mplayer_server: first version of the server

9 files changed, 315 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..07a33ba
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.o
+mplayer_server
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..b8d27b8
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,31 @@
+CC       ?= gcc
+CFLAGS   += -W -Wall -std=gnu99 -Wextra
+CFLAGS   += -D _XOPEN_SOURCE
+#CFLAGS   += -D LOGS
+NAME      = mplayer_server
+SRC       = main.c callbacks.c escape.c logs.c
+
+all: depend $(NAME)
+
+depend: .depend
+
+.depend: $(SRC)
+	@$(RM) .depend
+	@$(CC) $(CFLAGS) -MM $^ > .depend
+
+include .depend
+
+OBJ     = $(SRC:.c=.o)
+
+$(NAME): $(OBJ)
+	$(CC) -o $@ $^ $(LDFLAGS)
+
+clean:
+	$(RM) $(OBJ)
+
+fclean: clean
+	$(RM) $(NAME)
+
+re: fclean all
+
+.PHONY: all depend clean fclean all re
diff --git a/callbacks.c b/callbacks.c
new file mode 100644
index 0000000..e41fe8b
--- /dev/null
+++ b/callbacks.c
@@ -0,0 +1,108 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "mplayer_server.h"
+#include "request.h"
+
+#define CB(_name) int callback_##_name(const byte *buffer __attribute__((unused)), int size __attribute__((unused)))
+
+CB(load_url);
+CB(pause);
+CB(quit);
+CB(snd_down);
+CB(snd_up);
+CB(fullscreen);
+CB(mute);
+
+extern FILE *stream_g;
+
+typedef struct {
+    int opcode;
+    int (*cb)(const byte *, int);
+} callback_t;
+
+static callback_t callbacks_g[] = {
+    {0, callback_load_url},
+    {1, callback_pause},
+    {2, callback_quit},
+    {3, callback_snd_up},
+    {4, callback_snd_down},
+    {5, callback_fullscreen},
+    {6, callback_mute},
+};
+
+/*
+ * returns a new malloced() null terminated escaped string
+ * if the string is considered dangerous, then the function returns NULL
+ */
+
+char *real_escape_string(const byte *buf, int size);
+
+void *get_assoc_cb(int opcode)
+{
+    for (size_t i = 0; i < sizeof(callbacks_g) / sizeof(callbacks_g[0]); ++i) {
+        if (callbacks_g[i].opcode == opcode) {
+            return callbacks_g[i].cb;
+        }
+    }
+
+    return NULL;
+}
+
+#define SEND_CMD(_fmt, ...) \
+    do { \
+	_log(_fmt, ##__VA_ARGS__); \
+	fprintf(stream_g, _fmt "\n", ##__VA_ARGS__); \
+    } while (0)
+
+/* TODO refuse the execution of commands with arguments when they do not need */
+CB(load_url)
+{
+    /* XXX beware, someone may perform arbitrary code injection */
+    char *escaped = real_escape_string(buffer, size);
+
+    if (escaped == NULL) {
+	return -1;
+    }
+
+    SEND_CMD("loadfile '%s'", escaped);
+
+    free(escaped);
+    return 0;
+}
+
+CB(pause)
+{
+    SEND_CMD("pause");
+    return 0;
+}
+
+CB(quit)
+{
+    SEND_CMD("quit");
+    return 0;
+}
+
+CB(snd_down)
+{
+    SEND_CMD("volume -5");
+    return 0;
+}
+
+CB(snd_up)
+{
+    SEND_CMD("volume +5");
+    return 0;
+}
+
+CB(fullscreen)
+{
+    SEND_CMD("vo_fullscreen");
+    return 0;
+}
+
+CB(mute)
+{
+    SEND_CMD("mute");
+    return 0;
+}
diff --git a/escape.c b/escape.c
new file mode 100644
index 0000000..be801e2
--- /dev/null
+++ b/escape.c
@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+#include "request.h"
+
+char *real_escape_string(const byte *src, int size)
+{
+    char *escaped;
+    char *pos;
+
+    if (memchr(src, '\0', size - 1) || memchr(src, '\n', size) || memchr(src, '\r', size)) {
+	fprintf(stderr, "cannot handle this string\n");
+	return NULL;
+    }
+
+    pos = escaped = malloc(sizeof(char) * (size * 2 + 1));
+
+    if (escaped == NULL) {
+	fprintf(stderr, "malloc failed: %m\n");
+	return NULL;
+    }
+
+    for (int i = 0; i < size; ++i) {
+	if (!isalnum(src[i])) {
+	    *escaped++ = '\\';
+	}
+	*escaped++ = src[i];
+    }
+
+    *escaped = '\0';
+
+    return pos;
+}
diff --git a/logs.c b/logs.c
new file mode 100644
index 0000000..01d93fc
--- /dev/null
+++ b/logs.c
@@ -0,0 +1,18 @@
+#include <stdarg.h>
+#include <stdio.h>
+
+void _log(const char *fmt, ...)
