1 files changed, 371 insertions, 0 deletions
diff --git a/src/sysexec.c b/src/sysexec.c
new file mode 100644
index 0000000..79f4e74
--- /dev/null
+++ b/src/sysexec.c
@@ -0,0 +1,371 @@
+/*
+ *  rhdropbox
+ *
+ *  Copyright (C) 2009 Christian Pointner <equinox@helsinki.at>
+ *
+ *  This file is part of rhdropbox.
+ *
+ *  rhdropbox is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  any later version.
+ *
+ *  rhdropbox is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with rhdropbox. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "datatypes.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <sys/select.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sysexec.h"
+#include "log.h"
+
+char** dup_ptrptr(char* const ptrptr[])
+{
+  if(!ptrptr)
+    return NULL;
+
+  int n = 0;
+  while(ptrptr[n])
+    n++;
+
+  char** my_ptrptr;
+  my_ptrptr = malloc((n+1)*sizeof(char*));
+  if(!my_ptrptr)
+    return NULL;
+
+  int i;
+  for(i = 0; i < n; ++i) {
+    my_ptrptr[i] = strdup(ptrptr[i]); 
+    if(!my_ptrptr[i]) {
+      i--;
+      for(; i >= 0; --i)
+        free(my_ptrptr[i]);
+      
+      free(my_ptrptr);
+      return NULL;
+    }
+  }
+
+  my_ptrptr[n] = NULL;
+
+  return my_ptrptr;
+}
+
+void free_ptrptr(char** ptrptr)
+{
+  if(!ptrptr)
+    return;
+
+  int i;
+  for(i = 0; ptrptr[i]; ++i)
+    free(ptrptr[i]);
+  
+  free(ptrptr);
+}
+
+void child_list_init(child_list_t* list)
+{
+  if(!list)
+    return;
+  
+  list->first_ = NULL;
+}
+
+void child_list_clear(child_list_t* list)
+{
+  if(!list)
+    return;
+
+  while(list->first_) {
+    child_list_element_t* tmp;
+    tmp = list->first_;
+    list->first_ = tmp->next_;
+    if(tmp->script_)
+      free(tmp->script_);
+    free(tmp);
+  }
+}
+
+child_list_element_t* child_list_new(const char* script, char* const argv[], char* const evp[])
+{
+  child_list_element_t* new_child;
+
+  new_child = malloc(sizeof(child_list_element_t));
+  if(!new_child)
+    return NULL;
+  
+  new_child->next_ = 0;
+  new_child->pid_ = -1;
+  new_child->err_fd_ = -1;
+  new_child->running_ = 0;
+  new_child->script_ = strdup(script);
+  if(!new_child->script_) {
+    free(new_child);
+    return NULL;
+  }
+  
+  new_child->argv_ = dup_ptrptr(argv);
+  if(!new_child->argv_) {
+    free(new_child->script_);
+    free(new_child);
+    return NULL;
+    
+  }
+  
+  new_child->evp_ = dup_ptrptr(evp);
+  if(!new_child->evp_) {
+    free_ptrptr(new_child->argv_);
+    free(new_child->script_);
+    free(new_child);
+    return NULL;
+  }
+  return new_child;
+}
+
+child_list_element_t* child_list_add(child_list_t* list, const char* script, char* const argv[], char* const evp[])
+{
+  if(!list)
+    return NULL;
+
+  if(!list->first_) {
+    list->first_ = child_list_new(script, argv, evp);
+    return list->first_;
+  }
+  else {
+    child_list_element_t* tmp = list->first_;
+    while(tmp->next_)
+      tmp = tmp->next_;
+
+    tmp->next_  = child_list_new(script, argv, evp);
+    return tmp->next_;
+  }
+}
+
+void child_list_rm(child_list_t* list, child_list_element_t* child)
+{
+  if(!list || !child)
+    return;
+
+  if(child == list->first_) {
+    list->first_ = list->first_->next_;
+    free_ptrptr(child->argv_);
+    free_ptrptr(child->evp_);
+    if(child->script_)
+      free(child->script_);
+    free(child);
+    return;
+  }
+  else {
+    child_list_element_t* tmp = list->first_;
+    while(tmp) {
+      if(tmp->next_ == child) {
+        tmp->next_ = tmp->next_->next_;
+        free_ptrptr(child->argv_);
+        free_ptrptr(child->evp_);
+        if(child->script_)
+          free(child->script_);
+        free(child);
+        return;
+      }
+      tmp = tmp->next_;
+    }
+  }
+}
+
+void child_list_rm_pid(child_list_t* list, pid_t pid)
+{
+  if(!list)
+    return;
+  
+  child_list_element_t* tmp = NULL;
+  if(list->first_->pid_ == pid) {
+    tmp = list->first_;
+    list->first_ = list->first_->next_;
+    
+    free_ptrptr(tmp->argv_);
+    free_ptrptr(tmp->evp_);
+    if(tmp->script_)
+      free(tmp->script_);
+    free(tmp);
+    return;
+  }
+
+  child_list_element_t* prev = list->first_;
+  tmp = list->first_->next_;
+  while(tmp) {
+    if(tmp->pid_ == pid) {
