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Cygwin: always add sigmask to child info 

Even after fork, we might need the parent sigmask without having
access to the real _main_tls. There's a short time at process startup,
when _main_tls points to the system-allocated stack, but wait_sig is
already running. If we can't lock _main_tls, because find_tls can't
find it yet, we now access the parent's sigmask via child_info.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2022-05-03 15:16:18 +02:00
parent 28970dae34
commit 5a6de512ab
3 changed files with 18 additions and 7 deletions
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5
winsup/cygwin/child_info.h
View File

@ -37,7 +37,7 @@ enum child_status
#define EXEC_MAGIC_SIZE sizeof(child_info) #define EXEC_MAGIC_SIZE sizeof(child_info)
/* Change this value if you get a message indicating that it is out-of-sync. */ /* Change this value if you get a message indicating that it is out-of-sync. */
#define CURR_CHILD_INFO_MAGIC 0xecc930b9U #define CURR_CHILD_INFO_MAGIC 0xacbf4682U
#include "pinfo.h" #include "pinfo.h"
struct cchildren struct cchildren
@ -71,6 +71,8 @@ public:
unsigned fhandler_union_cb; unsigned fhandler_union_cb;
DWORD exit_code; // process exit code DWORD exit_code; // process exit code
static int retry_count;// retry count; static int retry_count;// retry count;
sigset_t sigmask;
child_info (unsigned, child_info_types, bool); child_info (unsigned, child_info_types, bool);
child_info (): subproc_ready (NULL), parent (NULL) {} child_info (): subproc_ready (NULL), parent (NULL) {}
~child_info (); ~child_info ();
@ -130,7 +132,6 @@ public:
int envc; int envc;
char **envp; char **envp;
HANDLE myself_pinfo; HANDLE myself_pinfo;
sigset_t sigmask;
int nchildren; int nchildren;
cchildren children[0]; cchildren children[0];
static cygheap_exec_info *alloc (); static cygheap_exec_info *alloc ();

2
winsup/cygwin/dcrt0.cc
View File

@ -845,7 +845,7 @@ dll_crt0_1 (void *)
_my_tls.incyg++; _my_tls.incyg++;
/* Inherit "parent" exec'ed process sigmask */ /* Inherit "parent" exec'ed process sigmask */
if (spawn_info && !in_forkee) if (spawn_info && !in_forkee)
_my_tls.sigmask = spawn_info->moreinfo->sigmask; _my_tls.sigmask = spawn_info->sigmask;
if (dynamically_loaded) if (dynamically_loaded)
sigproc_init (); sigproc_init ();

14
winsup/cygwin/sigproc.cc
View File

@ -820,7 +820,7 @@ child_info::child_info (unsigned in_cb, child_info_types chtype,
msv_count (0), cb (in_cb), intro (PROC_MAGIC_GENERIC), msv_count (0), cb (in_cb), intro (PROC_MAGIC_GENERIC),
magic (CHILD_INFO_MAGIC), type (chtype), cygheap (::cygheap), magic (CHILD_INFO_MAGIC), type (chtype), cygheap (::cygheap),
cygheap_max (::cygheap_max), flag (0), retry (child_info::retry_count), cygheap_max (::cygheap_max), flag (0), retry (child_info::retry_count),
rd_proc_pipe (NULL), wr_proc_pipe (NULL) rd_proc_pipe (NULL), wr_proc_pipe (NULL), sigmask (_my_tls.sigmask)
{ {
fhandler_union_cb = sizeof (fhandler_union); fhandler_union_cb = sizeof (fhandler_union);
user_h = cygwin_user_h; user_h = cygwin_user_h;
@ -902,7 +902,6 @@ cygheap_exec_info::alloc ()
sizeof (cygheap_exec_info) sizeof (cygheap_exec_info)
+ (chld_procs.count () + (chld_procs.count ()
* sizeof (children[0]))); * sizeof (children[0])));
res->sigmask = _my_tls.sigmask;
return res; return res;
} }
@ -1353,9 +1352,20 @@ wait_sig (VOID *)
threadlist_t *tl_entry; threadlist_t *tl_entry;
if (!pack.mask) if (!pack.mask)
{ {
/* There's a short time at process startup of a forked process,
when _main_tls points to the system-allocated stack, not to
the parent thread. In that case find_tls fails, and we fetch
the sigmask from the child_info passed from the parent. */
tl_entry = cygheap->find_tls (_main_tls); tl_entry = cygheap->find_tls (_main_tls);
if (tl_entry)
{
dummy_mask = _main_tls->sigmask; dummy_mask = _main_tls->sigmask;
cygheap->unlock_tls (tl_entry); cygheap->unlock_tls (tl_entry);
}
else if (child_proc_info)
dummy_mask = child_proc_info->sigmask;
else
dummy_mask = 0;
pack.mask = &dummy_mask; pack.mask = &dummy_mask;
} }