Add option to overwrite existing output file

init.c

@@ -257,6 +257,7 @@ static void print_help()
 	  "                                additional -a adds backup trackers\n"
 	  "-c, --comment=<comment>       : add a comment to the metainfo\n"
 	  "-d, --no-date                 : don't write the creation date\n"
+	  "-f, --force                   : overwrite output file if it exists\n"
 	  "-h, --help                    : show this help screen\n"
 	  "-l, --piece-length=<n>        : set the piece length to 2^n bytes,\n"
 	  "                                default is 18, that is 2^18 = 256kb\n"
@@ -278,6 +279,7 @@ static void print_help()
 	  "                    additional -a adds backup trackers\n"
 	  "-c <comment>      : add a comment to the metainfo\n"
 	  "-d                : don't write the creation date\n"
+	  "-f                : overwrite output file if it exists\n"
 	  "-h                : show this help screen\n"
 	  "-l <n>            : set the piece length to 2^n bytes,\n"
 	  "                    default is 18, that is 2^18 = 256kb\n"
@@ -413,6 +415,7 @@ EXPORT void init(struct metafile *m, int argc, char *argv[])
 		{"announce", 1, NULL, 'a'},
 		{"comment", 1, NULL, 'c'},
 		{"no-date", 0, NULL, 'd'},
+		{"force", 0, NULL, 'f'},
 		{"help", 0, NULL, 'h'},
 		{"piece-length", 1, NULL, 'l'},
 		{"name", 1, NULL, 'n'},
@@ -439,9 +442,9 @@ EXPORT void init(struct metafile *m, int argc, char *argv[])
 
 	/* now parse the command line options given */
 #ifdef USE_PTHREADS
-#define OPT_STRING "a:c:dhl:n:o:ps:t:vw:"
+#define OPT_STRING "a:c:dfhl:n:o:ps:t:vw:"
 #else
-#define OPT_STRING "a:c:dhl:n:o:ps:vw:"
+#define OPT_STRING "a:c:dfhl:n:o:ps:vw:"
 #endif
 #ifdef USE_LONG_OPTIONS
 	while ((c = getopt_long(argc, argv, OPT_STRING,
@@ -462,6 +465,9 @@ EXPORT void init(struct metafile *m, int argc, char *argv[])
 		case 'd':
 			m->no_creation_date = 1;
 			break;
+		case 'f':
+			m->force_overwrite = 1;
+			break;
 		case 'h':
 			print_help();
 			exit(EXIT_SUCCESS);

main.c

@@ -71,15 +71,19 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 /*
  * create and open the metainfo file for writing and create a stream for it
  * we don't want to overwrite anything, so abort if the file is already there
+ * and force is false
  */
-static FILE *open_file(const char *path)
+static FILE *open_file(const char *path, int force)
 {
 	int fd;  /* file descriptor */
 	FILE *f; /* file stream */
 
+	int flags = O_WRONLY | O_BINARY | O_CREAT;
+	if (!force)
+		flags |= O_EXCL;
+
 	/* open and create the file if it doesn't exist already */
-	fd = open(path, O_WRONLY | O_BINARY | O_CREAT | O_EXCL,
-		       S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+	fd = open(path, flags, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
 	FATAL_IF(fd < 0, "cannot create '%s': %s\n", path, strerror(errno));
 
 	/* create the stream from this filedescriptor */
@@ -118,6 +122,7 @@ int main(int argc, char *argv[])
 		0,    /* private */
 		NULL, /* source string */
 		0,    /* verbose */
+		0,    /* force_overwrite */
 #ifdef USE_PTHREADS
 		0,    /* threads, initialised by init() */
 #endif
@@ -136,7 +141,7 @@ int main(int argc, char *argv[])
 
 	/* open the file stream now, so we don't have to abort
 	   _after_ we did all the hashing in case we fail */
-	file = open_file(m.metainfo_file_path);
+	file = open_file(m.metainfo_file_path, m.force_overwrite);
 
 	/* calculate hash string... */
 	unsigned char *hash = make_hash(&m);

mktorrent.h

@@ -32,6 +32,7 @@ struct metafile {
 	int private;               /* set the private flag */
 	char *source;              /* set source for private trackers */
 	int verbose;               /* be verbose */
+	int force_overwrite;       /* overwrite existing output file */
 #ifdef USE_PTHREADS
 	long threads;              /* number of threads used for hashing */
 #endif