Add utils.c and utils.h

Move set_affinity(), print_time(), and dbg() to utils.c Add version.h Bump priority to both threads Make the data gathering thread use CPU 1 Make the udp thread use CPU 0
lfs-book · Oct 20, 2024 · 5e6ef87 · 5e6ef87
1 parent b7b06a8
commit 5e6ef87
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Showing 9 changed files with 85 additions and 62 deletions.
diff --git a/ABOUT b/ABOUT
@@ -18,6 +18,9 @@ techniques in a Linux envronment.  It demonstrates the following:
 - Using the fork command
 - Creating a thread 
 - Handling signals
+- Raising process priority
+- Attaching a process affinity to a CPU core
+- Using a mutex (mutual exclusion token)
 
 When the Linux kernel runs, it frequently updates files in the /proc
 and /sys virtual file systems.  For the purpose of this program we

diff --git a/Makefile b/Makefile
@@ -1,4 +1,4 @@
-objects = sysmond.o args.o udp.o daemonize.o signal.o data.o temps.o
+objects = sysmond.o args.o udp.o daemonize.o signal.o data.o temps.o utils.o
 
 sysmond: $(objects)
 	gcc -o sysmond $(CFLAGS) -s $(objects)
@@ -8,11 +8,15 @@ $(objects): %.o: %.c
 
 sysmond.o:   sysmond.c   sysmond.h 
 args.o:      args.c      sysmond.h args.h
-udp.o:       udp.c       sysmond.h udp.h
+udp.o:       udp.c       sysmond.h udp.h utils.h
 daemonize.o: daemonize.c sysmond.h
 signal.o:    signal.c    sysmond.h
 data.o:      data.c      sysmond.h
 temps.o:     temps.c     sysmond.h
+utils.o:     utils.c     utils.h
+
+install:
+	cp -v sysmond /usr/sbin
 
 clean:
 	rm -f $(objects) sysmond

diff --git a/args.c b/args.c
@@ -6,6 +6,7 @@
 
 #include "sysmond.h"
 #include "args.h"
+#include "version.h"
 
 static const char*         shortOptions = "c:p:d:u:s:h:";
 
@@ -38,7 +39,8 @@ char dbgFile[64];
 // Start functions
 
 void help( char* name )
-{  printf( "Syntax: %s {options} \nversion %s\n%s", name, version,
+{  
+   printf( "Syntax: %s {options} \nVersion %s\n%s", name, VERSION,
    "  -c, --config-file <filename>    -- config file location (default /etc/sysmond.conf)\n"
    "  -p, --pid-file    <filename>    -- pid file location    (default /run/sysmond.pid)\n"
    "  -d, --debug-file  <filname>     -- debug file location  (default /tmp/sysmond.dbg)\n"

diff --git a/daemonize.c b/daemonize.c
@@ -75,6 +75,6 @@ void daemonize()
    close( STDOUT_FILENO );
    close( STDERR_FILENO );
 
-   nice( -1 );
-   set_affinity( 1 );
+   nice( -1 );         // Bump priority
+   set_affinity( 1 );  // Just run on CPU 1
 }
diff --git a/sysmond.c b/sysmond.c
@@ -1,7 +1,6 @@
 #define _GNU_SOURCE
 
 #include <stdio.h>   // perror, snprintf, fopen, FILE, fgets, fwrite, fclose
-#include <time.h>    // time_t, time(), ctime, gmtime, struct tm
 #include <unistd.h>  // getuid, optind
 #include <string.h>  // strtok, strcmp, strlen
 #include <stdlib.h>  // strtol, exit, EXIT_FAILURE
@@ -12,24 +11,13 @@
 
 #include "sysmond.h"
 
-//#include <sys/time.h>
-
+// Globals
 int             data_available = 0;
 char            data[ 2 ][ 1024 ];
-const           char* version = "3.0.0";
-char*           time_string;
 pthread_mutex_t mutex;
 
