Merge remote-tracking branch 'origin/released'

Conflicts:
	xorg-server/include/misc.h
	xorg-server/os/utils.c

4 files changed, 250 insertions, 28 deletions

diff --git a/xorg-server/os/backtrace.c b/xorg-server/os/backtrace.c
index 81348f417..daac60cf6 100644
--- a/xorg-server/os/backtrace.c
+++ b/xorg-server/os/backtrace.c
@@ -45,29 +45,37 @@ xorg_backtrace(void)
     int size, i;
     Dl_info info;
 
-    ErrorF("\n");
-    ErrorF("Backtrace:\n");
+    ErrorFSigSafe("\n");
+    ErrorFSigSafe("Backtrace:\n");
     size = backtrace(array, 64);
     for (i = 0; i < size; i++) {
         int rc = dladdr(array[i], &info);
 
         if (rc == 0) {
-            ErrorF("%d: ?? [%p]\n", i, array[i]);
+            ErrorFSigSafe("%u: ?? [%p]\n", i, array[i]);
             continue;
         }
         mod = (info.dli_fname && *info.dli_fname) ? info.dli_fname : "(vdso)";
         if (info.dli_saddr)
-            ErrorF("%d: %s (%s+0x%lx) [%p]\n", i, mod,
-                   info.dli_sname,
-                   (long unsigned int) ((char *) array[i] -
-                                        (char *) info.dli_saddr), array[i]);
+            ErrorFSigSafe(
+                "%u: %s (%s+0x%x) [%p]\n",
+                i,
+                mod,
+                info.dli_sname,
+                (unsigned int)((char *) array[i] -
+                               (char *) info.dli_saddr),
+                array[i]);
         else
-            ErrorF("%d: %s (%p+0x%lx) [%p]\n", i, mod,
-                   info.dli_fbase,
-                   (long unsigned int) ((char *) array[i] -
-                                        (char *) info.dli_fbase), array[i]);
+            ErrorFSigSafe(
+                "%u: %s (%p+0x%x) [%p]\n",
+                i,
+                mod,
+                info.dli_fbase,
+                (unsigned int)((char *) array[i] -
+                               (char *) info.dli_fbase),
+                array[i]);
     }
-    ErrorF("\n");
+    ErrorFSigSafe("\n");
 }
 
 #else                           /* not glibc or glibc < 2.1 */
@@ -105,7 +113,7 @@ xorg_backtrace_frame(uintptr_t pc, int signo, void *arg)
             strcpy(signame, "unknown");
         }
 
-        ErrorF("** Signal %d (%s)\n", signo, signame);
+        ErrorFSigSafe("** Signal %u (%s)\n", signo, signame);
     }
 
     snprintf(header, sizeof(header), "%d: 0x%lx", depth, pc);
@@ -123,7 +131,8 @@ xorg_backtrace_frame(uintptr_t pc, int signo, void *arg)
             symname = "<section start>";
             offset = pc - (uintptr_t) dlinfo.dli_fbase;
         }
-        ErrorF("%s: %s:%s+0x%lx\n", header, dlinfo.dli_fname, symname, offset);
+        ErrorFSigSafe("%s: %s:%s+0x%x\n", header, dlinfo.dli_fname, symname,
+                     offset);
 
     }
     else {
@@ -131,7 +140,7 @@ xorg_backtrace_frame(uintptr_t pc, int signo, void *arg)
          * probably poke elfloader here, but haven't written that code yet,
          * so we just print the pc.
          */
-        ErrorF("%s\n", header);
+        ErrorFSigSafe("%s\n", header);
     }
 
     return 0;
@@ -183,7 +192,7 @@ xorg_backtrace_pstack(void)
 
             if (bytesread > 0) {
                 btline[bytesread] = 0;
-                ErrorF("%s", btline);
+                ErrorFSigSafe("%s", btline);
             }
             else if ((bytesread < 0) || ((errno != EINTR) && (errno != EAGAIN)))
                 done = 1;
@@ -203,8 +212,8 @@ void
 xorg_backtrace(void)
 {
 
-    ErrorF("\n");
-    ErrorF("Backtrace:\n");
+    ErrorFSigSafe("\n");
+    ErrorFSigSafe("Backtrace:\n");
 
