[PATCH 06/12] filter: add preliminary lua support

Jason A. Donenfeld Jason at zx2c4.com
Mon Jan 13 05:11:13 CET 2014


Signed-off-by: Jason A. Donenfeld <Jason at zx2c4.com>
---
 cgit.h   |   2 +-
 cgit.mk  |  13 ++-
 filter.c | 284 ++++++++++++++++++++++++++++++++++++++++++++++++---------------
 3 files changed, 230 insertions(+), 69 deletions(-)

diff --git a/cgit.h b/cgit.h
index db34493..519d2af 100644
--- a/cgit.h
+++ b/cgit.h
@@ -61,13 +61,13 @@ struct cgit_filter {
 	int (*close)(struct cgit_filter *);
 	void (*fprintf)(struct cgit_filter *, FILE *, const char *prefix);
 	void (*cleanup)(struct cgit_filter *);
+	int argument_count;
 };
 
 struct cgit_exec_filter {
 	struct cgit_filter base;
 	char *cmd;
 	char **argv;
-	int extra_args;
 	int old_stdout;
 	int pipe_fh[2];
 	int pid;
diff --git a/cgit.mk b/cgit.mk
index 9d6dea8..71bbe8b 100644
--- a/cgit.mk
+++ b/cgit.mk
@@ -25,6 +25,16 @@ ifdef NO_C99_FORMAT
 	CFLAGS += -DNO_C99_FORMAT
 endif
 
+ifdef NO_LUA
+	CFLAGS += -DNO_LUA
+else
+	CGIT_LIBS += -llua
+endif
+
+CGIT_LIBS += -ldl
+
+
+
 CGIT_OBJ_NAMES += cgit.o
 CGIT_OBJ_NAMES += cache.o
 CGIT_OBJ_NAMES += cmd.o
@@ -61,9 +71,6 @@ $(CGIT_VERSION_OBJS): $(CGIT_PREFIX)VERSION
 $(CGIT_VERSION_OBJS): EXTRA_CPPFLAGS = \
 	-DCGIT_VERSION='"$(CGIT_VERSION)"'
 
-CGIT_LIBS += -ldl
-
-
 # Git handles dependencies using ":=" so dependencies in CGIT_OBJ are not
 # handled by that and we must handle them ourselves.
 cgit_dep_files := $(foreach f,$(CGIT_OBJS),$(dir $f).depend/$(notdir $f).d)
diff --git a/filter.c b/filter.c
index 8990575..6f0e298 100644
--- a/filter.c
+++ b/filter.c
@@ -13,16 +13,73 @@
 #include <string.h>
 #include <stdlib.h>
 #include <dlfcn.h>
+#include <errno.h>
+#ifndef NO_LUA
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+#endif
 
 static ssize_t (*libc_write)(int fd, const void *buf, size_t count);
-static ssize_t (*filter_write)(const void *buf, size_t count) = NULL;
+static ssize_t (*filter_write)(struct cgit_filter *base, const void *buf, size_t count) = NULL;
+static struct cgit_filter *current_write_filter = NULL;
+
+static inline void reap_filter(struct cgit_filter *filter)
+{
+	if (filter && filter->cleanup)
+		filter->cleanup(filter);
+}
+
+void cgit_cleanup_filters(void)
+{
+	int i;
+	reap_filter(ctx.cfg.about_filter);
+	reap_filter(ctx.cfg.commit_filter);
+	reap_filter(ctx.cfg.source_filter);
+	for (i = 0; i < cgit_repolist.count; ++i) {
+		reap_filter(cgit_repolist.repos[i].about_filter);
+		reap_filter(cgit_repolist.repos[i].commit_filter);
+		reap_filter(cgit_repolist.repos[i].source_filter);
+	}
+}
+
+void cgit_init_filters(void)
+{
+	libc_write = dlsym(RTLD_NEXT, "write");
+	if (!libc_write)
+		die("Could not locate libc's write function");
+}
+
+ssize_t write(int fd, const void *buf, size_t count)
+{
+	if (fd != STDOUT_FILENO || !filter_write)
+		return libc_write(fd, buf, count);
+	return filter_write(current_write_filter, buf, count);
+}
+
+static inline void hook_write(struct cgit_filter *filter, ssize_t (*new_write)(struct cgit_filter *base, const void *buf, size_t count))
+{
+	/* We want to avoid buggy nested patterns. */
+	assert(filter_write == NULL);
+	assert(current_write_filter == NULL);
+	current_write_filter = filter;
+	filter_write = new_write;
+}
+
+static inline void unhook_write()
+{
+	assert(filter_write != NULL);
+	assert(current_write_filter != NULL);
+	filter_write = NULL;
+	current_write_filter = NULL;
+}
 
 static int open_exec_filter(struct cgit_filter *base, va_list ap)
 {
 	struct cgit_exec_filter *filter = (struct cgit_exec_filter *) base;
 	int i;
 
