From: Stefan Hajnoczi <stefa...@redhat.com>
Sometimes collecting output from stderr is inconvenient or does not fit
within the overall logging architecture. Add syslog(3) support for
cases where stderr cannot be used.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
dgilbert: Reworked as a logging function
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
contrib/virtiofsd/fuse_lowlevel.h | 1 +
contrib/virtiofsd/helper.c | 2 ++
contrib/virtiofsd/passthrough_ll.c | 34 +++++++++++++++++++++++++++---
contrib/virtiofsd/seccomp.c | 32 ++++++++++++++++++++--------
contrib/virtiofsd/seccomp.h | 4 +++-
5 files changed, 60 insertions(+), 13 deletions(-)
diff --git a/contrib/virtiofsd/fuse_lowlevel.h
b/contrib/virtiofsd/fuse_lowlevel.h
index 13fd9791d5..112596caaf 100644
--- a/contrib/virtiofsd/fuse_lowlevel.h
+++ b/contrib/virtiofsd/fuse_lowlevel.h
@@ -1798,6 +1798,7 @@ struct fuse_cmdline_opts {
int show_help;
int print_capabilities;
int clone_fd;
+ int syslog;
unsigned int max_idle_threads;
};
diff --git a/contrib/virtiofsd/helper.c b/contrib/virtiofsd/helper.c
index 08e00c0d13..b1e45aee05 100644
--- a/contrib/virtiofsd/helper.c
+++ b/contrib/virtiofsd/helper.c
@@ -53,6 +53,7 @@ static const struct fuse_opt fuse_helper_opts[] = {
#endif
FUSE_HELPER_OPT("clone_fd", clone_fd),
FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads),
+ FUSE_HELPER_OPT("--syslog", syslog),
FUSE_OPT_END
};
@@ -135,6 +136,7 @@ void fuse_cmdline_help(void)
" -V --version print version\n"
" --print-capabilities print vhost-user.json\n"
" -d -o debug enable debug output (implies
-f)\n"
+ " --syslog log to syslog (default stderr)\n"
" -f foreground operation\n"
" --daemonize run in background\n"
" -s disable multi-threaded
operation\n"
diff --git a/contrib/virtiofsd/passthrough_ll.c
b/contrib/virtiofsd/passthrough_ll.c
index 25f7ad854a..b413687720 100644
--- a/contrib/virtiofsd/passthrough_ll.c
+++ b/contrib/virtiofsd/passthrough_ll.c
@@ -42,6 +42,7 @@
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
+#include <syslog.h>
#include <limits.h>
#include <dirent.h>
#include <assert.h>
@@ -151,6 +152,7 @@ static const struct fuse_opt lo_opts[] = {
offsetof(struct lo_data, norace), 1 },
FUSE_OPT_END
};
+static bool use_syslog = false;
static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t
n);
@@ -2103,13 +2105,13 @@ static void setup_mount_namespace(const char *source)
* Lock down this process to prevent access to other processes or files outside
* source directory. This reduces the impact of arbitrary code execution bugs.
