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authorEric Andersen <andersen@codepoet.org>2001-04-23 17:43:54 +0000
committerEric Andersen <andersen@codepoet.org>2001-04-23 17:43:54 +0000
commit66f269d2a51dae6a2cb10f1a9ae4aaeba815219b (patch)
treee2094832990caf6d849ba90e4b1a82a6264f86b3 /ldso/libdl/dlib.c
parentc4a3f3f81ea90e3df93c352ac0e2161a4bfd3327 (diff)
Initial checkin for ld.so. This is a combination of effort from Manuel Novoa
III and me. I've been working on stripping out arch dependant stuff and replacing it with generic stuff whenever possible. -Erik
Diffstat (limited to 'ldso/libdl/dlib.c')
-rw-r--r--ldso/libdl/dlib.c648
1 files changed, 648 insertions, 0 deletions
diff --git a/ldso/libdl/dlib.c b/ldso/libdl/dlib.c
new file mode 100644
index 000000000..545b6745f
--- /dev/null
+++ b/ldso/libdl/dlib.c
@@ -0,0 +1,648 @@
+/*
+ * libdl.c
+ *
+ * Functions required for dlopen et. al.
+ */
+
+#include "dlfcn.h"
+/* #include "link.h" */
+#include <stdlib.h>
+#include <linux/mman.h>
+#include <linux/unistd.h>
+#include "sysdep.h"
+#include "syscall.h"
+#include "hash.h"
+#include "string.h"
+#include "linuxelf.h"
+
+extern int _dl_error_number;
+extern struct r_debug * _dl_debug_addr;
+
+extern void * (*_dl_malloc_function)(size_t size);
+
+static int do_fixup(struct elf_resolve * tpnt, int flag);
+static int do_dlclose(void *, int need_fini);
+
+void * _dlopen(char * filename, int flag);
+const char * _dlerror(void);
+void * _dlsym(void *, char *);
+int _dlclose(void *);
+int _dladdr(void * __address, Dl_info * __dlip );
+
+static const char * dl_error_names[] = {
+ "",
+ "File not found",
+ "Unable to open /dev/zero",
+ "Not an ELF file",
+#if defined (__i386__)
+ "Not i386 binary",
+#elif defined (__sparc__)
+ "Not sparc binary",
+#elif defined (__mc68000__)
+ "Not m68k binary",
+#else
+ "Unrecognized binary type",
+#endif
+ "Not an ELF shared library",
+ "Unable to mmap file",
+ "No dynamic section",
+#ifdef ELF_USES_RELOCA
+ "Unable to process REL relocs",
+#else
+ "Unable to process RELA relocs",
+#endif
+ "Bad handle",
+ "Unable to resolve symbol"
+};
+
+static void dl_cleanup(void) __attribute__ ((destructor));
+
+static void dl_cleanup(void)
+{
+ struct dyn_elf* d;
+
+ for (d = _dl_handles; d; d = d->next_handle)
+ if (d->dyn->libtype == loaded_file && d->dyn->dynamic_info[DT_FINI])
+ {
+ (*((int(*)(void))(d->dyn->loadaddr + d->dyn->dynamic_info[DT_FINI])))();
+ d->dyn->dynamic_info[DT_FINI] = 0;
+ }
+}
+
+void * _dlopen(char * libname, int flag)
+{
+ struct elf_resolve * tpnt, *tfrom;
+ struct dyn_elf * rpnt;
+ struct dyn_elf * dyn_chain;
+ struct dyn_elf * dpnt;
+ static int dl_init = 0;
+ char * from;
+ void (*dl_brk)(void);
+ int (*dl_elf_init)(void);
+
+ from = __builtin_return_address(0);
+
+ /* Have the dynamic linker use the regular malloc function now */
+ if (!dl_init) {
+ dl_init++;
+ _dl_malloc_function = malloc;
+ }
+
+ /* Cover the trivial case first */
+ if (!libname) return _dl_symbol_tables;
+
+#ifdef USE_CACHE
+ _dl_map_cache();
+#endif
+
+ /*
+ * Try and locate the module we were called from - we
+ * need this so that we get the correct RPATH. Note that
+ * this is the current behavior under Solaris, but the
+ * ABI+ specifies that we should only use the RPATH from
+ * the application. Thus this may go away at some time
+ * in the future.
