From 251c3931fedc9275bd57bc75c2153674a540bbce Mon Sep 17 00:00:00 2001

From: "Dmitry V. Levin" <ldv@altlinux.org>

Date: Thu, 18 May 2017 17:19:25 +0300

Subject: [PATCH] quotaops: check return code of ftruncate and lseek calls

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ftruncate and lseek syscalls may fail for different reasons,

do not ignore these errors.  Create a helper function and use it

instead of duplicating error checks and diagnostic messages.

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>

Signed-off-by: Jan Kara <jack@suse.cz>

Signed-off-by: Petr Písař <ppisar@redhat.com>

---

 quotaops.c | 53 +++++++++++++++++++++++++++++------------------------

 1 file changed, 29 insertions(+), 24 deletions(-)

diff --git a/quotaops.c b/quotaops.c

index 6f245b7..81d7be0 100644

--- a/quotaops.c

+++ b/quotaops.c

@@ -252,6 +252,28 @@ int editprivs(char *tmpfile)

 }

 /*

+ * Duplicate a file descriptor, resetting the file offset.

+ * If it's a write descriptor, also truncate the file.

+ */

+static FILE *dup_file(int fd, int is_write)

+{

+	FILE *fp;

+

+	if (is_write && ftruncate(fd, 0))

+		die(1, _("Cannot truncate a file: %s\n"), strerror(errno));

+	if (lseek(fd, 0, SEEK_SET))

+		die(1, _("Cannot reset a file offset: %s\n"), strerror(errno));

+	if ((fd = dup(fd)) < 0)

+		die(1, _("Cannot duplicate a file descriptor: %s\n"), strerror(errno));

+	if (!(fp = fdopen(fd, is_write ? "w" : "r")))

+		die(1, is_write ? _("Cannot open a stream to write to: %s\n")

+				: _("Cannot open a stream to read from: %s\n"),

+		    strerror(errno));

+

+	return fp;

+}

+

+/*

  * Convert a dquot list to an ASCII file.

  */

 int writeprivs(struct dquot *qlist, int outfd, char *name, int quotatype)

@@ -259,10 +281,7 @@ int writeprivs(struct dquot *qlist, int outfd, char *name, int quotatype)

 	struct dquot *q;

 	FILE *fd;

-	ftruncate(outfd, 0);

-	lseek(outfd, 0, SEEK_SET);

-	if (!(fd = fdopen(dup(outfd), "w")))

-		die(1, _("Cannot duplicate descriptor of file to write to: %s\n"), strerror(errno));

+	fd = dup_file(outfd, 1);

 	fprintf(fd, _("Disk quotas for %s %s (%cid %d):\n"),

 		_(type2name(quotatype)), name, *type2name(quotatype), qlist->dq_id);

@@ -323,9 +342,7 @@ int readprivs(struct dquot *qlist, int infd)

 	char inodesstring[BUFSIZ], isoftstring[BUFSIZ], ihardstring[BUFSIZ];

 	const char *error;

-	lseek(infd, 0, SEEK_SET);

-	if (!(fd = fdopen(dup(infd), "r")))

-		die(1, _("Cannot duplicate descriptor of temp file: %s\n"), strerror(errno));

+	fd = dup_file(infd, 0);

 	/*

 	 * Discard title lines, then read lines to process.

@@ -435,10 +452,7 @@ int writeindividualtimes(struct dquot *qlist, int outfd, char *name, int quotaty

 	time_t now;

 	char btimestr[MAXTIMELEN], itimestr[MAXTIMELEN];

-	ftruncate(outfd, 0);

-	lseek(outfd, 0, SEEK_SET);

-	if (!(fd = fdopen(dup(outfd), "w")))

-		die(1, _("Cannot duplicate descriptor of file to write to: %s\n"), strerror(errno));

+	fd = dup_file(outfd, 1);

 	fprintf(fd, _("Times to enforce softlimit for %s %s (%cid %d):\n"),

 		_(type2name(quotatype)), name, *type2name(quotatype), qlist->dq_id);

@@ -478,9 +492,7 @@ int readindividualtimes(struct dquot *qlist, int infd)

 	char iunits[BUFSIZ], bunits[BUFSIZ];

 	time_t now, bseconds, iseconds;

-	lseek(infd, 0, SEEK_SET);

-	if (!(fd = fdopen(dup(infd), "r")))

-		die(1, _("Cannot duplicate descriptor of temp file: %s\n"), strerror(errno));

+	fd = dup_file(infd, 0);

 	/*

 	 * Discard title lines, then read lines to process.

@@ -543,10 +555,7 @@ int writetimes(struct quota_handle **handles, int outfd)

 	if (!handles[0])

 		return 0;

-	ftruncate(outfd, 0);

-	lseek(outfd, 0, SEEK_SET);

-	if ((fd = fdopen(dup(outfd), "w")) == NULL)

-		die(1, _("Cannot duplicate descriptor of file to edit: %s\n"), strerror(errno));

+	fd = dup_file(outfd, 1);

 	fprintf(fd, _("Grace period before enforcing soft limits for %ss:\n"),

 		_(type2name(handles[0]->qh_type)));

@@ -575,12 +584,8 @@ int readtimes(struct quota_handle **handles, int infd)

 	if (!handles[0])

 		return 0;

-	lseek(infd, 0, SEEK_SET);

-	if (!(fd = fdopen(dup(infd), "r"))) {

-		errstr(_("Cannot reopen temp file: %s\n"),

-			strerror(errno));

-		return -1;

-	}

+

+	fd = dup_file(infd, 0);

 	/* Set all grace times to default values */

 	for (i = 0; handles[i]; i++) {

-- 

2.9.4