 #ifdef HAVE_PSTACK
 /* First try fork/exec of pstack - otherwise fall back to walkcontext
@@ -221,9 +230,9 @@ xorg_backtrace(void)
             walkcontext(&u, xorg_backtrace_frame, &depth);
         else
 #endif
-            ErrorF("Failed to get backtrace info: %s\n", strerror(errno));
+            ErrorFSigSafe("Failed to get backtrace info: %s\n", strerror(errno));
     }
-    ErrorF("\n");
+    ErrorFSigSafe("\n");
 }
 
 #else
diff --git a/xorg-server/os/log.c b/xorg-server/os/log.c
index efbf49a07..2e5b97a60 100644
--- a/xorg-server/os/log.c
+++ b/xorg-server/os/log.c
@@ -114,6 +114,7 @@ void (*OsVendorVErrorFProc) (const char *, va_list args) = NULL;
 #endif
 
 static FILE *logFile = NULL;
+static int logFileFd = -1;
 static Bool logFlush = FALSE;
 static Bool logSync = FALSE;
 static int logVerbosity = DEFAULT_LOG_VERBOSITY;
@@ -177,6 +178,14 @@ asm(".desc ___crashreporter_info__, 0x10");
 #define X_NONE_STRING			""
 #endif
 
+static size_t
+strlen_sigsafe(const char *s)
+{
+    size_t len;
+    for (len = 0; s[len]; len++);
+    return len;
+}
+
 /*
  * LogInit is called to start logging to a file.  It is also called (with
  * NULL arguments) when logging to a file is not wanted.  It must always be
@@ -217,6 +226,8 @@ LogInit(const char *fname, const char *backup)
             FatalError("Cannot open log file \"%s\"\n", logFileName);
         setvbuf(logFile, NULL, _IONBF, 0);
 
+        logFileFd = fileno(logFile);
+
         /* Flush saved log information. */
         if (saveBuffer && bufferSize > 0) {
             fwrite(saveBuffer, bufferPos, 1, logFile);
@@ -249,6 +260,7 @@ LogClose(enum ExitCode error)
                (error == EXIT_NO_ERROR) ? "successfully" : "with error", error);
         fclose(logFile);
         logFile = NULL;
+        logFileFd = -1;
     }
 }
 
@@ -273,16 +285,97 @@ LogSetParameter(LogParameter param, int value)
     }
 }
 
-/* This function does the actual log message writes. */
+static int
+pnprintf(char *string, size_t size, const char *f, va_list args)
+{
+    int f_idx = 0;
+    int s_idx = 0;
+    int f_len = strlen_sigsafe(f);
+    char *string_arg;
+    char number[21];
+    int p_len;
+    int i;
+    uint64_t ui;
+
+    for (; f_idx < f_len && s_idx < size - 1; f_idx++) {
+        if (f[f_idx] != '%') {
+            string[s_idx++] = f[f_idx];
+            continue;
+        }
+
+        switch (f[++f_idx]) {
+        case 's':
+            string_arg = va_arg(args, char*);
+            p_len = strlen_sigsafe(string_arg);
+
+            for (i = 0; i < p_len && s_idx < size - 1; i++)
+                string[s_idx++] = string_arg[i];
+            break;
+
+        case 'u':
+            ui = va_arg(args, unsigned);
+            FormatUInt64(ui, number);
+            p_len = strlen_sigsafe(number);
+
+            for (i = 0; i < p_len && s_idx < size - 1; i++)
+                string[s_idx++] = number[i];
+            break;
+
+        case 'p':
+            string[s_idx++] = '0';
+            if (s_idx < size - 1)
+                string[s_idx++] = 'x';
+            ui = (uintptr_t)va_arg(args, void*);
+            FormatUInt64Hex(ui, number);
+            p_len = strlen_sigsafe(number);
+
+            for (i = 0; i < p_len && s_idx < size - 1; i++)
+                string[s_idx++] = number[i];
+            break;
+
+        case 'x':
+            ui = va_arg(args, unsigned);
+            FormatUInt64Hex(ui, number);
+            p_len = strlen_sigsafe(number);
+
+            for (i = 0; i < p_len && s_idx < size - 1; i++)
+                string[s_idx++] = number[i];
+            break;
+
+        default:
+            va_arg(args, char*);
+            string[s_idx++] = '%';
+            if (s_idx < size - 1)
+                string[s_idx++] = f[f_idx];
+            break;
+        }
+    }
+
+    string[s_idx] = '\0';
+
+    return s_idx;
+}
+
+/* This function does the actual log message writes. It must be signal safe.
+ * When attempting to call non-signal-safe functions, guard them with a check
+ * of the inSignalContext global variable. */
 static void
 LogSWrite(int verb, const char *buf, size_t len, Bool end_line)
 {
     static Bool newline = TRUE;
 
