On 11/12/2015 12:19 PM, Daniel P. Berrange wrote:
> Introduce a qemuDomainLogContext object to encapsulate
> handling of I/O to/from the domain log file. This will
> hide details of the log file implementation from the
> rest of the driver, making it easier to introduce
> support for virtlogd later.
>
> Signed-off-by: Daniel P. Berrange <berrange@xxxxxxxxxx>
> ---
> src/qemu/qemu_domain.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++
> src/qemu/qemu_domain.h | 22 ++++++
> 2 files changed, 200 insertions(+)
>
[...]
>
> +qemuDomainLogContextPtr qemuDomainLogContextNew(virQEMUDriverPtr driver,
> + virDomainObjPtr vm,
> + qemuDomainLogContextMode mode)
> +{
> + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
> + qemuDomainLogContextPtr ctxt = NULL;
> + char *logfile = NULL;
> +
> + if (VIR_ALLOC(ctxt) < 0)
> + goto error;
> +
> + ctxt->writefd = -1;
> + ctxt->readfd = -1;
> + virAtomicIntSet(&ctxt->refs, 1);
> +
> + if (virAsprintf(&logfile, "%s/%s.log", cfg->logDir, vm->def->name) < 0)
> + goto error;
> +
> + if ((ctxt->writefd = open(logfile, O_WRONLY | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR)) < 0) {
> + virReportSystemError(errno, _("failed to create logfile %s"),
> + logfile);
> + goto error;
> + }
> + if (virSetCloseExec(ctxt->writefd) < 0) {
> + virReportSystemError(errno, _("failed to set close-on-exec flag on %s"),
> + logfile);
> + goto error;
> + }
> +
> + /* For unprivileged startup we must truncate the file since
> + * we can't rely on logrotate. We don't use O_TRUNC since
> + * it is better for SELinux policy if we truncate afterwards */
> + if (mode == QEMU_DOMAIN_LOG_CONTEXT_MODE_START &&
> + !virQEMUDriverIsPrivileged(driver) &&
> + ftruncate(ctxt->writefd, 0) < 0) {
> + virReportSystemError(errno, _("failed to truncate %s"),
> + logfile);
> + goto error;
> + }
> +
> + if (mode == QEMU_DOMAIN_LOG_CONTEXT_MODE_START) {
> + if ((ctxt->readfd = open(logfile, O_RDONLY, S_IRUSR | S_IWUSR)) < 0) {
> + virReportSystemError(errno, _("failed to open logfile %s"),
> + logfile);
> + goto error;
> + }
> + if (virSetCloseExec(ctxt->readfd) < 0) {
> + virReportSystemError(errno, _("failed to set close-on-exec flag on %s"),
> + logfile);
> + goto error;
> + }
> + }
should 'pos' be initialized here? Otherwise the first ContextRead would
use ctxt->pos == 0
> +
> + virObjectUnref(cfg);
> + return ctxt;
> +
> + error:
> + virObjectUnref(cfg);
> + qemuDomainLogContextFree(ctxt);
> + return NULL;
> +}
> +
> +
[...]
> +
> +ssize_t qemuDomainLogContextRead(qemuDomainLogContextPtr ctxt,
> + char **msg)
> +{
> + char *buf;
> + size_t buflen = 1024 * 128;
> + ssize_t got;
> +
> + /* Best effort jump to start of messages */
> + ignore_value(lseek(ctxt->readfd, ctxt->pos, SEEK_SET));
> +
> + if (VIR_ALLOC_N(buf, buflen) < 0)
> + return -1;
> +
> + got = saferead(ctxt->readfd, buf, buflen - 1);
> + if (got < 0) {
> + virReportSystemError(errno, "%s",
> + _("Unable to read from log file"));
Coverity points out buf is leaked.
> + return -1;
> + }
> +
> + buf[got] = '\0';
> +
> + ignore_value(VIR_REALLOC_N_QUIET(buf, got + 1));
> + *msg = buf;
> +
> + return got;
> +}
> +
> +
ACK with the obvious adjustment - not quite sure how to handle 'pos'
(yet) - although perhaps future patches will allow the light to shine.
John
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