From 54fb8b9b2bdd066cf95fba8da3d67b7cda39cbb8 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jeremy@system76.com>
Date: Sun, 28 Apr 2019 10:07:42 -0600
Subject: [PATCH] Fix select on regular files
---
src/header/sys_select/mod.rs | 58 +++++++++++++++++++++++-------------
tests/expected/select.stdout | 5 ++++
tests/select.c | 47 +++++++++++++++++++++++++++--
3 files changed, 86 insertions(+), 24 deletions(-)
diff --git a/src/header/sys_select/mod.rs b/src/header/sys_select/mod.rs
index bf77b819..d39f4316 100644
--- a/src/header/sys_select/mod.rs
+++ b/src/header/sys_select/mod.rs
@@ -72,8 +72,10 @@ pub fn select_epoll(
File::new(epfd)
};
+ // Keep track of the number of file descriptors that do not support epoll
+ let mut not_epoll = 0;
for fd in 0..nfds {
- if let Some(ref fd_set) = readfds {
+ if let Some(ref mut fd_set) = readfds {
if fd_set.isset(fd) {
let mut event = epoll_event {
events: EPOLLIN,
@@ -82,11 +84,17 @@ pub fn select_epoll(
},
};
if epoll_ctl(*ep, EPOLL_CTL_ADD, fd, &mut event) < 0 {
- return -1;
+ if unsafe { platform::errno == errno::EPERM } {
+ not_epoll += 1;
+ } else {
+ return -1;
+ }
+ } else {
+ fd_set.clr(fd);
}
}
}
- if let Some(ref fd_set) = writefds {
+ if let Some(ref mut fd_set) = writefds {
if fd_set.isset(fd) {
let mut event = epoll_event {
events: EPOLLOUT,
@@ -95,11 +103,17 @@ pub fn select_epoll(
},
};
if epoll_ctl(*ep, EPOLL_CTL_ADD, fd, &mut event) < 0 {
- return -1;
+ if unsafe { platform::errno == errno::EPERM } {
+ not_epoll += 1;
+ } else {
+ return -1;
+ }
+ } else {
+ fd_set.clr(fd);
}
}
}
- if let Some(ref fd_set) = exceptfds {
+ if let Some(ref mut fd_set) = exceptfds {
if fd_set.isset(fd) {
let mut event = epoll_event {
events: EPOLLERR,
@@ -108,17 +122,23 @@ pub fn select_epoll(
},
};
if epoll_ctl(*ep, EPOLL_CTL_ADD, fd, &mut event) < 0 {
- return -1;
+ if unsafe { platform::errno == errno::EPERM } {
+ not_epoll += 1;
+ } else {
+ return -1;
+ }
+ } else {
+ fd_set.clr(fd);
}
}
}
}
let mut events: [epoll_event; 32] = unsafe { mem::zeroed() };
- let res = epoll_wait(
- *ep,
- events.as_mut_ptr(),
- events.len() as c_int,
+ let epoll_timeout = if not_epoll > 0 {
+ // Do not wait if any non-epoll file descriptors were found
+ 0
+ } else {
match timeout {
Some(timeout) => {
//TODO: Check for overflow
@@ -127,22 +147,18 @@ pub fn select_epoll(
},
None => -1
}
+ };
+ let res = epoll_wait(
+ *ep,
+ events.as_mut_ptr(),
+ events.len() as c_int,
+ epoll_timeout
);
if res < 0 {
return -1;
}
- if let Some(ref mut fd_set) = readfds {
- fd_set.zero();
- }
- if let Some(ref mut fd_set) = writefds {
- fd_set.zero();
- }
- if let Some(ref mut fd_set) = exceptfds {
- fd_set.zero();
- }
-
- let mut count = 0;
+ let mut count = not_epoll;
for i in 0..res as usize {
let event = &events[i];
let fd = unsafe { event.data.fd };
diff --git a/tests/expected/select.stdout b/tests/expected/select.stdout
index 965e612d..a4a5b784 100644
--- a/tests/expected/select.stdout
+++ b/tests/expected/select.stdout
@@ -1,3 +1,8 @@
+Testing select on file
+Is set before? 1
+Amount of things ready: 1
+Is set after? 1
+Testing select on pipe
Is set before? 1
Amount of things ready: 1
Is set after? 1
diff --git a/tests/select.c b/tests/select.c
index 25326a75..dfe7161c 100644
--- a/tests/select.c
+++ b/tests/select.c
@@ -5,7 +5,36 @@
#include "test_helpers.h"
-int main(void) {
+int file_test(void) {
+ int fd = open("select.c", 0, 0);
+ if (fd < 0) {
+ perror("open");
+ return -1;
+ }
+
+ printf("Testing select on file\n");
+
+ fd_set read;
+ FD_ZERO(&read);
+ FD_SET(fd, &read);
+
+ printf("Is set before? %d\n", FD_ISSET(fd, &read));
+
+ int nfds = select(fd + 1, &read, NULL, NULL, NULL);
+ if (nfds < 0) {
+ perror("select");
+ return 1;
+ }
+ printf("Amount of things ready: %d\n", nfds);
+
+ printf("Is set after? %d\n", FD_ISSET(fd, &read));
+
+ close(fd);
+
+ return 0;
+}
+
+int pipe_test(void) {
int pipefd[2];
if (pipe2(pipefd, O_NONBLOCK) < 0) {
perror("pipe");
@@ -18,14 +47,14 @@ int main(void) {
return 1;
}
+ printf("Testing select on pipe\n");
+
fd_set read;
FD_ZERO(&read);
FD_SET(pipefd[0], &read);
printf("Is set before? %d\n", FD_ISSET(pipefd[0], &read));
- // This should actually test TCP streams and stuff, but for now I'm simply
- // testing whether it ever returns or not.
int nfds = select(pipefd[0] + 1, &read, NULL, NULL, NULL);
if (nfds < 0) {
perror("select");
@@ -40,3 +69,15 @@ int main(void) {
return 0;
}
+
+int main(void) {
+ if (file_test()) {
+ return 1;
+ }
+
+ if (pipe_test()) {
+ return 1;
+ }
+
+ return 0;
+}
--
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