+ */
+ tfrom = NULL;
+ for(dpnt = _dl_symbol_tables; dpnt; dpnt = dpnt->next)
+ {
+ tpnt = dpnt->dyn;
+ if( tpnt->loadaddr < from
+ && ( tfrom == NULL
+ || tfrom->loadaddr < tpnt->loadaddr))
+ tfrom = tpnt;
+ }
+
+ if(!(tpnt = _dl_load_shared_library(0, tfrom, libname)))
+ {
+#ifdef USE_CACHE
+ _dl_unmap_cache();
+#endif
+ return NULL;
+ }
+
+ tpnt->usage_count++;
+ dyn_chain = rpnt =
+ (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
+ _dl_memset (rpnt, 0, sizeof(*rpnt));
+ rpnt->dyn = tpnt;
+ rpnt->flags = flag;
+ if (!tpnt->symbol_scope) tpnt->symbol_scope = dyn_chain;
+
+ rpnt->next_handle = _dl_handles;
+ _dl_handles = rpnt;
+
+ /*
+ * OK, we have the requested file in memory. Now check for
+ * any other requested files that may also be required.
+ */
+ {
+ struct elf_resolve *tcurr;
+ struct elf_resolve * tpnt1;
+ struct dynamic * dpnt;
+ char * lpnt;
+
+ tcurr = tpnt;
+ do{
+ for(dpnt = (struct dynamic *) tcurr->dynamic_addr; dpnt->d_tag; dpnt++)
+ {
+
+ if(dpnt->d_tag == DT_NEEDED)
+ {
+ lpnt = tcurr->loadaddr + tcurr->dynamic_info[DT_STRTAB] +
+ dpnt->d_un.d_val;
+ if(!(tpnt1 = _dl_load_shared_library(0, tcurr, lpnt)))
+ goto oops;
+
+ rpnt->next =
+ (struct dyn_elf *) malloc(sizeof(struct dyn_elf));
+ _dl_memset (rpnt->next, 0, sizeof (*(rpnt->next)));
+ rpnt = rpnt->next;
+ tpnt1->usage_count++;
+ if (!tpnt1->symbol_scope) tpnt1->symbol_scope = dyn_chain;
+ rpnt->dyn = tpnt1;
+ };
+ }
+
+ tcurr = tcurr->next;
+ } while(tcurr);
+ }
+
+ /*
+ * OK, now attach the entire chain at the end
+ */
+
+ rpnt->next = _dl_symbol_tables;
+
+ if (do_fixup(tpnt, flag)) {
+ _dl_error_number = DL_NO_SYMBOL;
+ goto oops;
+ }
+
+ dl_brk = (void (*)()) _dl_debug_addr->r_brk;
+ if( dl_brk != NULL )
+ {
+ _dl_debug_addr->r_state = RT_ADD;
+ (*dl_brk)();
+
+ _dl_debug_addr->r_state = RT_CONSISTENT;
+ (*dl_brk)();
+ }
+
+ for(rpnt = dyn_chain; rpnt; rpnt = rpnt->next)
+ {
+ tpnt = rpnt->dyn;
+ /* Apparently crt1 for the application is responsible for handling this.
