Backported to glibc 2.8

[lttng-tools.git] / src / common / compat / compat-epoll.c

diff --git a/src/common/compat/compat-epoll.c b/src/common/compat/compat-epoll.c
index 903a9f8256eeafad9e678f565ba6c1b60f0e9c2a..368fae19f6c3615b00760ce99b07d0b3250c7cf1 100644 (file)
--- a/src/common/compat/compat-epoll.c
+++ b/src/common/compat/compat-epoll.c
@@ -51,6 +51,11 @@ static int resize_poll_event(struct lttng_poll_event *events,
                PERROR("realloc epoll add");
                goto error;
        }
+       if (new_size > events->alloc_size) {
+               /* Zero newly allocated memory */
+               memset(ptr + events->alloc_size, 0,
+                       (new_size - events->alloc_size) * sizeof(*ptr));
+       }
        events->events = ptr;
        events->alloc_size = new_size;
 
@@ -76,7 +81,7 @@ int compat_epoll_create(struct lttng_poll_event *events, int size, int flags)
                size = poll_max_size;
        }
 
-       ret = epoll_create1(flags);
+       ret = compat_glibc_epoll_create(size, flags);
        if (ret < 0) {
                /* At this point, every error is fatal */
                PERROR("epoll_create1");
@@ -119,6 +124,11 @@ int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_event
                goto error;
        }
 
+       /*
+        * Zero struct epoll_event to ensure all representations of its
+        * union are zeroed.
+        */
+       memset(&ev, 0, sizeof(ev));
        ev.events = req_events;
        ev.data.fd = fd;
 
@@ -250,6 +260,7 @@ error:
 void compat_epoll_set_max_size(void)
 {
        int ret, fd;
+       ssize_t size_ret;
        char buf[64];
 
        poll_max_size = DEFAULT_POLL_SIZE;
@@ -259,11 +270,16 @@ void compat_epoll_set_max_size(void)
                return;
        }
 
-       ret = read(fd, buf, sizeof(buf));
-       if (ret < 0) {
+       size_ret = lttng_read(fd, buf, sizeof(buf));
+       /*
+        * Allow reading a file smaller than buf, but keep space for
+        * final \0.
+        */
+       if (size_ret < 0 || size_ret >= sizeof(buf)) {
                PERROR("read set max size");
                goto error;
        }
+       buf[size_ret] = '\0';
 
        poll_max_size = atoi(buf);
        if (poll_max_size == 0) {