     if (verb < 0 || logVerbosity >= verb)
-        fwrite(buf, len, 1, stderr);
+        write(2, buf, len);
+
     if (verb < 0 || logFileVerbosity >= verb) {
-        if (logFile) {
+        if (inSignalContext && logFileFd >= 0) {
+            write(logFileFd, buf, len);
+#ifdef WIN32
+            if (logFlush && logSync)
+                fsync(logFileFd);
+#endif
+        }
+        else if (!inSignalContext && logFile) {
             if (newline)
                 fprintf(logFile, "[%10.3f] ", GetTimeInMillis() / 1000.0);
             newline = end_line;
@@ -295,7 +388,7 @@ LogSWrite(int verb, const char *buf, size_t len, Bool end_line)
 #endif
             }
         }
-        else if (needBuffer) {
+        else if (!inSignalContext && needBuffer) {
             if (len > bufferUnused) {
                 bufferSize += 1024;
                 bufferUnused += 1024;
@@ -376,6 +469,16 @@ LogVMessageVerb(MessageType type, int verb, const char *format, va_list args)
     Bool newline;
     size_t len = 0;
 
+    if (inSignalContext) {
+        BUG_WARN_MSG(inSignalContext,
+                     "Warning: attempting to log data in a signal unsafe "
+                     "manner while in signal context. Please update to check "
+                     "inSignalContext and/or use LogMessageVerbSigSafe() or "
+                     "ErrorFSigSafe(). The offending log format message is:\n"
+                     "%s\n", format);
+        return;
+    }
+
     type_str = LogMessageTypeVerbString(type, verb);
     if (!type_str)
         return;
@@ -417,6 +520,44 @@ LogMessage(MessageType type, const char *format, ...)
     va_end(ap);
 }
 
+/* Log a message using only signal safe functions. */
+void
+LogMessageVerbSigSafe(MessageType type, int verb, const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    LogVMessageVerbSigSafe(type, verb, format, ap);
+    va_end(ap);
+}
+
+void
+LogVMessageVerbSigSafe(MessageType type, int verb, const char *format, va_list args)
+{
+    const char *type_str;
+    char buf[1024];
+    int len;
+    Bool newline;
+
+    type_str = LogMessageTypeVerbString(type, verb);
+    if (!type_str)
+        return;
+
+    /* if type_str is not "", prepend it and ' ', to message */
+    if (type_str[0] != '\0') {
+        LogSWrite(verb, type_str, strlen_sigsafe(type_str), FALSE);
+        LogSWrite(verb, " ", 1, FALSE);
+    }
+
+    len = pnprintf(buf, sizeof(buf), format, args);
+
+    /* Force '\n' at end of truncated line */
+    if (sizeof(buf) - len == 1)
+        buf[len - 1] = '\n';
+
+    newline = (buf[len - 1] == '\n');
+    LogSWrite(verb, buf, len, newline);
+}
+
 void
 LogVHdrMessageVerb(MessageType type, int verb, const char *msg_format,
                    va_list msg_args, const char *hdr_format, va_list hdr_args)
@@ -427,6 +568,16 @@ LogVHdrMessageVerb(MessageType type, int verb, const char *msg_format,
     Bool newline;
     size_t len = 0;
 
