Homepage button now shows up in SDL port and works!

zsnes/src/linux/sdlintrf.asm

@@ -124,7 +124,7 @@ EXTSYM WinErrorA2,WinErrorB2,WinErrorC2
 EXTSYM GetLocalTime
 EXTSYM V8Mode,GrayscaleMode
 EXTSYM PrevWinMode,PrevFSMode
-EXTSYM sem_sleep
+EXTSYM sem_sleep,ZsnesPage
 
 ; NOTE: For timing, Game60hzcall should be called at 50hz or 60hz (depending
 ;   on romispal) after a call to InitPreGame and before DeInitPostGame are
@@ -1730,8 +1730,10 @@ NEWSYM WinErrorC
     call WinErrorC2
     ret
 
-; Not supported in Linux
 NEWSYM GotoHomepage
+    pushad
+    call ZsnesPage
+    popad    
     ret
 
 EXTSYM SystemTimewHour

zsnes/src/linux/sdllink.c

@@ -1179,3 +1179,146 @@ float sem_GetTicks()
 	ticks=((float)(now.tv_sec-sem_start.tv_sec))*1000.f+((float)(now.tv_usec-sem_start.tv_usec))*.001f;
 	return(ticks);
 }
+
+
+
+//Introducing the secure browser opener for POSIX systems ;) -Nach
+
+#include <sys/param.h>
+#include <paths.h>
+#include <grp.h>
+
+#ifndef OPEN_MAX
+#define OPEN_MAX 256
+#endif
+
+//C++ style code in C
+#define bool unsigned char
+#define true 1
+#define false 0
+
+//Taken from the secure programming cookbook, slightly modified
+bool spc_drop_privileges() {
+  gid_t newgid = getgid(), oldgid = getegid();
+  uid_t newuid = getuid(), olduid = geteuid();
+
+  /* If root privileges are to be dropped, be sure to pare down the ancillary
+   * groups for the process before doing anything else because the setgroups()
+   * system call requires root privileges.  Drop ancillary groups regardless of
+   * whether privileges are being dropped temporarily or permanently.
+   */
+  if (!olduid) setgroups(1, &newgid);
+
+  if (newgid != oldgid) {
+#if !defined(linux)
+    setegid(newgid);
+    if (setgid(newgid) == -1) return(false);
+#else
+    if (setregid(newgid, newgid) == -1) return(false);
+#endif
+  }
+
+  if (newuid != olduid) {
+#if !defined(linux)
+    seteuid(newuid);
+    if (setuid(newuid) == -1) return(false);
+#else
+    if (setregid(newuid, newuid) == -1) return(false);
+#endif
+  }
+
+  /* verify that the changes were successful */
+
+  if (newgid != oldgid && (setegid(oldgid) != -1 || getegid() != newgid))
+    return(false);
+  if (newuid != olduid && (seteuid(olduid) != -1 || geteuid() != newuid))
+    return(false);
+
+  return(true);
+}
+
+static int open_devnull(int fd) {
+  FILE *f = 0;
+
+  if (!fd) f = freopen(_PATH_DEVNULL, "rb", stdin);
+  else if (fd == 1) f = freopen(_PATH_DEVNULL, "wb", stdout);
+  else if (fd == 2) f = freopen(_PATH_DEVNULL, "wb", stderr);
+  return (f && fileno(f) == fd);
+}
+
+void spc_sanitize_files() {
+  int         fd, fds;
+  struct stat st;
+
+  /* Make sure all open descriptors other than the standard ones are closed */
+  if ((fds = getdtablesize()) == -1) fds = OPEN_MAX;
+  for (fd = 3;  fd < fds;  fd++) close(fd);
+
+  /* Verify that the standard descriptors are open.  If they're not, attempt to
+   * open them using /dev/null.  If any are unsuccessful, abort.
+   */
+  for (fd = 0;  fd < 3;  fd++)
+    if (fstat(fd, &st) == -1 && (errno != EBADF || !open_devnull(fd))) abort();
+}
+
+pid_t spc_fork() {
+  pid_t childpid;
+  
+  if ((childpid = fork()) == -1) return -1;
+  
+  //If this us the parent proccess nothing more to do
+  if (childpid != 0) return childpid;
+  
+  //This is the child proccess
+  
+  spc_sanitize_files();
+  
+  /*
+  There actually is a bug here which I submitted to the authors of the book -Nach
+  
+  The bug is as follows:
+  The parent returns the child proccess ID in event of success. 
+  The child returns 0 on success if and only if it's spc_drop_privileges() call is successful.
+  It is possible that the parent will return with a pid > 0, while the child never returns 
+  from spc_fork thus causing a programming error.
+
+  The function should be rewritten that the parent doesn't return till it knows if the 
+  child is able to return or not. And then return -1 or the child pid.
+  
+  For out purposes in ZSNES to launch a browser, this bug does not effect us. But
+  be careful if you copy this code to use somewhere else.
+  */
+  if (!spc_drop_privileges()) //Failed to drop special privliges
+  {
+    exit(0);
+  }
+  
+  return 0;
+}
+
+void LaunchBrowser(char *browser)
+{
+  char *arglist[] = { browser, "http://www.zsnes.com/", 0 };
+  execvp(browser, arglist);
+}
+
+void ZsnesPage()
+{
+  pid_t pid = spc_fork();
+  if (pid) //If fork failed, or we are the parent
+  { 
+    MouseX = 0;
+    MouseY = 0;    
+    return;
+  }
+  
+  //We are now the child proccess
+    
+  //If any of these LaunchBrowser() calls return that means it failed and we should try the next one
+  LaunchBrowser("mozilla");
+  LaunchBrowser("mozilla-firefox");
+  LaunchBrowser("konqueror");
+  LaunchBrowser("lynx");
+  
+  exit(0); //All browser launches failed, oh well
+}