/* filter.c: filter framework functions * * Copyright (C) 2006-2014 cgit Development Team <cgit@lists.zx2c4.com> * * Licensed under GNU General Public License v2 * (see COPYING for full license text) */ #include "cgit.h" #include "html.h" #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #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)(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); reap_filter(ctx.cfg.email_filter); reap_filter(ctx.cfg.auth_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); reap_filter(cgit_repolist.repos[i].email_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->base.argument_count; i++) filter->argv[i + 1] = va_arg(ap, char *); filter->old_stdout = chk_positive(dup(STDOUT_FILENO), "Unable to duplicate STDOUT"); chk_zero(pipe(filter->pipe_fh), "Unable to create pipe to subprocess"); filter->pid = chk_non_negative(fork(), "Unable to create subprocess"); if (filter->pid == 0) { close(filter->pipe_fh[1]); chk_non_negative(dup2(filter->pipe_fh[0], STDIN_FILENO), "Unable to use pipe as STDIN"); execvp(filter->cmd, filter->argv); die_errno("Unable to exec subprocess %s", filter->cmd); } close(filter->pipe_fh[0]); chk_non_negative(dup2(filter->pipe_fh[1], STDOUT_FILENO), "Unable to use pipe as STDOUT"); close(filter->pipe_fh[1]); return 0; } static int close_exec_filter(struct cgit_filter *base) { struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base; int i, exit_status = 0; chk_non_negative(dup2(filter->old_stdout, STDOUT_FILENO), "Unable to restore STDOUT"); close(filter->old_stdout); if (filter->pid < 0) goto done; waitpid(filter->pid, &exit_status, 0); if (WIFEXITED(exit_status)) goto done; die("Subprocess %s exited abnormally", filter->cmd); done: for (i = 0; i < filter->base.argument_count; i++) filter->argv[i + 1] = NULL; return WEXITSTATUS(exit_status); } static void fprintf_exec_filter(struct cgit_filter *base, FILE *f, const char *prefix) { struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base; fprintf(f, "%sexec:%s\n", prefix, filter->cmd); } static void cleanup_exec_filter(struct cgit_filter *base) { struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base; if (filter->argv) { free(filter->argv); filter->argv = NULL; } if (filter->cmd) { free(filter->cmd); filter->cmd = NULL; } } static struct cgit_filter *new_exec_filter(const char *cmd, int argument_count) { struct cgit_exec_filter *f; int args_size = 0; f = xmalloc(sizeof(*f)); /* We leave argv for now and assign it below. */ cgit_exec_filter_init(f, xstrdup(cmd), NULL); 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; return &f->base; } void cgit_exec_filter_init(struct cgit_exec_filter *filter, char *cmd, char **argv) { memset(filter, 0, sizeof(*filter)); filter->base.open = open_exec_filter; filter->base.close = close_exec_filter; filter->base.fprintf = fprintf_exec_filter; 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 void error_lua_filter(struct lua_filter *filter) { die("Lua error in %s: %s", filter->script_file, lua_tostring(filter->lua_state, -1)); lua_pop(filter->lua_state, 1); } 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)) { error_lua_filter(filter); errno = EIO; return -1; } return count; } static inline int hook_lua_filter(lua_State *lua_state, void (*fn)(const char *txt)) { const char *str; ssize_t (*save_filter_write)(struct cgit_filter *base, const void *buf, size_t count); struct cgit_filter *save_filter; str = lua_tostring(lua_state, 1); if (!str) return 0; save_filter_write = filter_write; save_filter = current_write_filter; unhook_write(); fn(str); hook_write(save_filter, save_filter_write); return 0; } static int html_lua_filter(lua_State *lua_state) { return hook_lua_filter(lua_state, html); } static int html_txt_lua_filter(lua_State *lua_state) { return hook_lua_filter(lua_state, html_txt); } static int html_attr_lua_filter(lua_State *lua_state) { return hook_lua_filter(lua_state, html_attr); } static int html_url_path_lua_filter(lua_State *lua_state) { return hook_lua_filter(lua_state, html_url_path); } static int html_url_arg_lua_filter(lua_State *lua_state) { return hook_lua_filter(lua_state, html_url_arg); } static int html_include_lua_filter(lua_State *lua_state) { return hook_lua_filter(lua_state, (void (*)(const char *))html_include); } 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"); lua_pushcfunction(filter->lua_state, html_txt_lua_filter); lua_setglobal(filter->lua_state, "html_txt"); lua_pushcfunction(filter->lua_state, html_attr_lua_filter); lua_setglobal(filter->lua_state, "html_attr"); lua_pushcfunction(filter->lua_state, html_url_path_lua_filter); lua_setglobal(filter->lua_state, "html_url_path"); lua_pushcfunction(filter->lua_state, html_url_arg_lua_filter); lua_setglobal(filter->lua_state, "html_url_arg"); lua_pushcfunction(filter->lua_state, html_include_lua_filter); lua_setglobal(filter->lua_state, "html_include"); if (luaL_dofile(filter->lua_state, filter->script_file)) { error_lua_filter(filter); 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)) { error_lua_filter(filter); 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, 1, 0)) { error_lua_filter(filter); ret = -1; } else { ret = lua_tonumber(filter->lua_state, -1); lua_pop(filter->lua_state, 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; va_list ap; if (!filter) return 0; va_start(ap, filter); result = filter->open(filter, ap); va_end(ap); return result; } int cgit_close_filter(struct cgit_filter *filter) { if (!filter) return 0; return filter->close(filter); } void cgit_fprintf_filter(struct cgit_filter *filter, FILE *f, const char *prefix) { filter->fprintf(filter, f, prefix); } static const struct { const char *prefix; 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) { char *colon; int i; size_t len; int argument_count; if (!cmd || !cmd[0]) return NULL; colon = strchr(cmd, ':'); len = colon - cmd; /* * In case we're running on Windows, don't allow a single letter before * the colon. */ if (len == 1) colon = NULL; switch (filtertype) { case AUTH: argument_count = 12; break; case EMAIL: argument_count = 2; break; 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, 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, argument_count); } die("Invalid filter type: %.*s", (int) len, cmd); }