+      prev->next_ = tmp->next_;
+
+      free_ptrptr(tmp->argv_);
+      free_ptrptr(tmp->evp_);
+      if(tmp->script_)
+        free(tmp->script_);
+      free(tmp);
+      return;      
+    }
+    prev = tmp;
+    tmp = tmp->next_;
+  }
+}
+
+child_list_element_t* child_list_find(child_list_t* list, pid_t pid)
+{
+  if(!list)
+    return NULL;
+  
+  child_list_element_t* tmp = list->first_;
+  while(tmp) {
+    if(tmp->pid_ == pid)
+      return tmp;
+    tmp = tmp->next_;
+  }
+  
+  return NULL;
+}
+
+int child_list_num_running(child_list_t* list)
+{
+  int num = 0;
+
+  if(!list)
+    return 0;
+  
+  child_list_element_t* tmp = list->first_;
+  for(;tmp;tmp=tmp->next_)
+    if(tmp->running_) num++;
+  
+  return num;
+}
+
+int rh_exec(const char* script, char* const argv[], char* const evp[], child_list_t* child_lst, options_t* opt)
+{
+  if(!script)
+    return -1;
+
+  child_list_element_t* child = child_list_add(child_lst, script, argv, evp);
+  if(!child)
+    return -2;
+
+  if(child_list_num_running(child_lst) >= opt->max_children_) {
+    log_printf(INFO, "deferring script execution '%s'", script);
+    return 0;
+  }
+
+  int ret = rh_exec_child(child);
+  if(ret)
+    child_list_rm(child_lst, child);
+
+  return ret;
+}
+
+int rh_exec_child(child_list_element_t* child)
+{
+  if(!child || child->pid_ != -1)
+    return -1;
+
+  int pipefd[2];
+  if(pipe(pipefd) == -1) {
+    log_printf(ERROR, "executing script '%s' failed: pipe() error: %s", child->script_, strerror(errno));
+    return -1;
+  }
+
+  pid_t pid;
+  pid = fork();
+  if(pid == -1) {
+    log_printf(ERROR, "executing script '%s' failed: fork() error: %s", child->script_, strerror(errno));
+    return -1;
+  }
+
+  if(!pid) {
+    int fd;
+    for (fd=getdtablesize();fd>=0;--fd) // close all file descriptors
+      if(fd != pipefd[1]) close(fd);
+
+    fd = open("/dev/null",O_RDWR);        // stdin
+    if(fd == -1)
+      log_printf(WARNING, "can't open stdin");
+    else {
+      if(dup(fd) == -1)   // stdout
+        log_printf(WARNING, "can't open stdout");
+      if(dup(fd) == -1)   // stderr
+        log_printf(WARNING, "can't open stderr");
+    }
+    execve(child->script_, child->argv_, child->evp_);
+        // if execve returns, an error occurred, but logging doesn't work 
+        // because we closed all file descriptors, so just write errno to
+        // pipe and call exit
+    write(pipefd[1], (void*)(&errno), sizeof(errno));
+    exit(-1);
+  }
+  close(pipefd[1]);
+
+  child->pid_ = pid;
+  child->err_fd_ = pipefd[0];
+  child->running_ = 1;
+
+  log_printf(INFO, "called script '%s' with pid %d", child->script_, child->pid_);
+
+  return 0;
+}
+
+int rh_waitpid(child_list_t* child_lst, options_t* opt)
+{
+  int status = 0;
+  pid_t pid = waitpid(-1, &status, WNOHANG);
+  if(!pid || (pid < 0 && errno == ECHILD))
+    return 0;
+  if(pid < 0) {
+    log_printf(ERROR, "waitpid returned with error: %s", strerror(errno));
+    return pid;
+  }
+
+  child_list_element_t* child = child_list_find(child_lst, pid);
+  if(!child) {
+    log_printf(ERROR, "waitpid returned unknown child pid (%d)", pid);
+    return 0;
+  }
+
+  fd_set rfds;
+  FD_ZERO(&rfds);
+  FD_SET(child->err_fd_, &rfds);
+  struct timeval tv = { 0 , 0 };
+  if(select(child->err_fd_+1, &rfds, NULL, NULL, &tv) == 1) {
+    int err = 0;
+    if(read(child->err_fd_, (void*)(&err), sizeof(err)) >= sizeof(err)) {
+      log_printf(INFO, "script '%s' exec() error: %s", child->script_, strerror(err));
+      close(child->err_fd_);
+      child_list_rm_pid(child_lst, pid);
+      return -1;
+    }
+  }
+  if(WIFEXITED(status))
+    log_printf(INFO, "script '%s' (pid %d) returned %d", child->script_, child->pid_, WEXITSTATUS(status));
+  else if(WIFSIGNALED(status))
+    log_printf(INFO, "script '%s' (pid %d) terminated after signal %d", child->script_, child->pid_, WTERMSIG(status));
+  else
+    log_printf(INFO, "executing script '%s' (pid %d): unkown error", child->script_, child->pid_);
+
+  close(child->err_fd_);
+
+  child_list_rm_pid(child_lst, pid);
+
+  if(child_list_num_running(child_lst) < opt->max_children_)
+    rh_exec_child(child_list_find(child_lst, -1));
+  
+  return status;
+}
+