feh_http_load_image: Use mkstemps to save image with correct suffix

This allows feh to load .gif images via libcurl, as some imlib2 versions only
load gif images if the suffix is correct. It's also more convenient when using
--keep-http.

To achieve this, feh needs to use mkstemps. mkstemps is a non-standard
extension that is available on several systems. Compile feh with
"mkstemps=0" to use mkstemp instead.

Closes #630

3 files changed, 31 insertions, 4 deletions

diff --git a/README.md b/README.md
index 2cedc53..4401af2 100644
--- a/README.md
+++ b/README.md
@@ -91,6 +91,7 @@ indicates that the corresponding feature is enabled by default.
 | help | 0 | include help text (refers to the manpage otherwise) |
 | inotify | 0 | enable inotify, needed for `--auto-reload` |
 | stat64 | 0 | Support CIFS shares from 64bit hosts on 32bit machines |
+| mkstemps | 1 | Whether your libc provides `mkstemps()`. If set to 0, feh will be unable to load gif images via libcurl |
 | verscmp | 1 | Whether your libc provides `strvercmp()`. If set to 0, feh will use an internal implementation. |
 | xinerama | 1 | Support Xinerama/XRandR multiscreen setups |
 
diff --git a/config.mk b/config.mk
index 5dfd7d3..35fdf4b 100644
--- a/config.mk
+++ b/config.mk
@@ -6,6 +6,7 @@ curl ?= 1
 debug ?= 0
 exif ?= 0
 help ?= 0
+mkstemps ?= 1
 verscmp ?= 1
 xinerama ?= 1
 
@@ -63,6 +64,10 @@ ifeq (${stat64},1)
 	CFLAGS += -D_FILE_OFFSET_BITS=64
 endif
 
+ifeq (${mkstemps},1)
+	CFLAGS += -DHAVE_MKSTEMPS
+endif
+
 ifeq (${verscmp},1)
 	CFLAGS += -DHAVE_STRVERSCMP
 endif
diff --git a/src/imlib.c b/src/imlib.c
index ea2f49c..add88d6 100644
--- a/src/imlib.c
+++ b/src/imlib.c
@@ -869,15 +869,32 @@ static char *feh_http_load_image(char *url)
 	}
 
 	basename = strrchr(url, '/') + 1;
-	tmpname = feh_unique_filename(path, basename);
 
-	if (strlen(tmpname) > (NAME_MAX-6))
-		tmpname[NAME_MAX-7] = '\0';
+#ifdef HAVE_MKSTEMPS
+	tmpname = estrjoin("_", "feh_curl_XXXXXX", basename, NULL);
 
-	sfn = estrjoin("_", tmpname, "XXXXXX", NULL);
+	if (strlen(tmpname) > NAME_MAX) {
+		tmpname[NAME_MAX] = '\0';
+	}
+#else
+	if (strlen(basename) > NAME_MAX-7) {
+		tmpname = estrdup("feh_curl_XXXXXX");
+	} else {
+		tmpname = estrjoin("_", "feh_curl", basename, "XXXXXX", NULL);
+	}
+#endif
+
+	sfn = estrjoin("", path, tmpname, NULL);
 	free(tmpname);
 
+	D(("sfn is %s\n", sfn))
+
+#ifdef HAVE_MKSTEMPS
+	fd = mkstemps(sfn, strlen(basename) + 1);
+#else
 	fd = mkstemp(sfn);
+#endif
+
 	if (fd != -1) {
 		sfp = fdopen(fd, "w+");
 		if (sfp != NULL) {
@@ -936,7 +953,11 @@ static char *feh_http_load_image(char *url)
 			close(fd);
 		}
 	} else {
+#ifdef HAVE_MKSTEMPS
+		weprintf("open url: mkstemps failed:");
+#else
 		weprintf("open url: mkstemp failed:");
+#endif
 		free(sfn);
 	}
 	curl_easy_cleanup(curl);