[PATCH 3/4] vircommand: Make sysconf(_SC_OPEN_MAX) failure non-fatal
The point of calling sysconf(_SC_OPEN_MAX) is to allocate big
enough bitmap so that subsequent call to
virCommandMassCloseGetFDsDir() can just set the bit instead of
expanding memory (this code runs in a forked off child and thus
using async-signal-unsafe functions like malloc() is a bit
tricky).
But on some systems the limit for opened FDs is virtually
non-existent (typically macOS Ventura started reporting EINVAL).
But with both glibc and musl using malloc() after fork() is safe.
And with sufficiently new glib too, as it's using malloc() with
newer releases instead of their own allocator.
Therefore, pick a sufficiently large value (glibc falls back to
256, [1], so 1024 should be good enough) to fall back to and make
the error non-fatal.
1:
https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/...
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/util/vircommand.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/src/util/vircommand.c b/src/util/vircommand.c
index c0aab85c53..e48f361114 100644
--- a/src/util/vircommand.c
+++ b/src/util/vircommand.c
@@ -493,7 +493,7 @@ virCommandMassCloseGetFDsDir(virBitmap *fds,
return -1;
}
- ignore_value(virBitmapSetBit(fds, fd));
+ virBitmapSetBitExpand(fds, fd);
}
if (rc < 0)
@@ -537,10 +537,8 @@ virCommandMassCloseFrom(virCommand *cmd,
* Therefore we can safely allocate memory here (and transitively call
* opendir/readdir) without a deadlock. */
- if (openmax < 0) {
- virReportSystemError(errno, "%s", _("sysconf(_SC_OPEN_MAX)
failed"));
- return -1;
- }
+ if (openmax <= 0)
+ openmax = 1024;
fds = virBitmapNew(openmax);
--
2.44.2