127 lines
3.5 KiB
Diff
127 lines
3.5 KiB
Diff
XXX: DO NOT REMOVE UNLESS VERIFIED THAT libvirt virCommandMassClose does not use malloc
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https://www.redhat.com/archives/libvir-list/2020-August/msg00598.html
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Add a portable generic implementation of virMassClose as fallback on
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non-FreeBSD and non-glibc.
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This implementation uses poll(2) to look for open files to keep
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performance reasonable while not using any mallocs.
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This solves a deadlock with musl libc.
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Signed-off-by: Natanael Copa <ncopa alpinelinux org>
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---
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src/util/vircommand.c | 66 +++++++++++++++++++++++++++++++++++++------
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1 file changed, 58 insertions(+), 8 deletions(-)
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diff --git a/src/util/vircommand.c b/src/util/vircommand.c
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index 8e372c3152..5319b9c9b3 100644
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--- a/src/util/vircommand.c
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+++ b/src/util/vircommand.c
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@@ -455,7 +455,7 @@ virExecCommon(virCommand *cmd, gid_t *groups, int ngroups)
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return 0;
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}
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-# ifdef __linux__
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+# if defined(__linux__) && defined(__GLIBC__)
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/* On Linux, we can utilize procfs and read the table of opened
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* FDs and selectively close only those FDs we don't want to pass
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* onto child process (well, the one we will exec soon since this
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@@ -500,7 +500,7 @@ virCommandMassCloseGetFDsGeneric(virCommand *cmd G_GNUC_UNUSED,
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virBitmapSetAll(fds);
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return 0;
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}
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-# endif /* !__linux__ */
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+# endif /* __linux__ && __GLIBC__ */
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# ifdef __FreeBSD__
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@@ -554,7 +554,7 @@ virCommandMassClose(virCommand *cmd,
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return 0;
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}
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-# else /* ! __FreeBSD__ */
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+# elif defined(__GLIBC__) /* ! __FreeBSD__ */
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static int
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virCommandMassClose(virCommand *cmd,
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@@ -581,13 +581,8 @@ virCommandMassClose(virCommand *cmd,
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fds = virBitmapNew(openmax);
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-# ifdef __linux__
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if (virCommandMassCloseGetFDsLinux(cmd, fds) < 0)
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return -1;
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-# else
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- if (virCommandMassCloseGetFDsGeneric(cmd, fds) < 0)
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- return -1;
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-# endif
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fd = virBitmapNextSetBit(fds, 2);
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for (; fd >= 0; fd = virBitmapNextSetBit(fds, fd)) {
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@@ -605,6 +600,61 @@ virCommandMassClose(virCommand *cmd,
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return 0;
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}
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+#else /* ! __FreeBSD__ && ! __GLIBC__ */
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+static int
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+virCommandMassClose(virCommand* cmd,
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+ int childin,
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+ int childout,
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+ int childerr)
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+{
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+ static struct pollfd pfds[1024];
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+ int fd = 0;
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+ int i, total;
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+ int max_fd = sysconf(_SC_OPEN_MAX);
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+
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+ if (max_fd < 0) {
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+ virReportSystemError(errno, "%s", _("sysconf(_SC_OPEN_MAX) failed"));
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+ return -1;
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+ }
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+
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+ total = max_fd - fd;
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+ for (i = 0; i < (total < 1024 ? total : 1024); i++)
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+ pfds[i].events = 0;
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+
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+ while (fd < max_fd) {
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+ int nfds, r = 0;
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+
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+ total = max_fd - fd;
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+ nfds = total < 1024 ? total : 1024;
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+
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+ for (i = 0; i < nfds; i++)
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+ pfds[i].fd = fd + i;
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+
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+ do {
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+ r = poll(pfds, nfds, 0);
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+ } while (r == -1 && errno == EINTR);
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+
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+ if (r < 0) {
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+ virReportSystemError(errno, "%s", _("poll() failed"));
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+ return -1;
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+ }
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+
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+ for (i = 0; i < nfds; i++)
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+ if (pfds[i].revents != POLLNVAL) {
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+ if (pfds[i].fd == childin || pfds[i].fd == childout || pfds[i].fd == childerr)
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+ continue;
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+ if (!virCommandFDIsSet(cmd, pfds[i].fd)) {
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+ VIR_MASS_CLOSE(pfds[i].fd);
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+ } else if (virSetInherit(pfds[i].fd, true) < 0) {
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+ virReportSystemError(errno, _("failed to preserve fd %d"), pfds[i].fd);
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+ return -1;
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+ }
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+ }
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+ fd += nfds;
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+ }
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+ return 0;
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+}
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+
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# endif /* ! __FreeBSD__ */
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/*
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--
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2.33.0
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