Ensure tshark/wireshark always get good err msgs from dumpcap:

1. Clean up dumpcap 'as a child' err msg handling so that:
   - all err msgs are properly formatted when being sent 
     back to the parent.
   - any log Critical, Warning, etc messages
     are sent back to parent and are properly formatted.
2. Change handling of -w <...> slightly in capture_opts.c
   so that wireshark provides a good error message if
   there is a 'write permissions' issue on the file.
   (Previously the error popup said only 
   "Child exited with status 2").
   This fixes bug #2288.

Add some conditionalized DEBUG_CHILD_DUMPCAP code for
   dumpcap debug logging to a file.

svn path=/trunk/; revision=24446

1 files changed, 108 insertions, 38 deletions

diff --git a/dumpcap.c b/dumpcap.c
index 9e2d15e5d9..88732b89e8 100644
--- a/dumpcap.c
+++ b/dumpcap.c
@@ -107,6 +107,13 @@
 #include "wiretap/libpcap.h"
 
 /*#define DEBUG_DUMPCAP*/
+/*#define DEBUG_CHILD_DUMPCAP*/
+
+#ifdef DEBUG_CHILD_DUMPCAP
+FILE *debug_log;   /* for logging debug messages to  */ 
+                   /*  a file if DEBUG_CHILD_DUMPCAP */
+                   /*  is defined                    */
+#endif
 
 static gboolean capture_child = FALSE; /* FALSE: standalone call, TRUE: this is an Wireshark capture child */
 #ifdef _WIN32
@@ -353,9 +360,12 @@ cmdarg_err(const char *fmt, ...)
   va_list ap;
 
   if(capture_child) {
-    /* Print a bare error */
+    gchar *msg;
+    /* Generate a 'special format' message back to parent */
     va_start(ap, fmt);
-    vfprintf(stderr, fmt, ap);
+    msg = g_strdup_vprintf(fmt, ap);
+    sync_pipe_errmsg_to_parent(2, msg, "");
+    g_free(msg);
     va_end(ap);
   } else {
     va_start(ap, fmt);
@@ -375,7 +385,12 @@ cmdarg_err_cont(const char *fmt, ...)
   va_list ap;
 
   if(capture_child) {
-    /* XXX - convert to g_log */
+    gchar *msg;
+    va_start(ap, fmt);
+    msg = g_strdup_vprintf(fmt, ap);
+    sync_pipe_errmsg_to_parent(2, msg, "");
+    g_free(msg);
+    va_end(ap);
   } else {
     va_start(ap, fmt);
     vfprintf(stderr, fmt, ap);
@@ -483,14 +498,14 @@ relinquish_privs_except_capture(void)
     if (started_with_special_privs()) {
         print_caps("Pre drop, pre set");
         if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) {
-            perror("prctl()");
+            cmdarg_err("prctl() fail return: %s", strerror(errno)); 
         }
 
         cap_set_flag(caps, CAP_PERMITTED,   cl_len, cap_list, CAP_SET);
         cap_set_flag(caps, CAP_INHERITABLE, cl_len, cap_list, CAP_SET);
 
         if (cap_set_proc(caps)) {
-            perror("capset()");
+            cmdarg_err("cap_set_proc() fail return: %s", strerror(errno)); 
         }
         print_caps("Pre drop, post set");
     }
@@ -500,7 +515,7 @@ relinquish_privs_except_capture(void)
     print_caps("Post drop, pre set");
     cap_set_flag(caps, CAP_EFFECTIVE,   cl_len, cap_list, CAP_SET);
     if (cap_set_proc(caps)) {
-        perror("capset()");
+        cmdarg_err("cap_set_proc() fail return: %s", strerror(errno)); 
     }
     print_caps("Post drop, post set");
     cap_free(caps);
@@ -2198,6 +2213,7 @@ main(int argc, char *argv[])
   gboolean             machine_readable = FALSE;
   gboolean             print_statistics = FALSE;
   int                  status, run_once_args = 0;
+  gint                 i;
 
 #ifdef HAVE_PCAP_REMOTE
 #define OPTSTRING_INIT "a:A:b:c:Df:hi:Lm:MprSs:uvw:y:Z:"
@@ -2214,6 +2230,61 @@ main(int argc, char *argv[])
   char optstring[sizeof(OPTSTRING_INIT) + sizeof(OPTSTRING_WIN32) - 1] =
     OPTSTRING_INIT OPTSTRING_WIN32;
 
