[PATCH] log: respect rte_openlog_stream calls before rte_eal_init

[John Ousterhout <ouster@cs.stanford.edu>]

Before this patch, rte_eal_init invoked rte_openlog_stream, cancelling
any application-specific logger and making it it impossible for an
application to capture the initial log messages generated during
rte_eal_init. With this patch, applications can capture all of the
log messages.

Signed-off-by: John Ousterhout <ouster@cs.stanford.edu>
---
 lib/librte_eal/bsdapp/eal/eal_log.c     |  3 +--
 lib/librte_eal/common/eal_common_log.c  | 13 +++++++------
 lib/librte_eal/common/include/rte_log.h |  2 +-
 lib/librte_eal/linuxapp/eal/eal_log.c   |  3 +--
 4 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/lib/librte_eal/bsdapp/eal/eal_log.c b/lib/librte_eal/bsdapp/eal/eal_log.c
index a425f7a..c5b1dee 100644
--- a/lib/librte_eal/bsdapp/eal/eal_log.c
+++ b/lib/librte_eal/bsdapp/eal/eal_log.c
@@ -52,6 +52,5 @@ rte_eal_log_init(const char *id __rte_unused, int facility __rte_unused)
 int
 rte_eal_log_early_init(void)
 {
-	rte_openlog_stream(stderr);
-	return 0;
+	return rte_eal_common_log_init(stderr);
 }
diff --git a/lib/librte_eal/common/eal_common_log.c b/lib/librte_eal/common/eal_common_log.c
index 967991a..cfc4c8b 100644
--- a/lib/librte_eal/common/eal_common_log.c
+++ b/lib/librte_eal/common/eal_common_log.c
@@ -48,11 +48,12 @@ struct rte_logs rte_logs = {
 	.file = NULL,
 };
 
+/* Stream to use for logging if rte_logs.file is NULL */
 static FILE *default_log_stream;
 
 /**
  * This global structure stores some informations about the message
- * that is currently beeing processed by one lcore
+ * that is currently being processed by one lcore
  */
 struct log_cur_msg {
 	uint32_t loglevel; /**< log level - see rte_log.h */
@@ -68,10 +69,7 @@ static RTE_DEFINE_PER_LCORE(struct log_cur_msg, log_cur_msg);
 int
 rte_openlog_stream(FILE *f)
 {
-	if (f == NULL)
-		rte_logs.file = default_log_stream;
-	else
-		rte_logs.file = f;
+	rte_logs.file = f;
 	return 0;
 }
 
@@ -127,6 +125,8 @@ rte_vlog(uint32_t level, uint32_t logtype, const char *format, va_list ap)
 {
 	int ret;
 	FILE *f = rte_logs.file;
+	if (f == NULL)
+		f = default_log_stream;
 
 	if ((level > rte_logs.level) || !(logtype & rte_logs.type))
 		return 0;
@@ -158,7 +158,8 @@ rte_log(uint32_t level, uint32_t logtype, const char *format, ...)
 }
 
 /*
- * called by environment-specific log init function
+ * Called during initialization to specify where to log messages if
+ * openlog_stream hasn't been called.
  */
 int
 rte_eal_common_log_init(FILE *default_log)
diff --git a/lib/librte_eal/common/include/rte_log.h b/lib/librte_eal/common/include/rte_log.h
index 919563c..d99baf3 100644
--- a/lib/librte_eal/common/include/rte_log.h
+++ b/lib/librte_eal/common/include/rte_log.h
@@ -54,7 +54,7 @@ extern "C" {
 struct rte_logs {
 	uint32_t type;  /**< Bitfield with enabled logs. */
 	uint32_t level; /**< Log level. */
-	FILE *file;     /**< Pointer to current FILE* for logs. */
+	FILE *file;     /**< Output file set by rte_openlog_stream, or NULL. */
 };
 
 /** Global log informations */
diff --git a/lib/librte_eal/linuxapp/eal/eal_log.c b/lib/librte_eal/linuxapp/eal/eal_log.c
index d391100..aafc41c 100644
--- a/lib/librte_eal/linuxapp/eal/eal_log.c
+++ b/lib/librte_eal/linuxapp/eal/eal_log.c
@@ -136,6 +136,5 @@ rte_eal_log_early_init(void)
 		printf("Cannot configure early_log_stream\n");
 		return -1;
 	}
-	rte_openlog_stream(early_log_stream);
-	return 0;
+	return rte_eal_common_log_init(early_log_stream);
 }
-- 
2.8.3