[PATCH 03/38] perf tools: Introduce copyfile_offset() function

From: Namhyung Kim
Date: Mon Mar 02 2015 - 22:21:52 EST


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@xxxxxxxxxx>
---
tools/perf/util/util.c | 38 +++++++++++++++++++++++++++++---------
tools/perf/util/util.h | 1 +
2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 6104afb7e1ef..0c264bc685ac 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -145,11 +145,38 @@ static int slow_copyfile(const char *from, const char *to, mode_t mode)
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 ba31979fcdcc..91535bceb1bf 100644
--- 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);
--
2.2.2

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