use poll() instead of select() for checking file descriptor activity to also correctly work if more than FD_SETSIZE files are already open

git-svn-id: http://arthurdejong.org/svn/nss-pam-ldapd/nss-pam-ldapd@1783 ef36b2f9-881f-0410-afb5-c4e39611909c

4 files changed, 57 insertions, 109 deletions

diff --git a/common/nslcd-prot.c b/common/nslcd-prot.c
index c0ecc99..3bb3e0c 100644
--- a/common/nslcd-prot.c
+++ b/common/nslcd-prot.c
@@ -38,6 +38,11 @@
 #include "nslcd-prot.h"
 #include "compat/socket.h"
 
+/* read timeout is 60 seconds because looking up stuff may take some time
+   write timeout is 10 secods because nslcd could be loaded with requests */
+#define READ_TIMEOUT 60*1000
+#define WRITE_TIMEOUT 10*1000
+
 /* buffer sizes for I/O */
 #define READBUFFER_MINSIZE 1024
 #define READBUFFER_MAXSIZE 2*1024*1024
@@ -56,7 +61,6 @@ TFILE *nslcd_client_open()
 {
   int sock;
   struct sockaddr_un addr;
-  struct timeval readtimeout,writetimeout;
   TFILE *fp;
   /* create a socket */
   if ( (sock=socket(PF_UNIX,SOCK_STREAM,0))<0 )
@@ -72,13 +76,8 @@ TFILE *nslcd_client_open()
     (void)close(sock);
     return NULL;
   }
-  /* set the timeouts */
-  readtimeout.tv_sec=60; /* looking up stuff may take some time */
-  readtimeout.tv_usec=0;
-  writetimeout.tv_sec=10; /* nslcd could be loaded with requests */
-  writetimeout.tv_usec=0;
   /* create a stream object */
-  if ((fp=tio_fdopen(sock,&readtimeout,&writetimeout,
+  if ((fp=tio_fdopen(sock,READ_TIMEOUT,WRITE_TIMEOUT,
                      READBUFFER_MINSIZE,READBUFFER_MAXSIZE,
                      WRITEBUFFER_MINSIZE,WRITEBUFFER_MAXSIZE))==NULL)
   {
diff --git a/common/tio.c b/common/tio.c
index 75d1f64..0dffff4 100644
--- a/common/tio.c
+++ b/common/tio.c
@@ -35,6 +35,7 @@
 #include <signal.h>
 #include <stdio.h>
 #include <limits.h>
+#include <poll.h>
 
 #include "tio.h"
 
@@ -63,8 +64,8 @@ struct tio_fileinfo {
   int fd;
   struct tio_buffer readbuffer;
   struct tio_buffer writebuffer;
-  struct timeval readtimeout;
-  struct timeval writetimeout;
+  int readtimeout;
+  int writetimeout;
   int read_resettable; /* whether the tio_reset() function can be called */
 #ifdef DEBUG_TIO_STATS
   /* this is used to collect statistics on the use of the streams
@@ -74,21 +75,8 @@ struct tio_fileinfo {
 #endif /* DEBUG_TIO_STATS */
 };
 
-/* add the second timeval to the first modifing the first */
-static inline void tio_tv_add(struct timeval *tv1, const struct timeval *tv2)
-{
-  /* BUG: we hope that this does not overflow */
-  tv1->tv_usec+=tv2->tv_usec;
-  if (tv1->tv_usec>=1000000)
-  {
-    tv1->tv_usec-=1000000;
-    tv1->tv_sec+=1;
-  }
-  tv1->tv_sec+=tv2->tv_sec;
-}
-
 /* build a timeval for comparison to when the operation should be finished */
-static inline void tio_tv_prepare(struct timeval *deadline, const struct timeval *timeout)
+static inline void tio_get_deadline(struct timeval *deadline,int timeout)
 {
   if (gettimeofday(deadline,NULL))
   {
@@ -97,39 +85,27 @@ static inline void tio_tv_prepare(struct timeval *deadline, const struct timeval
     deadline->tv_usec=0;
     return;
   }
-  tio_tv_add(deadline,timeout);
+  deadline->tv_sec+=timeout/1000;
+  deadline->tv_sec+=(timeout%1000)*1000;
 }
 
