Issue #403: Don't generate an error if we're analysing a shared

library (indicated by the presence of a DT_SONAME tag) and not all the
NEEDED resolve to files successfully.  Shared libraries can
legitimately use dynamic link information from the applications that
link against them in order to resolve all their dependencies
correctly.

libpkg/pkg_elf.c

@@ -65,6 +65,7 @@ filter_system_shlibs(const char *name, char *path, size_t pathlen)
 
 	shlib_path = shlib_list_find_by_name(name);
 	if (shlib_path == NULL) {
+		/* dynamic linker could not resolve */
 		return (EPKG_FATAL);
 	}
 
@@ -73,10 +74,6 @@ filter_system_shlibs(const char *name, char *path, size_t pathlen)
 	    strncmp(shlib_path, "/usr/lib", 7) == 0)
 		return (EPKG_END); /* ignore libs from base */
 
-	/* When running in DEVELOPER_MODE check that shlib names
-	 * conform to the correct pattern.  Only warn on error --
-	 * shlibs may belong to a different package. */
-
 	if (path != NULL)
 		strncpy(path, shlib_path, pathlen);
 
@@ -88,14 +85,16 @@ filter_system_shlibs(const char *name, char *path, size_t pathlen)
 /* ARGSUSED */
 static int
 do_nothing(__unused void *actdata, __unused struct pkg *pkg,
-	   __unused const char *fpath, __unused const char *name)
+	   __unused const char *fpath, __unused const char *name,
+	   __unused bool is_shlib)
 {
 	return (EPKG_OK);
 }
 
 /* ARGSUSED */
 static int
-add_shlibs_to_pkg(__unused void *actdata, struct pkg *pkg, const char *fpath, const char *name)
+add_shlibs_to_pkg(__unused void *actdata, struct pkg *pkg, const char *fpath,
+		  const char *name, bool is_shlib)
 {
 	switch(filter_system_shlibs(name, NULL, 0)) {
 	case EPKG_OK:		/* A non-system library */
@@ -104,14 +103,20 @@ add_shlibs_to_pkg(__unused void *actdata, struct pkg *pkg, const char *fpath, co
 	case EPKG_END:		/* A system library */
 		return (EPKG_OK);
 	default:
+		/* Ignore link resolution errors if we're analysing a
+		   shared library. */
+		if (is_shlib)
+			return (EPKG_OK);
+
 		warnx("(%s-%s) %s - shared library %s not found",
 		      pkg_name(pkg), pkg_version(pkg), fpath, name);
 		return (EPKG_FATAL);
 	}
 }
 
 static int
-test_depends(void *actdata, struct pkg *pkg, const char *fpath, const char *name)
+test_depends(void *actdata, struct pkg *pkg, const char *fpath,
+	     const char *name, bool is_shlib)
 {
 	struct pkgdb *db = actdata;
 	struct pkg_dep *dep = NULL;
@@ -133,6 +138,11 @@ test_depends(void *actdata, struct pkg *pkg, const char *fpath, const char *name
 	case EPKG_END:		/* A system library */
 		return (EPKG_OK);
 	default:
+		/* Ignore link resolution errors if we're analysing a
+		   shared library. */
+		if (is_shlib)
+			return (EPKG_OK);
+
 		warnx("(%s-%s) %s - shared library %s not found",
 		      pkg_name(pkg), pkg_version(pkg), fpath, name);
 		return (EPKG_FATAL);
@@ -180,7 +190,7 @@ warn_about_name_format(struct pkg *pkg, const char *fpath, const char *shlib)
 	unsigned	len;
 
 	/* Shlib names in NEEDED records in the Dynamic section of an
-           ELF object are expect to look like libfoo.so.N where the
+           ELF object are expected to look like libfoo.so.N where the
            ABI version N is an integer or libfoo.so without ABI
            version at all. */
 
@@ -215,8 +225,9 @@ warn_about_name_format(struct pkg *pkg, const char *fpath, const char *shlib)
 }
 
 static int
-analyse_elf(struct pkg *pkg, const char *fpath, 
-    int (action)(void *, struct pkg *, const char *, const char *), void *actdata)
+analyse_elf(struct pkg *pkg, const char *fpath,
+	int (action)(void *, struct pkg *, const char *, const char *, bool),
+	void *actdata)
 {
 	Elf *e = NULL;
 	GElf_Ehdr elfhdr;
@@ -238,6 +249,7 @@ analyse_elf(struct pkg *pkg, const char *fpath,
 	bool shlibs = false;
 	bool autodeps = false;
 	bool developer = false;
+	bool is_shlib = false;
 
 	pkg_config_bool(PKG_CONFIG_AUTODEPS, &autodeps);
 	pkg_config_bool(PKG_CONFIG_SHLIBS, &shlibs);
@@ -333,7 +345,13 @@ analyse_elf(struct pkg *pkg, const char *fpath,
 	   find any RPATH or RUNPATH settings.  These are colon
 	   separated paths to prepend to the ld.so search paths from
 	   the ELF hints file.  These always seem to come right after
-	   the NEEDED entries */
+	   the NEEDED shared library entries.
+
+	   NEEDED entries should resolve to a filename for installed
+	   executables, but need not resolve for installed shared
+	   libraries -- additional info from the apps that link
+	   against them would be required.  Shared libraries are
+	   distinguished by a DT_SONAME tag */
 
 	rpath_list_init();
 	for (dynidx = 0; dynidx < numdyn; dynidx++) {
@@ -344,6 +362,9 @@ analyse_elf(struct pkg *pkg, const char *fpath,
 			goto cleanup;
 		}
 
+		if (dyn->d_tag == DT_SONAME)
+			is_shlib = true;
+
 		if (dyn->d_tag != DT_RPATH && dyn->d_tag != DT_RUNPATH)
 			continue;
 
@@ -352,7 +373,7 @@ analyse_elf(struct pkg *pkg, const char *fpath,
 		break;
 	}
 
-	/* Now find all of the NEEDED shared libraries */
+	/* Now find all of the NEEDED shared libraries. */
 
 	for (dynidx = 0; dynidx < numdyn; dynidx++) {
 		if ((dyn = gelf_getdyn(data, dynidx, &dyn_mem)) == NULL) {
@@ -367,10 +388,15 @@ analyse_elf(struct pkg *pkg, const char *fpath,
 
 		shlib = elf_strptr(e, sh_link, dyn->d_un.d_val);
 
+		/* When running in DEVELOPER_MODE check that shlib
+		   names conform to the correct pattern.  Only issue a
+		   warning on mismatch -- shlibs may belong to a
+		   different package. */
+
 		if (developer)
 			warn_about_name_format(pkg, fpath, shlib);
 
-		action(actdata, pkg, fpath, shlib);
+		action(actdata, pkg, fpath, shlib, is_shlib);
 	}
 
 cleanup:
@@ -412,7 +438,7 @@ pkg_analyse_files(struct pkgdb *db, struct pkg *pkg)
 	bool shlibs = false;
 	bool autodeps = false;
 	bool developer = false;
-	int (*action)(void *, struct pkg *, const char *, const char *);
+	int (*action)(void *, struct pkg *, const char *, const char *, bool);
 
 	pkg_config_bool(PKG_CONFIG_SHLIBS, &shlibs);
 	pkg_config_bool(PKG_CONFIG_AUTODEPS, &autodeps);