MAJOR refactoring of Sensors code

[matches/MCTX3420.git] / server / sensors / piped.c

diff --git a/server/sensors/piped.c b/server/sensors/piped.c
new file mode 100644 (file)
index 0000000..6444e8b
--- /dev/null
+++ b/server/sensors/piped.c
@@ -0,0 +1,101 @@
+/**
+ * @file piped.h
+ * @brief Sensor run by an external process and sent to this one through a pipe
+ * PURELY INCLUDED FOR TESTING PURPOSES
+ *     This will work with any sensor that can unbuffer stdout
+ * ... So, although it's not recommended, you could write a sensor purely in something like python
+ *        The FastCGI process will handle all the time stamps and stuff
+ */
+
+#include "../log.h"
+#include "../common.h"
+
+#include "piped.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/signal.h>
+#include <ctype.h>
+
+
+typedef struct
+{
+       int pid;
+       int sv[2];
+       FILE * stream;
+       
+} Piped;
+
+static Piped g_piped[PIPED_MAX];
+static int g_num_piped = 0;
+
+bool Piped_Init(const char * name, int id)
+{
+       if (++g_num_piped > PIPED_MAX)
+       {
+               Fatal("Too many sensors; Increase PIPED_MAX from %d in piped.h and recompile", PIPED_MAX);
+       }
+
+       if (socketpair(AF_UNIX, SOCK_STREAM, 0, g_piped[id].sv) != 0)
+                       Fatal("socketpair failed - %s", strerror(errno));
+
+       g_piped[id].pid = fork();
+       if (g_piped[id].pid == 0)
+       {
+               dup2(g_piped[id].sv[0], fileno(stdin));
+               dup2(g_piped[id].sv[0], fileno(stdout));
+
+               if (access(name, X_OK) == 0) //Check we STILL have permissions to start the file
+               {
+                       execl(name, name, (char*)(NULL)); ///Replace process with desired executable
+                       //execv(executablePath,arguments); ///Replace process with desired executable
+               }
+               else
+               {
+                       Fatal("Can't execute file %s", name);
+               }
+               Fatal("execl error - %s", strerror(errno));
+       }
+       else
+       {
+               g_piped[id].stream = fdopen(g_piped[id].sv[1], "r");
+               setbuf(g_piped[id].stream, NULL);
+       }
+       return true;
+       
+}
+
+bool Piped_Read(int id, double * value)
+{
+       if (g_piped[id].stream == NULL)
+               return false;
+
+       static char line[BUFSIZ];
+       
+       fgets(line, BUFSIZ, g_piped[id].stream);
+       int len = strlen(line);
+       //Log(LOGDEBUG, "Read %s (%d) chars", line, len);
+       while (--len >= 0 && len < BUFSIZ && isspace(line[len]))
+       {
+               line[len] = '\0';
+       }
+       char * end = line;
+       *value = strtod(line, &end);
+       if (*end != '\0')
+       {
+               Log(LOGERR, "Couldn't interpret %s as double - %s", line, strerror(errno));
+               return false;
+       }
+       return true;
+}
+
+bool Piped_Cleanup(int id)
+{
+       fclose(g_piped[id].stream);
+       if (kill(g_piped[id].pid, 15) != 0)
+       {
+               Log(LOGWARN, "Couldn't kill piped %d - %s", g_piped[id].pid, strerror(errno));
+               return false;
+       }
+       return true;
+}