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, 3 insertions, 1 deletions

diff --git a/sys/src/ape/lib/ap/plan9/execlp.c b/sys/src/ape/lib/ap/plan9/execlp.c
index ff5d71761..2bb8d3980 100644
--- a/sys/src/ape/lib/ap/plan9/execlp.c
+++ b/sys/src/ape/lib/ap/plan9/execlp.c
@@ -16,9 +16,11 @@ execlp(const char *name, const char *arg0, ...)
 	char buf[PATH_MAX];
 
 	if((n=execve(name, &arg0, environ)) < 0){
+		if(strchr("/.", name[0]) != 0 || strlen(name) >= sizeof(buf)-5)
+			return n;
 		strcpy(buf, "/bin/");
 		strcpy(buf+5, name);
-		n = execve(buf, &name+1, environ);
+		n = execve(buf, &arg0, environ);
 	}
 	return n;
 }