+ * We only need to run the init/fini for shared libraries
+ */
+ if (tpnt->libtype == elf_executable) continue;
+ if (tpnt->init_flag & INIT_FUNCS_CALLED) continue;
+ tpnt->init_flag |= INIT_FUNCS_CALLED;
+
+ if(tpnt->dynamic_info[DT_INIT]) {
+ dl_elf_init = (int (*)(void)) (tpnt->loadaddr +
+ tpnt->dynamic_info[DT_INIT]);
+ (*dl_elf_init)();
+ }
+ }
+
+#ifdef USE_CACHE
+ _dl_unmap_cache();
+#endif
+ return (void *) dyn_chain;
+
+oops:
+ /* Something went wrong. Clean up and return NULL. */
+#ifdef USE_CACHE
+ _dl_unmap_cache();
+#endif
+ do_dlclose (dyn_chain, 0);
+ return NULL;
+}
+
+static int do_fixup(struct elf_resolve * tpnt, int flag)
+{
+ int goof = 0;
+ if(tpnt->next) goof += do_fixup(tpnt->next, flag);
+
+ if(tpnt->dynamic_info[DT_REL]) {
+#ifdef ELF_USES_RELOCA
+ goof++;
+#else
+ if (tpnt->init_flag & RELOCS_DONE) return goof;
+ tpnt->init_flag |= RELOCS_DONE;
+
+ goof += _dl_parse_relocation_information(tpnt, tpnt->dynamic_info[DT_REL],
+ tpnt->dynamic_info[DT_RELSZ], 0);
+#endif
+ }
+ if(tpnt->dynamic_info[DT_RELA]) {
+#ifdef ELF_USES_RELOCA
+ if (tpnt->init_flag & RELOCS_DONE) return goof;
+ tpnt->init_flag |= RELOCS_DONE;
+
+ goof += _dl_parse_relocation_information(tpnt, tpnt->dynamic_info[DT_RELA],
+ tpnt->dynamic_info[DT_RELASZ], 0);
+#else
+ goof++;
+#endif
+ }
+ if(tpnt->dynamic_info[DT_JMPREL])
+ {
+ if (tpnt->init_flag & JMP_RELOCS_DONE) return goof;
+ tpnt->init_flag |= JMP_RELOCS_DONE;
+
+ if(flag == RTLD_LAZY)
+ _dl_parse_lazy_relocation_information(tpnt, tpnt->dynamic_info[DT_JMPREL],
+ tpnt->dynamic_info[DT_PLTRELSZ], 0);
+ else
+ goof += _dl_parse_relocation_information(tpnt,
+ tpnt->dynamic_info[DT_JMPREL],
+ tpnt->dynamic_info[DT_PLTRELSZ], 0);
+ };
+ return goof;
+}
+
+void * _dlsym(void * vhandle, char * name)
+{
+ struct elf_resolve * tpnt, *tfrom;
+ struct dyn_elf * handle;
+ char * from;
+ struct dyn_elf * rpnt;
+ void *ret;
+
+ handle = (struct dyn_elf *) vhandle;
+
+ /* First of all verify that we have a real handle
+ of some kind. Return NULL if not a valid handle. */
+
+ if (handle == NULL)
+ handle = _dl_symbol_tables;
+ else if (handle != RTLD_NEXT && handle != _dl_symbol_tables) {
+ for(rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle)
+ if (rpnt == handle) break;
+ if (!rpnt) {
+ _dl_error_number = DL_BAD_HANDLE;
+ return NULL;
+ }
+ }
+ else if (handle == RTLD_NEXT )
+ {
+ /*
+ * Try and locate the module we were called from - we
+ * need this so that we know where to start searching
+ * from. We never pass RTLD_NEXT down into the actual
+ * dynamic loader itself, as it doesn't know
+ * how to properly treat it.
+ */
+ from = __builtin_return_address(0);
+
+ tfrom = NULL;
+ for(rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next)
+ {
+ tpnt = rpnt->dyn;
+ if( tpnt->loadaddr < from
+ && ( tfrom == NULL
+ || tfrom->loadaddr < tpnt->loadaddr))
+ {
+ tfrom = tpnt;
+ handle = rpnt->next;
+ }
+ }
+ }
+
+ ret = _dl_find_hash(name, handle, 1, NULL, 1);
+
+ /*
+ * Nothing found.
