diff options
| author | Liu Pan <patteliu@gmail.com> | 2023-03-20 11:07:20 +0800 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2023-03-20 11:59:45 -0700 |
| commit | 01dc26c980b0a92d9ba94c28652b2675968727b6 (patch) | |
| tree | 7388951da70b69cc950d92679cc7667594784456 | |
| parent | bb4a6a9237293346cf1b3b7bc4ff4dfc1977a103 (diff) | |
| download | bpf-01dc26c980b0a92d9ba94c28652b2675968727b6.tar.gz | |
libbpf: Explicitly call write to append content to file
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: Liu Pan <patteliu@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230320030720.650-1-patteliu@gmail.com
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4c34fbd7b5bea6..149864ea88d133 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -9918,16 +9918,20 @@ 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); |