OpenBSD-4.6/gnu/usr.bin/ld/lib.c
/* * $OpenBSD: lib.c,v 1.13 2008/02/12 21:17:53 miod Exp $ - library routines*/
/*
*/
#include <sys/param.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/time.h>
#include <err.h>
#include <fcntl.h>
#include <ar.h>
#include <ranlib.h>
#include <a.out.h>
#include <stab.h>
#include <string.h>
#include <dirent.h>
#include <ctype.h>
#include "ld.h"
static void linear_library(int, struct file_entry *);
static void symdef_library(int, struct file_entry *, int);
static struct file_entry *decode_library_subfile(int,
struct file_entry *,
int, int *);
/*
* Search the library ENTRY, already open on descriptor FD. This means
* deciding which library members to load, making a chain of `struct
* file_entry' for those members, and entering their global symbols in the
* hash table.
*/
void
search_library(int fd, struct file_entry *entry)
{
int member_length;
char *name;
struct file_entry *subentry;
if (!(link_mode & FORCEARCHIVE) && !undefined_global_sym_count)
return;
/* Examine its first member, which starts SARMAG bytes in. */
subentry = decode_library_subfile(fd, entry, SARMAG, &member_length);
if (!subentry)
return;
name = subentry->filename;
free(subentry);
/* Search via __.SYMDEF if that exists, else linearly. */
if (!strcmp(name, "__.SYMDEF"))
symdef_library(fd, entry, member_length);
else
linear_library(fd, entry);
}
/*
* Construct and return a file_entry for a library member. The library's
* file_entry is library_entry, and the library is open on FD.
* SUBFILE_OFFSET is the byte index in the library of this member's header.
* We store the length of the member into *LENGTH_LOC.
*/
static struct file_entry *
decode_library_subfile(int fd, struct file_entry *library_entry,
int subfile_offset, int *length_loc)
{
int bytes_read;
int namelen;
int member_length, content_length;
int starting_offset;
char *name;
struct ar_hdr hdr1;
struct file_entry *subentry;
lseek(fd, subfile_offset, 0);
bytes_read = read(fd, &hdr1, sizeof hdr1);
if (!bytes_read)
return 0; /* end of archive */
if (sizeof hdr1 != bytes_read)
errx(1, "%s: malformed library archive",
get_file_name(library_entry));
if (sscanf(hdr1.ar_size, "%d", &member_length) != 1)
errx(1, "%s: malformatted header of archive member: %.*s",
get_file_name(library_entry),
(int) sizeof(hdr1.ar_name), hdr1.ar_name);
subentry = (struct file_entry *) xmalloc(sizeof(struct file_entry));
bzero(subentry, sizeof(struct file_entry));
for (namelen = 0;
namelen < sizeof hdr1.ar_name
&& hdr1.ar_name[namelen] != 0 && hdr1.ar_name[namelen] != ' '
&& hdr1.ar_name[namelen] != '/';
namelen++);
starting_offset = subfile_offset + sizeof hdr1;
content_length = member_length;
#ifdef AR_EFMT1
/*
* BSD 4.4 extended AR format: #1/<namelen>, with name as the
* first <namelen> bytes of the file
*/
if (strncmp(hdr1.ar_name, AR_EFMT1, sizeof(AR_EFMT1) - 1) == 0 &&
isdigit(hdr1.ar_name[sizeof(AR_EFMT1) - 1])) {
namelen = atoi(&hdr1.ar_name[sizeof(AR_EFMT1) - 1]);
name = (char *)xmalloc(namelen + 1);
if (read(fd, name, namelen) != namelen)
errx(1, "%s: malformatted archive member: %.*s",
get_file_name(library_entry),
(int) sizeof(hdr1.ar_name), hdr1.ar_name);
name[namelen] = 0;
content_length -= namelen;
starting_offset += namelen;
} else
#endif
{
name = (char *)xmalloc(namelen + 1);
strncpy(name, hdr1.ar_name, namelen);
name[namelen] = 0;
}
subentry->filename = name;
subentry->local_sym_name = name;
subentry->starting_offset = starting_offset;
subentry->superfile = library_entry;
subentry->total_size = content_length;
#if 0
subentry->symbols = 0;
subentry->strings = 0;
subentry->subfiles = 0;
subentry->chain = 0;
subentry->flags = 0;
#endif
(*length_loc) = member_length;
return subentry;
}
static int subfile_wanted_p(struct file_entry *);
/*
* Search a library that has a __.SYMDEF member. FD is a descriptor on
* which the library is open. The file pointer is assumed to point at the
* __.SYMDEF data. ENTRY is the library's file_entry. MEMBER_LENGTH is the
* length of the __.SYMDEF data.