+ */
+ if (!ret)
+ _dl_error_number = DL_NO_SYMBOL;
+ return ret;
+}
+
+int _dlclose(void * vhandle)
+{
+ return do_dlclose(vhandle, 1);
+}
+
+static int do_dlclose(void * vhandle, int need_fini)
+{
+ struct dyn_elf * rpnt, *rpnt1;
+ struct dyn_elf *spnt, *spnt1;
+ struct elf_phdr * ppnt;
+ struct elf_resolve * tpnt;
+ int (*dl_elf_fini)(void);
+ void (*dl_brk)(void);
+ struct dyn_elf * handle;
+ unsigned int end;
+ int i = 0;
+
+ handle = (struct dyn_elf *) vhandle;
+ rpnt1 = NULL;
+ for(rpnt = _dl_handles; rpnt; rpnt = rpnt->next_handle)
+ {
+ if(rpnt == handle) {
+ break;
+ }
+ rpnt1 = rpnt;
+ }
+
+ if (!rpnt) {
+ _dl_error_number = DL_BAD_HANDLE;
+ return 1;
+ }
+
+ /* OK, this is a valid handle - now close out the file.
+ * We check if we need to call fini () on the handle. */
+ spnt = need_fini ? handle : handle->next;
+ for(; spnt; spnt = spnt1)
+ {
+ spnt1 = spnt->next;
+
+ /* We appended the module list to the end - when we get back here,
+ quit. The access counts were not adjusted to account for being here. */
+ if (spnt == _dl_symbol_tables) break;
+ if(spnt->dyn->usage_count==1 && spnt->dyn->libtype == loaded_file) {
+ tpnt = spnt->dyn;
+ /* Apparently crt1 for the application is responsible for handling this.
+ * We only need to run the init/fini for shared libraries
+ */
+
+ if(tpnt->dynamic_info[DT_FINI]) {
+ dl_elf_fini = (int (*)(void)) (tpnt->loadaddr +
+ tpnt->dynamic_info[DT_FINI]);
+ (*dl_elf_fini)();
+ }
+ }
+ }
+ if(rpnt1)
+ rpnt1->next_handle = rpnt->next_handle;
+ else
+ _dl_handles = rpnt->next_handle;
+
+ /* OK, this is a valid handle - now close out the file */
+ for(rpnt = handle; rpnt; rpnt = rpnt1)
+ {
+ rpnt1 = rpnt->next;
+
+ /* We appended the module list to the end - when we get back here,
+ quit. The access counts were not adjusted to account for being here. */
+ if (rpnt == _dl_symbol_tables) break;
+
+ rpnt->dyn->usage_count--;
+ if(rpnt->dyn->usage_count == 0 && rpnt->dyn->libtype == loaded_file)
+ {
+ tpnt = rpnt->dyn;
+ /* Apparently crt1 for the application is responsible for handling this.
+ * We only need to run the init/fini for shared libraries
+ */
+#if 0
+/* We have to do this above, before we start closing objects.
+Otherwise when the needed symbols for _fini handling are
+resolved a coredump would occur. Rob Ryan (robr@cmu.edu)*/
+ if(tpnt->dynamic_info[DT_FINI]) {
+ dl_elf_fini = (int (*)(void)) (tpnt->loadaddr +
+ tpnt->dynamic_info[DT_FINI]);
+ (*dl_elf_fini)();
+ }
+#endif
+ end = 0;
+ for(i = 0, ppnt = rpnt->dyn->ppnt;
+ i < rpnt->dyn->n_phent; ppnt++, i++) {
+ if (ppnt->p_type != PT_LOAD) continue;
+ if (end < ppnt->p_vaddr + ppnt->p_memsz)
+ end = ppnt->p_vaddr + ppnt->p_memsz;
+ }
+ _dl_munmap (rpnt->dyn->loadaddr, end);
+ /* Next, remove rpnt->dyn from the loaded_module list */
+ if (_dl_loaded_modules == rpnt->dyn)
+ {
+ _dl_loaded_modules = rpnt->dyn->next;
+ if (_dl_loaded_modules)
