From 89944e70b8e100e39ef65190ad1816dafde326eb Mon Sep 17 00:00:00 2001
From: Max Christian Pohle
Date: Sun, 14 Nov 2021 15:23:27 +0100
Subject: Now that I can parse individual fields I see potential optimizations.

Well-- If I had read the entire input stream into the buffer, I would
afterwards be able to change the buffer in memory and append \0 in
places, where a name/value pair exists and that would every second pair
a name and avoid many unnecessary memcpy.
---
 main.c | 79 +++++++++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 54 insertions(+), 25 deletions(-)

diff --git a/main.c b/main.c
index 9c1d177..6613df0 100644
--- a/main.c
+++ b/main.c
@@ -64,50 +64,80 @@ void * next_customer(void * new_socket) {
 	char boundary[64] = {0};
 	int boundary_size = 0;
 
+	char current_name[64] = {0};
+
 	usleep(100); // wait to avoid poll, epoll or evil select
 
+	char * output_buffer = NULL;
+	size_t output_buffer_length = 0;
+	FILE * output = open_memstream(&output_buffer, &output_buffer_length);
+
 	FILE * f = fdopen((size_t) new_socket, "r");
 	char buffer[MAX_HEADER_LINE_LENGTH];
-	while(fgets(buffer, MAX_HEADER_LINE_LENGTH, f)) {
-		printf("%s [%d]", buffer, errno);
+	char * s = NULL;
+	while(1) {
+		// printf("[errno: %d] %s", errno, buffer);
+		s = fgets(buffer, MAX_HEADER_LINE_LENGTH, f);
+
+		if(boundary[0] != '\0' && buffer[0] == '-') { // first char minus. could be a new chunk of post data
+			int i = 0;
+			for(i = 1; i < MAX_HEADER_LINE_LENGTH; i++) {
+				if(buffer[i] != '-') { // skip all minus
+					if(0 == strncmp(&buffer[i], boundary, boundary_size)) {
+							fflush(output);
+							printf("> name='%s' value='%*s'\n", current_name, (int) output_buffer_length, output_buffer);
+							setenv(current_name, output_buffer, 0);
+							current_name[0] = '\0';
+							rewind(output);
+							i = 0;
+
+							puts("================================================================================");
+					}
+					break;
+				}
+			}
+			if (i == 0) continue;
+		}
+
 
-		if(buffer[0] == '\n' || (buffer[0] == '\r' && buffer[1] == '\n')) { // either LF or CR/LF (windows)
+		if(!s || strspn(buffer, "\n\r") > 0) { // either LF or CR/LF (windows)
 			puts("END HEADER\n");
-			if (!boundary[0]) break;
-			continue;
+			// s != NULL ? break : continue;
+			if(!s) break; else continue; // either eof or only end of (chunk-)header
 		}
 
 		const char header_multipart[] = "Content-Type: multipart/form-data; boundary=";
 		if (!boundary[0] && 0 == strncasecmp(buffer, header_multipart, sizeof(header_multipart) - 1)) {
+			// we could potentially optimize this part with strspn and moving the buffer point, why not?
 			for(int i=sizeof(header_multipart); i<MAX_HEADER_LINE_LENGTH; i++)
 				if(buffer[i] != '-') {
 					strncpy(boundary, &buffer[i], 64);
 					boundary_size = strnlen(boundary, 64);
 					boundary[boundary_size] = '\0';
-					printf("BOUNDARY[%d]: %s\n", boundary_size, boundary);
+					printf("> [%s] %s\n", header_multipart, boundary);
 					break;
 				}
+			continue;
 		}
 
 		const char header_disposition[] = "Content-Disposition: form-data; ";
 		if (boundary[0] && 0 == strncasecmp(header_disposition, buffer, sizeof(header_disposition) - 1)) {
-			printf("FFFFFFFFFFFFFFFFFFFFFFF %s\n", buffer);
+			printf("> %s :: %s\n", header_disposition, buffer);
+			const char header_disposition_name[] = "name=\"";
+			s = strstr(&buffer[sizeof(header_disposition) - 1], header_disposition_name);
+			if(s) {
+				s += sizeof(header_disposition_name) - 1;
+				s[strcspn(s, "\"")] = '\0';
+				strncpy(current_name, s, 64);
+				printf("> /%s.*%s/ :: \"%s\"\n", header_disposition, header_disposition_name, s);
+			} else {
+				warnx("string not found in \"%s\".", &buffer[sizeof(header_disposition)]);
+			}
 			continue;
 		}// else { printf("FUCK: %*s [%d/%ld]\n", (int) sizeof(header_disposition), buffer, strncasecmp(header_disposition, buffer, sizeof(header_disposition)), sizeof(header_disposition)); }
 
-		if(buffer[0] == '-') { // first char minus. could be a new chunk of post data
-			for(int i=1; i<MAX_HEADER_LINE_LENGTH; i++) {
-				if(buffer[i] != '-') { // skip all minus
-					if(0 == strncmp(&buffer[i], boundary, boundary_size)) {
-							printf("\n\n> NEXT CHUNK: %s\n", buffer);
-							i = 0;
-					}
-					break;
-				}
-			}
-		} else {
-			printf("%s", buffer);
-		}
+		printf("> [unknown] %s", buffer);
+		fputs(buffer, output);
 
 
 		// I think another if could now search for "Content-Disposition: form-data; " and store the remaining fields
@@ -161,16 +191,15 @@ int main(int argc, char const *argv[])
   address.sin_port = htons(PORT);
 
   0 == (server_fd = socket(AF_INET, SOCK_STREAM, 0))
-    ? err(EXIT_FAILURE, NULL)
+    ? err(errno, NULL)
   : setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))
-    ? err(EXIT_FAILURE, "setsockopt failed on socket with fileno %d", server_fd)
+    ? err(errno, "setsockopt failed on socket with fileno %d", server_fd)
   : bind(server_fd, (struct sockaddr*) &address, sizeof(address))
-    ? err(EXIT_FAILURE, NULL)
+    ? err(errno, NULL)
   : listen(server_fd, SOMAXCONN)
-    ? err(EXIT_FAILURE, NULL)
+    ? err(errno, NULL)
   : serve(server_fd);
 
-
   return 0;
 }
 
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