Add a stat member to devsw and a sampstat function

c01b7d28 · Silas Boyd-Wickizer · 1258b4c3 · c01b7d28 · c01b7d28 · c01b7d28
--- a/file.hh
+++ b/file.hh
@@ -53,6 +53,7 @@ struct inode : public rcu_freed {
 struct devsw {
  int (*read)(struct inode*, char*, u32, u32);
  int (*write)(struct inode*, char*, u32, u32);
+  void (*stat)(struct inode*, struct stat*);
 };

 extern struct devsw devsw[];

--- a/fs.cc
+++ b/fs.cc
@@ -529,6 +529,14 @@ itrunc(struct inode *ip)
 void
 stati(struct inode *ip, struct stat *st)
 {
+  if(ip->type == T_DEV){
+    if(ip->major < 0 || ip->major >= NDEV || !devsw[ip->major].stat)
+      memset(st, 0, sizeof(*st));
+    else
+      devsw[ip->major].stat(ip, st);
+    return;
+  }
+
  st->dev = ip->dev;
  st->ino = ip->inum;
  st->type = ip->type;

--- a/perf.cc
+++ b/perf.cc
@@ -29,36 +29,6 @@ conf(int fd, sampop_t op)
  close(fd);
 }

-static void
-save(void)
-{
-  static char buf[4096];
-  int fd, sfd;
-  int r;
-
-  fd = open("/dev/sampler", O_RDONLY);
-  if (fd < 0)
-    die("perf: open failed");
-
-  unlink("perf.data");
-  sfd = open("perf.data", O_RDWR|O_CREATE);
-  if (sfd < 0)
-    die("perf: open failed");
-
-  while (1) {
-    r = read(fd, buf, sizeof(buf));
-    if (r < 0)
-      die("perf: read failed");
-    if (r == 0)
-      break;
-    if (write(sfd, buf, r) != r)
-      die("perf: truncated write");
-  }
-
-  close(sfd);
-  close(fd);
-}
-
 int
 main(int ac, const char *av[])
 {
@@ -78,6 +48,5 @@ main(int ac, const char *av[])
  
  wait();
  conf(fd, SAMP_DISABLE);
-  save();
  exit();
 }
--- a/print-perf.c
+++ b/print-perf.c
@@ -11,7 +11,7 @@
 int
 main(int ac, char **av)
 {
-  static const char *pathname = "perf.data";
+  static const char *pathname = "sampler";
  struct logheader *header;
  struct stat buf;
  void *x;

--- a/sampler.cc
+++ b/sampler.cc
@@ -4,6 +4,7 @@ extern "C" {
 #include "condvar.h"
 #include "fs.h"
 #include "kernel.h"
+#include "stat.h"
 }

 #include "file.hh"
@@ -15,6 +16,9 @@ extern "C" {
 #include "sampler.h"
 }

+#define LOGHEADER_SZ (sizeof(struct logheader) + \
+                      sizeof(((struct logheader*)0)->cpu[0])*NCPU)
+
 static volatile u64 selector;
 static volatile u64 period;

@@ -153,20 +157,36 @@ readlog(char *dst, u32 off, u32 n)
  return ret;
 }

+static void
+sampstat(struct inode *ip, struct stat *st)
+{
+  struct pmulog *q = &pmulog[NCPU];
+  struct pmulog *p;
+  u64 sz = 0;
+  
+  sz += LOGHEADER_SZ;
+  for (p = &pmulog[0]; p != q; p++)
+    sz += p->count * sizeof(struct pmuevent);
+
+  st->dev = ip->dev;
+  st->ino = ip->inum;
+  st->type = ip->type;
+  st->nlink = ip->nlink;
+  st->size = sz;
+}
+
 static int
 sampread(struct inode *ip, char *dst, u32 off, u32 n)
 {
  struct pmulog *q = &pmulog[NCPU];
  struct pmulog *p;
  struct logheader *hdr;
-  u64 hdrlen;
  int ret;
  int i;
  
  ret = 0;
-  hdrlen = sizeof(*hdr) + sizeof(hdr->cpu[0])*NCPU;
-  if (off < hdrlen) {
-    u64 len = hdrlen;
+  if (off < LOGHEADER_SZ) {
+    u64 len = LOGHEADER_SZ;
    u64 cc;
    
    hdr = (logheader*) kmalloc(len);
@@ -182,7 +202,7 @@ sampread(struct inode *ip, char *dst, u32 off, u32 n)
      i++;
    }

-    cc = MIN(hdrlen-off, n);
+    cc = MIN(LOGHEADER_SZ-off, n);
    memmove(dst, (char*)hdr + off, cc);
    kmfree(hdr);

@@ -192,8 +212,8 @@ sampread(struct inode *ip, char *dst, u32 off, u32 n)
    dst += cc;
  }

-  if (off >= hdrlen)
-    ret += readlog(dst, off-hdrlen, n);
+  if (off >= LOGHEADER_SZ)
+    ret += readlog(dst, off-LOGHEADER_SZ, n);
  return ret;
 }

@@ -257,4 +277,5 @@ initsamp(void)

  devsw[SAMPLER].write = sampwrite;
  devsw[SAMPLER].read = sampread;
+  devsw[SAMPLER].stat = sampstat;
 }