Most of the seccomp functions return errnos as a negative return value. The code is currently ignoring these and reporting a generic error message for all seccomp failure scenarios making debugging painful. Report a more precise error from each failed call and include errno if it is available.
Signed-off-by: Daniel P. Berrangé <berra...@redhat.com> --- qemu-seccomp.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/qemu-seccomp.c b/qemu-seccomp.c index 36d5829831..8daa9e0528 100644 --- a/qemu-seccomp.c +++ b/qemu-seccomp.c @@ -138,21 +138,23 @@ static uint32_t qemu_seccomp_get_kill_action(void) } -static int seccomp_start(uint32_t seccomp_opts) +static int seccomp_start(uint32_t seccomp_opts, Error **errp) { - int rc = 0; + int rc = -1; unsigned int i = 0; scmp_filter_ctx ctx; uint32_t action = qemu_seccomp_get_kill_action(); ctx = seccomp_init(SCMP_ACT_ALLOW); if (ctx == NULL) { - rc = -1; + error_setg(errp, "failed to initialize seccomp context"); goto seccomp_return; } rc = seccomp_attr_set(ctx, SCMP_FLTATR_CTL_TSYNC, 1); if (rc != 0) { + error_setg_errno(errp, -rc, + "failed to set seccomp thread synchronization"); goto seccomp_return; } @@ -164,15 +166,21 @@ static int seccomp_start(uint32_t seccomp_opts) rc = seccomp_rule_add_array(ctx, action, blacklist[i].num, blacklist[i].narg, blacklist[i].arg_cmp); if (rc < 0) { + error_setg_errno(errp, -rc, + "failed to add seccomp blacklist rules"); goto seccomp_return; } } rc = seccomp_load(ctx); + if (rc < 0) { + error_setg_errno(errp, -rc, + "failed to load seccomp syscall filter in kernel"); + } seccomp_return: seccomp_release(ctx); - return rc; + return rc < 0 ? -1 : 0; } #ifdef CONFIG_SECCOMP @@ -242,9 +250,7 @@ int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) } } - if (seccomp_start(seccomp_opts) < 0) { - error_setg(errp, "failed to install seccomp syscall filter " - "in the kernel"); + if (seccomp_start(seccomp_opts, errp) < 0) { return -1; } } -- 2.20.1