*/
static void
symdef_library(int fd, struct file_entry *entry, int member_length)
{
int *symdef_data = (int *) xmalloc(member_length);
struct ranlib *symdef_base;
char *sym_name_base;
int nsymdefs;
int length_of_strings;
int not_finished;
int bytes_read;
int i;
struct file_entry *prev = 0;
int prev_offset = 0;
bytes_read = read(fd, symdef_data, member_length);
if (bytes_read != member_length)
errx(1, "%s: malformatted __.SYMDEF",
get_file_name(entry));
nsymdefs = md_swap_long(*symdef_data) / sizeof(struct ranlib);
if (nsymdefs < 0 ||
nsymdefs * sizeof(struct ranlib) + 2 * sizeof(int) > member_length)
errx(1, "%s: malformatted __.SYMDEF",
get_file_name(entry));
symdef_base = (struct ranlib *) (symdef_data + 1);
length_of_strings = md_swap_long(*(int *) (symdef_base + nsymdefs));
if (length_of_strings < 0
|| nsymdefs * sizeof(struct ranlib) + length_of_strings
+ 2 * sizeof(int) > member_length)
errx(1, "%s: malformatted __.SYMDEF",
get_file_name(entry));
sym_name_base = sizeof(int) + (char *) (symdef_base + nsymdefs);
/* Check all the string indexes for validity. */
md_swapin_ranlib_hdr(symdef_base, nsymdefs);
for (i = 0; i < nsymdefs; i++) {
int index = symdef_base[i].ran_un.ran_strx;
if (index < 0 || index >= length_of_strings
|| (index && *(sym_name_base + index - 1)))
errx(1, "%s: malformatted __.SYMDEF",
get_file_name(entry));
}
/*
* Search the symdef data for members to load. Do this until one
* whole pass finds nothing to load.
*/
not_finished = 1;
while (not_finished) {
not_finished = 0;
/*
* Scan all the symbols mentioned in the symdef for ones that
* we need. Load the library members that contain such
* symbols.
*/
for (i = 0; (i < nsymdefs &&
((link_mode & FORCEARCHIVE) ||
undefined_global_sym_count ||
common_defined_global_count)); i++) {
symbol *sp;
int junk;
int j;
int offset = symdef_base[i].ran_off;
struct file_entry *subentry;
if (symdef_base[i].ran_un.ran_strx < 0)
continue;
sp = getsym_soft(sym_name_base
+ symdef_base[i].ran_un.ran_strx);
/*
* If we find a symbol that appears to be needed,
* think carefully about the archive member that the
* symbol is in.
*/
/*
* Per Mike Karels' recommendation, we no longer load
* library files if the only reference(s) that would
* be satisfied are 'common' references. This
* prevents some problems with name pollution (e.g. a
* global common 'utime' linked to a function).
*
* If we're not forcing the archive in then we don't
* need to bother if: we've never heard of the symbol,
* or if it is already defined. The last clause causes
* archive members to be searched for definitions
* satisfying undefined shared object symbols.
*/
if (!(link_mode & FORCEARCHIVE) &&
(!sp || sp->defined ||
(!(sp->flags & GS_REFERENCED) &&
!sp->sorefs)))
continue;
/*
* Don't think carefully about any archive member
* more than once in a given pass.