+ _dl_loaded_modules->prev = 0;
+ }
+ else
+ for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next)
+ if (tpnt->next == rpnt->dyn) {
+ tpnt->next = tpnt->next->next;
+ if (tpnt->next)
+ tpnt->next->prev = tpnt;
+ break;
+ }
+ free(rpnt->dyn->libname);
+ free(rpnt->dyn);
+ }
+ free(rpnt);
+ }
+
+
+ dl_brk = (void (*)()) _dl_debug_addr->r_brk;
+ if( dl_brk != NULL )
+ {
+ _dl_debug_addr->r_state = RT_DELETE;
+ (*dl_brk)();
+
+ _dl_debug_addr->r_state = RT_CONSISTENT;
+ (*dl_brk)();
+ }
+
+ return 0;
+}
+
+const char * _dlerror()
+{
+ const char * retval;
+ if(!_dl_error_number) return NULL;
+ retval = dl_error_names[_dl_error_number];
+ _dl_error_number = 0;
+ return retval;
+}
+
+/* Generate the correct symbols that we need. */
+#if 1
+#pragma weak dlopen = _dlopen
+#pragma weak dlerror = _dlerror
+#pragma weak dlclose = _dlclose
+#pragma weak dlsym = _dlsym
+#pragma weak dladdr = _dladdr
+#else
+__asm__(".weak dlopen;dlopen=_dlopen");
+__asm__(".weak dlerror;dlerror=_dlerror");
+__asm__(".weak dlclose;dlclose=_dlclose");
+__asm__(".weak dlsym;dlsym=_dlsym");
+__asm__(".weak dladdr;dladdr=_dladdr");
+#endif
+
+/* This is a real hack. We need access to the dynamic linker, but we
+also need to make it possible to link against this library without any
+unresolved externals. We provide these weak symbols to make the link
+possible, but at run time the normal symbols are accessed. */
+
+static void foobar()
+{
+ _dl_fdprintf(2,"libdl library not correctly linked\n");
+ _dl_exit(1);
+}
+
+static int foobar1 = (int)foobar; /* Use as pointer */
+
+#if 1
+#pragma weak _dl_find_hash = foobar
+#pragma weak _dl_symbol_tables = foobar1
+#pragma weak _dl_handles = foobar1
+#pragma weak _dl_loaded_modules = foobar1
+#pragma weak _dl_debug_addr = foobar1
+#pragma weak _dl_error_number = foobar1
+#pragma weak _dl_load_shared_library = foobar
+#ifdef USE_CACHE
+#pragma weak _dl_map_cache = foobar
+#pragma weak _dl_unmap_cache = foobar
+#endif
+#pragma weak _dl_malloc_function = foobar1
+#pragma weak _dl_parse_relocation_information = foobar
+#pragma weak _dl_parse_lazy_relocation_information = foobar
+#pragma weak _dl_fdprintf = foobar
+#else
+__asm__(".weak _dl_find_hash; _dl_find_hash = foobar");
+__asm__(".weak _dl_symbol_tables; _dl_symbol_tables = foobar1");
+__asm__(".weak _dl_handles; _dl_handles = foobar1");
+__asm__(".weak _dl_loaded_modules; _dl_loaded_modules = foobar1");
+__asm__(".weak _dl_debug_addr; _dl_debug_addr = foobar1");
+__asm__(".weak _dl_error_number; _dl_error_number = foobar1");
+__asm__(".weak _dl_load_shared_library; _dl_load_shared_library = foobar");
+#ifdef USE_CACHE
+__asm__(".weak _dl_map_cache; _dl_map_cache = foobar");
+__asm__(".weak _dl_unmap_cache; _dl_unmap_cache = foobar");
+#endif
+__asm__(".weak _dl_malloc_function; _dl_malloc_function = foobar1");
+__asm__(".weak _dl_parse_relocation_information; _dl_parse_relocation_information = foobar");
