verifies if the object @ base is a valid ELF object
+/* verify_elf_header
+ * Verifies the content of an ELF header.
*
* Args:
*
@@ -684,10 +684,8 @@
* -1 if no valid ELF object is found @ base.
*/
static int
-verify_elf_object(void *base, const char *name)
+verify_elf_header(const Elf32_Ehdr* hdr)
{
- Elf32_Ehdr *hdr = (Elf32_Ehdr *) base;
-
if (hdr->e_ident[EI_MAG0] != ELFMAG0) return -1;
if (hdr->e_ident[EI_MAG1] != ELFMAG1) return -1;
if (hdr->e_ident[EI_MAG2] != ELFMAG2) return -1;
@@ -736,7 +734,7 @@
int cnt;
TRACE("[ %5d Computing extents for '%s'. ]\n", pid, name);
- if (verify_elf_object(_hdr, name) < 0) {
+ if (verify_elf_header(ehdr) < 0) {
DL_ERR("%5d - %s is not a valid ELF object", pid, name);
return (unsigned)-1;
}
@@ -778,7 +776,6 @@
*total_sz = (max_vaddr - min_vaddr);
return (unsigned)req_base;
}
-
/* reserve_mem_region
*
* This function reserves a chunk of memory to be used for mapping in
@@ -795,7 +792,7 @@
* the virtual address at which the library will be mapped.
*/
-static int reserve_mem_region(soinfo *si)
+static int soinfo_reserve_mem_region(soinfo *si)
{
void *base = mmap((void *)si->base, si->size, PROT_NONE,
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
@@ -815,11 +812,11 @@
return 0;
}
-static int alloc_mem_region(soinfo *si)
+static int soinfo_alloc_mem_region(soinfo *si)
{
if (si->base) {
/* Attempt to mmap a prelinked library. */
- return reserve_mem_region(si);
+ return soinfo_reserve_mem_region(si);
}
/* This is not a prelinked library, so we use the kernel's default
@@ -864,7 +861,7 @@
* 0 on success, -1 on failure.
*/
static int
-load_segments(int fd, void *header, soinfo *si)
+soinfo_load_segments(soinfo* si, int fd, void* header)
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)header;
Elf32_Phdr *phdr = (Elf32_Phdr *)((unsigned char *)header + ehdr->e_phoff);
@@ -885,6 +882,7 @@
pid, si->name, (unsigned)si->base);
for (cnt = 0; cnt < ehdr->e_phnum; ++cnt, ++phdr) {
+
if (phdr->p_type == PT_LOAD) {
phdr0 = phdr;
/*
@@ -898,6 +896,7 @@
break;
}
}
+
/* "base" might wrap around UINT32_MAX. */
base = (Elf32_Addr)(si->base - si->load_offset);
@@ -1149,6 +1148,7 @@
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,
(req_base ? "prelinked" : "not pre-linked"), req_base, ext_sz);
@@ -1158,7 +1158,7 @@
* soinfo struct here is a lot more convenient.
*/
bname = strrchr(name, '/');
- si = alloc_info(bname ? bname + 1 : name);
+ si = soinfo_alloc(bname ? bname + 1 : name);
if (si == NULL)
goto fail;
@@ -1169,14 +1169,14 @@
si->flags = 0;
si->entry = 0;
si->dynamic = (unsigned *)-1;
- if (alloc_mem_region(si) < 0)
+ if (soinfo_alloc_mem_region(si) < 0)
goto fail;
TRACE("[ %5d allocated memory for %s @ %p (0x%08x) ]\n",
pid, name, (void *)si->base, (unsigned) ext_sz);
/* Now actually load the library's segments into right places in memory */
- if (load_segments(fd, hdr, si) < 0) {
+ if (soinfo_load_segments(si, fd, hdr) < 0) {
goto fail;
}
@@ -1185,7 +1185,7 @@
return si;
fail:
- if (si) free_info(si);
+ if (si) soinfo_free(si);
if (hdr != MAP_FAILED) munmap(hdr, sb.st_size);
close(fd);
return NULL;
@@ -1201,7 +1201,7 @@
TRACE("[ %5d init_library base=0x%08x sz=0x%08x name='%s') ]\n",
pid, si->base, si->size, si->name);
