ape: fix more bugs, use /env and /proc instead of #e and #p, cleanup

remove envname length limitation in _envsetup()
by using allocated buffer and use /env instead of #e

use /proc and getpid() instead of #p and #c in
readprocfdinit()

fix buffer overflow in execlp(), check if name
of failed exec starts with / . or is \0

make sure not to close our own filedescriptors
for FD_CLOEXEC in execve(), fix wrong length
check for flushing buffer to /env/_fdinfo.
fix error handling cases. copy the enviroment
before decoding \1 to \0 because the strings in
environ[] array might not be writable.

remove bogus close if we fail to open ppid file
in getppid() and use /dev/ppid instead of #c/ppid

1 files changed, 9 insertions, 10 deletions

diff --git a/sys/src/ape/lib/ap/plan9/getppid.c b/sys/src/ape/lib/ap/plan9/getppid.c
index 01759221b..6d40a3cc9 100644
--- a/sys/src/ape/lib/ap/plan9/getppid.c
+++ b/sys/src/ape/lib/ap/plan9/getppid.c
@@ -9,15 +9,14 @@
 pid_t
 getppid(void)
 {
-	int n, f;
-	char ppidbuf[15];
+	char b[20];
+	int f;
 
-	f = open("#c/ppid", 0);
-	n = read(f, ppidbuf, sizeof ppidbuf);
-	if(n < 0)
-		errno = EINVAL;
-	else
-		n = atoi(ppidbuf);
-	close(f);
-	return n;
+	memset(b, 0, sizeof(b));
+	f = open("/dev/ppid", 0);
+	if(f >= 0) {
+		read(f, b, sizeof(b));
+		close(f);
+	}
+	return atol(b);
 }