tmore debugging - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
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---
(DIR) commit 32116738e10e88f4d8eb136652fa945c6415d462
(DIR) parent aa200fe309dbb3292a218bcdf93615738963109a
(HTM) Author: rsc <devnull@localhost>
Date: Fri, 22 Oct 2004 17:12:38 +0000
more debugging
Diffstat:
M src/lib9/rfork.c | 40 +++++++++++++++++++++++++------
1 file changed, 33 insertions(+), 7 deletions(-)
---
(DIR) diff --git a/src/lib9/rfork.c b/src/lib9/rfork.c
t@@ -4,6 +4,12 @@
#include <libc.h>
#undef rfork
+static void
+nop(int x)
+{
+ USED(x);
+}
+
int
p9rfork(int flags)
{
t@@ -21,6 +27,13 @@ p9rfork(int flags)
return -1;
}
if(flags&RFNOWAIT){
+ /*
+ * BUG - should put the signal handler back after we
+ * finish, but I just don't care. If a program calls with
+ * NOWAIT once, they're not likely to want child notes
+ * after that.
+ */
+ signal(SIGCHLD, nop);
if(pipe(p) < 0)
return -1;
}
t@@ -35,20 +48,33 @@ p9rfork(int flags)
* Then read pid from pipe. Assume pipe buffer can absorb the write.
*/
close(p[1]);
- wait4(pid, &status, 0, 0);
+ status = 0;
+ if(wait4(pid, &status, 0, 0) < 0){
+ werrstr("pipe dance - wait4 - %r");
+ close(p[0]);
+ return -1;
+ }
n = readn(p[0], buf, sizeof buf-1);
close(p[0]);
if(!WIFEXITED(status) || WEXITSTATUS(status)!=0 || n <= 0){
- werrstr("pipe dance failed in rfork");
+ if(!WIFEXITED(status))
+ werrstr("pipe dance - !exited 0x%ux", status);
+ else if(WEXITSTATUS(status) != 0)
+ werrstr("pipe dance - non-zero status 0x%ux", status);
+ else if(n < 0)
+ werrstr("pipe dance - pipe read error - %r");
+ else if(n == 0)
+ werrstr("pipe dance - pipe read eof");
+ else
+ werrstr("pipe dance - unknown failure");
return -1;
}
buf[n] = 0;
- n = strtol(buf, &q, 0);
- if(*q != 0){
- werrstr("%s", q);
+ if(buf[0] == 'x'){
+ werrstr("%s", buf+2);
return -1;
}
- pid = n;
+ pid = strtol(buf, &q, 0);
}else{
/*
* Child - fork a new child whose wait message can't
t@@ -62,7 +88,7 @@ p9rfork(int flags)
if(pid > 0)
fprint(p[1], "%d", pid);
else
- fprint(p[1], " %r");
+ fprint(p[1], "x %r");
close(p[1]);
_exit(0);
}else{