A FILE implementation that uses sys_async

772fa427 · Silas Boyd-Wickizer · d41ef66a · 772fa427 · 772fa427 · 772fa427
--- a/bin/Makefrag
+++ b/bin/Makefrag
@@ -18,6 +18,7 @@ UPROGS= \
 	usertests \
 	lockstat \
 	preadtest \
+	ftest \
 	perf

 ifeq ($(HAVE_LWIP),y)

--- a/bin/ftest.cc
+++ b/bin/ftest.cc
+#include "types.h"
+#include "stat.h"
+#include "fcntl.h"
+#include "user.h"
+#include "lib.h"
+#include "amd64.h"
+#include "ipc.hh"
+extern "C" {
+#include "fstream.h"
+}
+
+#define FSIZE (64 << 10)
+#define BSIZE 4096
+static char wbuf[512];
+static char rbuf[BSIZE];
+
+static int check = 0;
+
+int
+main(int ac, char **av)
+{
+  size_t count;
+  off_t off;
+  FILE *fp;
+  int fd;
+  int i;
+
+  memset(ipcctl, 0, sizeof(*ipcctl));
+
+  for (i = 0; i < sizeof(wbuf); i++)
+    wbuf[i] = i % 16;
+  
+  unlink("ftest.x");
+  fd = open("ftest.x", O_CREATE|O_RDWR);
+  for (i = 0; i < FSIZE; ) {
+    count = MIN(sizeof(wbuf), FSIZE-i);
+    if (write(fd, wbuf, count) != count)
+      die("write failed");
+    i += count;
+  }
+
+  fp = fdopen(fd, "r");
+  if (fp == 0)
+    die("fdopen");
+
+  off = 0;
+  while ((count = fread(rbuf, 1, BSIZE, fp))) {
+    if (check) {
+      for (i = 0; i < count; i++)
+        if (rbuf[i] != (i+off)%16)
+          die("ftest %u: %u != %u", i, (int)(rbuf[i]), (off+i)%16);
+      off += count;
+    }
+  }
+
+  fclose(fp);
+  exit();
+}
--- a/bin/preadtest.cc
+++ b/bin/preadtest.cc
@@ -7,9 +7,6 @@
 #include "amd64.h"
 #include "ipc.hh"

-// XXX(sbw) add a memlayout.h?
-#define KSHARED 0xFFFFF00000000000ull
-
 #define FSIZE (64 << 10)
 #define BSIZE 4096
 #define PSIZE (4*BSIZE)
@@ -18,8 +15,6 @@ static int use_async;

 static char buf[BSIZE];

-struct ipcctl *ipcctl = (struct ipcctl*)KSHARED;
-
 struct {
  u64 acount;
  u64 atot;
@@ -28,50 +23,6 @@ struct {
  u64 ptot;
 } stats;

-static msgid_t
-ipc_msg_alloc(void)
-{
-  if (ipcctl->msghead - ipcctl->msgtail == IPC_NMSG)
-    return NULL_MSGID;
-
-  msgid_t i = ipcctl->msghead % IPC_NMSG;
-  ipcctl->msghead++;
-  return i;
-}
-
-static void
-ipc_msg_free(int msgid)
-{
-  msgid_t i;
-
-  i = ipcctl->msgtail % IPC_NMSG;
-  if (i != msgid)
-    die("ipc_free_msg: oops");
-  ipcctl->msgtail++;
-}
-
-static pageid_t
-ipc_page_alloc(void)
-{
-  if (ipcctl->pagehead - ipcctl->pagetail == IPC_NPAGE)
-    return NULL_PAGEID;
-
-  pageid_t i = ipcctl->pagehead % IPC_NPAGE;
-  ipcctl->pagehead++;
-  return i;
-}
-
-static void
-ipc_page_free(pageid_t pageid)
-{
-  pageid_t i;
-
-  i = ipcctl->pagetail % IPC_NPAGE;
-  if (i != pageid)
-    die("ipc_free_page: oops");
-  ipcctl->pagetail++;
-}
-
 static void
 kernlet_pread(int fd, size_t count, off_t off)
 {