- if(link_image(si, wr_offset)) {
+ if(soinfo_link_image(si, wr_offset)) {
/* We failed to link. However, we can only restore libbase
** if no additional libraries have moved it since we updated it.
*/
@@ -1252,7 +1252,7 @@
* for non-prelinked libraries, find a way to decrement libbase
*/
static void call_destructors(soinfo *si);
-unsigned unload_library(soinfo *si)
+unsigned soinfo_unload(soinfo *si)
{
unsigned *d;
if (si->refcount == 1) {
@@ -1261,7 +1261,7 @@
/*
* Make sure that we undo the PT_GNU_RELRO protections we added
- * in link_image. This is needed to undo the DT_NEEDED hack below.
+ * in soinfo_link_image. This is needed to undo the DT_NEEDED hack below.
*/
if ((si->gnu_relro_start != 0) && (si->gnu_relro_len != 0)) {
Elf32_Addr start = (si->gnu_relro_start & ~PAGE_MASK);
@@ -1279,13 +1279,13 @@
// The next line will segfault if the we don't undo the
// PT_GNU_RELRO protections (see comments above and in
- // link_image().
+ // soinfo_link_image().
d[1] = 0;
if (validate_soinfo(lsi)) {
TRACE("%5d %s needs to unload %s\n", pid,
si->name, lsi->name);
- unload_library(lsi);
+ soinfo_unload(lsi);
}
else
DL_ERR("%5d %s: could not unload dependent library",
@@ -1295,7 +1295,7 @@
munmap((char *)si->base, si->size);
notify_gdb_of_unload(si);
- free_info(si);
+ soinfo_free(si);
si->refcount = 0;
}
else {
@@ -1310,7 +1310,7 @@
* ideal. They should probably be either uint32_t, Elf32_Addr, or unsigned
* long.
*/
-static int reloc_library(soinfo *si, Elf32_Rel *rel, unsigned count)
+static int soinfo_relocate(soinfo *si, Elf32_Rel *rel, unsigned count)
{
Elf32_Sym *symtab = si->symtab;
const char *strtab = si->strtab;
@@ -1331,7 +1331,7 @@
si->name, idx);
if(sym != 0) {
sym_name = (char *)(strtab + symtab[sym].st_name);
- s = _do_lookup(si, sym_name, &base, &offset);
+ s = soinfo_do_lookup(si, sym_name, &base, &offset);
if(s == NULL) {
/* We only allow an undefined symbol if this is a weak
reference.. */
@@ -1550,7 +1550,7 @@
}
}
-void call_constructors_recursive(soinfo *si)
+void soinfo_call_constructors(soinfo *si)
{
if (si->constructors_called)
return;
@@ -1561,9 +1561,9 @@
// libc_malloc_debug_leak.so:
// 1. The program depends on libc, so libc's constructor is called here.
// 2. The libc constructor calls dlopen() to load libc_malloc_debug_leak.so.
- // 3. dlopen() calls call_constructors_recursive() with the newly created
+ // 3. dlopen() calls soinfo_call_constructors() with the newly created
// soinfo for libc_malloc_debug_leak.so.
- // 4. The debug so depends on libc, so call_constructors_recursive() is
+ // 4. The debug so depends on libc, so soinfo_call_constructors() is
// called again with the libc soinfo. If it doesn't trigger the early-
// out above, the libc constructor will be called again (recursively!).
