Have win32strerror() return a g_malloc()ated UTF-8 error message.

Use FormatMessageW() to get a UTF-16-encoded Unicode error string,
rather than an error string in the local code page, and then convert it
from UTF-16 to UTF-8.

Make it dynamically-allocated, so it's big enough and so that we are
thread-safe.  Make the callers free the result.

Change-Id: I217aec5a644fa0176a829f181eb05561cb9d10f4
Reviewed-on: https://code.wireshark.org/review/31846
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 20 insertions, 10 deletions

diff --git a/capchild/capture_sync.c b/capchild/capture_sync.c
index c3bd19cc5e..ece0ae00ad 100644
--- a/capchild/capture_sync.c
+++ b/capchild/capture_sync.c
@@ -206,6 +206,7 @@ sync_pipe_start(capture_options *capture_opts, capture_session *cap_session, inf
     PROCESS_INFORMATION pi;
     char control_id[ARGV_NUMBER_LEN];
     gchar *signal_pipe_name;
+    char *errmsg;
 #else
     char errmsg[1024+1];
     int sync_pipe[2];                       /* pipe used to send messages from child to parent */
@@ -433,8 +434,9 @@ sync_pipe_start(capture_options *capture_opts, capture_session *cap_session, inf
     /* (increase this value if you have trouble while fast capture file switches) */
     if (! CreatePipe(&sync_pipe_read, &sync_pipe_write, &sa, 5120)) {
         /* Couldn't create the pipe between parent and child. */
-        report_failure("Couldn't create sync pipe: %s",
-                       win32strerror(GetLastError()));
+        errmsg = win32strerror(GetLastError());
+        report_failure("Couldn't create sync pipe: %s", errmsg);
+        g_free(errmsg);
         free_argv(argv, argc);
         return FALSE;
     }
@@ -464,8 +466,9 @@ sync_pipe_start(capture_options *capture_opts, capture_session *cap_session, inf
 
     if (signal_pipe == INVALID_HANDLE_VALUE) {
         /* Couldn't create the signal pipe between parent and child. */
-        report_failure("Couldn't create signal pipe: %s",
-                       win32strerror(GetLastError()));
+        errmsg = win32strerror(GetLastError());
+        report_failure("Couldn't create signal pipe: %s", errmsg);
+        g_free(errmsg);
         ws_close(sync_pipe_read_fd);    /* Should close sync_pipe_read */
         CloseHandle(sync_pipe_write);
         free_argv(argv, argc);
@@ -523,8 +526,10 @@ sync_pipe_start(capture_options *capture_opts, capture_session *cap_session, inf
     /* call dumpcap */
     if(!win32_create_process(argv[0], args->str, NULL, NULL, TRUE,
                                CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi)) {
+        errmsg = win32strerror(GetLastError());
         report_failure("Couldn't run %s in child process: %s",
-                       args->str, win32strerror(GetLastError()));
+                       args->str, errmsg);
+        g_free(errmsg);
         ws_close(sync_pipe_read_fd);    /* Should close sync_pipe_read */
         CloseHandle(sync_pipe_write);
         CloseHandle(signal_pipe);
@@ -647,6 +652,7 @@ sync_pipe_open_command(char* const argv[], int *data_read_fd,
     STARTUPINFO si;
     PROCESS_INFORMATION pi;
     int i;
+    char *errmsg;
 #else
     char errmsg[1024+1];
     int sync_pipe[2];                       /* pipe used to send messages from child to parent */
@@ -675,8 +681,9 @@ sync_pipe_open_command(char* const argv[], int *data_read_fd,
     /* (increase this value if you have trouble while fast capture file switches) */
     if (! CreatePipe(&sync_pipe[PIPE_READ], &sync_pipe[PIPE_WRITE], &sa, 5120)) {
         /* Couldn't create the message pipe between parent and child. */
-        *msg = g_strdup_printf("Couldn't create sync pipe: %s",
-                               win32strerror(GetLastError()));
+        errmsg = win32strerror(GetLastError());
+        *msg = g_strdup_printf("Couldn't create sync pipe: %s", errmsg);
+        g_free(errmsg);
         return -1;
     }
 
@@ -699,8 +706,9 @@ sync_pipe_open_command(char* const argv[], int *data_read_fd,
     /* (increase this value if you have trouble while fast capture file switches) */
     if (! CreatePipe(&data_pipe[PIPE_READ], &data_pipe[PIPE_WRITE], &sa, 5120)) {
         /* Couldn't create the message pipe between parent and child. */
-        *msg = g_strdup_printf("Couldn't create data pipe: %s",
-                               win32strerror(GetLastError()));
+        errmsg = win32strerror(GetLastError());
+        *msg = g_strdup_printf("Couldn't create data pipe: %s", errmsg);
+        g_free(errmsg);
         ws_close(*message_read_fd);    /* Should close sync_pipe[PIPE_READ] */
         CloseHandle(sync_pipe[PIPE_WRITE]);
         return -1;
@@ -752,8 +760,10 @@ sync_pipe_open_command(char* const argv[], int *data_read_fd,
     /* call dumpcap */
     if(!win32_create_process(argv[0], args->str, NULL, NULL, TRUE,
                                CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi)) {
+        errmsg = win32strerror(GetLastError());
         *msg = g_strdup_printf("Couldn't run %s in child process: %s",
-                               args->str, win32strerror(GetLastError()));
+                               args->str, errmsg);
+        g_free(errmsg);
         ws_close(*data_read_fd);       /* Should close data_pipe[PIPE_READ] */
         CloseHandle(data_pipe[PIPE_WRITE]);
         ws_close(*message_read_fd);    /* Should close sync_pipe[PIPE_READ] */