-/* update the timeval to the value that is remaining before deadline
+/* update the timeout to the value that is remaining before deadline
    returns non-zero if there is no more time before the deadline */
-static inline int tio_tv_remaining(struct timeval *tv, const struct timeval *deadline)
+static inline int tio_time_remaining(const struct timeval *deadline)
 {
+  struct timeval tv;
   /* get the current time */
-  if (gettimeofday(tv,NULL))
+  if (gettimeofday(&tv,NULL))
   {
     /* 1 second default if gettimeofday() is broken */
-    tv->tv_sec=1;
-    tv->tv_usec=0;
-    return 0;
-  }
-  /* check if we're too late */
-  if ( (tv->tv_sec>deadline->tv_sec) ||
-       ( (tv->tv_sec==deadline->tv_sec) && (tv->tv_usec>deadline->tv_usec) ) )
-    return -1;
-  /* update tv */
-  tv->tv_sec=deadline->tv_sec-tv->tv_sec;
-  if (tv->tv_usec<=deadline->tv_usec)
-    tv->tv_usec=deadline->tv_usec-tv->tv_usec;
-  else
-  {
-    tv->tv_sec--;
-    tv->tv_usec=1000000+deadline->tv_usec-tv->tv_usec;
+    return 1000;
   }
-  return 0;
+  /* calculate time remaining in miliseconds */
+  return (deadline->tv_sec-tv.tv_sec)*1000 + (deadline->tv_usec-tv.tv_usec)/1000;
 }
 
 /* open a new TFILE based on the file descriptor */
-TFILE *tio_fdopen(int fd,struct timeval *readtimeout,struct timeval *writetimeout,
+TFILE *tio_fdopen(int fd,int readtimeout,int writetimeout,
                   size_t initreadsize,size_t maxreadsize,
                   size_t initwritesize,size_t maxwritesize)
 {
@@ -162,10 +138,8 @@ TFILE *tio_fdopen(int fd,struct timeval *readtimeout,struct timeval *writetimeou
   fp->writebuffer.start=0;
   fp->writebuffer.len=0;
   /* initialize other attributes */
-  fp->readtimeout.tv_sec=readtimeout->tv_sec;
-  fp->readtimeout.tv_usec=readtimeout->tv_usec;
-  fp->writetimeout.tv_sec=writetimeout->tv_sec;
-  fp->writetimeout.tv_usec=writetimeout->tv_usec;
+  fp->readtimeout=readtimeout;
+  fp->writetimeout=writetimeout;
   fp->read_resettable=0;
 #ifdef DEBUG_TIO_STATS
   fp->byteswritten=0;
@@ -176,23 +150,15 @@ TFILE *tio_fdopen(int fd,struct timeval *readtimeout,struct timeval *writetimeou
 