si->constructors_called = 1;
@@ -1591,7 +1591,7 @@
DL_ERR("%5d bad DT_NEEDED pointer in %s",
pid, si->name);
} else {
- call_constructors_recursive(lsi);
+ soinfo_call_constructors(lsi);
}
}
}
@@ -1637,7 +1637,7 @@
int dev_null, i, status;
int return_value = 0;
- dev_null = open("/dev/null", O_RDWR);
+ dev_null = TEMP_FAILURE_RETRY(open("/dev/null", O_RDWR));
if (dev_null < 0) {
DL_ERR("Cannot open /dev/null.");
return -1;
@@ -1700,7 +1700,7 @@
return return_value;
}
-static int link_image(soinfo *si, unsigned wr_offset)
+static int soinfo_link_image(soinfo *si, unsigned wr_offset)
{
unsigned *d;
/* "base" might wrap around UINT32_MAX. */
@@ -1941,12 +1941,12 @@
if(si->plt_rel) {
DEBUG("[ %5d relocating %s plt ]\n", pid, si->name );
- if(reloc_library(si, si->plt_rel, si->plt_rel_count))
+ if(soinfo_relocate(si, si->plt_rel, si->plt_rel_count))
goto fail;
}
if(si->rel) {
DEBUG("[ %5d relocating %s ]\n", pid, si->name );
- if(reloc_library(si, si->rel, si->rel_count))
+ if(soinfo_relocate(si, si->rel, si->rel_count))
goto fail;
}
@@ -2131,7 +2131,7 @@
INFO("[ android linker & debugger ]\n");
DEBUG("%5d elfdata @ 0x%08x\n", pid, (unsigned)elfdata);
- si = alloc_info(argv[0]);
+ si = soinfo_alloc(argv[0]);
if(si == 0) {
exit(-1);
}
@@ -2151,7 +2151,7 @@
/* gdb expects the linker to be in the debug shared object list,
* and we need to make sure that the reported load address is zero.
* Without this, gdb gets the wrong idea of where rtld_db_dlactivity()
- * is. Don't use alloc_info(), because the linker shouldn't
+ * is. Don't use soinfo_alloc(), because the linker shouldn't
* be on the soinfo list.
*/
strlcpy((char*) linker_soinfo.name, "/system/bin/linker", sizeof linker_soinfo.name);
@@ -2203,14 +2203,14 @@
parse_preloads(ldpreload_env, " :");
}
- if(link_image(si, 0)) {
+ if(soinfo_link_image(si, 0)) {
char errmsg[] = "CANNOT LINK EXECUTABLE\n";
write(2, __linker_dl_err_buf, strlen(__linker_dl_err_buf));
write(2, errmsg, sizeof(errmsg));
exit(-1);
}
- call_constructors_recursive(si);
+ soinfo_call_constructors(si);
#if ALLOW_SYMBOLS_FROM_MAIN
/* Set somain after we've loaded all the libraries in order to prevent
@@ -2315,7 +2315,7 @@
linker_so.gnu_relro_start = 0;
linker_so.gnu_relro_len = 0;
- if (link_image(&linker_so, 0)) {
+ if (soinfo_link_image(&linker_so, 0)) {
// It would be nice to print an error message, but if the linker
// can't link itself, there's no guarantee that we'll be able to
// call write() (because it involves a GOT reference).
diff --git a/linker/linker.h b/linker/linker.h
index c6b81ea..e84458e 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -206,13 +206,14 @@
#endif
soinfo *find_library(const char *name);
-unsigned unload_library(soinfo *si);
-Elf32_Sym *lookup_in_library(soinfo *si, const char *name);
Elf32_Sym *lookup(const char *name, soinfo **found, soinfo *start);
soinfo *find_containing_library(const void *addr);
-Elf32_Sym *find_containing_symbol(const void *addr, soinfo *si);
const char *linker_get_error(void);
-void call_constructors_recursive(soinfo *si);
+
+unsigned soinfo_unload(soinfo *si);
+Elf32_Sym *soinfo_find_symbol(soinfo* si, const void *addr);
+Elf32_Sym *soinfo_lookup(soinfo *si, const char *name);
+void soinfo_call_constructors(soinfo *si);
#ifdef ANDROID_ARM_LINKER
typedef long unsigned int *_Unwind_Ptr;
diff --git a/linker/linker_environ.c b/linker/linker_environ.c
index b71dd80..fadcb60 100644
--- a/linker/linker_environ.c
+++ b/linker/linker_environ.c
@@ -192,13 +192,11 @@
"TZDIR",
"LD_AOUT_LIBRARY_PATH",
"LD_AOUT_PRELOAD",
+ NULL
};
- const char* const* cp = unsec_vars;
- const char* const* endp = cp + sizeof(unsec_vars)/sizeof(unsec_vars[0]);
-
- while (cp < endp) {
- linker_env_unset(*cp);
- cp++;
+ int count;
+ for (count = 0; unsec_vars[count] != NULL; count++) {
+ linker_env_unset(unsec_vars[count]);
}
}
