From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf0-x242.google.com ([2a00:1450:4010:c07::242]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bPABY-0003MP-49 for linux-mtd@lists.infradead.org; Mon, 18 Jul 2016 15:10:21 +0000 Received: by mail-lf0-x242.google.com with SMTP id l89so11467762lfi.2 for ; Mon, 18 Jul 2016 08:09:58 -0700 (PDT) From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= To: Brian Norris , linux-mtd@lists.infradead.org Cc: Richard Weinberger , =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= Subject: [PATCH V2] nanddump: check write function result for errors Date: Mon, 18 Jul 2016 17:09:45 +0200 Message-Id: <1468854585-9705-1-git-send-email-zajec5@gmail.com> In-Reply-To: <1468833493-28311-1-git-send-email-zajec5@gmail.com> References: <1468833493-28311-1-git-send-email-zajec5@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 --- 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