--- a/include/fstream.h
+++ b/include/fstream.h
+typedef struct fstream {
+  int fd;
+  off_t off;
+  off_t poff;
+  struct stat stat;
+  int err:1;
+  int eof:1;
+  int pfill:1;
+} FILE;
+
+FILE  *fdopen(int fd, const char *mode);
+int    fclose(FILE *fp);
+size_t fread(void *ptr, size_t size, size_t nmemb, FILE *fp);
+int    feof(FILE *fp);
+int    ferror(FILE *fp);
--- a/include/ipc.hh
+++ b/include/ipc.hh
-#define IPC_NMSG 16
-typedef u32 msgid_t;
-#define NULL_MSGID (-1)
+// XXX(sbw) add a memlayout.h?
+#define KSHARED 0xFFFFF00000000000ull

-#define IPC_NPAGE ((KSHAREDSIZE/PGSIZE) - 1)
 typedef u32 pageid_t;
+typedef u32 msgid_t;
+
+#define IPC_CTLSIZE 4096
+#define IPC_PGSIZE  4096
+#define IPC_NMSG    16
+#define NULL_MSGID  (-1)
 #define NULL_PAGEID (-1)
+#define IPC_NPAGE   ((KSHAREDSIZE/IPC_PGSIZE) - 1)

 struct ipcmsg {
  volatile char done:1;
@@ -16,10 +21,28 @@ struct ipcmsg {
 };

 struct ipcctl {
-  int msghead;
-  int msgtail;
+  volatile int msghead;
+  volatile int msgtail;
  struct ipcmsg msg[IPC_NMSG];

-  int pagehead;
-  int pagetail;
+  volatile int pagehead;
+  volatile int pagetail;
 };
+extern struct ipcctl *ipcctl;
+
+msgid_t  ipc_msg_alloc(void);
+void     ipc_msg_free(int msgid);
+pageid_t ipc_page_alloc(void);
+void     ipc_page_free(pageid_t pageid);
+
+static inline struct ipcmsg*
+getmsg(msgid_t id)
+{
+  return &ipcctl->msg[id];
+}
+
+static inline char*
+getpage(pageid_t id)
+{
+  return (char*)(KSHARED+IPC_CTLSIZE+(id*IPC_PGSIZE));
+}
--- a/lib/Makefrag
+++ b/lib/Makefrag
-ULIB = ulib.o usys.o printf.o umalloc.o uthread.o fmt.o
+ULIB = ulib.o usys.o printf.o umalloc.o uthread.o fmt.o fstream.o ipc.o
 ULIB := $(addprefix $(O)/lib/, $(ULIB))