*/
if (prev_offset == offset)
continue;
prev_offset = offset;
/*
* Read the symbol table of the archive member.
*/
subentry = decode_library_subfile(fd,
entry, offset, &junk);
if (subentry == 0)
errx(1,
"invalid offset for %s in symbol table of %s",
sym_name_base
+ symdef_base[i].ran_un.ran_strx,
entry->filename);
read_entry_symbols(fd, subentry);
subentry->strings = (char *)
xmalloc(subentry->string_size);
read_entry_strings(fd, subentry);
/*
* Now scan the symbol table and decide whether to
* load.
*/
if (!(link_mode & FORCEARCHIVE) &&
!subfile_wanted_p(subentry)) {
free(subentry->symbols);
free(subentry->strings);
free(subentry);
} else {
/*
* This member is needed; load it. Since we
* are loading something on this pass, we
* must make another pass through the symdef
* data.
*/
not_finished = 1;
read_entry_relocation(fd, subentry);
enter_file_symbols(subentry);
if (prev)
prev->chain = subentry;
else
entry->subfiles = subentry;
prev = subentry;
/*
* Clear out this member's symbols from the
* symdef data so that following passes won't
* waste time on them.
*/
for (j = 0; j < nsymdefs; j++) {
if (symdef_base[j].ran_off == offset)
symdef_base[j].ran_un.ran_strx = -1;
}
/*
* We'll read the strings again
* if we need them.
*/
free(subentry->strings);
subentry->strings = 0;
}
}
}
free(symdef_data);
}
/*
* Search a library that has no __.SYMDEF. ENTRY is the library's file_entry.
* FD is the descriptor it is open on.
*/
static void
linear_library(int fd, struct file_entry *entry)
{
struct file_entry *prev = 0;
int this_subfile_offset = SARMAG;
while ((link_mode & FORCEARCHIVE) ||
undefined_global_sym_count || common_defined_global_count) {
int member_length;
struct file_entry *subentry;
subentry = decode_library_subfile(fd, entry,
this_subfile_offset, &member_length);
if (!subentry)
return;
read_entry_symbols(fd, subentry);
subentry->strings = (char *)xmalloc(subentry->string_size);
read_entry_strings(fd, subentry);
if (!(link_mode & FORCEARCHIVE) &&
!subfile_wanted_p(subentry)) {
free(subentry->symbols);
free(subentry->strings);
free(subentry);
} else {
read_entry_relocation(fd, subentry);
enter_file_symbols(subentry);
if (prev)
prev->chain = subentry;
else
entry->subfiles = subentry;
prev = subentry;
free(subentry->strings);
subentry->strings = 0;
}
this_subfile_offset += member_length + sizeof(struct ar_hdr);
if (this_subfile_offset & 1)
this_subfile_offset++;
}
}
/*
* ENTRY is an entry for a library member. Its symbols have been read into
* core, but not entered. Return nonzero if we ought to load this member.
*/
static int
subfile_wanted_p(struct file_entry *entry)
{
struct localsymbol *lsp, *lspend;
#ifdef DOLLAR_KLUDGE
int dollar_cond = 0;
#endif
lspend = entry->symbols + entry->nsymbols;
for (lsp = entry->symbols; lsp < lspend; lsp++) {
struct nlist *p = &lsp->nzlist.nlist;
int type = p->n_type;
char *name = p->n_un.n_strx + entry->strings;
symbol *sp = getsym_soft(name);
/*
* If the symbol has an interesting definition, we could
* potentially want it.