+__asm__(".weak _dl_parse_lazy_relocation_information; _dl_parse_lazy_relocation_information = foobar");
+__asm__(".weak _dl_fdprintf; _dl_fdprintf = foobar");
+#endif
+
+/*
+ * Dump information to stderrr about the current loaded modules
+ */
+static char * type[] = {"Lib","Exe","Int","Mod"};
+
+void _dlinfo()
+{
+ struct elf_resolve * tpnt;
+ struct dyn_elf * rpnt, *hpnt;
+ _dl_fdprintf(2, "List of loaded modules\n");
+ /* First start with a complete list of all of the loaded files. */
+ for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next)
+ _dl_fdprintf(2, "\t%8.8x %8.8x %8.8x %s %d %s\n",
+ (unsigned)tpnt->loadaddr, (unsigned)tpnt,
+ (unsigned)tpnt->symbol_scope,
+ type[tpnt->libtype],
+ tpnt->usage_count,
+ tpnt->libname);
+
+ /* Next dump the module list for the application itself */
+ _dl_fdprintf(2, "\nModules for application (%x):\n",
+ (unsigned)_dl_symbol_tables);
+ for (rpnt = _dl_symbol_tables; rpnt; rpnt = rpnt->next)
+ _dl_fdprintf(2, "\t%8.8x %s\n", (unsigned)rpnt->dyn,
+ rpnt->dyn->libname);
+
+ for (hpnt = _dl_handles; hpnt; hpnt = hpnt->next_handle)
+ {
+ _dl_fdprintf(2, "Modules for handle %x\n", (unsigned)hpnt);
+ for(rpnt = hpnt; rpnt; rpnt = rpnt->next)
+ _dl_fdprintf(2, "\t%8.8x %s\n", (unsigned)rpnt->dyn,
+ rpnt->dyn->libname);
+ }
+}
+
+int _dladdr(void * __address, Dl_info * __dlip )
+{
+ struct elf_resolve * pelf;
+ struct elf_resolve * rpnt;
+
+#ifdef USE_CACHE
+ _dl_map_cache();
+#endif
+
+ /*
+ * Try and locate the module address is in
+ */
+ pelf = NULL;
+
+#if 0
+ _dl_fdprintf( 2,
+ "dladdr( 0x%p, 0x%p )\n",
+ __address, __dlip );
+#endif
+
+ for(rpnt = _dl_loaded_modules; rpnt; rpnt = rpnt->next)
+ {
+ struct elf_resolve * tpnt;
+ tpnt = rpnt;
+#if 0
+ _dl_fdprintf( 2,
+ "Module \"%s\" at 0x%p\n",
+ tpnt->libname,
+ tpnt->loadaddr );
+#endif
+ if( tpnt->loadaddr < (char*)__address
+ && ( pelf == NULL
+ || pelf->loadaddr < tpnt->loadaddr))
+ pelf = tpnt;
+ }
+
+ if ( ! pelf )
+ {
+ return 0;
+ }
+
+ /*
+ * Try and locate the symbol of address
+ */
+
+ {
+ char * strtab;
+ struct elf32_sym * symtab;
+ int hn, si;
+ int sf;
+ int sn = 0;
+ void* sa = 0;
+
+ symtab = (struct elf32_sym *) (pelf->dynamic_info[DT_SYMTAB] +
+ pelf->loadaddr);
+ strtab = (char *) (pelf->dynamic_info[DT_STRTAB] + pelf->loadaddr);
+
+ sf = 0;
+ for(hn = 0; hn < pelf->nbucket; hn++)
+ {
+ for(si = pelf->elf_buckets[hn]; si; si = pelf->chains[si])
+ {
+ void* symbol_addr;
+ symbol_addr = pelf->loadaddr + symtab[si].st_value;
+ if ( symbol_addr <= __address &&
+ ( !sf || sa < symbol_addr ) )
+ {
+ sa = symbol_addr;
+ sn = si;
+ sf = 1;
+ }
+#if 0
+ _dl_fdprintf( 2,
+ "Symbol \"%s\" at 0x%p\n",
+ strtab + symtab[si].st_name,
+ symbol_addr );
+#endif
+ }
+ }
+
+ if ( sf )
+ {
+ __dlip->dli_fname = pelf->libname;
+ __dlip->dli_fbase = pelf->loadaddr;
+ __dlip->dli_sname = strtab + symtab[sn].st_name;
+ __dlip->dli_saddr = sa;
+ }
+ return 1;
+ }
+}