On 8/3/24 00:54, Clément Léger wrote:
In order for this function to be usable by tap.c code, add a list of
file descriptors that should not be closed.
Signed-off-by: Clément Léger <cle...@rivosinc.com>
---
include/qemu/osdep.h | 8 ++-
system/async-teardown.c | 2 +-
util/oslib-posix.c | 106 ++++++++++++++++++++++++++++++++++------
3 files changed, 97 insertions(+), 19 deletions(-)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index de77c5c254..4cc4c32b14 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -760,9 +760,13 @@ int qemu_fdatasync(int fd);
/**
* qemu_close_all_open_fd:
*
- * Close all open file descriptors
+ * Close all open file descriptors except the ones supplied in the @skip array
+ *
+ * @skip: ordered array of distinct file descriptors that should not be closed
+ * if any, or NULL.
+ * @nskip: number of entries in the @skip array or 0 if @skip is NULL.
*/
-void qemu_close_all_open_fd(void);
+void qemu_close_all_open_fd(const int *skip, unsigned int nskip);
/**
* Sync changes made to the memory mapped file back to the backing
diff --git a/system/async-teardown.c b/system/async-teardown.c
index edf49e1007..9148ee8d04 100644
--- a/system/async-teardown.c
+++ b/system/async-teardown.c
@@ -52,7 +52,7 @@ static int async_teardown_fn(void *arg)
* Close all file descriptors that might have been inherited from the
* main qemu process when doing clone, needed to make libvirt happy.
*/
- qemu_close_all_open_fd();
+ qemu_close_all_open_fd(NULL, 0);
/* Set up a handler for SIGHUP and unblock SIGHUP. */
sigaction(SIGHUP, &sa, NULL);
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 9b79fc7cff..2636dcd1e0 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -808,11 +808,12 @@ int qemu_msync(void *addr, size_t length, int fd)
return msync(addr, length, MS_SYNC);
}
-static bool qemu_close_all_open_fd_proc(void)
+static bool qemu_close_all_open_fd_proc(const int *skip, unsigned int nskip)
{
struct dirent *de;
int fd, dfd;
DIR *dir;
+ unsigned int skip_start = 0, skip_end = nskip;
dir = opendir("/proc/self/fd");
if (!dir) {
@@ -823,8 +824,33 @@ static bool qemu_close_all_open_fd_proc(void)
dfd = dirfd(dir);
for (de = readdir(dir); de; de = readdir(dir)) {
+ bool close_fd = true;
+
+ if (de->d_name[0] == '.') {
+ continue;
+ }
fd = atoi(de->d_name);
- if (fd != dfd) {
+ if (fd == dfd) {
+ continue;
+ }
+
+ for (unsigned int i = skip_start; i < skip_end; i++) {
+ if (fd < skip[i]) {
+ /* We are below the next skipped fd, break */
+ break;
+ } else if (fd == skip[i]) {
+ close_fd = false;
+ /* Restrict the range as we found fds matching start/end */
+ if (i == skip_start) {
+ skip_start++;
+ } else if (i == skip_end) {
+ skip_end--;
+ }
+ break;
+ }
+ }
+
+ if (close_fd) {
close(fd);
}
}
@@ -833,24 +859,68 @@ static bool qemu_close_all_open_fd_proc(void)
return true;
}
-static bool qemu_close_all_open_fd_close_range(void)
+static bool qemu_close_all_open_fd_close_range(const int *skip,
+ unsigned int nskip,
+ int open_max)
{
#ifdef CONFIG_CLOSE_RANGE
- int r = close_range(0, ~0U, 0);
- if (!r) {
- /* Success, no need to try other ways. */
- return true;
- }
-#endif
+ int first = 0, last = open_max - 1;
+ unsigned int cur_skip = 0;
+ int ret;
+
+ do {
+ /* Find the start boundary of the range to close */
+ while (cur_skip < nskip && first == skip[cur_skip]) {
+ cur_skip++;
+ first++;
+ }
+
+ /* Find the upper boundary of the range to close */
+ if (cur_skip < nskip) {
+ last = skip[cur_skip] - 1;
+ }
+ /*
+ * Adjust the maximum fd to close if it's above what the system
+ * supports
+ */
+ if (last > open_max) {
+ last = open_max;
You wanted open_max - 1 here as well.
I have fixed this up, and tidied a bit more while queuing for pull.
r~
