httpd: tests lwIP and a potential way to get profile data off the machine.

lwIP/net/e1000 seem to have a few nagging bugs, but httpd is able to serve files.

httpd: tests lwIP and a potential way to get profile data off the machine.
455ed1b8 · Silas Boyd-Wickizer · 8643fbac · 455ed1b8 · 455ed1b8 · 455ed1b8
--- a/Makefile
+++ b/Makefile
@@ -150,8 +150,8 @@ mscan.kern: $(O)/kernel
 ## qemu
 ##
 QEMUOPTS = -smp $(QEMUSMP) -m 512 -serial mon:stdio -nographic \
-	-net user -net nic,model=e1000 \
-	-net dump,file=qemu.pcap -redir tcp:2323::23
+	-net user -net nic,model=e1000 -net dump,file=qemu.pcap \
+	-redir tcp:2323::23 -redir tcp:8080::80

 qemu: $(O)/kernel
 	$(QEMU) $(QEMUOPTS) -kernel $(O)/kernel

--- a/httpd.c
+++ b/httpd.c
+#include "types.h"
+#include "user.h"
+#include "lib.h"
+#include "unet.h"
+#include "fcntl.h"
+#include "stat.h"
+
+#define VERSION "0.1"
+#define HTTP_VERSION "1.0"
+#define BUFSIZE 512
+
+static void
+error(int s, int code)
+{
+  static struct {
+    int code;
+    const char *msg;
+  } errors[] = {
+    { 400, "Bad Request" },
+    { 404, "Page Not Found" },
+  };
+  
+  char buf[512];
+  int i;
+  int r;
+
+  for (i = 0; i < NELEM(errors); i++)
+    if (errors[i].code == code)
+      break;
+
+  if (i == NELEM(errors))
+    die("httpd error: unknown code %u", code);
+
+  snprintf(buf, 512, "HTTP/" HTTP_VERSION" %d %s\r\n"
+           "Server: xv6-httpd/" VERSION "\r\n"
+           "Connection: close"
+           "Content-type: text/html\r\n"
+           "\r\n"
+           "<html><body><p>%d - %s</p></body></html>\r\n",
+           errors[i].code, errors[i].msg, 
+           errors[i].code, errors[i].msg);
+  r = strlen(buf);
+
+  if (write(s, buf, r) != r)
+    die("httpd error: incomplete write %d", r);
+}
+
+static int
+header(int s)
+{
+  static const char *h = "HTTP/" HTTP_VERSION " 200 OK\r\n"
+    "Server: xv6-httpd/" VERSION "\r\n";
+
+  int len;
+  int r;
+
+  len = strlen(h);
+  r = write(s, h, len);
+  if (r != len)
+    die("httpd header: incomplete write %d", r);
+
+  return 0;
+}
+
+static int
+header_fin(int s)
+{
+  static const char *f = "\r\n";
+  
+  int len;
+  int r;
+
+  len = strlen(f);
+  r = write(s, f, len);
+  if (r != len)
+    die("httpd fin: incomplete write %d", r);
+
+  return 0;
+}
+
+static int
+content_length(int s, u64 size)
+{
+  char buf[128];
+  int len;
+  int r;
+
+  snprintf(buf, 128, "Content-Length: %lu\r\n", size);
+  len = strlen(buf);
+
+  r = write(s, buf, len);
+  if (r != len)
+    die("httpd size: incomplete write %d", r);
+  return 0;
+}
+
+static int
+content_type(int s)
+{
+  static const char *t = "Content-Type: text/plain\r\n";
+
+  int len;
+  int r;
+
+  len = strlen(t);
+  r = write(s, t, len);
+  if (r != len)
+    die("httpd content_type: incomplete write %d", r);
+  return 0;
+}
+
+static int
+content(int s, int fd)
+{
