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libposix: introduce POSIX_signal_execute and PosixSignalDisposition enum

This commit is contained in:
Giacomo Tesio 2017-05-03 01:14:53 +02:00
parent 47573e2122
commit bd5063666f
2 changed files with 104 additions and 17 deletions
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19
sys/include/posix.h
View File

@ -32,6 +32,7 @@
typedef unsigned long clock_t;
#define __POSIX_EXIT_PREFIX "posix error "
#define __POSIX_EXIT_SIGNAL_PREFIX "terminated by posix signal "
#define __POSIX_SIGNAL_PREFIX "posix: "
extern void POSIX_exit(int code) __attribute__((noreturn));
@ -63,6 +64,22 @@ extern void POSIX_free(void *ptr);
extern unsigned int POSIX_sleep(unsigned int seconds);
extern int POSIX_pipe(int *errnop, int fildes[2]);
typedef enum PosixSignalDisposition
{
SignalHandled = 0, /* the application handled the signal */
TerminateTheProcess,
TerminateTheProcessAndCoreDump,
StopTheProcess,
ResumeTheProcess
} PosixSignalDisposition;
/* Executes a PosixSignalDisposition for pid.
*
* MUST be called instead of POSIX_kill for unblockable signals.
*/
extern int POSIX_signal_execute(int sig, PosixSignalDisposition action, int pid);
/* Library initialization
*/
#define _ERRNO_H // skip the Posix part, we just need the enum
@ -164,7 +181,7 @@ extern int libposix_translate_exit_status(PosixExitStatusTranslator translator);
/* Dispatch the signal to the registered handlers.
*/
typedef int (*PosixSignalTrampoline)(int signal);
typedef PosixSignalDisposition (*PosixSignalTrampoline)(int signal);
extern int libposix_set_signal_trampoline(PosixSignalTrampoline trampoline);

102
sys/src/lib/posix/processes.c
View File

@ -29,10 +29,9 @@ static int __libposix_wnohang;
#define __POSIX_SIGNAL_PREFIX_LEN (sizeof(__POSIX_SIGNAL_PREFIX)-1)
void
POSIX_exit(int code)
static void
free_wait_list(void)
{
char buf[64], *s;
WaitList *wl, *c;
/* free the wait list as the memory is shared */
@ -47,6 +46,14 @@ POSIX_exit(int code)
}
while (wl != nil);
}
}
void
POSIX_exit(int code)
{
char buf[64], *s;
free_wait_list();
if(__libposix_exit_status_translator != nil
&&(s = __libposix_exit_status_translator(code)) != nil){
@ -73,6 +80,8 @@ POSIX_execve(int *errnop, const char *name, char * const*argv, char * const*env)
__libposix_setup_exec_environment(env);
}
free_wait_list();
ret = sys_exec(name, argv);
switch(ret){
case 0:
@ -93,7 +102,7 @@ POSIX_wait(int *errnop, int *status)
Waitmsg *w;
WaitList *l;
char *s;
int ret = 0, pid;
int ret = 0, sig = 0, pid;
l = *__libposix_wait_list;
if(l != nil){
@ -117,12 +126,22 @@ POSIX_wait(int *errnop, int *status)
s += (sizeof(__POSIX_EXIT_PREFIX)/sizeof(char) - 1);
ret = atoi(s);
} else {
/* TODO: setup configurable interpretations */
ret = 127;
s = strstr(w->msg, __POSIX_EXIT_SIGNAL_PREFIX);
if(s){
s += (sizeof(__POSIX_EXIT_SIGNAL_PREFIX)/sizeof(char) - 1);
sig = atoi(s);
} else {
/* TODO: setup configurable interpretations */
ret = 127;
}
}
}
if(status != nil)
*status = ret << 8;
if(status != nil){
if(sig == 0)
*status = ret << 8;
else
*status = sig;
}
free(w);
return pid;
}
@ -133,7 +152,7 @@ POSIX_waitpid(int *errnop, int reqpid, int *status, int options)
Waitmsg *w;
WaitList *c, **nl;
char *s;
int ret = 0, nohang = 0, pid;
int ret = 0, sig = 0, nohang = 0, pid;
if(options & __libposix_wnohang){
@ -168,13 +187,14 @@ POSIX_waitpid(int *errnop, int reqpid, int *status, int options)
nl = __libposix_wait_list;
c = *nl;
while(c != nil){
*nl = c->next;
if(c->pid == reqpid){
if(status != nil)
*status = c->status;
*nl = c->next;
free(c);
return reqpid;
}
nl = &c->next;
c = *nl;
}
@ -191,19 +211,32 @@ WaitAgain:
s += (sizeof(__POSIX_EXIT_PREFIX)/sizeof(char) - 1);
ret = atoi(s);
} else {
/* TODO: setup configurable interpretations */
ret = 127;
s = strstr(w->msg, __POSIX_EXIT_SIGNAL_PREFIX);
if(s){
s += (sizeof(__POSIX_EXIT_SIGNAL_PREFIX)/sizeof(char) - 1);
sig = atoi(s);
} else {
/* TODO: setup configurable interpretations */
ret = 127;
}
}
}
if(pid == reqpid){
if(status != nil)
*status = ret << 8;
if(status != nil){
if(sig == 0)
*status = ret << 8;
else
*status = sig;
}
return reqpid;
}
c = malloc(sizeof(WaitList));
c->next = nil;
c->pid = pid;
c->status = ret << 8;
if(sig == 0)
c->status= ret << 8;
else
c->status = sig;
*nl = c;
if(!nohang)
goto WaitAgain;
@ -289,14 +322,51 @@ translate_jehanne_note(char *note)
return 0;
}
static void
terminated_by_signal(int sig)
{
char buf[64];
free_wait_list();
snprint(buf, sizeof(buf), __POSIX_EXIT_SIGNAL_PREFIX "%d", sig);
exits(buf);
}
int
POSIX_signal_execute(int sig, PosixSignalDisposition action, int pid)
{
switch(action){
case SignalHandled:
return 1;
case TerminateTheProcess:
case TerminateTheProcessAndCoreDump:
terminated_by_signal(sig);
break;
case StopTheProcess:
if(pid < 0)
sysfatal("libposix: stop signal reached the target process");
// TODO: write stop to ctl file
return 1;
case ResumeTheProcess:
if(pid < 0)
sysfatal("libposix: continue signal reached the target process");
// TODO: write start to ctl file
return 1;
}
return 0;
}
int
__libposix_note_handler(void *ureg, char *note)
{
int sig;
PosixSignalDisposition action;
if(strncmp(note, __POSIX_SIGNAL_PREFIX, __POSIX_SIGNAL_PREFIX_LEN) != 0)
return translate_jehanne_note(note); // TODO: should we translate common notes?
sig = atoi(note+__POSIX_SIGNAL_PREFIX_LEN);
return __libposix_signal_trampoline(sig);
action = __libposix_signal_trampoline(sig);
return POSIX_signal_execute(sig, action, -1);
}
int