Date: Wed, 9 Aug 2023 05:28:47 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 21a52f99440c - main - libc dlfcn.c: make dl_iterate_phdr() from libc more useful Message-ID: <202308090528.3795SlFA023331@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=21a52f99440c9bec7679f3b0c5c9d888901c3694 commit 21a52f99440c9bec7679f3b0c5c9d888901c3694 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2023-08-09 05:07:05 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2023-08-09 05:07:05 +0000 libc dlfcn.c: make dl_iterate_phdr() from libc more useful Apparently there are applications that resolve dl_iterate_phdr from libc and try to call the symbol. Our libc only provides stubs for dl* to satisfy static linker or statically linked binaries, and is not prepared to this situation. Add a code to dso libc to find real dl_iterate_phdr and redirect the call to it. Reported by: yuri PR: 272992 Sponsored by: The FreeBSD Foundation MFC after: 1 week --- lib/libc/gen/dlfcn.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/lib/libc/gen/dlfcn.c b/lib/libc/gen/dlfcn.c index 61984e2fe86c..f1ee86ec1934 100644 --- a/lib/libc/gen/dlfcn.c +++ b/lib/libc/gen/dlfcn.c @@ -169,7 +169,9 @@ _rtld_thread_init(void *li __unused) #ifndef IN_LIBDL static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT; static struct dl_phdr_info phdr_info; +#ifndef PIC static mutex_t dl_phdr_info_lock = MUTEX_INITIALIZER; +#endif static void dl_init_phdr_info(void) @@ -208,7 +210,16 @@ int dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused, void *data __unused) { -#ifndef IN_LIBDL +#if defined IN_LIBDL + return (0); +#elif defined PIC + int (*r)(int (*)(struct dl_phdr_info *, size_t, void *), void *); + + r = dlsym(RTLD_DEFAULT, "dl_iterate_phdr"); + if (r == NULL) + return (0); + return (r(callback, data)); +#else tls_index ti; int ret; @@ -223,8 +234,6 @@ dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused, ret = callback(&phdr_info, sizeof(phdr_info), data); mutex_unlock(&dl_phdr_info_lock); return (ret); -#else - return (0); #endif }
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