From 529844c77c7eb584746c1544a2bc32904571cfd2 Mon Sep 17 00:00:00 2001 From: Alexander Leidinger Date: Wed, 9 Feb 2011 20:23:22 +0000 Subject: [PATCH] Linux' shm_open() fails because it wants to find some funky shmfs to construct the full pathname. It starts to search at the default mountpoint which is /dev/shm. If this fails it runs through fstab and searches for shmfs and tmpfs. Whatever it finds will be statfs()'ed to be checked for Linux' fs magic for shmfs (0x01021994). Ideally our tmpfs should deliver this fs magic to Linux processes, but as our tmpfs is considered to be an experimental feature we can not assume that there is always a tmpfs available. To make shared memory work in the Linuxulator, force the fs type of /dev/shm (which can be a symlink) to match what Linux expects. The user is responsible (info has to be added to the linux base ports and the docs) to setup a suitable link for /dev/shm. Noticed by: Andre Albsmeier Submitted by: Andre Albsmeier MFC after: 1 month --- sys/compat/linux/linux_stats.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/sys/compat/linux/linux_stats.c b/sys/compat/linux/linux_stats.c index 907d2014c1e..8fa08b690f9 100644 --- a/sys/compat/linux/linux_stats.c +++ b/sys/compat/linux/linux_stats.c @@ -58,6 +58,8 @@ __FBSDID("$FreeBSD$"); #include #include +#define LINUX_SHMFS_MAGIC 0x01021994 + static void translate_vnhook_major_minor(struct vnode *vp, struct stat *sb) { @@ -394,7 +396,7 @@ linux_statfs(struct thread *td, struct linux_statfs_args *args) struct l_statfs linux_statfs; struct statfs bsd_statfs; char *path; - int error; + int error, dev_shm; LCONVPATHEXIST(td, args->path, &path); @@ -402,11 +404,17 @@ linux_statfs(struct thread *td, struct linux_statfs_args *args) if (ldebug(statfs)) printf(ARGS(statfs, "%s, *"), path); #endif + dev_shm = 0; error = kern_statfs(td, path, UIO_SYSSPACE, &bsd_statfs); + if (strncmp(path, "/dev/shm", sizeof("/dev/shm") - 1) == 0) + dev_shm = (path[8] == '\0' + || (path[8] == '/' && path[9] == '\0')); LFREEPATH(path); if (error) return (error); bsd_to_linux_statfs(&bsd_statfs, &linux_statfs); + if (dev_shm) + linux_statfs.f_type = LINUX_SHMFS_MAGIC; return copyout(&linux_statfs, args->buf, sizeof(linux_statfs)); }