[PATCH V2] nanddump: check write function result for errors
Rafał Miłecki
zajec5 at gmail.com
Mon Jul 18 08:09:45 PDT 2016
Errors may happen, it's e.g. easy on embedded devices to run out of space
when dumping big partitions. This patch adds a helper function for
writing. It deals with partial writes and just returns 0 on success or
error number.
The old code didn't check for errors at all which could result in
incomplete dumps without exiting with an error.
Signed-off-by: Rafał Miłecki <zajec5 at gmail.com>
---
V2: Use sys_errmsg as in patch pointed by Richard.
Call ofd_write also when using pretty output.
---
nand-utils/nanddump.c | 48 ++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 42 insertions(+), 6 deletions(-)
diff --git a/nand-utils/nanddump.c b/nand-utils/nanddump.c
index 4ee7ed4..db1e1e5 100644
--- a/nand-utils/nanddump.c
+++ b/nand-utils/nanddump.c
@@ -293,6 +293,31 @@ nil:
linebuf[lx++] = '\0';
}
+/**
+ * ofd_write - writes whole buffer to the file associated with a descriptor
+ *
+ * On failure an error (negative number) is returned. Otherwise 0 is returned.
+ */
+static int ofd_write(int ofd, const void *buf, size_t nbyte)
+{
+ const unsigned char *data = buf;
+ ssize_t bytes;
+
+ while (nbyte) {
+ bytes = write(ofd, data, nbyte);
+ if (bytes < 0) {
+ int err = -errno;
+
+ sys_errmsg("Unable to write to output");
+
+ return err;
+ }
+ data += bytes;
+ nbyte -= bytes;
+ }
+
+ return 0;
+}
/*
* Main program
@@ -309,6 +334,7 @@ int main(int argc, char * const argv[])
bool eccstats = false;
unsigned char *readbuf = NULL, *oobbuf = NULL;
libmtd_t mtd_desc;
+ int err;
process_options(argc, argv);
@@ -443,10 +469,15 @@ int main(int argc, char * const argv[])
for (i = 0; i < bs; i += PRETTY_ROW_SIZE) {
pretty_dump_to_buffer(readbuf + i, PRETTY_ROW_SIZE,
pretty_buf, PRETTY_BUF_LEN, true, canonical, ofs + i);
- write(ofd, pretty_buf, strlen(pretty_buf));
+ err = ofd_write(ofd, pretty_buf, strlen(pretty_buf));
+ if (err)
+ goto closeall;
}
- } else
- write(ofd, readbuf, bs);
+ } else {
+ err = ofd_write(ofd, readbuf, bs);
+ if (err)
+ goto closeall;
+ }
if (omitoob)
continue;
@@ -466,10 +497,15 @@ int main(int argc, char * const argv[])
for (i = 0; i < mtd.oob_size; i += PRETTY_ROW_SIZE) {
pretty_dump_to_buffer(oobbuf + i, mtd.oob_size - i,
pretty_buf, PRETTY_BUF_LEN, false, canonical, 0);
- write(ofd, pretty_buf, strlen(pretty_buf));
+ err = ofd_write(ofd, pretty_buf, strlen(pretty_buf));
+ if (err)
+ goto closeall;
}
- } else
- write(ofd, oobbuf, mtd.oob_size);
+ } else {
+ err = ofd_write(ofd, oobbuf, mtd.oob_size);
+ if (err)
+ goto closeall;
+ }
}
/* Close the output file and MTD device, free memory */
--
1.8.4.5
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