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authorFlorian Weimer <fweimer@redhat.com>2021-09-20 14:56:08 +0200
committerFlorian Weimer <fweimer@redhat.com>2021-09-20 14:56:08 +0200
commit95dba35bf05e4a5d69dfae5e9c9d4df3646a7f93 (patch)
tree0a20e738355959c33d3e61fc66bd07bf57845e0b /nptl
parenta93d9e03a31ec14405cb3a09aa95413b67067380 (diff)
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nptl: pthread_kill needs to return ESRCH for old programs (bug 19193)
The fix for bug 19193 breaks some old applications which appear to use pthread_kill to probe if a thread is still running, something that is not supported by POSIX.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/pthread_kill.c37
1 files changed, 29 insertions, 8 deletions
diff --git a/nptl/pthread_kill.c b/nptl/pthread_kill.c
index fb7862e..a44dc8f 100644
--- a/nptl/pthread_kill.c
+++ b/nptl/pthread_kill.c
@@ -21,8 +21,11 @@
#include <pthreadP.h>
#include <shlib-compat.h>
-int
-__pthread_kill_internal (pthread_t threadid, int signo)
+/* Sends SIGNO to THREADID. If the thread is about to exit or has
+ already exited on the kernel side, return NO_TID. Otherwise return
+ 0 or an error code. */
+static int
+__pthread_kill_implementation (pthread_t threadid, int signo, int no_tid)
{
struct pthread *pd = (struct pthread *) threadid;
if (pd == THREAD_SELF)
@@ -52,11 +55,8 @@ __pthread_kill_internal (pthread_t threadid, int signo)
signal is either not observable (the target thread has already
blocked signals at this point), or it will fail, or it might be
delivered to a new, unrelated thread that has reused the TID.
- So do not actually send the signal. Do not report an error
- because the threadid argument is still valid (the thread ID
- lifetime has not ended), and ESRCH (for example) would be
- misleading. */
- ret = 0;
+ So do not actually send the signal. */
+ ret = no_tid;
else
{
/* Using tgkill is a safety measure. pd->exit_lock ensures that
@@ -72,6 +72,15 @@ __pthread_kill_internal (pthread_t threadid, int signo)
}
int
+__pthread_kill_internal (pthread_t threadid, int signo)
+{
+ /* Do not report an error in the no-tid case because the threadid
+ argument is still valid (the thread ID lifetime has not ended),
+ and ESRCH (for example) would be misleading. */
+ return __pthread_kill_implementation (threadid, signo, 0);
+}
+
+int
__pthread_kill (pthread_t threadid, int signo)
{
/* Disallow sending the signal we use for cancellation, timers,
@@ -81,6 +90,7 @@ __pthread_kill (pthread_t threadid, int signo)
return __pthread_kill_internal (threadid, signo);
}
+
/* Some architectures (for instance arm) might pull raise through libgcc, so
avoid the symbol version if it ends up being used on ld.so. */
#if !IS_IN(rtld)
@@ -88,6 +98,17 @@ libc_hidden_def (__pthread_kill)
versioned_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_34);
# if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_34)
-compat_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_0);
+/* Variant which returns ESRCH in the no-TID case, for backwards
+ compatibility. */
+int
+attribute_compat_text_section
+__pthread_kill_esrch (pthread_t threadid, int signo)
+{
+ if (__is_internal_signal (signo))
+ return EINVAL;
+
+ return __pthread_kill_implementation (threadid, signo, ESRCH);
+}
+compat_symbol (libc, __pthread_kill_esrch, pthread_kill, GLIBC_2_0);
# endif
#endif