-	for (i = 0; i < filter->extra_args; i++)
+	for (i = 0; i < filter->base.argument_count; i++)
 		filter->argv[i+1] = va_arg(ap, char *);
 
 	filter->old_stdout = chk_positive(dup(STDOUT_FILENO),
@@ -59,7 +116,7 @@ static int close_exec_filter(struct cgit_filter *base)
 	die("Subprocess %s exited abnormally", filter->cmd);
 
 done:
-	for (i = 0; i < filter->extra_args; i++)
+	for (i = 0; i < filter->base.argument_count; i++)
 		filter->argv[i+1] = NULL;
 	return 0;
 
@@ -78,9 +135,18 @@ static void cleanup_exec_filter(struct cgit_filter *base)
 		free(filter->argv);
 		filter->argv = NULL;
 	}
+
+/* We can't enable this code block because cgit_exec_filter_init sometimes takes
+ * non-malloc'd cmd. Refactor the callers of that before uncommenting this block */
+#if 0
+	if (filter->cmd) {
+		free(filter->cmd);
+		filter->cmd = NULL;
+	}
+#endif
 }
 
-static struct cgit_filter *new_exec_filter(const char *cmd, filter_type filtertype)
+static struct cgit_filter *new_exec_filter(const char *cmd, int argument_count)
 {
 	struct cgit_exec_filter *f;
 	int args_size = 0;
@@ -88,20 +154,8 @@ static struct cgit_filter *new_exec_filter(const char *cmd, filter_type filterty
 	f = xmalloc(sizeof(*f));
 	/* We leave argv for now and assign it below. */
 	cgit_exec_filter_init(f, xstrdup(cmd), NULL);
-
-	switch (filtertype) {
-		case SOURCE:
-		case ABOUT:
-			f->extra_args = 1;
-			break;
-
-		case COMMIT:
-		default:
-			f->extra_args = 0;
-			break;
-	}
-
-	args_size = (2 + f->extra_args) * sizeof(char *);
+	f->base.argument_count = argument_count;
+	args_size = (2 + argument_count) * sizeof(char *);
 	f->argv = xmalloc(args_size);
 	memset(f->argv, 0, args_size);
 	f->argv[0] = f->cmd;
@@ -117,8 +171,135 @@ void cgit_exec_filter_init(struct cgit_exec_filter *filter, char *cmd, char **ar
 	filter->base.cleanup = cleanup_exec_filter;
 	filter->cmd = cmd;
 	filter->argv = argv;
+	/* The argument count for open_filter is zero by default, unless called from new_filter, above. */
+	filter->base.argument_count = 0;
+}
+
+#ifndef NO_LUA
+struct lua_filter {
+	struct cgit_filter base;
+	char *script_file;
+	lua_State *lua_state;
+};
+
+static ssize_t write_lua_filter(struct cgit_filter *base, const void *buf, size_t count)
+{
+	struct lua_filter *filter = (struct lua_filter *) base;
+
+	lua_getglobal(filter->lua_state, "filter_write");
+	lua_pushlstring(filter->lua_state, buf, count);
+	if (lua_pcall(filter->lua_state, 1, 0, 0)) {
+		errno = EPROTO;
+		return -1;
+	}
+	return count;
+}
+
+static int html_lua_filter(lua_State *lua_state)
+{
+	size_t len;
+	const char *str;
+
+	str = lua_tostring(lua_state, 1);
+	if (!str)
+		return 0;
+	len = strlen(str);
+	libc_write(STDOUT_FILENO, str, len);
+	return 0;
+}
+
+static void cleanup_lua_filter(struct cgit_filter *base)
+{
+	struct lua_filter *filter = (struct lua_filter *) base;
+
+	if (!filter->lua_state)
+		return;
+
+	lua_close(filter->lua_state);
+	filter->lua_state = NULL;
+	if (filter->script_file) {
+		free(filter->script_file);
+		filter->script_file = NULL;
+	}
+}
+
+static int init_lua_filter(struct lua_filter *filter)
+{
+	if (filter->lua_state)
+		return 0;
+
+	if (!(filter->lua_state = luaL_newstate()))
+		return 1;
+
+	luaL_openlibs(filter->lua_state);
+
+	lua_pushcfunction(filter->lua_state, html_lua_filter);
+	lua_setglobal(filter->lua_state, "html");
+
+	if (luaL_dofile(filter->lua_state, filter->script_file)) {
+		lua_close(filter->lua_state);
+		filter->lua_state = NULL;
+		return 1;
+	}
+	return 0;
+}
+
+static int open_lua_filter(struct cgit_filter *base, va_list ap)
+{
+	struct lua_filter *filter = (struct lua_filter *) base;
+	int i;
+
+	if (init_lua_filter(filter))
+		return 1;
+
+	hook_write(base, write_lua_filter);
+
+	lua_getglobal(filter->lua_state, "filter_open");
+	for (i = 0; i < filter->base.argument_count; ++i)
+		lua_pushstring(filter->lua_state, va_arg(ap, char *));
+	if (lua_pcall(filter->lua_state, filter->base.argument_count, 0, 0))
+		return 1;
+	return 0;
+}
+
+static int close_lua_filter(struct cgit_filter *base)
+{
+	struct lua_filter *filter = (struct lua_filter *) base;
+	int ret = 0;
+
+	lua_getglobal(filter->lua_state, "filter_close");
+	if (lua_pcall(filter->lua_state, 0, 0, 0))
+		ret = 1;
+	unhook_write();
+	return ret;
+}
+
+static void fprintf_lua_filter(struct cgit_filter *base, FILE *f, const char *prefix)
+{
+	struct lua_filter *filter = (struct lua_filter *) base;
+	fprintf(f, "%slua:%s\n", prefix, filter->script_file);
+}
+
+
+static struct cgit_filter *new_lua_filter(const char *cmd, int argument_count)
+{
+	struct lua_filter *filter;
+
+	filter = xmalloc(sizeof(*filter));
+	memset(filter, 0, sizeof(*filter));
+	filter->base.open = open_lua_filter;
+	filter->base.close = close_lua_filter;
+	filter->base.fprintf = fprintf_lua_filter;
+	filter->base.cleanup = cleanup_lua_filter;
+	filter->base.argument_count = argument_count;
+	filter->script_file = xstrdup(cmd);
+
+	return &filter->base;
 }
 