+#ifdef DEBUG_CHILD_DUMPCAP
+  if ((debug_log = fopen("dumpcap_debug_log.tmp","w")) == NULL) {
+          fprintf (stderr, "Unable to open debug log file !\n");
+          exit (1);
+  }
+#endif
+
+  /* Determine if dumpcap is running as a child process by going thru  */
+  /*  the command line args to see if a -Z option (which is the        */
+  /*  hidden option which indicates that dumpcap has been invoked      */
+  /*  from a parent process using a pipe).                            */
+  /* "Child" status needs to be determined immediately upon startup so */
+  /* that any messages generated by dumpcap (eg: during initialization)*/
+  /* will be formatted properly if being sent back to a parent via     */
+  /* a pipe.                                                           */
+
+  for (i=1; i<argc; i++) {
+      if (g_ascii_strcasecmp("-Z", argv[i]) == 0) {
+          capture_child = TRUE;
+#ifdef _WIN32
+          /* set output pipe to binary mode, to avoid ugly text conversions */
+	  _setmode(2, O_BINARY);
+#endif
+      }
+  }
+          
+  /* The default_log_handler will use stdout, which makes trouble in   */
+  /* capture child mode, as it uses stdout for it's sync_pipe.         */
+  /* So: the filtering is done in the console_log_handler and not here.*/
+  /* We set the log handlers right up front to make sure that any log  */ 
+  /* messages when running as child will be sent back to the parent    */
+  /* with the correct format.                                          */
+
+  log_flags =  
+                    G_LOG_LEVEL_ERROR|
+                    G_LOG_LEVEL_CRITICAL|
+                    G_LOG_LEVEL_WARNING|
+                    G_LOG_LEVEL_MESSAGE|
+                    G_LOG_LEVEL_INFO|
+                    G_LOG_LEVEL_DEBUG|
+                    G_LOG_FLAG_FATAL|G_LOG_FLAG_RECURSION;
+
+  g_log_set_handler(NULL,
+                    log_flags,
+                    console_log_handler, NULL /* user_data */);
+  g_log_set_handler(LOG_DOMAIN_MAIN,
+                    log_flags,
+                    console_log_handler, NULL /* user_data */);
+  g_log_set_handler(LOG_DOMAIN_CAPTURE,
+                    log_flags,
+                    console_log_handler, NULL /* user_data */);
+  g_log_set_handler(LOG_DOMAIN_CAPTURE_CHILD,
+                    log_flags,
+                    console_log_handler, NULL /* user_data */);
+
 #ifdef _WIN32
   /* Load wpcap if possible. Do this before collecting the run-time version information */
   load_wpcap();
@@ -2245,31 +2316,6 @@ main(int argc, char *argv[])
   relinquish_privs_except_capture();
 #endif
 
-  /* the default_log_handler will use stdout, which makes trouble in */
-  /* capture child mode, as it uses stdout for it's sync_pipe */
-  /* so do the filtering in the console_log_handler and not here */
-  log_flags =
-		    G_LOG_LEVEL_ERROR|
-		    G_LOG_LEVEL_CRITICAL|
-		    G_LOG_LEVEL_WARNING|
-		    G_LOG_LEVEL_MESSAGE|
-		    G_LOG_LEVEL_INFO|
-		    G_LOG_LEVEL_DEBUG|
-		    G_LOG_FLAG_FATAL|G_LOG_FLAG_RECURSION;
-
-  g_log_set_handler(NULL,
-		    log_flags,
-		    console_log_handler, NULL /* user_data */);
-  g_log_set_handler(LOG_DOMAIN_MAIN,
-		    log_flags,
-		    console_log_handler, NULL /* user_data */);
-  g_log_set_handler(LOG_DOMAIN_CAPTURE,
-		    log_flags,
-            console_log_handler, NULL /* user_data */);
-  g_log_set_handler(LOG_DOMAIN_CAPTURE_CHILD,
-		    log_flags,
-            console_log_handler, NULL /* user_data */);
-
   /* Set the initial values in the capture_opts. This might be overwritten
      by the command line parameters. */
   capture_opts_init(capture_opts, NULL);
@@ -2475,13 +2521,13 @@ console_log_handler(const char *log_domain, GLogLevelFlags log_level,
 		    const char *message, gpointer user_data _U_)
 {
   time_t curr;
-  struct tm *today;
+  struct tm  *today;
   const char *level;
-
+  gchar      *msg;
 
   /* ignore log message, if log_level isn't interesting */
   if( !(log_level & G_LOG_LEVEL_MASK & ~(G_LOG_LEVEL_DEBUG|G_LOG_LEVEL_INFO))) {
-#ifndef DEBUG_DUMPCAP
+#if !defined(DEBUG_DUMPCAP) && !defined(DEBUG_CHILD_DUMPCAP)
     return;
 #endif
   }
@@ -2515,19 +2561,43 @@ console_log_handler(const char *log_domain, GLogLevelFlags log_level,
     g_assert_not_reached();
   }
 
-  /* don't use printf (stdout), in child mode we're using stdout for the sync_pipe */
+  /* Generate the output message                                  */
   if(log_level & G_LOG_LEVEL_MESSAGE) {
     /* normal user messages without additional infos */
-    fprintf(stderr, "%s\n", message);
-    fflush(stderr);
+    msg =  g_strdup_printf("%s\n", message);
   } else {
     /* info/debug messages with additional infos */
-    fprintf(stderr, "%02u:%02u:%02u %8s %s %s\n",
+    msg = g_strdup_printf("%02u:%02u:%02u %8s %s %s\n",
             today->tm_hour, today->tm_min, today->tm_sec,
             log_domain != NULL ? log_domain : "",
             level, message);
+  }
+
+  /* DEBUG & INFO msgs (if we're debugging today)                 */
+#if defined(DEBUG_DUMPCAP) || defined(DEBUG_CHILD_DUMPCAP)
+  if( !(log_level & G_LOG_LEVEL_MASK & ~(G_LOG_LEVEL_DEBUG|G_LOG_LEVEL_INFO))) {
+#ifdef DEBUG_DUMPCAP
+      fprintf(stderr, "%s", msg);
+      fflush(stderr);
+#endif
+#ifdef DEBUG_CHILD_DUMPCAP
+      fprintf(debug_log, "%s", msg);
+      fflush(debug_log);
+#endif
+      g_free(msg);
+      return;
+  }
+#endif
+
+  /* ERROR, CRITICAL, WARNING, MESSAGE messages goto stderr or    */
+  /*  to parent especially formatted if dumpcap running as child. */
+  if (capture_child) {
+    sync_pipe_errmsg_to_parent(2, msg, "");
+  } else {
+    fprintf(stderr, "%s", msg);
     fflush(stderr);
   }
+  g_free(msg);
 }