Prior to this change a single line of logging performing several fprintf.
This change gets all the data for a line to be logged in a single
fprintf call. This reduced the chances of writes from another thread
getting intermixed with a log line.
It also makes it easier to change where logs are output to in the future.
---
libusb/core.c | 41 ++++++++++++++++++++++++++++++++++-------
libusb/libusbi.h | 10 ++++++++++
2 files changed, 44 insertions(+), 7 deletions(-)
diff --git a/libusb/core.c b/libusb/core.c
index bc44415..53f716f 100644
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -2017,12 +2017,19 @@ int usbi_gettimeofday(struct timeval *tp, void *tzp)
}
#endif
+static void usbi_log_str(struct libusb_context *ctx, const char * str)
+{
+ UNUSED(ctx);
+ fprintf(stderr, str);
+}
+
void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
const char *function, const char *format, va_list args)
{
const char *prefix = "";
+ char buf[USBI_MAX_LOG_LEN];
struct timeval now;
- int global_debug;
+ int global_debug, header_len, text_len;
static int has_debug_header_been_displayed = 0;
#ifdef ENABLE_DEBUG_LOGGING
@@ -2068,8 +2075,8 @@ void usbi_log_v(struct libusb_context *ctx, enum
libusb_log_level level,
usbi_gettimeofday(&now, NULL);
if ((global_debug) && (!has_debug_header_been_displayed)) {
has_debug_header_been_displayed = 1;
- fprintf(stderr, "[timestamp] [threadID] facility level
[function call] <message>\n");
- fprintf(stderr,
"--------------------------------------------------------------------------------\n");
+ usbi_log_str(ctx, "[timestamp] [threadID] facility level
[function call] <message>\n");
+ usbi_log_str(ctx,
"--------------------------------------------------------------------------------\n");
}
if (now.tv_usec < timestamp_origin.tv_usec) {
now.tv_sec--;
@@ -2099,15 +2106,35 @@ void usbi_log_v(struct libusb_context *ctx, enum
libusb_log_level level,
}
if (global_debug) {
- fprintf(stderr, "[%2d.%06d] [%08x] libusbx: %s [%s] ",
+ header_len = snprintf(buf, sizeof(buf),
+ "[%2d.%06d] [%08x] libusbx: %s [%s] ",
(int)now.tv_sec, (int)now.tv_usec, usbi_get_tid(),
prefix, function);
} else {
- fprintf(stderr, "libusbx: %s [%s] ", prefix, function);
+ header_len = snprintf(buf, sizeof(buf),
+ "libusbx: %s [%s] ", prefix, function);
}
- vfprintf(stderr, format, args);
+ if (header_len < 0 || header_len >= sizeof(buf)) {
+ /* Somehow snprintf failed to write to the buffer,
+ * remove the header so something useful is output. */
+ header_len = 0;
+ }
+ /* Make sure buffer is NUL terminated */
+ buf[header_len] = '\0';
+ text_len = vsnprintf(buf + header_len, sizeof(buf) - header_len,
+ format, args);
+ if (text_len < 0 || text_len + header_len >= sizeof(buf)) {
+ /* Truncated log output. On some platforms a -1 return value
means
+ * that the output was truncated. */
+ text_len = sizeof(buf) - header_len;
+ }
+ if (header_len + text_len + sizeof(USBI_LOG_LINE_END) >= sizeof(buf)) {
+ /* Need to truncate the text slightly to fit on the terminator.
*/
+ text_len -= (header_len + text_len + sizeof(USBI_LOG_LINE_END))
- sizeof(buf);
+ }
+ strcpy(buf + header_len + text_len, USBI_LOG_LINE_END);
- fprintf(stderr, "\n");
+ usbi_log_str(ctx, buf);
#endif
}
diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index c9b402d..7293901 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -56,6 +56,11 @@
#define USBI_CAP_HAS_HID_ACCESS
0x00010000
#define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000
+/* Maximum number of bytes in a log line */
+#define USBI_MAX_LOG_LEN 256
+/* Terminator for log lines */
+#define USBI_LOG_LINE_END "\n"
+
/* The following is used to silence warnings for unused variables */
#define UNUSED(var) do { (void)(var); } while(0)
@@ -447,6 +452,11 @@ int usbi_gettimeofday(struct timeval *tp, void *tzp);
#endif
#endif
+#if (defined(OS_WINDOWS) || defined(OS_WINCE)) && !defined(__GCC__)
+#define snprintf _snprintf
+#define vsnprintf _vsnprintf
+#endif
+
struct usbi_pollfd {
/* must come first */
struct libusb_pollfd pollfd;
--
1.7.9.5
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