/* filter.c: filter framework functions * * Copyright (C) 2006-2014 cgit Development Team * * Licensed under GNU General Public License v2 * (see COPYING for full license text) */ #include "cgit.h" #include #include #include #include #include #include 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); 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->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; 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) && !WEXITSTATUS(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 0; } 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; } int cgit_open_filter(struct cgit_filter *filter, ...) { int result; va_list ap; va_start(ap, filter); result = filter->open(filter, ap); va_end(ap); return result; } int cgit_close_filter(struct cgit_filter *filter) { 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 }, }; 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 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); }