stdio: implement tmpnam() and tempnam() functions

include/stdio.h

@@ -47,6 +47,7 @@ extern "C" {
 #define FOPEN_MAX 16
 #define L_ctermid 11 /* Fit at least /dev/pts/XX */
 #define L_tmpnam  16
+#define P_tmpdir  "/tmp"
 #define TMP_MAX   32767
 
 typedef off_t fpos_t;
@@ -194,6 +195,10 @@ extern FILE *tmpfile(void);
 extern char *tmpnam(char *str);
 
 
+/* Generates a pathname that may be used for a temporary file. */
+extern char *tempnam(const char *dir, const char *pfx);
+
+
 /* Sends formatted output to a stream. */
 extern int fprintf(FILE *stream, const char *format, ...)
 	__attribute__((format(printf, 2, 3)));

posix/stubs.c

@@ -199,10 +199,6 @@ char *gets(char *str)
 	return NULL;
 }
 
-char *tmpnam(char *str)
-{
-	return NULL;
-}
 
 int wctomb(char *str, wchar_t wchar)
 {

stdlib/mktemp.c

@@ -16,7 +16,9 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #include <sys/msg.h>
@@ -119,3 +121,61 @@ char *mkdtemp(char *templt)
 
 	return templt;
 }
+
+
+char *tmpnam(char *str)
+{
+	static char template[L_tmpnam];
+	int err;
+
+	if (str == NULL) {
+		str = template;
+	}
+
+	do {
+		(void)strcpy(str, "/tmp/fileXXXXXX");
+		err = __mktemp(str, 0);
+	} while ((err < 0) && errno == EEXIST);
+
+	return (err < 0) ? NULL : str;
+}
+
+
+char *tempnam(const char *dir, const char *pfx)
+{
+	struct stat statbuf;
+	int err, dirlen, pfxlen, sep = 0;
+
+	if (dir == NULL || stat(dir, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) {
+		if (access(P_tmpdir, W_OK | X_OK) < 0) {
+			dir = "/";
+		}
+		else {
+			dir = P_tmpdir;
+		}
+	}
+
+	dirlen = strlen(dir);
+	pfxlen = (pfx == NULL) ? 4 /* strlen("file") */ : strlen(pfx);
+	if (dir[dirlen - 1] != '/') {
+		sep = 1;
+	}
+
+	char *name = malloc(dirlen + sep + pfxlen + 6 /* "XXXXXX" */ + 1);
+	if (name == NULL) {
+		errno = ENOMEM;
+		return NULL;
+	}
+
+	do {
+		sprintf(name, "%s%s%sXXXXXX", dir, (sep != 0) ? "/" : "", (pfx == NULL) ? "file" : pfx);
+		err = __mktemp(name, 0);
+	} while ((err < 0) && errno == EEXIST);
+
+	if (err < 0) {
+		free(name);
+		name = NULL;
+	}
+
+	return name;
+}