+#endif
+
+
 int cgit_open_filter(struct cgit_filter *filter, ...)
 {
 	int result;
@@ -143,9 +324,12 @@ void cgit_fprintf_filter(struct cgit_filter *filter, FILE *f, const char *prefix
 
 static const struct {
 	const char *prefix;
-	struct cgit_filter *(*ctor)(const char *cmd, filter_type filtertype);
+	struct cgit_filter *(*ctor)(const char *cmd, int argument_count);
 } filter_specs[] = {
 	{ "exec", new_exec_filter },
+#ifndef NO_LUA
+	{ "lua", new_lua_filter },
+#endif
 };
 
 struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
@@ -153,6 +337,8 @@ struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
 	char *colon;
 	int i;
 	size_t len;
+	int argument_count;
+
 	if (!cmd || !cmd[0])
 		return NULL;
 
@@ -165,60 +351,28 @@ struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
 	if (len == 1)
 		colon = NULL;
 
+	switch (filtertype) {
+		case SOURCE:
+		case ABOUT:
+			argument_count = 1;
+			break;
+
+		case COMMIT:
+		default:
+			argument_count = 0;
+			break;
+	}
+
 	/* If no prefix is given, exec filter is the default. */
 	if (!colon)
-		return new_exec_filter(cmd, filtertype);
+		return new_exec_filter(cmd, argument_count);
 
 	for (i = 0; i < ARRAY_SIZE(filter_specs); i++) {
 		if (len == strlen(filter_specs[i].prefix) &&
 		    !strncmp(filter_specs[i].prefix, cmd, len))
-			return filter_specs[i].ctor(colon + 1, filtertype);
+			return filter_specs[i].ctor(colon + 1, argument_count);
 	}
 
 	die("Invalid filter type: %.*s", (int) len, cmd);
 }
 
-static inline void reap_filter(struct cgit_filter *filter)
-{
-	if (filter && filter->cleanup)
-		filter->cleanup(filter);
-}
-
-void cgit_cleanup_filters(void)
-{
-	int i;
-	reap_filter(ctx.cfg.about_filter);
-	reap_filter(ctx.cfg.commit_filter);
-	reap_filter(ctx.cfg.source_filter);
-	for (i = 0; i < cgit_repolist.count; ++i) {
-		reap_filter(cgit_repolist.repos[i].about_filter);
-		reap_filter(cgit_repolist.repos[i].commit_filter);
-		reap_filter(cgit_repolist.repos[i].source_filter);
-	}
-}
-
-void cgit_init_filters(void)
-{
-	libc_write = dlsym(RTLD_NEXT, "write");
-	if (!libc_write)
-		die("Could not locate libc's write function");
-}
-
-ssize_t write(int fd, const void *buf, size_t count)
-{
-	if (fd != STDOUT_FILENO || !filter_write)
-		return libc_write(fd, buf, count);
-	return filter_write(buf, count);
-}
-
-static inline void hook_write(ssize_t (*new_write)(const void *buf, size_t count))
-{
-	/* We want to avoid buggy nested patterns. */
-	assert(filter_write == NULL);
-	filter_write = new_write;
-}
-static inline void unhook_write()
-{
-	assert(filter_write != NULL);
-	filter_write = NULL;
-}
-- 
1.8.5.2



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