*/
if (! (type & N_EXT)
|| (type == (N_UNDF | N_EXT) && p->n_value == 0
#ifdef DOLLAR_KLUDGE
&& name[1] != '$'
#endif
)
#ifdef SET_ELEMENT_P
|| SET_ELEMENT_P(type)
|| set_element_prefixed_p(name)
#endif
)
continue;
#ifdef DOLLAR_KLUDGE
if (name[1] == '$') {
sp = getsym_soft(&name[2]);
dollar_cond = 1;
if (!sp)
continue;
if (sp->flags & SP_REFERENCED) {
if (write_map) {
print_file_name(entry, stdout);
fprintf(stdout, " needed due to $-conditional %s\n", name);
}
return 1;
}
continue;
}
#endif
/*
* If this symbol has not been hashed, we can't be
* looking for it.
*/
if (!sp)
continue;
/*
* We don't load a file if it merely satisfies a
* common reference (see explanation above in
* symdef_library()).
*/
if ((sp->flags & GS_REFERENCED) && !sp->defined) {
/*
* This is a symbol we are looking for. It
* is either not yet defined or defined as a
* common.
*/
#ifdef DOLLAR_KLUDGE
if (dollar_cond)
continue;
#endif
if (type == (N_UNDF | N_EXT)) {
/*
* Symbol being defined as common.
* Remember this, but don't load
* subfile just for this.
*/
/*
* If it didn't used to be common, up
* the count of common symbols.
*/
if (!sp->common_size)
common_defined_global_count++;
if (sp->common_size < p->n_value)
sp->common_size = p->n_value;
if (!sp->defined)
undefined_global_sym_count--;
sp->defined = type;
continue;
}
if (sp->flags & GS_WEAK)
/* Weak symbols don't pull archive members */
continue;
if (write_map) {
print_file_name(entry, stdout);
fprintf(stdout, " needed due to %s\n", sp->name);
}
return 1;
} else if (!sp->defined && sp->sorefs) {
/*
* Check for undefined symbols or commons
* in shared objects.
*/
struct localsymbol *lsp;
for (lsp = sp->sorefs; lsp; lsp = lsp->next) {
int type = lsp->nzlist.nlist.n_type;
if ( (type & N_EXT) &&
(type & N_STAB) == 0 &&
type != (N_UNDF | N_EXT))
break; /* We don't need it */
}
if (lsp != NULL)
/*
* We have a worthy definition in a shared
* object that was specified ahead of the
* archive we're examining now. So, punt.
*/
continue;
/*
* At this point, we have an undefined shared
* object reference. Again, if the archive member
* defines a common we just note the its size.
* Otherwise, the member gets included.
*/
if (type == (N_UNDF|N_EXT) && p->n_value) {
/*
* New symbol is common, just takes its
* size, but don't load.
*/
sp->common_size = p->n_value;
sp->defined = type;
continue;
}
/*
* THIS STILL MISSES the case where one shared
* object defines a common and the next defines
* more strongly; fix this someday by making
* `struct glosym' and enter_global_ref() more
* symmetric.
*/
if (write_map) {
print_file_name(entry, stdout);
fprintf(stdout,
" needed due to shared lib ref %s (%d)\n",
sp->name,
lsp ? lsp->nzlist.nlist.n_type : -1);
}
return 1;
}
}
return 0;
}
/*
* Read the symbols of dynamic entity ENTRY into core. Assume it is already
* open, on descriptor FD.