+{
+#ifdef LOGS
+    va_list ap;
+
+    va_start(ap, fmt);
+
+    vfprintf(stderr, fmt, ap);
+    fputc('\n', stderr);
+
+    va_end(ap);
+#else
+    (void) fmt;
+#endif
+}
diff --git a/logs.h b/logs.h
new file mode 100644
index 0000000..f36695d
--- /dev/null
+++ b/logs.h
@@ -0,0 +1,9 @@
+#ifndef LOGS_H
+#define LOGS_H
+
+#include <stdarg.h>
+
+__attribute__((format(printf, 1, 2)))
+void _log(const char *fmt, ...);
+
+#endif /* LOGS_H */
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..bb74011
--- /dev/null
+++ b/main.c
@@ -0,0 +1,92 @@
+#include <signal.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "mplayer_server.h"
+#include "request.h"
+
+FILE *stream_g;
+
+static request_t buffer_g;
+
+void *get_assoc_cb(int opcode);
+
+/* returns a socket listing to port or -1 if something failed */
+static int bind_socket(uint16_t port)
+{
+    int sock = socket(AF_INET, SOCK_STREAM, 0);
+    struct sockaddr_in sin;
+
+    if (sock < 0) {
+        perror("socket");
+        return -1;
+    }
+
+    sin.sin_addr.s_addr = htonl(INADDR_ANY);
+    sin.sin_family      = AF_INET;
+    sin.sin_port        = htons(port);
+    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (int []){1}, sizeof(int));
+
+    if (bind(sock, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
+        perror("bind");
+        return -1;
+    }
+
+    if (listen(sock, 10) < 0) {
+        perror("listen");
+        return -1;
+    }
+
+    return sock;
+}
+
+/* TODO allow multiple clients to send queries */
+static int event_loop(int sock)
+{
+    for (;;) {
+        int csock = accept(sock, NULL, NULL);
+
+        int size = read(csock, &buffer_g, sizeof(buffer_g));
+
+        _log("received: [%.*s]\n", size - (int)sizeof(buffer_g.opcode), buffer_g.data);
+
+        if (size >= (int)sizeof(buffer_g.opcode)) {
+            int (*cb)(const byte *, int) = get_assoc_cb(buffer_g.opcode);
+
+            if (cb != NULL) {
+                (*cb)(buffer_g.data, size - (int)sizeof(buffer_g.opcode));
+            }
+        }
+
+        close(csock);
+    }
+
+    return 0;
+}
+
+int main(int argc, char *argv[])
+{
+    stream_g = popen("/usr/bin/mplayer -quiet -slave -idle", "w");
+
+    if (stream_g == NULL) {
+        fprintf(stderr, "cannot run mplayer: %m\n");
+        return -1;
+    }
+
+    setvbuf(stream_g, NULL, _IONBF, 0);
+
+    int sock = bind_socket((argc < 2) ? 4333 : atoi(argv[1]));
+
+    if (sock >= 0) {
+        signal(SIGPIPE, SIG_IGN);
+
+        event_loop(sock);
+    }
+
+    pclose(stream_g);
+    return 0;
+}
diff --git a/mplayer_server.h b/mplayer_server.h
new file mode 100644
index 0000000..c3046da
--- /dev/null
+++ b/mplayer_server.h
@@ -0,0 +1,6 @@
+#ifndef MPLAYER_SERVER_H
+#define MPLAYER_SERVER_H
+
+#include "logs.h"
+
+#endif /* MPLAYER_SERVER_H */
diff --git a/request.h b/request.h
new file mode 100644
index 0000000..6c5925a
--- /dev/null
+++ b/request.h
@@ -0,0 +1,14 @@
+#ifndef REQUEST_H
+#define REQUEST_H
+
+#include <stdint.h>
+
+typedef uint8_t byte;
+
+typedef struct {
+    byte opcode;
+
+    byte data[512];
+} request_t;
+
+#endif /* REQUEST_H */