Move xorg_backtrace() up to the OS level so we can call it from DIX.

2 files changed, 202 insertions, 0 deletions

diff --git a/os/Makefile.am b/os/Makefile.am
index 16ecc15ae..f89da6ba2 100644
--- a/os/Makefile.am
+++ b/os/Makefile.am
@@ -11,6 +11,7 @@ libos_la_SOURCES = 	\
 	WaitFor.c	\
 	access.c	\
 	auth.c		\
+	backtrace.c	\
 	connection.c	\
 	io.c		\
 	mitauth.c	\
diff --git a/os/backtrace.c b/os/backtrace.c
new file mode 100644
index 000000000..b52dcded8
--- /dev/null
+++ b/os/backtrace.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright 2008 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software")
+ * to deal in the software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * them Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTIBILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include "os.h"
+#include "misc.h"
+
+#ifdef HAVE_BACKTRACE
+#include <execinfo.h>
+
+void xorg_backtrace(void)
+{
+    void *array[32]; /* deeper nesting than this means something's wrong */
+    size_t size, i;
+    char **strings;
+    ErrorF("\nBacktrace:\n");
+    size = backtrace(array, 32);
+    strings = backtrace_symbols(array, size);
+    for (i = 0; i < size; i++)
+        ErrorF("%d: %s\n", i, strings[i]);
+    free(strings);
+}
+
+#else /* not glibc or glibc < 2.1 */
+
+# if defined(sun) && defined(__SVR4)
+#  define HAVE_PSTACK
+# endif
+
+# if defined(HAVE_WALKCONTEXT) /* Solaris 9 & later */
+
+# include <ucontext.h>
+# include <signal.h>
+# include <dlfcn.h>
+# include <sys/elf.h>
+
+#ifdef _LP64
+# define ElfSym Elf64_Sym
+#else
+# define ElfSym Elf32_Sym
+#endif
+
+/* Called for each frame on the stack to print it's contents */
+static int xorg_backtrace_frame(uintptr_t pc, int signo, void *arg)
+{
+    Dl_info dlinfo;
+    ElfSym *dlsym;
+    char header[32];
+    int depth = *((int *) arg);
+
+    if (signo) {
+	char signame[SIG2STR_MAX];
+
+	if (sig2str(signo, signame) != 0) {
+	    strcpy(signame, "unknown");
+	}
+
+	ErrorF("** Signal %d (%s)\n", signo, signame);
+    }
+
+    snprintf(header, sizeof(header), "%d: 0x%lx", depth, pc);
+    *((int *) arg) = depth + 1;
+
+    /* Ask system dynamic loader for info on the address */
+    if (dladdr1((void *) pc, &dlinfo, (void **) &dlsym, RTLD_DL_SYMENT)) {
+	unsigned long offset = pc - (uintptr_t) dlinfo.dli_saddr;
+	const char *symname;
+	
+	if (offset < dlsym->st_size) { /* inside a function */
+	    symname = dlinfo.dli_sname;
+	} else { /* found which file it was in, but not which function */
+	    symname = "<section start>";
+	    offset = pc - (uintptr_t)dlinfo.dli_fbase;
+	}
+	ErrorF("%s: %s:%s+0x%lx\n", header, dlinfo.dli_fname,
+	       symname, offset);
+
+    } else {
+	/* Couldn't find symbol info from system dynamic loader, should
+	 * probably poke elfloader here, but haven't written that code yet,
+	 * so we just print the pc.
+	 */
+	ErrorF("%s\n", header);
+    }
+
+    return 0;
+}
+# endif /* HAVE_WALKCONTEXT */
+
+# ifdef HAVE_PSTACK
+static int xorg_backtrace_pstack(void) {
+    pid_t kidpid;
+    int pipefd[2];
+
+    if (pipe(pipefd) != 0) {
+	return -1;
+    }
+
+    kidpid = fork1();
+
+    if (kidpid == -1) {
+	/* ERROR */
+	return -1;
+    } else if (kidpid == 0) {
+	/* CHILD */
+	char parent[16];
+	
+	seteuid(0);
+	close(STDIN_FILENO);
+	close(STDOUT_FILENO);
+	dup2(pipefd[1],STDOUT_FILENO);
+	closefrom(STDERR_FILENO);
+
+	snprintf(parent, sizeof(parent), "%d", getppid());
+	execle("/usr/bin/pstack", "pstack", parent, NULL);
+	exit(1);
+    } else {
+	/* PARENT */
+	char btline[256];
+	int kidstat;
+	int bytesread;
+	int done = 0;
+	
+	close(pipefd[1]);
+
+	while (!done) {
+	    bytesread = read(pipefd[0], btline, sizeof(btline) - 1);
+
+	    if (bytesread > 0) {
+		btline[bytesread] = 0;
+		ErrorF("%s", btline);
+	    }
+	    else if ((bytesread < 0) ||
+		     ((errno != EINTR) && (errno != EAGAIN)))
+		done = 1;
+	}
+	close(pipefd[0]);
+	waitpid(kidpid, &kidstat, 0);
+	if (kidstat != 0)
+	    return -1;
+    }
+    return 0;
+}
+# endif /* HAVE_PSTACK */
+
+
+# if defined(HAVE_PSTACK) || defined(HAVE_WALKCONTEXT)
+
+void xorg_backtrace(void) {
+
+    ErrorF("\nBacktrace:\n");
+
+#  ifdef HAVE_PSTACK
+/* First try fork/exec of pstack - otherwise fall back to walkcontext
+   pstack is preferred since it can print names of non-exported functions */
+
+    if (xorg_backtrace_pstack() < 0)
+#  endif	
+    {
+#  ifdef HAVE_WALKCONTEXT
+	ucontext_t u;
+	int depth = 1;
+	
+	if (getcontext(&u) == 0)
+	    walkcontext(&u, xorg_backtrace_frame, &depth);
+	else
+#  endif
+	    Error("Failed to get backtrace info");
+    }
+    ErrorF("\n");	
+}
+
+# else
+
+/* Default fallback if we can't find any way to get a backtrace */
+void xorg_backtrace(void) { return; }
+
+# endif
+#endif