[lcd4linux @ 2004-04-08 10:48:23 by reinelt]

finished plugin_exec
modified thread handling
added '%x' format to qprintf (hexadecimal)

git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@410 3ae390bd-cb1e-0410-b409-cd5a39f66f1f

plugin_exec.c

@@ -1,4 +1,4 @@
-/* $Id: plugin_exec.c,v 1.1 2004/03/20 11:49:40 reinelt Exp $
+/* $Id: plugin_exec.c,v 1.2 2004/04/08 10:48:25 reinelt Exp $
  *
  * plugin for external processes
  *
@@ -27,6 +27,11 @@
  *
  *
  * $Log: plugin_exec.c,v $
+ * Revision 1.2  2004/04/08 10:48:25  reinelt
+ * finished plugin_exec
+ * modified thread handling
+ * added '%x' format to qprintf (hexadecimal)
+ *
  * Revision 1.1  2004/03/20 11:49:40  reinelt
  * forgot to add plugin_exec.c ...
  *
@@ -46,63 +51,215 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
-
-// #include <string.h>
-// #include <ctype.h>
-// #include <errno.h>
-
-#include <sys/ipc.h>
-#include <sys/sem.h>
-#include <sys/shm.h>
+#include <string.h>
+#include <errno.h>
 
 #include "debug.h"
 #include "plugin.h"
 #include "hash.h"
 #include "cfg.h"
 #include "thread.h"
+#include "qprintf.h"
+
+
+#define NUM_THREADS 16
+#define SHM_SIZE 256
+
+typedef struct {
+  int   delay;
+  int   mutex;
+  pid_t pid;
+  int   shmid;
+  char *cmd;
+  char *key;
+  char *ret;
+} EXEC_THREAD;
+
+static EXEC_THREAD Thread[NUM_THREADS];
+static int max_thread = -1;
 
 static HASH EXEC = { 0, };
-static int fatal = 0;
 
-static int do_exec (void)
-{
-  int age;
-  
-  // if a fatal error occured, do nothing
-  if (fatal != 0) return -1;
-  
-  // reread every 100 msec only
-  age=hash_age(&EXEC, NULL, NULL);
-  if (age>0 && age<=100) return 0;
-  return 0;
-} 
 
-static void my_junk (char *name)
+// x^0 + x^5 + x^12
+#define CRCPOLY 0x8408 
+  
+static unsigned short CRC (unsigned char *s)
 {
   int i;
+  unsigned short crc;
+
+  // seed value
+  crc=0xffff;
   
-  debug ("junk thread starting!");
-  
-  for (i=0; i<10; i++) {
-    debug ("junk look %d", i);
-    sleep (1);
+  while (*s!='\0') {
+    crc ^= *s++;
+    for (i = 0; i < 8; i++)
+      crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY : 0);
   }
-  debug ("junk thread done!");
+  return crc;
 }
 
 
-static void my_exec (RESULT *result, int argc, RESULT *argv[])
+static void exec_thread (void *data)
 {
-  char *key, *val;
+  EXEC_THREAD *Thread = (EXEC_THREAD*)data;
+  FILE *pipe;
+  char buffer[SHM_SIZE];
+  int len;
   
