From 24c97f5b1fe1b666a3c53e8d36b0bea0ede307e0 Mon Sep 17 00:00:00 2001
From: cbdev <cb@cbcdn.com>
Date: Sat, 8 Jul 2023 16:33:24 +0200
Subject: Implement command output scanning

---
 command.c     | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++------
 nfcommander.c |  1 -
 nfcommander.h |  1 +
 3 files changed, 69 insertions(+), 8 deletions(-)

diff --git a/command.c b/command.c
index 12e24c6..b222997 100644
--- a/command.c
+++ b/command.c
@@ -15,13 +15,16 @@
 #define COMMAND_ALIVE 1
 #define COMMAND_STOPPED 2
 
-#define INPUT_BUFFER_MAX 4096
+#define INPUT_BUFFER_MAX 2048
 
 typedef struct {
 	uint8_t flags;
 	pid_t child;
 	int iopipe[2];
 	nfc_tag_info_t* tag;
+
+	size_t input_head;
+	uint8_t input[INPUT_BUFFER_MAX];
 } command_t;
 
 static size_t ncommands = 0;
@@ -29,16 +32,61 @@ static command_t* commands = NULL;
 
 //TODO timeouting / SIGKILL
 
+static int command_scan_input(command_t* cmd, size_t bytes){
+	size_t n = 0;
+
+	//check for line ending
+	for(n = 0; n < bytes; n++){
+		if(cmd->input[cmd->input_head + n] == '\r' || 
+				cmd->input[cmd->input_head + n] == '\n'){
+			//terminate string
+			cmd->input[cmd->input_head + n] = 0;
+			//handle line
+			if(!strncmp((char*) cmd->input, "UPDATE ", strlen("UPDATE "))){
+				printf("Update: %s\n", cmd->input + 7);
+			}
+
+			//find beginning of next line
+			n++;
+			for(; n < bytes && !isprint(cmd->input[cmd->input_head + n]); n++){
+			}
+
+			if(n == bytes){
+				cmd->input_head = 0;
+				return 0;
+			}
+
+			//move back
+			memmove(cmd->input, cmd->input + cmd->input_head + n, bytes - n);
+			cmd->input_head = 0;
+
+			//try to find another sentence
+			return command_scan_input(cmd, bytes - n);
+		}
+	}
+
+	if(cmd->input_head + bytes > INPUT_BUFFER_MAX - 10){
+		//line too long - ignore it entirely until the next linebreak
+		cmd->input_head = 1;
+		cmd->input[0] = 0; //fail any test for UPDATE
+		return 0;
+	}
+
+	//no newline
+	cmd->input_head += bytes;
+	return 0;
+}
+
 int command_handle(int fd){
 	size_t n = 0;
 	ssize_t bytes;
-	uint8_t input_buffer[INPUT_BUFFER_MAX];
 
 	//find matching command
 	for(n = 0; n < ncommands; n++){
 		if(commands[n].flags & COMMAND_ALIVE
 				&& fd == commands[n].iopipe[0]){
-			bytes = read(fd, input_buffer, sizeof(input_buffer) - 1);
+			bytes = read(fd, commands[n].input + commands[n].input_head,
+					sizeof(commands[n].input) - commands[n].input_head - 1);
 			if(bytes < 0){
 				perror("cmd/recv");
 			}
@@ -47,11 +95,11 @@ int command_handle(int fd){
 				core_manage_fd(commands[n].iopipe[0], 0, system_command);
 				close(commands[n].iopipe[0]);
 				commands[n].iopipe[0] = -1;
+				commands[n].input_head = 0;
 			}
 			else{
-				//TODO handle
-				input_buffer[bytes] = 0;
-				printf("%d bytes from command %lu: %s\n", bytes, n, input_buffer);
+				//printf("%ld bytes from command %lu\n", bytes, n);
+				command_scan_input(commands + n, bytes);
 			}
 			return 0;
 		}
@@ -96,6 +144,8 @@ void command_reap(){
 static int command_spawn(command_t* cmd, char* command_name, char* command_static, size_t arg_length){
 	char* workdir = config_get("command", "chdir");
 	char* handler = config_get("command", "handler");
+	size_t bytes;
+	char tag_uid[12] = "";
 
 	printf("Starting command %s, static %s\n", command_name, command_static);
 	if(pipe(cmd->iopipe)){
@@ -127,7 +177,17 @@ static int command_spawn(command_t* cmd, char* command_name, char* command_stati
 			}
 			close(cmd->iopipe[1]);
 
-			//TODO set environment
+			//set environment
+			bytes = snprintf(tag_uid, sizeof(tag_uid), "%02X%02X%02X%02X",
+					cmd->tag->uid[0], cmd->tag->uid[1],
+					cmd->tag->uid[2], cmd->tag->uid[3]);
+			if(cmd->tag->uid_length > 4){
+				bytes += snprintf(tag_uid + bytes, sizeof(tag_uid) - bytes, "%02X%02X%02X",
+						cmd->tag->uid[4], cmd->tag->uid[5],
+						cmd->tag->uid[6]);
+			}
+			setenv("TAG_UID", tag_uid, 1);
+			//DYNAMIC_SIZE
 
 			//run actual command
 			if(handler){
@@ -209,6 +269,7 @@ int command_start(nfc_tag_info_t* info){
 	}
 
 	commands[p].tag = info;
+	commands[p].input_head = 0;
 	if(command_spawn(commands + p, (char*) command_name, (char*) command_static, arg_length)){
 		//TODO clean up and free command instance
 	}
diff --git a/nfcommander.c b/nfcommander.c
index 66838aa..125b237 100644
--- a/nfcommander.c
+++ b/nfcommander.c
@@ -86,7 +86,6 @@ int main(int argc, char** argv){
 
 	//start reader api
 	if(reader_init()){
-		printf("Failed to start reader\n");
 		//TODO cleanup
 		return EXIT_FAILURE;
 	}
diff --git a/nfcommander.h b/nfcommander.h
index 0c24236..d380f78 100644
--- a/nfcommander.h
+++ b/nfcommander.h
@@ -34,6 +34,7 @@ typedef struct {
 	uint8_t* static_data;
 	size_t dynamic_length;
 	uint8_t* dynamic_data;
+	size_t dynamic_max;
 } nfc_tag_info_t;
 
 typedef int (*reader_plugin_init)(void);
-- 
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