 // Start functions
 
-// Populate time_string with formatted time without newline
-void print_time()
-{
-   const time_t now         = time( NULL );
-                time_string = ctime( &now );
-   time_string[ 24 ]        = 0;             // Remove newline
-}
-
 // Determine if 'name' is already running
 int is_running( char* name)
 {
@@ -48,12 +36,12 @@ int is_running( char* name)
 
     while( (ent = readdir(dir)) != NULL )
     {   
-        /* If endptr is not a null character, the directory is not
-         * entirely numeric, so ignore it */
+        // If endptr is not a null character, the directory is not
+        // entirely numeric, so ignore it 
         long lpid = strtol( ent->d_name, &endptr, 10 );
         if (*endptr != '\0') continue;
 
-        /* Try to open the cmdline file */
+        // Try to open the cmdline file
         snprintf( buf, sizeof(buf), "/proc/%ld/cmdline", lpid );
         FILE* fp = fopen( buf, "r" );
 
@@ -63,9 +51,9 @@ int is_running( char* name)
             {   
                 char* first = basename( strtok( buf, " " ) );
 
-                /* Check the first token in the file, the program name.
-                 * We should always match this instance, but if another 
-                 * is running, we will get more than 1.*/
+                // Check the first token in the file, the program name.
+                // We should always match this instance, but if another 
+                // is running, we will get more than 1.
 
                 if ( ! strcmp( first, base) ) running++;
             }
@@ -78,42 +66,6 @@ int is_running( char* name)
     return running;
 }
 
-void set_affinity( int cpu )
-{
-   cpu_set_t  mask;
-
-   CPU_ZERO( &mask );
-   CPU_SET( cpu, &mask );
-   pthread_setaffinity_np( 0, sizeof(mask), &mask );
-   // Ignore result
-}
-
-
-
-// Write txt to debug file
-void dbg( char* txt )
-{
-   FILE* file;
-
-   file = fopen( sysmond_args.dbgFile, "a" );
-   if ( file != NULL )
-   {
-      print_time();
-      strcat( time_string, " " );
-      fwrite( time_string, 
-              strlen( time_string ),
-              1,
-              file );
-
-      fwrite( txt, 
-              strlen( txt ),
-              1,
-              file );
-
-      fclose( file );
-   }
-}
-
 int main( int argc, char* argv[])
 {
   // This is really to get the config file. 

diff --git a/sysmond.h b/sysmond.h
@@ -25,7 +25,5 @@ extern void  get_temps         ( char* );       // temps.c
 extern void  set_affinity      ( int );         // sysmond.c
 
 // Local functions
-void         dbg               ( char* );
 int          is_running        ( char* );
-void         print_time        ( void );
 
diff --git a/utils.c b/utils.c
@@ -0,0 +1,58 @@
+#define _GNU_SOURCE
+
+#include <stdio.h>   // perror, snprintf, fopen, FILE, fgets, fwrite, fclose
+#include <time.h>    // time_t, time(), ctime, gmtime, struct tm
+#include <string.h>  // strlen
+#include <pthread.h> // pthread_create, pthread_setaffinity_np, CPU_ZERO, CPU_SET
+
+#include "sysmond.h"
+#include "utils.h"
+
+// Globals
+char*           time_string;
+
+// Start functions
+
+// Populate time_string with formatted time without newline
+void print_time()
+{
+   const time_t now         = time( NULL );
+                time_string = ctime( &now );
+   time_string[ 24 ]        = 0;             // Remove newline
+}
+
+// Write txt to debug file
+void dbg( char* txt )
+{
+   FILE* file;
+
+   file = fopen( sysmond_args.dbgFile, "a" );
+   if ( file != NULL )
+   {
+      print_time();
+      strcat( time_string, " " );
+      fwrite( time_string, 
+              strlen( time_string ),
+              1,
+              file );
+
+      fwrite( txt, 
+              strlen( txt ),
+              1,
+              file );
+
+      fclose( file );
+   }
+}
+
+// Attach a process/threaad to a specific CPU
+void set_affinity( int cpu )
+{
+   cpu_set_t  mask;
+
+   CPU_ZERO( &mask );
+   CPU_SET( cpu, &mask );
+   pthread_setaffinity_np( pthread_self(), sizeof(mask), &mask );
+   // Ignore result
+}
+
diff --git a/utils.h b/utils.h
@@ -0,0 +1,4 @@
+void set_affinity( int );
+void print_time  ( void );
+void dbg         ( char* );
+
diff --git a/version.h b/version.h
@@ -0,0 +1,2 @@
+#define VERSION "3.0.0"
+