*/
-static void setup_sandbox(struct lo_data *lo)
+static void setup_sandbox(struct lo_data *lo, bool enable_syslog)
{
setup_pid_namespace();
setup_proc_self_fd(lo);
setup_net_namespace();
setup_mount_namespace(lo->source);
- setup_seccomp();
+ setup_seccomp(enable_syslog);
}
/* Raise the maximum number of open file descriptors to the system limit */
@@ -2142,6 +2144,27 @@ static void setup_nofile_rlimit(void)
g_free(nr_open);
}
+static void log_func(enum fuse_log_level level,
+ const char *fmt, va_list ap)
+{
+ if (use_syslog) {
+ int priority = LOG_ERR;
+ switch (level) {
+ case FUSE_LOG_EMERG: priority = LOG_EMERG; break;
+ case FUSE_LOG_ALERT: priority = LOG_ALERT; break;
+ case FUSE_LOG_CRIT: priority = LOG_CRIT; break;
+ case FUSE_LOG_ERR: priority = LOG_ERR; break;
+ case FUSE_LOG_WARNING: priority = LOG_WARNING; break;
+ case FUSE_LOG_NOTICE: priority = LOG_NOTICE; break;
+ case FUSE_LOG_INFO: priority = LOG_INFO; break;
+ case FUSE_LOG_DEBUG: priority = LOG_DEBUG; break;
+ }
+ vsyslog(priority, fmt, ap);
+ } else {
+ vfprintf(stderr, fmt, ap);
+ }
+}
+
int main(int argc, char *argv[])
{
struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
@@ -2179,6 +2202,11 @@ int main(int argc, char *argv[])
if (fuse_parse_cmdline(&args, &opts) != 0)
return 1;
+ fuse_set_log_func(log_func);
+ use_syslog = opts.syslog;
+ if (use_syslog) {
+ openlog("virtiofsd", LOG_PID, LOG_DAEMON);
+ }
if (opts.show_help) {
printf("usage: %s [options]\n\n", argv[0]);
fuse_cmdline_help();
@@ -2260,7 +2288,7 @@ int main(int argc, char *argv[])
fuse_daemonize(opts.foreground);
- setup_sandbox(&lo);
+ setup_sandbox(&lo, opts.syslog);
/* Block until ctrl+c or fusermount -u */
ret = virtio_loop(se);
diff --git a/contrib/virtiofsd/seccomp.c b/contrib/virtiofsd/seccomp.c
index df1390d6be..77bc405bdc 100644
--- a/contrib/virtiofsd/seccomp.c
+++ b/contrib/virtiofsd/seccomp.c
@@ -88,11 +88,28 @@ static const int syscall_whitelist[] = {
SCMP_SYS(writev),
};
-void setup_seccomp(void)
+/* Syscalls used when --syslog is enabled */
+static const int syscall_whitelist_syslog[] = {
+ SCMP_SYS(sendto),
+};
+
+static void add_whitelist(scmp_filter_ctx ctx, const int syscalls[], size_t
len)
{
- scmp_filter_ctx ctx;
size_t i;
+ for (i = 0; i < len; i++) {
+ if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, syscalls[i], 0) != 0) {
+ fuse_log(FUSE_LOG_ERR, "seccomp_rule_add syscall %d failed\n",
+ syscalls[i]);
+ exit(1);
+ }
+ }
+}
+
+void setup_seccomp(bool enable_syslog)
+{
+ scmp_filter_ctx ctx;
+
#ifdef SCMP_ACT_KILL_PROCESS
ctx = seccomp_init(SCMP_ACT_KILL_PROCESS);
/* Handle a newer libseccomp but an older kernel */
@@ -107,13 +124,10 @@ void setup_seccomp(void)
exit(1);
}
- for (i = 0; i < G_N_ELEMENTS(syscall_whitelist); i++) {
- if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW,
- syscall_whitelist[i], 0) != 0) {
- fuse_log(FUSE_LOG_ERR, "seccomp_rule_add syscall %d",
- syscall_whitelist[i]);
- exit(1);
- }
+ add_whitelist(ctx, syscall_whitelist, G_N_ELEMENTS(syscall_whitelist));
+ if (enable_syslog) {
+ add_whitelist(ctx, syscall_whitelist_syslog,
+ G_N_ELEMENTS(syscall_whitelist_syslog));
}
/* libvhost-user calls this for post-copy migration, we don't need it */
diff --git a/contrib/virtiofsd/seccomp.h b/contrib/virtiofsd/seccomp.h
index 86bce72652..d47c8eade6 100644
--- a/contrib/virtiofsd/seccomp.h
+++ b/contrib/virtiofsd/seccomp.h
@@ -9,6 +9,8 @@
#ifndef VIRTIOFSD_SECCOMP_H
#define VIRTIOFSD_SECCOMP_H
-void setup_seccomp(void);
+#include <stdbool.h>
+
+void setup_seccomp(bool enable_syslog);
#endif /* VIRTIOFSD_SECCOMP_H */
--
2.23.0
