git: 7bbfb5d95932 - stable/13 - rtld: make dlerror() thread-local
Konstantin Belousov
kib at FreeBSD.org
Fri Apr 23 11:15:05 UTC 2021
The branch stable/13 has been updated by kib:
URL: https://cgit.FreeBSD.org/src/commit/?id=7bbfb5d959329fe0c322c0b59c9268b75ddddace
commit 7bbfb5d959329fe0c322c0b59c9268b75ddddace
Author: Konstantin Belousov <kib at FreeBSD.org>
AuthorDate: 2021-04-07 22:02:33 +0000
Commit: Konstantin Belousov <kib at FreeBSD.org>
CommitDate: 2021-04-23 11:14:08 +0000
rtld: make dlerror() thread-local
(cherry picked from commit 4d9128da54f8f8e2a29190ffb18880c4f116a205)
---
lib/libthr/thread/thr_private.h | 4 ++++
lib/libthr/thread/thr_rtld.c | 21 +++++++++++++++++++++
libexec/rtld-elf/rtld.c | 38 ++++++++++++++++++++------------------
libexec/rtld-elf/rtld_lock.c | 33 +++++++++++++++++++++++++++++++++
libexec/rtld-elf/rtld_lock.h | 7 ++++++-
5 files changed, 84 insertions(+), 19 deletions(-)
diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h
index a1258940a896..a5bbc5997d30 100644
--- a/lib/libthr/thread/thr_private.h
+++ b/lib/libthr/thread/thr_private.h
@@ -577,6 +577,10 @@ struct pthread {
/* pthread_set/get_name_np */
char *name;
+
+ /* rtld thread-local dlerror message and seen control */
+ char dlerror_msg[512];
+ int dlerror_seen;
};
#define THR_SHOULD_GC(thrd) \
diff --git a/lib/libthr/thread/thr_rtld.c b/lib/libthr/thread/thr_rtld.c
index 5848fc6d5f61..1967ea14859d 100644
--- a/lib/libthr/thread/thr_rtld.c
+++ b/lib/libthr/thread/thr_rtld.c
@@ -189,6 +189,24 @@ _thr_rtld_clr_flag(int mask __unused)
extern char _pli_rtli_version;
char _pli_rtli_version;
+static char *
+_thr_dlerror_loc(void)
+{
+ struct pthread *curthread;
+
+ curthread = _get_curthread();
+ return (curthread->dlerror_msg);
+}
+
+static int *
+_thr_dlerror_seen(void)
+{
+ struct pthread *curthread;
+
+ curthread = _get_curthread();
+ return (&curthread->dlerror_seen);
+}
+
void
_thr_rtld_init(void)
{
@@ -221,6 +239,9 @@ _thr_rtld_init(void)
li.thread_set_flag = _thr_rtld_set_flag;
li.thread_clr_flag = _thr_rtld_clr_flag;
li.at_fork = NULL;
+ li.dlerror_loc = _thr_dlerror_loc;
+ li.dlerror_loc_sz = sizeof(curthread->dlerror_msg);
+ li.dlerror_seen = _thr_dlerror_seen;
/*
* Preresolve the symbols needed for the fork interposer. We
diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 5e99b8db8ff7..d50774868908 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -195,7 +195,6 @@ int __sys_openat(int, const char *, int, ...);
/*
* Data declarations.
*/
-static char *error_message; /* Message for dlerror(), or NULL */
struct r_debug r_debug __exported; /* for GDB; */
static bool libmap_disable; /* Disable libmap */
static bool ld_loadfltr; /* Immediate filters processing */
@@ -441,6 +440,8 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
assert(aux_info[AT_BASE] != NULL);
init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
+ dlerror_dflt_init();
+
__progname = obj_rtld.path;
argv0 = argv[0] != NULL ? argv[0] : "(null)";
environ = env;
@@ -919,14 +920,14 @@ _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
void
_rtld_error(const char *fmt, ...)
{
- static char buf[512];
- va_list ap;
+ va_list ap;
- va_start(ap, fmt);
- rtld_vsnprintf(buf, sizeof buf, fmt, ap);
- error_message = buf;
- va_end(ap);
- LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
+ va_start(ap, fmt);
+ rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz,
+ fmt, ap);
+ va_end(ap);
+ *lockinfo.dlerror_seen() = 0;
+ LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc());
}
/*
@@ -935,7 +936,7 @@ _rtld_error(const char *fmt, ...)