-  if (do_exec()<0) {
+  // use a safe path
+  putenv ("PATH=/usr/local/bin:/usr/bin:/bin");
+  
+  // forever...
+  while (1) {
+    pipe = popen(Thread->cmd, "r");
+    if (pipe == NULL) {
+      error("exec error: could not run pipe '%s': %s", Thread->cmd, strerror(errno));
+      len = 0;
+    } else {
+      len = fread(buffer, 1, SHM_SIZE-1, pipe);
+      if (len <= 0) {
+	error("exec error: could not read from pipe '%s': %s", Thread->cmd, strerror(errno));
+	len = 0;
+      }
+      pclose(pipe);
+    }
+    
+    // force trailing zero
+    buffer[len] = '\0';
+    
+    // remove trailing CR/LF
+    while (len>0 && (buffer[len-1]=='\n' || buffer[len-1]=='\r')) {
+      buffer[--len]='\0';
+    }
+    
+    // lock shared memory
+    mutex_lock(Thread->mutex);
+    // write data
+    strncpy(Thread->ret, buffer, SHM_SIZE);
+    // unlock shared memory
+    mutex_unlock(Thread->mutex);
+    usleep (Thread->delay);
+  }
+}
+
+
+static void destroy_exec_thread (int n)
+{
+  if (Thread[n].mutex != 0) mutex_destroy(Thread[n].mutex); 
+  if (Thread[n].cmd) free (Thread[n].cmd);
+  if (Thread[n].key) free (Thread[n].key);
+  if (Thread[n].ret) shm_destroy (Thread[n].shmid, Thread[n].ret);
+  
+  Thread[n].delay = 0;
+  Thread[n].mutex = 0;
+  Thread[n].pid   = 0;
+  Thread[n].shmid = 0;
+  Thread[n].cmd   = NULL;
+  Thread[n].key   = NULL;
+  Thread[n].ret   = NULL;
+}
+
+
+static int create_exec_thread (char *cmd, char *key, int delay)
+{
+  char name[10];
+
+  if (max_thread >= NUM_THREADS) {
+    error ("cannot create exec thread <%s>: thread buffer full!", cmd);
+    return -1;
+  }
+
+  max_thread++;
+  Thread[max_thread].delay = delay;
+  Thread[max_thread].mutex = mutex_create(); 
+  Thread[max_thread].pid   = -1;
+  Thread[max_thread].cmd   = strdup(cmd);
+  Thread[max_thread].key   = strdup(key);
+  Thread[max_thread].ret   = NULL;
+    
+  // create communication buffer
+  Thread[max_thread].shmid = shm_create ((void**)&Thread[max_thread].ret, SHM_SIZE);
+
+  // catch error
+  if (Thread[max_thread].shmid < 0) {
+    error ("cannot create exec thread <%s>: shared memory allocation failed!", cmd);
+    destroy_exec_thread (max_thread--);
+    return -1;
+  }
+  
+  // create thread
+  qprintf(name, sizeof(name), "exec-%s", key); 
+  Thread[max_thread].pid = thread_create (name, exec_thread, &Thread[max_thread]);
+
+  // catch error
+  if (Thread[max_thread].pid < 0) {
+    error ("cannot create exec thread <%s>: fork failed?!", cmd);
+    destroy_exec_thread (max_thread--);
+    return -1;
+  }
+  
+  return 0;
+}    
+
+
+static int do_exec (char *cmd, char *key, int delay)
+{
+  int i, age;
+  
+  age = hash_age(&EXEC, key, NULL);
+  
+  if (age < 0) {
+    hash_set (&EXEC, key, "");
+    // first-time call: create thread
+    if (delay < 10) {
+      error ("exec(%s): delay %d is too short! using 10 msec", cmd, delay);
+      delay = 10;
+    }
+    if (create_exec_thread (cmd, key, 1000*delay)) {
+      return -1;
+    }
+    return 0;
+  }
+  
+  // reread every 10 msec only
+  if (age > 0 && age <= 10) return 0;
+  
+  // find thread
+  for (i = 0; i <= max_thread; i++) {
+    if (strcmp(key, Thread[i].key) == 0) {
+      // lock shared memory
+      mutex_lock(Thread[i].mutex);
+      // copy data
+      hash_set (&EXEC, key, Thread[i].ret);
+      // unlock shared memory
+      mutex_unlock(Thread[i].mutex);
+      return 0;
+    }
+  }
+  
+  error ("internal error: could not find thread exec-%s", key);
+  return -1;
+}
+
+static void my_exec (RESULT *result, RESULT *arg1, RESULT *arg2)
+{
+  char *cmd, key[5], *val;
+  int delay;
+  
+  cmd = R2S(arg1);
+  delay = (int)R2N(arg2);
+
+  qprintf (key, sizeof(key), "%x", CRC(cmd));
+  
+  if (do_exec(cmd, key, delay) < 0) {
     SetResult(&result, R_STRING, ""); 
     return;
   }
   
-  // key=R2S(arg1);
-  val=hash_get(&EXEC, key);
-  if (val==NULL) val="";
+  val = hash_get(&EXEC, key);
+  if (val == NULL) val = "";
   
   SetResult(&result, R_STRING, val); 
 }
@@ -110,18 +267,18 @@ static void my_exec (RESULT *result, int argc, RESULT *argv[])
 
 int plugin_init_exec (void)
 {
-  int junk;
-  
-  AddFunction ("exec", -1, my_exec);
-
-  // junk=thread_create ("Junk", my_junk);
-  // debug ("junk=%d", junk);
-
+  AddFunction ("exec", 2, my_exec);
   return 0;
 }
 
 
 void plugin_exit_exec(void) 
 {
+  int i;
+  
+  for (i=0; i<=max_thread; i++) {
+    destroy_exec_thread(i);
+  }
+  
   hash_destroy(&EXEC);
 }