 /* wait for any activity on the specified file descriptor using
    the specified deadline */
-static int tio_select(TFILE *fp, int readfd, const struct timeval *deadline)
+static int tio_wait(TFILE *fp,int readfd,const struct timeval *deadline)
 {
-  struct timeval tv;
-  fd_set fdset;
+  int timeout;
+  struct pollfd fds[1];
   int rv;
   while (1)
   {
-    /* prepare our filedescriptorset */
-    if (fp->fd>=FD_SETSIZE)
-    {
-      errno=EBADFD;
-      return -1;
-    }
-    FD_ZERO(&fdset);
-    FD_SET(fp->fd,&fdset);
     /* figure out the time we need to wait */
-    if (tio_tv_remaining(&tv,deadline))
+    if ((timeout=tio_time_remaining(deadline))<0)
     {
       errno=ETIME;
       return -1;
@@ -200,18 +166,21 @@ static int tio_select(TFILE *fp, int readfd, const struct timeval *deadline)
     /* wait for activity */
     if (readfd)
     {
+      fds[0].fd=fp->fd;
+      fds[0].events=POLLIN;
       /* santiy check for moving clock */
-      if (tv.tv_sec>fp->readtimeout.tv_sec)
-        tv.tv_sec=fp->readtimeout.tv_sec;
-      rv=select(FD_SETSIZE,&fdset,NULL,NULL,&tv);
+      if (timeout>fp->readtimeout)
+        timeout=fp->readtimeout;
     }
     else
     {
+      fds[0].fd=fp->fd;
+      fds[0].events=POLLOUT;
       /* santiy check for moving clock */
-      if (tv.tv_sec>fp->writetimeout.tv_sec)
-        tv.tv_sec=fp->writetimeout.tv_sec;
-      rv=select(FD_SETSIZE,NULL,&fdset,NULL,&tv);
+      if (timeout>fp->writetimeout)
+        timeout=fp->writetimeout;
     }
+    rv=poll(fds,1,timeout);
     if (rv>0)
       return 0; /* we have activity */
     else if (rv==0)
@@ -239,7 +208,7 @@ int tio_read(TFILE *fp, void *buf, size_t count)
   /* have a more convenient storage type for the buffer */
   uint8_t *ptr=(uint8_t *)buf;
   /* build a time by which we should be finished */
-  tio_tv_prepare(&deadline,&(fp->readtimeout));
+  tio_get_deadline(&deadline,fp->readtimeout);
   /* loop until we have returned all the needed data */
   while (1)
   {
@@ -297,7 +266,7 @@ int tio_read(TFILE *fp, void *buf, size_t count)
       }
     }
     /* wait until we have input */
-    if (tio_select(fp,1,&deadline))
+    if (tio_wait(fp,1,&deadline))
       return -1;
     /* read the input in the buffer */
     len=fp->readbuffer.size-fp->readbuffer.start;
@@ -331,8 +300,7 @@ int tio_skip(TFILE *fp, size_t count)
 /* Read all available data from the stream and empty the read buffer. */
 int tio_skipall(TFILE *fp)
 {
-  struct timeval tv;
-  fd_set fdset;
+  struct pollfd fds[1];
   int rv;
   size_t len;
   /* clear the read buffer */
@@ -347,19 +315,11 @@ int tio_skipall(TFILE *fp)
 #endif /* SSIZE_MAX */
   while (1)
   {
-    /* prepare our file descriptor set */
-    if (fp->fd>=FD_SETSIZE)
-    {
-      errno=EBADFD;
-      return -1;
-    }
-    FD_ZERO(&fdset);
-    FD_SET(fp->fd,&fdset);
-    /* prepare the time to wait */
-    tv.tv_sec=0;
-    tv.tv_usec=0;
     /* see if any data is available */
-    rv=select(FD_SETSIZE,&fdset,NULL,NULL,&tv);
+    fds[0].fd=fp->fd;
+    fds[0].events=POLLIN;
+    rv=poll(fds,1,0);
+    /* check the poll() result */
     if (rv==0)
       return 0; /* no file descriptor ready */
     if ((rv<0)&&((errno==EINTR)||(errno==EAGAIN)))
@@ -434,12 +394,12 @@ int tio_flush(TFILE *fp)
 {
   struct timeval deadline;
   /* build a time by which we should be finished */
-  tio_tv_prepare(&deadline,&(fp->writetimeout));
+  tio_get_deadline(&deadline,fp->writetimeout);
   /* loop until we have written our buffer */
   while (fp->writebuffer.len > 0)
   {
     /* wait until we can write */
-    if (tio_select(fp,0,&deadline))
+    if (tio_wait(fp,0,&deadline))
       return -1;
     /* write one block */
     if (tio_writebuf(fp))
@@ -452,22 +412,12 @@ int tio_flush(TFILE *fp)
    will accept data */
 static int tio_flush_nonblock(TFILE *fp)
 {
-  struct timeval tv;
-  fd_set fdset;
+  struct pollfd fds[1];
   int rv;
-  /* prepare our filedescriptorset */
-  if (fp->fd>=FD_SETSIZE)
-  {
-    errno=EBADFD;
-    return -1;
-  }
-  FD_ZERO(&fdset);
-  FD_SET(fp->fd,&fdset);
-  /* set the timeout to 0 to poll */
-  tv.tv_sec=0;
-  tv.tv_usec=0;
   /* wait for activity */
-  rv=select(FD_SETSIZE,NULL,&fdset,NULL,&tv);
+  fds[0].fd=fp->fd;
+  fds[0].events=POLLOUT;
+  rv=poll(fds,1,0);
   /* check if any file descriptors were ready (timeout) or we were
      interrupted */
   if ((rv==0)||((rv<0)&&(errno==EINTR)))
diff --git a/common/tio.h b/common/tio.h
index 59f26df..cd3f370 100644
--- a/common/tio.h
+++ b/common/tio.h
@@ -46,9 +46,8 @@
 typedef struct tio_fileinfo TFILE;
 