+    if (inSignalContext) {
+        BUG_WARN_MSG(inSignalContext,
+                     "Warning: attempting to log data in a signal unsafe "
+                     "manner while in signal context. Please update to check "
+                     "inSignalContext and/or use LogMessageVerbSigSafe(). The "
+                     "offending header and log message formats are:\n%s %s\n",
+                     hdr_format, msg_format);
+        return;
+    }
+
     type_str = LogMessageTypeVerbString(type, verb);
     if (!type_str)
         return;
@@ -665,6 +816,22 @@ ErrorF(const char *f, ...)
 }
 
 void
+VErrorFSigSafe(const char *f, va_list args)
+{
+    LogVMessageVerbSigSafe(X_ERROR, -1, f, args);
+}
+
+void
+ErrorFSigSafe(const char *f, ...)
+{
+    va_list args;
+
+    va_start(args, f);
+    VErrorFSigSafe(f, args);
+    va_end(args);
+}
+
+void
 LogPrintMarkers(void)
 {
     /* Show what the message marker symbols mean. */
diff --git a/xorg-server/os/osinit.c b/xorg-server/os/osinit.c
index 4c444a04f..c2cff757b 100644
--- a/xorg-server/os/osinit.c
+++ b/xorg-server/os/osinit.c
@@ -113,7 +113,7 @@ OsSigHandler(int signo)
     const char *dlerr = dlerror();
 
     if (dlerr) {
-        LogMessage(X_ERROR, "Dynamic loader error: %s\n", dlerr);
+        LogMessageVerbSigSafe(X_ERROR, 1, "Dynamic loader error: %s\n", dlerr);
     }
 #endif                          /* RTLD_DI_SETSIGNAL */
 
@@ -129,8 +129,8 @@ OsSigHandler(int signo)
 
 #ifdef SA_SIGINFO
     if (sip->si_code == SI_USER) {
-        ErrorF("Recieved signal %d sent by process %ld, uid %ld\n",
-               signo, (long) sip->si_pid, (long) sip->si_uid);
+        ErrorFSigSafe("Recieved signal %u sent by process %u, uid %u\n", signo,
+                     sip->si_pid, sip->si_uid);
     }
     else {
         switch (signo) {
@@ -138,7 +138,7 @@ OsSigHandler(int signo)
         case SIGBUS:
         case SIGILL:
         case SIGFPE:
-            ErrorF("%s at address %p\n", strsignal(signo), sip->si_addr);
+            ErrorFSigSafe("%s at address %p\n", strsignal(signo), sip->si_addr);
         }
     }
 #endif
diff --git a/xorg-server/os/utils.c b/xorg-server/os/utils.c
index 47bc7b5c3..e94179518 100644
--- a/xorg-server/os/utils.c
+++ b/xorg-server/os/utils.c
@@ -204,6 +204,8 @@ int auditTrailLevel = 1;
 
 char *SeatId = NULL;
 
+sig_atomic_t inSignalContext = FALSE;
+
 #ifdef _MSC_VER
 static HANDLE s_hSmartScheduleTimer = NULL;
 static HANDLE s_hSmartScheduleTimerQueue = NULL;
@@ -1852,3 +1854,47 @@ xstrtokenize(const char *str, const char *separators)
     free(list);
     return NULL;
 }
+
+/* Format a number into a string in a signal safe manner. The string should be
+ * at least 21 characters in order to handle all uint64_t values. */
+void
+FormatUInt64(uint64_t num, char *string)
+{
+    uint64_t divisor;
+    int len;
+    int i;
+
+    for (len = 1, divisor = 10;
+         len < 20 && num / divisor;
+         len++, divisor *= 10);
+
+    for (i = len, divisor = 1; i > 0; i--, divisor *= 10)
+        string[i - 1] = '0' + ((num / divisor) % 10);
+
+    string[len] = '\0';
+}
+
+/* Format a number into a hexadecimal string in a signal safe manner. The string
+ * should be at least 17 characters in order to handle all uint64_t values. */
+void
+FormatUInt64Hex(uint64_t num, char *string)
+{
+    uint64_t divisor;
+    int len;
+    int i;
+
+    for (len = 1, divisor = 0x10;
+         len < 16 && num / divisor;
+         len++, divisor *= 0x10);
+
+    for (i = len, divisor = 1; i > 0; i--, divisor *= 0x10) {
+        int val = (num / divisor) % 0x10;
+
+        if (val < 10)
+            string[i - 1] = '0' + val;
+        else
+            string[i - 1] = 'a' + val - 10;
+    }
+
+    string[len] = '\0';
+}