/* 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.owner_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);
		reap_filter(cgit_repolist.repos[i].owner_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(void)
{
	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;
}

<style>pre { line-height: 125%; }
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.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span><span class="cp">#ifndef UI_SNAPSHOT_H</span>
<span class="cp">#define UI_SNAPSHOT_H</span>

<span class="k">extern</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">cgit_print_snapshot</span><span class="p">(</span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="w"> </span><span class="o">*</span><span class="n">head</span><span class="p">,</span><span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="w"> </span><span class="o">*</span><span class="n">hex</span><span class="p">,</span>
<span class="w">				</span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="w"> </span><span class="o">*</span><span class="n">prefix</span><span class="p">,</span><span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="w"> </span><span class="o">*</span><span class="n">filename</span><span class="p">,</span>
<span class="w">				</span><span class="kt">int</span><span class="w"> </span><span class="n">snapshot</span><span class="p">);</span>

<span class="cp">#endif </span><span class="cm">/* UI_SNAPSHOT_H */</span>
</pre></div>
</code></pre></td></tr></table>
</div> <!-- class=content -->
<div class='footer'>generated by <a href='https://git.zx2c4.com/cgit/about/'>cgit v1.2.3-54-g00ecf</a> (<a href='https://git-scm.com/'>git 2.39.0</a>) at 2025-04-03 12:36:16 +0000</div>
</div> <!-- id=cgit -->
</body>
</html>
ruct 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 OWNER:
			argument_count = 0;
			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);
}