Write data to fd by calling "vdprintf", in most implementations
of the standard library, the data is finally written by the writev syscall.
But "uprobe_events/kprobe_events" does not allow segmented writes,
so switch the "append_to_file" function to explicit write() call.
Signed-off-by: liupan <patteliu@xxxxxxxxx>
---
tools/lib/bpf/libbpf.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index a557718401e4..7d865ca95c81 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9912,16 +9912,20 @@ static int append_to_file(const char *file, const char *fmt, ...)
{
int fd, n, err = 0;
va_list ap;
+ char buf[1024];
+
+ va_start(ap, fmt);
+ n = vsnprintf(buf, sizeof(buf), fmt, ap);
+ va_end(ap);
+
+ if (n < 0 || n >= sizeof(buf))
+ return -EINVAL;
fd = open(file, O_WRONLY | O_APPEND | O_CLOEXEC, 0);
if (fd < 0)
return -errno;
- va_start(ap, fmt);
- n = vdprintf(fd, fmt, ap);
- va_end(ap);
-
- if (n < 0)
+ if (write(fd, buf, n) < 0)
err = -errno;
close(fd);
--
2.20.1