*/
void
read_shared_object(int fd, struct file_entry *entry)
{
struct _dynamic dyn;
struct section_dispatch_table sdt;
struct nlist *np;
struct nzlist *nzp;
int n, i, has_nz = 0;
if (!(entry->flags & E_HEADER_VALID))
read_header(fd, entry);
/* Read DYNAMIC structure (first in data segment) */
if (lseek(fd, text_offset(entry) + entry->header.a_text, L_SET) ==
(off_t)-1)
err(1, "%s: lseek", get_file_name(entry));
if (read(fd, &dyn, sizeof dyn) != sizeof dyn) {
errx(1, "%s: premature EOF reading _dynamic",
get_file_name(entry));
}
md_swapin__dynamic(&dyn);
/* Check version */
switch (dyn.d_version) {
default:
errx(1, "%s: unsupported _DYNAMIC version: %d",
get_file_name(entry), dyn.d_version);
break;
case LD_VERSION_SUN:
break;
case LD_VERSION_BSD:
has_nz = 1;
break;
}
/* Read Section Dispatch Table (from data segment) */
if (lseek(fd,
text_offset(entry) + (long)dyn.d_un.d_sdt -
(DATA_START(entry->header) - N_DATOFF(entry->header)),
L_SET) == (off_t)-1)
err(1, "%s: lseek", get_file_name(entry));
if (read(fd, &sdt, sizeof sdt) != sizeof sdt)
errx(1, "%s: premature EOF reading sdt",
get_file_name(entry));
md_swapin_section_dispatch_table(&sdt);
/* Read symbols (text segment) */
n = sdt.sdt_strings - sdt.sdt_nzlist;
entry->nsymbols = n /
(has_nz ? sizeof(struct nzlist) : sizeof(struct nlist));
nzp = (struct nzlist *)(np = (struct nlist *)alloca (n));
entry->symbols = (struct localsymbol *)
xmalloc(entry->nsymbols * sizeof(struct localsymbol));
if (lseek(fd,
text_offset(entry) + (long)sdt.sdt_nzlist -
(TEXT_START(entry->header) - N_TXTOFF(entry->header)),
L_SET) == (off_t)-1)
err(1, "%s: lseek", get_file_name(entry));
if (read(fd, (char *)nzp, n) != n)
errx(1, "%s: premature EOF reading symbols ",
get_file_name(entry));
if (has_nz) {
md_swapin_zsymbols(nzp, entry->nsymbols);
} else {
md_swapin_symbols(np, entry->nsymbols);
}
/* Convert to structs localsymbol */
for (i = 0; i < entry->nsymbols; i++) {
if (has_nz) {
entry->symbols[i].nzlist = *nzp++;
} else {
entry->symbols[i].nzlist.nlist = *np++;
entry->symbols[i].nzlist.nz_size = 0;
}
entry->symbols[i].symbol = NULL;
entry->symbols[i].next = NULL;
entry->symbols[i].entry = entry;
entry->symbols[i].gotslot_offset = -1;
entry->symbols[i].flags = 0;
}
/* Read strings (text segment) */
n = entry->string_size = sdt.sdt_str_sz;
entry->strings = (char *)alloca(n);
entry->strings_offset = text_offset(entry) + sdt.sdt_strings;
if (lseek(fd,
entry->strings_offset -
(TEXT_START(entry->header) - N_TXTOFF(entry->header)),
L_SET) == (off_t)-1)
err(1, "%s: lseek", get_file_name(entry));
if (read(fd, entry->strings, n) != n)
errx(1, "%s: premature EOF reading strings",
get_file_name(entry));
enter_file_symbols (entry);
entry->strings = 0;
/*
* Load any subsidiary shared objects.
