From: schwarze@mandoc.bsd.lv
To: source@mandoc.bsd.lv
Subject: mandoc: After opening a file with gzdopen(3), we have to call gzclose(3)
Date: Fri, 23 Feb 2018 16:35:49 -0500 (EST) [thread overview]
Message-ID: <84f4c559624fd54b@fantadrom.bsd.lv> (raw)
Log Message:
-----------
After opening a file with gzdopen(3), we have to call gzclose(3) or
we leak memory internally used by zlib to keep compression state.
Bug reported by Wolfgang Mueller <vehk at vehk dot de> who also
provided an incomplete patch, part of which i'm using in this commit.
Modified Files:
--------------
mandoc:
read.c
Revision Data
-------------
Index: read.c
===================================================================
RCS file: /home/cvs/mandoc/mandoc/read.c,v
retrieving revision 1.193
retrieving revision 1.194
diff -Lread.c -Lread.c -u -p -r1.193 -r1.194
--- read.c
+++ read.c
@@ -556,6 +556,7 @@ read_whole_file(struct mparse *curp, con
gzFile gz;
size_t off;
ssize_t ssz;
+ int gzerrnum, retval;
if (fstat(fd, &st) == -1) {
mandoc_vmsg(MANDOCERR_FILE, curp, 0, 0,
@@ -583,9 +584,22 @@ read_whole_file(struct mparse *curp, con
}
if (curp->gzip) {
+ /*
+ * Duplicating the file descriptor is required
+ * because we will have to call gzclose(3)
+ * to free memory used internally by zlib,
+ * but that will also close the file descriptor,
+ * which this function must not do.
+ */
+ if ((fd = dup(fd)) == -1) {
+ mandoc_vmsg(MANDOCERR_FILE, curp, 0, 0,
+ "dup: %s", strerror(errno));
+ return 0;
+ }
if ((gz = gzdopen(fd, "rb")) == NULL) {
mandoc_vmsg(MANDOCERR_FILE, curp, 0, 0,
"gzdopen: %s", strerror(errno));
+ close(fd);
return 0;
}
} else
@@ -598,6 +612,7 @@ read_whole_file(struct mparse *curp, con
*with_mmap = 0;
off = 0;
+ retval = 0;
fb->sz = 0;
fb->buf = NULL;
for (;;) {
@@ -614,19 +629,29 @@ read_whole_file(struct mparse *curp, con
read(fd, fb->buf + (int)off, fb->sz - off);
if (ssz == 0) {
fb->sz = off;
- return 1;
+ retval = 1;
+ break;
}
if (ssz == -1) {
- mandoc_vmsg(MANDOCERR_FILE, curp, 0, 0,
- "read: %s", strerror(errno));
+ if (curp->gzip)
+ (void)gzerror(gz, &gzerrnum);
+ mandoc_vmsg(MANDOCERR_FILE, curp, 0, 0, "read: %s",
+ curp->gzip && gzerrnum != Z_ERRNO ?
+ zError(gzerrnum) : strerror(errno));
break;
}
off += (size_t)ssz;
}
- free(fb->buf);
- fb->buf = NULL;
- return 0;
+ if (curp->gzip && (gzerrnum = gzclose(gz)) != Z_OK)
+ mandoc_vmsg(MANDOCERR_FILE, curp, 0, 0, "gzclose: %s",
+ gzerrnum == Z_ERRNO ? strerror(errno) :
+ zError(gzerrnum));
+ if (retval == 0) {
+ free(fb->buf);
+ fb->buf = NULL;
+ }
+ return retval;
}
static void
--
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