Add option to specify the directory for temporary files

README.rst

@@ -14,6 +14,7 @@ SYNOPSIS
 ::
 
    ./elbestream
+	[-d <directory>]
 	[-i <input buffer size> (default: 1048576 bytes)]
 	[-o <output buffer size> (default: 1048576 bytes)]
 	[-m <minimum output size>]
@@ -81,9 +82,13 @@ on the remainder of `stdin(3)`, with its output being sent to
 `stdout(3)` as if only *try command* was run to begin with.
 
 If, however, *try command* is considered to have failed, the input
-buffer and the rest of `stdin(3)` are written to a temporary
-file. Then, the ``%f`` argument of *fin command* is replaced with the
-name of that file and *fin command* is run.
+buffer and the rest of `stdin(3)` are written to a temporary file
+created in the directory specified by the ``-d`` argument or, if it is
+not given, the current working directory. Then, the ``%f`` argument of
+*fin command* is replaced with the name of that file and *fin command*
+is run.
+
+The ``-d`` argument can not be the empty string.
 
 IMPLEMENTATION DETAILS
 ======================

elbestream.c

@@ -66,6 +66,15 @@
 
 #define closefif(fd) if (fd >= 0) closef(fd)
 
+// from varnish-cache
+/* Safe printf into a fixed-size buffer */
+#define bprintf(buf, fmt, ...)						\
+	do {								\
+		int ibprintf;						\
+		ibprintf = snprintf(buf, sizeof buf, fmt, __VA_ARGS__); \
+		assert(ibprintf >= 0 && ibprintf < (int)sizeof buf);	\
+	} while (0)
+
 static void
 blockf(int fd)
 {
@@ -81,6 +90,7 @@ static void
 usage(char * const argv[])
 {
 	fprintf(stderr, "Usage: %s\n"
+	    "\t[-d <directory>]\n"
 	    "\t[-i <input buffer size> (default: %d bytes)]\n"
 	    "\t[-o <output buffer size> (default: %d bytes)]\n"
 	    "\t[-m <minimum output size>]\n"
@@ -362,6 +372,7 @@ main(int argc, char *argv[], char * const envp[])
 {
 	size_t ibufsz = DEF_IBUF, obufsz = DEF_OBUF, min = 0,
 	    isz = 0, tryisz, osz;
+	char *dir = ".";
 	ssize_t r = 0;
 	char *ibufr;
 	int icompl, i, opt, finc;
@@ -372,7 +383,7 @@ main(int argc, char *argv[], char * const envp[])
 	pid_t pid;
 	pthread_t thr;
 
-	while ((opt = getopt(argc, argv, "i:o:m:")) != -1) {
+	while ((opt = getopt(argc, argv, "i:o:m:d:")) != -1) {
 		ep = NULL;
 		switch (opt) {
 		case 'i':
@@ -390,6 +401,9 @@ main(int argc, char *argv[], char * const envp[])
 			if (*ep != '\0')
 				argerr(argv, "-m", ep);
 			break;
+		case 'd':
+			dir = optarg;
+			break;
 		default: /* '?' */
 			usage(argv);
 			exit(EXIT_FAILURE);
@@ -408,6 +422,10 @@ main(int argc, char *argv[], char * const envp[])
 		fprintf(stderr, "-o argument can not be zero\n");
 		exit(EXIT_FAILURE);
 	}
+	if (*dir == '\0') {
+		fprintf(stderr, "-d argument can not be empty\n");
+		exit(EXIT_FAILURE);
+	}
 
 	tryv = &argv[optind];
 
@@ -488,8 +506,14 @@ main(int argc, char *argv[], char * const envp[])
 		closefif(readfd);
 		closefif(writefd);
 
-		strcpy(fn, "elbebuf.XXXXXX");
+		bprintf(fn, "%s/elbebuf.XXXXXX", dir);
 		writefd = mkstemp(fn);
+		if (writefd < 0) {
+			fprintf(stderr, "mkstemp(%s) failed: %s (%d)\n\n",
+			    fn, strerror(errno), errno);
+			cleanup();
+			exit(EXIT_FAILURE);
+		}
 		assert(writefd >= 0);
 		if (isz > 0) {
 			r = write(writefd, ibuf, isz);

test.sh

@@ -22,3 +22,23 @@ for i in 1 4 10 29 30 31 40 ; do
 	fi
     done
 done
+
+# empty -d argument
+if ./elbestream -d '' -i $i -o $o -m 1 -- $false  ---- $cat %f ; then
+    echo >&2 FAIL
+    exit 9
+fi
+
+# -d OK
+if ! echo "${t}" | ./elbestream -d /tmp -i $i -o $o -m 1 -- $false \
+			      ---- $cat %f ; then
+    echo >&2 FAIL
+    exit 9
+fi
+
+# -d does not exist
+if echo "${t}" | ./elbestream -d xxx -i $i -o $o -m 1 -- $false \
+			      ---- $cat %f ; then
+    echo >&2 FAIL
+    exit 9
+fi