*/
if (sdt.sdt_sods) {
struct sod sod;
off_t offset;
struct file_entry *prev = NULL;
offset = (off_t)sdt.sdt_sods;
while (1) {
struct file_entry *subentry;
char *libname, name[MAXPATHLEN]; /*XXX*/
if (lseek(fd,
offset - (TEXT_START(entry->header) -
N_TXTOFF(entry->header)),
L_SET) == (off_t)-1)
err(1, "%s: lseek", get_file_name(entry));
if (read(fd, &sod, sizeof(sod)) != sizeof(sod))
errx(1, "%s: premature EOF reding sod",
get_file_name(entry));
md_swapin_sod(&sod, 1);
if (lseek(fd,
(off_t)sod.sod_name - (TEXT_START(entry->header) -
N_TXTOFF(entry->header)),
L_SET) == (off_t)-1)
err(1, "%s: lseek", get_file_name(entry));
(void)read(fd, name, sizeof(name)); /*XXX*/
/* Optimization */
if (sod.sod_library && will_see_later(name)) {
if ((offset = (off_t)sod.sod_next) == 0)
break;
else
continue;
}
subentry = (struct file_entry *)
xmalloc(sizeof(struct file_entry));
bzero(subentry, sizeof(struct file_entry));
subentry->superfile = entry;
subentry->flags = E_SECONDCLASS;
if (sod.sod_library) {
int sod_major = sod.sod_major;
int sod_minor = sod.sod_minor;
libname = findshlib(name,
&sod_major, &sod_minor, 0);
if (libname == NULL)
errx(1,"no shared -l%s.%d.%d available",
name, sod.sod_major, sod.sod_minor);
subentry->filename = libname;
subentry->local_sym_name = concat("-l", name, "");
} else {
subentry->filename = strdup(name);
subentry->local_sym_name = strdup(name);
}
/* Sanity check */
if (strcmp(subentry->filename,
subentry->superfile->filename) == 0)
errx(1, "loop in library dependencies: %s",
subentry->filename);
read_file_symbols(subentry);
if (prev)
prev->chain = subentry;
else
entry->subfiles = subentry;
prev = subentry;
fd = file_open(entry);
if ((offset = (off_t)sod.sod_next) == 0)
break;
}
}
#ifdef SUN_COMPAT
if (link_mode & SILLYARCHIVE) {
char *cp, *sa_name;
char armag[SARMAG];
int fd;
struct file_entry *subentry;
sa_name = strdup(entry->filename);
if (sa_name == NULL)
goto out;
cp = sa_name + strlen(sa_name) - 1;
while (cp > sa_name) {
if (!isdigit(*cp) && *cp != '.')
break;
--cp;
}
if (cp <= sa_name || *cp != 'o') {
/* Not in `libxxx.so.n.m' form */
free(sa_name);
goto out;
}
*cp = 'a';
if ((fd = open(sa_name, O_RDONLY, 0)) < 0)
goto out;
/* Read archive magic */
bzero(armag, SARMAG);
(void)read(fd, armag, SARMAG);
(void)close(fd);
if (strncmp(armag, ARMAG, SARMAG) != 0) {
warnx("%s: malformed silly archive",
get_file_name(entry));
goto out;
}
subentry = (struct file_entry *)
xmalloc(sizeof(struct file_entry));
bzero(subentry, sizeof(struct file_entry));
entry->silly_archive = subentry;
subentry->superfile = entry;
subentry->filename = sa_name;
subentry->local_sym_name = sa_name;
subentry->flags |= E_IS_LIBRARY;
search_library(file_open(subentry), subentry);
out:
;
}
#endif
}
#undef major
#undef minor
int
findlib(struct file_entry *p)
{
int i;
int fd = -1;
int major = -1, minor = -1;
char *cp, *fname = NULL;
if (!(p->flags & E_SEARCH_DYNAMIC))
goto dot_a;
fname = findshlib(p->filename, &major, &minor, 1);
if (fname && (fd = open(fname, O_RDONLY, 0)) >= 0) {
p->filename = fname;
p->lib_major = major;
p->lib_minor = minor;
p->flags &= ~E_SEARCH_DIRS;
return fd;
}
(void)free(fname);
dot_a:
p->flags &= ~E_SEARCH_DYNAMIC;
if ((cp = strrchr(p->filename, '/'))) {
char *tmp;
*cp++ = '\0';
tmp = concat(p->filename, "/lib", cp);
fname = concat(tmp, ".a", "");
free(tmp);
*(--cp) = '/';
} else
fname = concat("lib", p->filename, ".a");
for (i = 0; i < n_search_dirs; i++) {
char *path = concat(search_dirs[i], "/", fname);
fd = open(path, O_RDONLY, 0);
if (fd >= 0) {
p->filename = path;
p->flags &= ~E_SEARCH_DIRS;
break;
}
(void)free(path);
}
(void)free(fname);
return fd;
}