 .PRECIOUS: $(O)/lib/%.o

--- a/lib/fstream.cc
+++ b/lib/fstream.cc
+extern "C" {
+#include "types.h"
+#include "stat.h"
+#include "user.h"
+#include "fstream.h"
+#include "lib.h"
+#include "amd64.h"
+}
+#include "ipc.hh"
+
+static const size_t pstride = 4096*4;
+
+static ssize_t
+fasync(FILE *fp, size_t count, off_t off)
+{
+  struct ipcmsg *msg;
+  msgid_t msgid;
+  pageid_t pageid;
+
+  msgid = ipc_msg_alloc();
+  if (msgid == NULL_MSGID) {
+    fprintf(2, "fasync: ipc_msg_alloc failed\n");
+    return -1;
+  }
+
+  pageid = ipc_page_alloc();
+  if (pageid == NULL_PAGEID) {
+    fprintf(2, "fasync: ipc_alloc_page failed\n");
+    return -1;
+  }
+
+  msg = &ipcctl->msg[msgid];
+  msg->done = 0;
+  msg->pageid = pageid;
+
+  if (async(fp->fd, count, off, msgid, pageid) != 0) {
+    fprintf(2, "fasync: async failed\n");
+    return -1;
+  }
+
+  return count;
+}
+
+static void
+fprefill(FILE *fp)
+{
+  size_t target;
+
+  if (!fp->pfill)
+    return;
+  
+  target = MIN(fp->off + pstride, fp->stat.size);
+  while (target - fp->poff >= IPC_PGSIZE)
+  {
+    size_t count;
+    int r;
+
+    count = MIN(target - fp->poff, IPC_PGSIZE);
+    r = fasync(fp, count, fp->poff);
+    if (r < 0)
+      return;
+    fp->poff += r;
+  }
+}
+
+FILE*
+fdopen(int fd, const char *mode)
+{
+  FILE *fp;
+
+  if (mode[0] != 'r')
+    return 0;
+  fp = (FILE*)malloc(sizeof(*fp));
+  if (fp == 0)
+    return 0;
+  if (fstat(fd, &fp->stat))
+    return 0;
+  fp->fd = fd;
+  fp->off = 0;
+  fp->poff = 0;
+  fp->pfill = mode[1] == 'p';
+  fprefill(fp);
+  return fp;
+}
+
+int
+fclose(FILE *fp)
+{
+  int r;
+
+  r = close(fp->fd);
+  free(fp);
+  return r;
+  // XXX(sbw) free ipcmsgs
+}
+
+static ssize_t
+fpostfill(void *ptr, size_t count, FILE*fp)
+{
+  struct ipcmsg *msg;
+  msgid_t msgid;
+
+  if (!fp->pfill)
+    return -2;
+
+again:
+  msgid = ipcctl->msgtail % IPC_NMSG;
+  msg = getmsg(msgid);
+
+  if (!msg->submitted)
+    return -2;
+  while (msg->done == 0)
+    nop_pause(); // XXX(sbw) yield somewhere?
+  if (msg->result == -1)
+    return -1;
+
+  if (msg->off > fp->off) {
+    return -2;
+  } else if ((msg->off + msg->result) < fp->off) {
+    msg->submitted = 0;
+    ipc_page_free(msg->pageid);
+    ipc_msg_free(msgid);
+    goto again;
+  }
+
+  char *buf = getpage(msg->pageid);
+  off_t boff = fp->off - msg->off;
+  size_t bcount = MIN(count, msg->result-boff);
+  memmove(ptr, buf+boff, bcount);
+  
+  msg->submitted = 0;
+  ipc_page_free(msg->pageid);
+  ipc_msg_free(msgid);
+  return bcount;
+}
+
+size_t
+fread(void *ptr, size_t size, size_t nmemb, FILE *fp)
+{
+  ssize_t r;
+
+  r = fpostfill(ptr, size*nmemb, fp);
+  if (r == -2)
+    r = pread(fp->fd, ptr, size*nmemb, fp->off);
+
+  if (r < 0) {
+    fp->err = 1;
+    return 0;
+  } else if (r == 0) {
+    fp->eof = 1;
+    return 0;
+  }
+  fp->off += r;
+  fprefill(fp);
+  return r;
+}
+
+int
+feof(FILE *fp)
+{
+  return fp->eof;
+}
+
+int
+ferror(FILE *fp)
+{
+  return fp->err;
+}
--- a/lib/ipc.cc
+++ b/lib/ipc.cc
+#include "types.h"
+#include "user.h"
+#include "ipc.hh"
+
+struct ipcctl *ipcctl = (struct ipcctl*)KSHARED;
+
+msgid_t
+ipc_msg_alloc(void)
+{
+  if (ipcctl->msghead - ipcctl->msgtail == IPC_NMSG)
+    return NULL_MSGID;
+
+  msgid_t i = ipcctl->msghead % IPC_NMSG;
+  ipcctl->msghead++;
+  return i;
+}
+
+void
+ipc_msg_free(int msgid)
+{
+  msgid_t i;
+
+  i = ipcctl->msgtail % IPC_NMSG;
+  if (i != msgid)
+    die("ipc_free_msg: oops %u %u", i, msgid);
+  ipcctl->msgtail++;
+}
+
+pageid_t
+ipc_page_alloc(void)
+{
+  if (ipcctl->pagehead - ipcctl->pagetail == IPC_NPAGE)
+    return NULL_PAGEID;
+
+  pageid_t i = ipcctl->pagehead % IPC_NPAGE;
+  ipcctl->pagehead++;
+  return i;
+}
+
+void
+ipc_page_free(pageid_t pageid)
+{
+  pageid_t i;
+
+  i = ipcctl->pagetail % IPC_NPAGE;
+  if (i != pageid)
+    die("ipc_free_page: oops");
+  ipcctl->pagetail++;
+}