 /* Open a new TFILE based on the file descriptor. The timeout is set for any
-   operation. The timeout value is copied so may be dereferenced after the
-   call. */
-TFILE *tio_fdopen(int fd,struct timeval *readtimeout,struct timeval *writetimeout,
+   operation (value in milliseconds). */
+TFILE *tio_fdopen(int fd,int readtimeout,int writetimeout,
                   size_t initreadsize,size_t maxreadsize,
                   size_t initwritesize,size_t maxwritesize)
   LIKE_MALLOC MUST_USE;
diff --git a/nslcd/nslcd.c b/nslcd/nslcd.c
index fd836ae..54b97f3 100644
--- a/nslcd/nslcd.c
+++ b/nslcd/nslcd.c
@@ -66,6 +66,12 @@
 #include "compat/getpeercred.h"
 #include "compat/socket.h"
 
+/* read timeout is half a second because clients should send their request
+   quickly, write timeout is 60 seconds because clients could be taking some
+   time to process the results */
+#define READ_TIMEOUT 500
+#define WRITE_TIMEOUT 60*1000
+
 /* buffer sizes for I/O */
 #define READBUFFER_MINSIZE 32
 #define READBUFFER_MAXSIZE 64
@@ -378,7 +384,6 @@ static void handleconnection(int sock,MYLDAP_SESSION *session)
 {
   TFILE *fp;
   int32_t action;
-  struct timeval readtimeout,writetimeout;
   uid_t uid=(uid_t)-1;
   gid_t gid=(gid_t)-1;
   pid_t pid=(pid_t)-1;
@@ -388,13 +393,8 @@ static void handleconnection(int sock,MYLDAP_SESSION *session)
   else
     log_log(LOG_DEBUG,"connection from pid=%d uid=%d gid=%d",
                       (int)pid,(int)uid,(int)gid);
-  /* set the timeouts */
-  readtimeout.tv_sec=0; /* clients should send their request quickly */
-  readtimeout.tv_usec=500000;
-  writetimeout.tv_sec=60; /* clients could be taking some time to process the results */
-  writetimeout.tv_usec=0;
   /* create a stream object */
-  if ((fp=tio_fdopen(sock,&readtimeout,&writetimeout,
+  if ((fp=tio_fdopen(sock,READ_TIMEOUT,WRITE_TIMEOUT,
                      READBUFFER_MINSIZE,READBUFFER_MAXSIZE,
                      WRITEBUFFER_MINSIZE,WRITEBUFFER_MAXSIZE))==NULL)
   {