static char *
errmsg_save(void)
{
- return error_message == NULL ? NULL : xstrdup(error_message);
+ return (xstrdup(lockinfo.dlerror_loc()));
}
/*
@@ -945,12 +946,12 @@ errmsg_save(void)
static void
errmsg_restore(char *saved_msg)
{
- if (saved_msg == NULL)
- error_message = NULL;
- else {
- _rtld_error("%s", saved_msg);
- free(saved_msg);
- }
+ if (saved_msg == NULL)
+ _rtld_error("");
+ else {
+ _rtld_error("%s", saved_msg);
+ free(saved_msg);
+ }
}
static const char *
@@ -3369,9 +3370,10 @@ dlclose_locked(void *handle, RtldLockState *lockstate)
char *
dlerror(void)
{
- char *msg = error_message;
- error_message = NULL;
- return msg;
+ if (*(lockinfo.dlerror_seen()) != 0)
+ return (NULL);
+ *lockinfo.dlerror_seen() = 1;
+ return (lockinfo.dlerror_loc());
}
/*
diff --git a/libexec/rtld-elf/rtld_lock.c b/libexec/rtld-elf/rtld_lock.c
index 4d54c687ee6f..94e931c2f760 100644
--- a/libexec/rtld-elf/rtld_lock.c
+++ b/libexec/rtld-elf/rtld_lock.c
@@ -59,6 +59,21 @@ void _rtld_thread_init(struct RtldLockInfo *) __exported;
void _rtld_atfork_pre(int *) __exported;
void _rtld_atfork_post(int *) __exported;
+static char def_dlerror_msg[512];
+static int def_dlerror_seen_val;
+
+static char *
+def_dlerror_loc(void)
+{
+ return (def_dlerror_msg);
+}
+
+static int *
+def_dlerror_seen(void)
+{
+ return (&def_dlerror_seen_val);
+}
+
#define WAFLAG 0x1 /* A writer holds the lock */
#define RC_INCR 0x2 /* Adjusts count of readers desiring lock */
@@ -299,6 +314,14 @@ lock_restart_for_upgrade(RtldLockState *lockstate)
}
}
+void
+dlerror_dflt_init(void)
+{
+ lockinfo.dlerror_loc = def_dlerror_loc;
+ lockinfo.dlerror_loc_sz = sizeof(def_dlerror_msg);
+ lockinfo.dlerror_seen = def_dlerror_seen;
+}
+
void
lockdflt_init(void)
{
@@ -313,6 +336,9 @@ lockdflt_init(void)
deflockinfo.thread_set_flag = def_thread_set_flag;
deflockinfo.thread_clr_flag = def_thread_clr_flag;
deflockinfo.at_fork = NULL;
+ deflockinfo.dlerror_loc = def_dlerror_loc;
+ deflockinfo.dlerror_loc_sz = sizeof(def_dlerror_msg);
+ deflockinfo.dlerror_seen = def_dlerror_seen;
for (i = 0; i < RTLD_LOCK_CNT; i++) {
rtld_locks[i].mask = (1 << i);
@@ -404,6 +430,13 @@ _rtld_thread_init(struct RtldLockInfo *pli)
lockinfo.thread_set_flag = pli->thread_set_flag;
lockinfo.thread_clr_flag = pli->thread_clr_flag;
lockinfo.at_fork = pli->at_fork;
+ if (lockinfo.rtli_version > RTLI_VERSION_ONE && pli != NULL) {
+ strlcpy(pli->dlerror_loc(), lockinfo.dlerror_loc(),
+ lockinfo.dlerror_loc_sz);
+ lockinfo.dlerror_loc = pli->dlerror_loc;
+ lockinfo.dlerror_loc_sz = pli->dlerror_loc_sz;
+ lockinfo.dlerror_seen = pli->dlerror_seen;
+ }
/* restore thread locking state, this time with new locks */
thread_mask_clear(~0);
diff --git a/libexec/rtld-elf/rtld_lock.h b/libexec/rtld-elf/rtld_lock.h
index 7a61a1a525e2..fdbdc9917075 100644
--- a/libexec/rtld-elf/rtld_lock.h
+++ b/libexec/rtld-elf/rtld_lock.h
@@ -31,7 +31,7 @@
#define _RTLD_LOCK_H_
#define RTLI_VERSION_ONE 0x01
-#define RTLI_VERSION 0x01
+#define RTLI_VERSION 0x02
#define MAX_RTLD_LOCKS 8
@@ -46,6 +46,9 @@ struct RtldLockInfo
int (*thread_set_flag)(int);
int (*thread_clr_flag)(int);
void (*at_fork)(void);
+ char *(*dlerror_loc)(void);
+ int *(*dlerror_seen)(void);
+ int dlerror_loc_sz;
};
#if defined(IN_RTLD) || defined(PTHREAD_KERNEL)
@@ -80,6 +83,8 @@ void lock_release(rtld_lock_t, RtldLockState *);
void lock_upgrade(rtld_lock_t, RtldLockState *);
void lock_restart_for_upgrade(RtldLockState *);
+void dlerror_dflt_init(void);
+
#endif /* IN_RTLD */
#endif
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