perf header: Add a buffer to struct feat_fd

Extend struct feat_fd to use a temporal buffer in pipe-mode, instead of
perf.data's file descriptor.

The header features build_id and aux_trace already have logic to print
in file-mode that heavily rely on lseek the file. For now, leave such
features inactive in pipe-mode and print a warning if their functions
are called in pipe-mode.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Acked-by: David Ahern <dsahern@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170718042549.145161-13-davidcc@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index d5359e3384e33eb28159fc3c11245d45edf2a803..5e6d4d29a7a357d62118acc17a3928f10478982c 100644 (file)
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -62,6 +62,7 @@ struct perf_file_attr {
 struct feat_fd {
        struct perf_header      *ph;
        int                     fd;
+       void                    *buf;   /* Either buf != NULL or fd >= 0 */
        ssize_t                 offset;
        size_t                  size;
 };
@@ -81,18 +82,51 @@ bool perf_header__has_feat(const struct perf_header *header, int feat)
        return test_bit(feat, header->adds_features);
 }
 
-/* Return: 0 if succeded, -ERR if failed. */
-int do_write(struct feat_fd *ff, const void *buf, size_t size)
+static int __do_write_fd(struct feat_fd *ff, const void *buf, size_t size)
 {
-       ssize_t ret;
+       ssize_t ret = writen(ff->fd, buf, size);
 
-       ret  = writen(ff->fd, buf, size);
        if (ret != (ssize_t)size)
                return ret < 0 ? (int)ret : -1;
+       return 0;
+}
+
+static int __do_write_buf(struct feat_fd *ff,  const void *buf, size_t size)
+{
+       /* struct perf_event_header::size is u16 */
+       const size_t max_size = 0xffff - sizeof(struct perf_event_header);
+       size_t new_size = ff->size;
+       void *addr;
+
+       if (size + ff->offset > max_size)
+               return -E2BIG;
+
+       while (size > (new_size - ff->offset))
+               new_size <<= 1;
+       new_size = min(max_size, new_size);
+
+       if (ff->size < new_size) {
+               addr = realloc(ff->buf, new_size);
+               if (!addr)
+                       return -ENOMEM;
+               ff->buf = addr;
+               ff->size = new_size;
+       }
+
+       memcpy(ff->buf + ff->offset, buf, size);
+       ff->offset += size;
 
        return 0;
 }
 
+/* Return: 0 if succeded, -ERR if failed. */
+int do_write(struct feat_fd *ff, const void *buf, size_t size)
+{
+       if (!ff->buf)
+               return __do_write_fd(ff, buf, size);
+       return __do_write_buf(ff, buf, size);
+}
+
 /* Return: 0 if succeded, -ERR if failed. */
 int write_padded(struct feat_fd *ff, const void *bf,
                 size_t count, size_t count_aligned)
@@ -126,7 +160,7 @@ static int do_write_string(struct feat_fd *ff, const char *str)
        return write_padded(ff, str, olen, len);
 }
 
-static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
+static int __do_read_fd(struct feat_fd *ff, void *addr, ssize_t size)
 {
        ssize_t ret = readn(ff->fd, addr, size);
 
@@ -135,6 +169,25 @@ static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
        return 0;
 }
 
+static int __do_read_buf(struct feat_fd *ff, void *addr, ssize_t size)
+{
+       if (size > (ssize_t)ff->size - ff->offset)
+               return -1;
+
+       memcpy(addr, ff->buf + ff->offset, size);
+       ff->offset += size;
+
+       return 0;
+
+}
+
+static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
+{
+       if (!ff->buf)
+               return __do_read_fd(ff, addr, size);
+       return __do_read_buf(ff, addr, size);
+}
+
 static int do_read_u32(struct feat_fd *ff, u32 *addr)
 {
        int ret;
@@ -189,6 +242,9 @@ static char *do_read_string(struct feat_fd *ff)
 static int write_tracing_data(struct feat_fd *ff,
                              struct perf_evlist *evlist)
 {
+       if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+               return -1;
+
        return read_tracing_data(ff->fd, &evlist->entries);
 }
 
@@ -203,6 +259,9 @@ static int write_build_id(struct feat_fd *ff,
        if (!perf_session__read_build_ids(session, true))
                return -1;
 
+       if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+               return -1;
+
        err = perf_session__write_buildid_table(session, ff);
        if (err < 0) {
                pr_debug("failed to write buildid table\n");
@@ -912,6 +971,9 @@ static int write_auxtrace(struct feat_fd *ff,
        struct perf_session *session;
        int err;
 
+       if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+               return -1;
+
        session = container_of(ff->ph, struct perf_session, header);
 
        err = auxtrace_index__write(ff->fd, &session->auxtrace_index);
@@ -2197,6 +2259,9 @@ static int do_write_feat(struct feat_fd *ff, int type,
                if (!feat_ops[type].write)
                        return -1;
 
+               if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+                       return -1;
+
                (*p)->offset = lseek(ff->fd, 0, SEEK_CUR);
 
                err = feat_ops[type].write(ff, evlist);