nttp-get: retrieve mail from using NNTP

1 files changed, 126 insertions, 0 deletions

diff --git a/nntp-get.c b/nntp-get.c
new file mode 100644
index 0000000..9fbfd82
--- /dev/null
+++ b/nntp-get.c
@@ -0,0 +1,126 @@
+#include <stdio.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <netdb.h>
+
+enum state {
+	STATE_CONNECTED,
+	STATE_GROUP_JOINED,
+	STATE_ARTICLE_RECV,
+	STATE_LAST
+};
+
+int main(int argc, char **argv) {
+	struct addrinfo hints = {0};
+	struct addrinfo *addr;
+	int sockfd;
+	FILE *sockf;
+	char *host, *group, *messageid;
+
+	if (argc == 2 && strchr(argv[1], '@')) {
+		host = "news.gmane.org";
+		group = strdup("gmane.linux.kernel");
+		messageid = argv[1];
+	} else if (argc == 3 && strchr(argv[2], '@')) {
+		host = "news.gmane.org";
+
+		group = argv[1];
+		if (strncmp(group, "gmane.", sizeof("gmane.") - 1)) {
+			group = malloc(strlen(argv[1]) + sizeof("gmane."));
+			sprintf(group, "gmane.%s", argv[1]);
+		}
+		char *g = group;
+		while ((g = strchr(g, '-'))) *g = '.';
+
+		messageid = argv[2];
+	} else if (argc == 4) {
+		host = argv[1];
+		group = strdup(argv[2]);
+		messageid = argv[3];
+	} else {
+		fprintf(stderr, "Usage: %s host group message-id\n"
+				"or:    %s message-id\n",
+				*argv, *argv);
+		return 1;
+	}
+
+	hints.ai_protocol = IPPROTO_TCP;
+
+	if (getaddrinfo(host, "119", &hints, &addr)) {
+		perror("getaddrinfo");
+		return 1;
+	}
+
+	sockfd = socket(addr->ai_family, SOCK_STREAM, addr->ai_protocol);
+	if (sockfd < 0) {
+		perror("socket");
+		goto err_free_addr;
+	}
+	sockf = fdopen(sockfd, "r");
+
+	if (connect(sockfd, addr->ai_addr, addr->ai_addrlen)) {
+		perror("connect");
+		goto err_close_sock;
+	}
+
+	enum state state = STATE_CONNECTED;
+	while (state != STATE_LAST) {
+		char buff[512];
+		int r = -1;
+		if (fgets(buff, sizeof(buff), sockf) == NULL) {
+			perror("read response");
+			goto err_close_sock;
+		}
+		switch (state) {
+		case STATE_CONNECTED:
+			if (strncmp(buff, "200 ", 4)) {
+				fprintf(stderr, "Invalid response: %s\n", buff);
+				goto err_close_sock;
+			}
+			r = snprintf(buff, sizeof(buff), "group %s\r\n", group);
+		break;
+		case STATE_GROUP_JOINED:
+			if (strncmp(buff, "211 ", 4)) {
+				fprintf(stderr, "Invalid response: %s\n", buff);
+				goto err_close_sock;
+			}
+			if (messageid[0] == '<') {
+				r = snprintf(buff, sizeof(buff), "article %s\r\n", messageid);
+			} else {
+				r = snprintf(buff, sizeof(buff), "article <%s>\r\n", messageid);
+			}
+			break;
+		case STATE_ARTICLE_RECV:
+			if (strncmp(buff, "220 ", 4)) {
+				fprintf(stderr, "Invalid response: %s\n", buff);
+				goto err_close_sock;
+			}
+			while (fgets(buff, sizeof(buff), sockf) != NULL) {
+				if (!strcmp(buff, "..\r\n")) puts(".");
+				else if (!strcmp(buff, ".\r\n")) break;
+				else fputs(buff, stdout);
+			}
+			r = snprintf(buff, sizeof(buff), "quit\r\n");
+			break;
+		case STATE_LAST:
+			break;
+		}
+		state++;
+		if (r > 0) write(sockfd, buff, r);
+	}
+	
+	close(sockfd);
+	freeaddrinfo(addr);
+	free(group);
+	return 0;
+err_close_sock:
+	close(sockfd);
+err_free_addr:
+	freeaddrinfo(addr);
+	free(group);
+	return 1;
+}