perf tools: Add writen function

Adding 'writen' function as a synchronous wrapper for write syscall with
following prototype:

  ssize_t writen(int fd, void *buf, size_t n)

Returns the number of bytes written on success or -1 in case of err.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Requested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1385634619-8129-5-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 6ea0b4ae956936942f566ecca6cf34b65174b8be..b1d5376b9dd9d7d4243d6b17ade37a0347d20365 100644 (file)
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -152,16 +152,14 @@ unsigned long convert_unit(unsigned long value, char *unit)
        return value;
 }
 
-/*
- * Read exactly 'n' bytes or return an error.
- */
-ssize_t readn(int fd, void *buf, size_t n)
+static ssize_t ion(bool is_read, int fd, void *buf, size_t n)
 {
        void *buf_start = buf;
        size_t left = n;
 
        while (left) {
-               ssize_t ret = read(fd, buf, left);
+               ssize_t ret = is_read ? read(fd, buf, left) :
+                                       write(fd, buf, left);
 
                if (ret <= 0)
                        return ret;
@@ -174,6 +172,22 @@ ssize_t readn(int fd, void *buf, size_t n)
        return n;
 }
 
+/*
+ * Read exactly 'n' bytes or return an error.
+ */
+ssize_t readn(int fd, void *buf, size_t n)
+{
+       return ion(true, fd, buf, n);
+}
+
+/*
+ * Write exactly 'n' bytes or return an error.
+ */
+ssize_t writen(int fd, void *buf, size_t n)
+{
+       return ion(false, fd, buf, n);
+}
+
 size_t hex_width(u64 v)
 {
        size_t n = 1;

diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 9f6b928f6b2b17a4084b03a08e0eddd72829aea1..ce0f73d4d91f78965647690fab6e2a07fe16ac26 100644 (file)
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -254,6 +254,7 @@ int strtailcmp(const char *s1, const char *s2);
 char *strxfrchar(char *s, char from, char to);
 unsigned long convert_unit(unsigned long value, char *unit);
 ssize_t readn(int fd, void *buf, size_t n);
+ssize_t writen(int fd, void *buf, size_t n);
 
 struct perf_event_attr;