perf tools: Introduce copyfile_offset() function

The copyfile_offset() function is to copy source data from given offset
to a destination file with an offset.  It'll be used to build an indexed
data file.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20150304145824.GD7519@krava.brq.redhat.com
Link: http://lkml.kernel.org/r/1431909055-21442-4-git-send-email-namhyung@kernel.org
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 6104afb..0c264bc 100644 (file)
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -145,11 +145,38 @@ out:
        return err;
 }
 
+int copyfile_offset(int ifd, loff_t off_in, int ofd, loff_t off_out, u64 size)
+{
+       void *ptr;
+       loff_t pgoff;
+
+       pgoff = off_in & ~(page_size - 1);
+       off_in -= pgoff;
+
+       ptr = mmap(NULL, off_in + size, PROT_READ, MAP_PRIVATE, ifd, pgoff);
+       if (ptr == MAP_FAILED)
+               return -1;
+
+       while (size) {
+               ssize_t ret = pwrite(ofd, ptr + off_in, size, off_out);
+               if (ret < 0 && errno == EINTR)
+                       continue;
+               if (ret <= 0)
+                       break;
+
+               size -= ret;
+               off_in += ret;
+               off_out -= ret;
+       }
+       munmap(ptr, off_in + size);
+
+       return size ? -1 : 0;
+}
+
 int copyfile_mode(const char *from, const char *to, mode_t mode)
 {
        int fromfd, tofd;
        struct stat st;
-       void *addr;
        int err = -1;
 
        if (stat(from, &st))
@@ -166,15 +193,8 @@ int copyfile_mode(const char *from, const char *to, mode_t mode)
        if (tofd < 0)
                goto out_close_from;
 
-       addr = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fromfd, 0);
-       if (addr == MAP_FAILED)
-               goto out_close_to;
-
-       if (write(tofd, addr, st.st_size) == st.st_size)
-               err = 0;
+       err = copyfile_offset(fromfd, 0, tofd, 0, st.st_size);
 
-       munmap(addr, st.st_size);
-out_close_to:
        close(tofd);
        if (err)
                unlink(to);

diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index c4fe38a..8bce58b 100644 (file)
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -252,6 +252,7 @@ int mkdir_p(char *path, mode_t mode);
 int rm_rf(char *path);
 int copyfile(const char *from, const char *to);
 int copyfile_mode(const char *from, const char *to, mode_t mode);
+int copyfile_offset(int fromfd, loff_t from_ofs, int tofd, loff_t to_ofs, u64 size);
 
 s64 perf_atoll(const char *str);
 char **argv_split(const char *str, int *argcp);