+  char buf[256];
+  int n;
+  int r;
+
+  for (;;) {
+    n = read(fd, buf, sizeof(buf));
+    if (n < 0) {
+      printf(2, "send_data: read failed %d\n", n);
+      return n;
+    } else if (n == 0) {
+      return 0;
+    }
+    
+    r = write(s, buf, n);
+    if (r != n)
+      die("httpd content: read failed %d", r);
+  }
+}
+
+static void
+resp(int s, const char *url)
+{
+  struct stat stat;
+  int fd;
+  int r;
+
+  fd = open(url, O_RDONLY);
+  if (fd < 0) {
+    error(s, 404);
+    return;
+  }
+
+  r = fstat(fd, &stat);
+  if (r < 0) {
+    printf(2, "httpd resp: fstat %d\n", r);
+    close(fd);
+    return error(s, 404);
+  }
+
+  if (stat.type != T_FILE && stat.type != T_DEV) {
+    close(fd);
+    return error(s, 404);
+  }
+
+  r = header(s);
+  if (r < 0)
+    goto error;
+
+  r = content_length(s, stat.size);
+  if (r < 0)
+    goto error;
+
+  r = content_type(s);
+  if (r < 0)
+    goto error;
+
+  r = header_fin(s);
+  if (r < 0)
+    goto error;
+
+  r = content(s, fd);
+  if (r < 0)
+    goto error;
+  
+  close(fd);
+  return;
+
+error:
+  close(fd);
+  error(s, -r);
+}
+
+static int
+parse(const char *b, char **rurl)
+{
+  const char *url;
+  int len;
+  char *r;
+
+  if (strncmp(b, "GET ", 4) != 0)
+    return -1;
+
+  b += 4;
+  url = b;
+  while (*b && *b != ' ')
+    b++;
+  len = b - url;
+
+  r = malloc(len+1);
+  if (r == NULL)
+    return -1;
+  memmove(r, url, len);
+  r[len] = 0;
+
+  *rurl = r;
+  return 0;
+}
+
+static void
+client(int s)
+{
+  char b[BUFSIZE];
+  char *url;
+  int r;
+
+  r = read(s, b, NELEM(b)-1);
+  if (r < 0)
+    printf(1, "httpd client: read %d\n", r);
+  b[r] = 0;
+  
+  r = parse(b, &url);
+  if (r < 0) {
+    error(s, 400);
+    return;
+  }    
+
+  printf(1, "httpd client: url %s\n", url);
+  resp(s, url);
+  free(url);
+}
+
+int
+main(void)
+{
+  int s;
+  int r;
+
+  s = socket(AF_INET, SOCK_STREAM, 0);
+  if (s < 0)
+    die("httpd socket: %d\n", s);
+
+  struct sockaddr_in sin;
+  sin.sin_family = AF_INET;
+  sin.sin_addr.s_addr = htonl(INADDR_ANY);
+  sin.sin_port = htons(80);
+  r = bind(s, (struct sockaddr *)&sin, sizeof(sin));
+  if (r < 0)
+    die("httpd bind: %d\n", r);
+  
+  r = listen(s, 5);
+  if (r < 0)
+    die("httpd listen: %d\n", r);
+
+  printf(1, "httpd: port 80\n");
+
+  for (;;) {
+    socklen_t socklen;
+    int ss;
+    
+    socklen = sizeof(sin);
+    ss = accept(s, (struct sockaddr *)&sin, &socklen);
+    if (ss < 0) {
+      printf(2, "telnetd accept: %d\n", ss);
+      continue;
+    }
+    printf(1, "httpd: connection\n");
+
+    client(ss);
+    close(ss);
+  }
+}
--- a/net.mk
+++ b/net.mk
@@ -9,7 +9,9 @@ ifeq ($(HAVE_LWIP),y)
 -include $(O)/net/*.d

 OBJS += $(O)/liblwip.a
-UPROGS += $(O)/_telnetd
+UPROGS += \
+       $(O)/_telnetd \
+       $(O)/_httpd

 CFLAGS += -Ilwip/src/include -Inet -Ilwip/src/include/ipv4 -I. -DLWIP