import cinit from unix.schottelius.org

Signed-off-by: Nico Schottelius <nico@ikn.schottelius.org>

software/cinit/browse_source/cinit-0.0.4/client/exec_svc.c

@@ -0,0 +1,246 @@
+/* 
+ * (c) 2005 Nico Schottelius (nico-linux at schottelius.org)
+ * run_svc
+ * part of cinit
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+
+#include "cinit.h"
+
+/***********************************************************************
+ * exec_svc: exec service abspath C_ON or C_OFF
+ */
+
+pid_t exec_svc(char *abspath, int on)
+{
+   pid_t pid;
+   int tmp;
+   char *p, pathtmp[PATH_MAX];
+   char *sbuf = NULL, **nargv = NULL, **nenv = NULL;
+   int fd, argc;
+   struct stat buf;
+   
+   pid = fork();
+   if( pid == -1 ) {
+      perror("fork");
+      return 0;
+   }
+   
+   /***** PARENT ******/
+   if(pid > 0) {
+      waitpid(pid,&tmp,0);
+      if( WIFEXITED(tmp) ) {
+         D_PRINTF("EXEC SVC ERFOLGREICH");
+         return pid;
+      } else {
+         D_PRINTF("EXEC SVC FEHLGESCHLAGEN");
+         return 0;
+      }
+   }
+
+   /*********** CHILD EXECUTION ***********/
+   strcpy(pathtmp,abspath);
+   strcat(pathtmp,"/");
+
+   if(on) {
+      strcat(pathtmp,C_ON);
+   } else {
+      strcat(pathtmp,C_OFF);
+   }
+
+   D_PRINTF(pathtmp);
+
+   /* readlink retrieves real name, if it is a symlink */
+   if ( (tmp = readlink(pathtmp,pathtmp,PATH_MAX) ) == -1) {
+
+      /* nothing there? fine, exit */
+      if(errno == ENOENT) {
+        _exit(0);
+      } else if (errno != EINVAL) {
+         perror("readlink");
+         _exit(1);
+      }
+
+      /* restore original name, file is not a link */
+      strcpy(pathtmp,abspath);
+      strcat(pathtmp,"/");
+
+      if(on) { 
+         strcat(pathtmp,C_ON);
+      } else {
+         strcat(pathtmp,C_OFF);
+      }
+      tmp = strlen(pathtmp);
+   } else {
+      /* add '\0', readlink forgets it */
+      pathtmp[tmp] = '\0'; 
+   }
+   tmp++; /* add memory for \0 */
+
+   /********** build argv0 ********/
+   nargv = (char **) malloc( sizeof(char *) );
+   if(nargv == NULL) _exit(1);
+
+   *nargv = (char *) malloc( tmp );
+   if(*nargv == NULL) _exit(1);
+
+   strcpy(*nargv,pathtmp);
+
+   /********************** read params *********************/
+   strcpy(pathtmp,abspath);
+   strcat(pathtmp,"/");
+
+   if(on) {
+      strcat(pathtmp,C_ONARG);
+   } else {
+      strcat(pathtmp,C_OFFARG);
+   }
+
+   /* open params file */
+   if( !stat(pathtmp,&buf) ) {
+      fd = open(pathtmp,O_RDONLY);
+
+      if(fd == -1) {
+         perror("open");
+         _exit(1);
+      }
+
+      argc = 0;
+
+      /* most likely one round */
+      while ( (tmp = read(fd,pathtmp,PATH_MAX) ) != 0 ) {
+         if(tmp == -1) { 
+            perror("read");
+            _exit(1);
+         }
+
+         sbuf = realloc(sbuf,argc + tmp + 1);
+         strncpy(&sbuf[argc],pathtmp,tmp);
+         argc += tmp;
+      }
+      close(fd);
+
+      if(argc)
+         sbuf[argc] = '\0'; /* terminate string */
+
+   } else {
+      sbuf = NULL;
+   }
+
+   /************** build string **************/
+   /* The idea is to reuse the allocated memory. We'll simply
+   * replace the \n with \0 and set a char* to it.
+   * We'll lose the last byte (the initial \0), but we
+   * don't care, as we die some seconds later with execv() */
+   
+   argc = 1; /* argv0 */
+   while( sbuf != NULL) {
+      p = strchr(sbuf,'\n');
+      nargv = realloc(nargv, sizeof(char *) * (argc + 1));
+
+      if(nargv == NULL) {
+         LOG("realloc failed");
+         _exit(1);
+      }
+
+      nargv[argc] = sbuf;
+      *p = '\0';
+      if( *(p+1) == '\0') {
+         sbuf = NULL;
+      } else {
+         sbuf = p+1;
+      }
+      argc++;
+   }
+
+   /************ close argv list **************/
+   nargv = realloc(nargv, sizeof(char *) * (argc + 1)); /* 1: NULL-pointer */
+   if(nargv == NULL) {
+      LOG("realloc failed");
+      _exit(1);
+   }
+   nargv[argc] = NULL;  /* terminate argv list */
+
+   /********************** read environment *********************/
+   strcpy(pathtmp,abspath);
+   strcat(pathtmp,SLASH);
+   if(on) {
+      strcat(pathtmp,C_ONENV);
+   } else {
+      strcat(pathtmp,C_OFFENV);
+   }
+
+   argc = 0;
+   sbuf = NULL;
+   if( !stat(pathtmp,&buf) ) {
+      fd = open(pathtmp,O_RDONLY);
+
+      /* if a file exists, failing to open it is an error */
+      if(fd == -1) {
+         perror("open");
+         _exit(1);
+      }
+
+      while ( (tmp = read(fd,pathtmp,PATH_MAX) ) != 0 ) {
+         if(tmp == -1) { 
+            perror("read");
+            _exit(1);
+         }
+
+         sbuf = realloc(sbuf,argc + tmp + 1);
+         strncpy(&sbuf[argc],pathtmp,tmp);
+         argc += tmp;
+      }
+      close(fd);
+      if(argc)
+         sbuf[argc] = '\0'; /* terminate string */
+   }
+
+   /************** build environment string **************/
+   argc = 0;
+   while( sbuf != NULL ) {
+      p = strchr(sbuf,'\n');
+         
+      nenv = realloc(nenv, sizeof(char *) * (argc + 1));
+      if(nenv == NULL) {
+         LOG("realloc failed");
+         _exit(1);
+      }
+
+      nenv[argc] = sbuf;
+      *p = '\0';
+      if( *(p+1) == '\0') {
+         sbuf = NULL;
+      } else {
+         sbuf = p+1;
+      }
+      argc++;
+   }
+
+   /************ close env list **************/
+   nenv = realloc(nenv, sizeof(char *) * (argc + 1));
+   if(nenv == NULL) {
+      LOG(MSG_ERR_ALLOC);
+      _exit(1);
+   }
+   nenv[argc] = NULL;
+
+   /****************** EXECUTE ********************/
+
+   execve(nargv[0],nargv,nenv);
+
+   /* we should never reach this block */
+   perror(MSG_ERR_EXECVE);
+   _exit(1);
+}