mkstemp() and mkstemp64() wrappers: Fixed filling of "template" argument

2 files changed, 60 insertions, 3 deletions

diff --git a/preload/interface.master b/preload/interface.master
index 3ff03e9..7f6511a 100644
--- a/preload/interface.master
+++ b/preload/interface.master
@@ -294,8 +294,6 @@ WRAP: int mknod(const char *pathname, mode_t mode, dev_t dev) : \
 	map(pathname) fail_if_readonly(pathname,-1,EROFS)
 WRAP: int mknodat(int dirfd, const char *pathname, mode_t mode, dev_t dev) : \
 	map_at(dirfd,pathname) fail_if_readonly(pathname,-1,EROFS)
-WRAP: int mkstemp(char *template) : map(template) fail_if_readonly(template,-1,EROFS)
-WRAP: int mkstemp64(char *template) : map(template) fail_if_readonly(template,-1,EROFS)
 WRAP: int nftw(const char *dir, int (*fn)(const char *file, const struct stat *sb, int flag, struct FTW *s), int nopenfd, int flags) : map(dir)
 #ifdef HAVE_NFTW64
 WRAP: int nftw64(const char *dir, int (*fn)(const char *file, const struct stat64 *sb, int flag, struct FTW *s), int nopenfd, int flags) : map(dir)
@@ -405,7 +403,6 @@ WRAP: int utime(const char *filename, const struct utimbuf *buf) : \
 	map(filename) fail_if_readonly(filename,-1,EROFS)
 WRAP: int utimes(const char *filename, const struct timeval tv[2]) : \
 	map(filename) fail_if_readonly(filename,-1,EROFS)
-
 --
 -- 7. Socket API
 --    ----------
@@ -413,3 +410,19 @@ WRAP: int utimes(const char *filename, const struct timeval tv[2]) : \
 
 GATE: int bind(int sockfd, const struct sockaddr *my_addr, socklen_t addrlen)
 GATE: int connect(int sockfd, const struct sockaddr *serv_addr, socklen_t addrlen)
+
+--
+-- 8. Wrappers, where argument buffer is modified
+--    -------------------------------------------
+--
+
+-- mkstemp() returns name of the generated filename in "template"
+WRAP: int mkstemp(char *template) : \
+	map(template) \
+	postprocess(template) \
+	fail_if_readonly(template,-1,EROFS)
+WRAP: int mkstemp64(char *template) : \
+	map(template) \
+	postprocess(template) \
+	fail_if_readonly(template,-1,EROFS)
+
diff --git a/preload/libsb2.c b/preload/libsb2.c
index d5c4a17..2b1bc8e 100644
--- a/preload/libsb2.c
+++ b/preload/libsb2.c
@@ -819,3 +819,47 @@ int freopen_errno(FILE *stream)
 	return (EROFS);
 }
 
+/* mkstemp() modifies "template". This locates the part which should be 
+ * modified, and copies the modification back from mapped buffer (which
+ * was modified by the real function) to callers buffer.
+*/
+void mkstemp_postprocess_template(char *mapped__template, char *template)
+{
+	char *first_X = strchr(template, 'X');
+	char *generated_id;
+	int mapped_len = strlen(mapped__template);
+
+	if (!first_X) {
+		SB_LOG(SB_LOGLEVEL_WARNING,
+			"%s: orig.template did not contain X (%s,%s), won't "
+			"do anything", __func__, template, mapped__template);
+		return;
+	}
+	
+	/* by definition, the template should have six trailing 'X's: */
+	if (strcmp(first_X, "XXXXXX")) {
+		SB_LOG(SB_LOGLEVEL_WARNING,
+			"%s: orig.template did not end with XXXXXX (%s,%s), won't "
+			"do anything", __func__, template, mapped__template);
+		return;
+	}
+
+	if(mapped_len < 6) {
+		SB_LOG(SB_LOGLEVEL_WARNING,
+			"%s: mapped.template is too short (%s,%s), won't "
+			"do anything", __func__, template, mapped__template);
+		return;
+	}
+
+	/* now copy last six characters from mapping result to caller's buffer*/
+	strncpy(first_X, mapped__template + (mapped_len-6), 6);
+
+	SB_LOG(SB_LOGLEVEL_DEBUG,
+		"%s: template set to (%s)", __func__, template);
+}
+
+void mkstemp64_postprocess_template(char *mapped__template, char *template)
+{
+	mkstemp_postprocess_template(mapped__template, template);
+}
+