lttd changes for lockless lttng

[ltt-control.git] / ltt / branches / poly / lttd / lttd.c

diff --git a/ltt/branches/poly/lttd/lttd.c b/ltt/branches/poly/lttd/lttd.c
index e090729c369aa0feb24a19b96d76c536f96f18e0..6da2924292581e44a66b37f1e870f6f09caba348 100644 (file)
--- a/ltt/branches/poly/lttd/lttd.c
+++ b/ltt/branches/poly/lttd/lttd.c
@@ -10,6 +10,10 @@
  *     Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  */
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 #define _GNU_SOURCE
 #include <stdio.h>
 #include <unistd.h>
@@ -31,7 +35,7 @@
 /* Get the next sub buffer that can be read. */
 #define RELAYFS_GET_SUBBUF        _IOR(0xF4, 0x00,__u32)
 /* Release the oldest reserved (by "get") sub buffer. */
-#define RELAYFS_PUT_SUBBUF        _IO(0xF4, 0x01)
+#define RELAYFS_PUT_SUBBUF        _IOW(0xF4, 0x01,__u32)
 /* returns the number of sub buffers in the per cpu channel. */
 #define RELAYFS_GET_N_SUBBUFS     _IOR(0xF4, 0x02,__u32)
 /* returns the size of the sub buffers. */
@@ -71,6 +75,7 @@ volatile static int   quit_program = 0;       /* For signal handler */
  * -c directory                Root directory of the relayfs trace channels.
  * -d                          Run in background (daemon).
  * -a                                                  Trace append mode.
+ * -s                                                  Send SIGUSR1 to parent when ready for IO.
  */
 void show_arguments(void)
 {
@@ -188,22 +193,21 @@ int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
        char path_trace[PATH_MAX];
        int path_trace_len;
        char *path_trace_ptr;
+  int open_ret = 0;
 
        if(channel_dir == NULL) {
                perror(subchannel_name);
-               return ENOENT;
+               open_ret = ENOENT;
+    goto end;
        }
 
-       //FIXME : check if the directory already exist, and ask the user if he wants
-       //to append to the traces.
        printf("Creating trace subdirectory %s\n", subtrace_name);
        ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO);
        if(ret == -1) {
-               if(errno == EEXIST && append_mode) {
-                       printf("Appending to directory %s as resquested\n", subtrace_name);
-               } else {
+               if(errno != EEXIST) {
                        perror(subtrace_name);
-                       return -1;
+      open_ret = -1;
+                       goto end;
                }
        }
 
@@ -250,12 +254,14 @@ int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
                                open(path_channel, O_RDONLY | O_NONBLOCK);
                        if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
                                perror(path_channel);
+                               fd_pairs->num_pairs--;
+                               continue;
                        }
                        /* Open the trace in write mode, only append if append_mode */
                        ret = stat(path_trace, &stat_buf);
                        if(ret == 0) {
                                if(append_mode) {
-                                       printf("Appending to file %s as resquested\n", path_trace);
+                                       printf("Appending to file %s as requested\n", path_trace);
 
                                        fd_pairs->pair[fd_pairs->num_pairs-1].trace = 
                                                open(path_trace, O_WRONLY|O_APPEND,
@@ -266,7 +272,8 @@ int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
                                        }
                                } else {
                                        printf("File %s exists, cannot open. Try append mode.\n", path_trace);
-                                       return -1;
+                                       open_ret = -1;
+          goto end;
                                }
                        } else {
                                if(errno == ENOENT) {
@@ -281,44 +288,54 @@ int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
                }
        }
        
+end:
        closedir(channel_dir);
 
-       return 0;
+       return open_ret;
 }
 
 
 int read_subbuffer(struct fd_pair *pair)
 {
-       unsigned int    subbuf_index;
-       int ret;
+       unsigned int    consumed_old;
+       int err, ret;
 
 
-       ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF, 
-                                                               &subbuf_index);
-       if(ret != 0) {
+       err = ioctl(pair->channel, RELAYFS_GET_SUBBUF, 
+                                                               &consumed_old);
+       printf("cookie : %u\n", consumed_old);
+       if(err != 0) {
                perror("Error in reserving sub buffer");
-               goto error;
+               ret = -EPERM;
+               goto get_error;
        }
-
-       ret = TEMP_FAILURE_RETRY(write(pair->trace,
-                               pair->mmap + (subbuf_index * pair->subbuf_size),
-                               pair->subbuf_size));
        
-       if(ret != 0) {
+       err = TEMP_FAILURE_RETRY(write(pair->trace,
+                               pair->mmap + (consumed_old & (~(pair->subbuf_size-1))),
+                               pair->subbuf_size));
+
+       if(err < 0) {
                perror("Error in writing to file");
-               goto error;
+               ret = err;
+               goto write_error;
        }
 
 
-       ret = ioctl(pair->channel, RELAYFS_PUT_SUBBUF);
-       if(ret != 0) {
-               perror("Error in unreserving sub buffer");
-               goto error;
+write_error:
+       err = ioctl(pair->channel, RELAYFS_PUT_SUBBUF, &consumed_old);
+       if(err != 0) {
+               if(errno == -EFAULT) {
+                       perror("Error in unreserving sub buffer");
+                       ret = -EFAULT;
+               } else if(errno == -EIO) {
+                       perror("Reader has been pushed by the writer, last subbuffer corrupted.");
+                       ret = -EIO;
+               }
+               goto get_error;
        }
 
-       return 0;
-error:
-       return -1;
+get_error:
+       return ret;
 }
 
 
@@ -346,6 +363,11 @@ int read_channels(struct channel_trace_fd *fd_pairs)
        int high_prio;
        int ret;
 
+       if(fd_pairs->num_pairs <= 0) {
+               printf("No channel to read\n");
+               goto end;
+       }
+       
        /* Get the subbuf sizes and number */
 
        for(i=0;i<fd_pairs->num_pairs;i++) {
@@ -395,7 +417,7 @@ int read_channels(struct channel_trace_fd *fd_pairs)
                printf("Press a key for next poll...\n");
                char buf[1];
                read(STDIN_FILENO, &buf, 1);
-               printf("Next poll :\n");
+               printf("Next poll (polling %d fd) :\n", fd_pairs->num_pairs);
 #endif //DEBUG
                
                /* Have we received a signal ? */
@@ -488,7 +510,6 @@ void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
 int main(int argc, char ** argv)
 {
        int ret;
-       pid_t pid;
        struct channel_trace_fd fd_pairs = { NULL, 0 };
        struct sigaction act;
        
@@ -501,18 +522,13 @@ int main(int argc, char ** argv)
        show_info();
 
        if(daemon_mode) {
-               pid = fork();
-               
-               if(pid > 0) {
-                       /* parent */
-                       return 0;
-               } else if(pid < 0) {
-                       /* error */
-                       printf("An error occured while forking.\n");
-                       return -1;
-               }
-               /* else, we are the child, continue... */
-       }
+               ret = daemon(0, 0);
+    
+    if(ret == -1) {
+      perror("An error occured while daemonizing.");
+      exit(-1);
+    }
+  }
 
        /* Connect the signal handlers */
        act.sa_handler = handler;