dtrace.c

Sun Solaris 10 中的 DTrace 组件的源代码。请参看: http://www.sun.com/software/solaris/observability.jsp

/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only.
 * See the file usr/src/LICENSING.NOTICE in this distribution or
 * http://www.opensolaris.org/license/ for details.
 */

#pragma ident	"@(#)dtrace.c	1.15	04/12/18 SMI"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>

#include <dtrace.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <strings.h>
#include <unistd.h>
#include <limits.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <alloca.h>
#include <libgen.h>
#include <libproc.h>

typedef struct dtrace_cmd {
	void (*dc_func)(struct dtrace_cmd *);	/* function to compile arg */
	dtrace_probespec_t dc_spec;		/* probe specifier context */
	char *dc_arg;				/* argument from main argv */
	const char *dc_name;			/* name for error messages */
	const char *dc_desc;			/* desc for error messages */
	dtrace_prog_t *dc_prog;			/* program compiled from arg */
} dtrace_cmd_t;

#define	DMODE_VERS	0	/* display version information and exit (-V) */
#define	DMODE_EXEC	1	/* compile program for enabling (-a/e/E) */
#define	DMODE_ANON	2	/* compile program for anonymous tracing (-A) */
#define	DMODE_LINK	3	/* compile program for linking with ELF (-G) */
#define	DMODE_LIST	4	/* compile program and list probes (-l) */

#define	E_SUCCESS	0
#define	E_ERROR		1
#define	E_USAGE		2

static const char DTRACE_OPTSTR[] =
	"3:6:aAb:c:CD:ef:FGHi:I:lL:m:n:o:p:P:qs:SU:vVwx:X:Z";

static int g_fd;
static char **g_argv;
static int g_argc;
static char **g_objv;
static int g_objc;
static dtrace_cmd_t *g_cmdv;
static int g_cmdc;
static struct ps_prochandle **g_psv;
static int g_psc;
static int g_pslive;
static char *g_pname;
static int g_quiet;
static int g_flowindent;
static int g_intr;
static int g_impatient;
static int g_newline;
static int g_total;
static int g_cflags;
static int g_oflags;
static int g_verbose;
static int g_exec = 1;
static int g_mode = DMODE_EXEC;
static int g_status = E_SUCCESS;
static int g_grabanon = 0;
static const char *g_ofile = NULL;
static FILE *g_ofp = stdout;
static dtrace_hdl_t *g_dtp;
static char *g_etcfile = "/etc/system";
static const char *g_etcbegin = "* vvvv Added by DTrace";
static const char *g_etcend = "* ^^^^ Added by DTrace";

static const char *g_etc[] =  {
"*",
"* The following forceload directives were added by dtrace(1M) to allow for",
"* tracing during boot.  If these directives are removed, the system will",
"* continue to function, but tracing will not occur during boot as desired.",
"* To remove these directives (and this block comment) automatically, run",
"* \"dtrace -A\" without additional arguments.  See the \"Anonymous Tracing\"",
"* chapter of the Solaris Dynamic Tracing Guide for details.",
"*",
NULL };

static int
usage(FILE *fp)
{
	static const char predact[] = "[[ predicate ] action ]";

	(void) fprintf(fp, "Usage: %s [-32|-64] [-aACeFGHlqSvVwZ] "
	    "[-b bufsz] [-c cmd] [-D name[=def]]\n\t[-I path] [-L path] "
	    "[-o output] [-p pid] [-s script] [-U name]\n\t"
	    "[-x opt[=val]] [-X a|c|s|t]\n\n"
	    "\t[-P provider %s]\n"
	    "\t[-m [ provider: ] module %s]\n"
	    "\t[-f [[ provider: ] module: ] func %s]\n"
	    "\t[-n [[[ provider: ] module: ] func: ] name %s]\n"
	    "\t[-i probe-id %s] [ args ... ]\n\n", g_pname,
	    predact, predact, predact, predact, predact);

	(void) fprintf(fp, "\tpredicate -> '/' D-expression '/'\n");
	(void) fprintf(fp, "\t   action -> '{' D-statements '}'\n");

	(void) fprintf(fp, "\n"
	    "\t-32 generate 32-bit D programs and ELF files\n"
	    "\t-64 generate 64-bit D programs and ELF files\n\n"
	    "\t-a  claim anonymous tracing state\n"
	    "\t-A  generate driver.conf(4) directives for anonymous tracing\n"
	    "\t-b  set trace buffer size\n"
	    "\t-c  run specified command and exit upon its completion\n"
	    "\t-C  run cpp(1) preprocessor on script files\n"
	    "\t-D  define symbol when invoking preprocessor\n"
	    "\t-e  exit after compiling request but prior to enabling probes\n"
	    "\t-f  enable or list probes matching the specified function name\n"
	    "\t-F  coalesce trace output by function\n"
	    "\t-G  generate an ELF file containing embedded dtrace program\n"
	    "\t-H  print included files when invoking preprocessor\n"
	    "\t-i  enable or list probes matching the specified probe id\n"
	    "\t-I  add include directory to preprocessor search path\n"
	    "\t-l  list probes matching specified criteria\n"
	    "\t-L  add library directory to library search path\n"
	    "\t-m  enable or list probes matching the specified module name\n"
	    "\t-n  enable or list probes matching the specified probe name\n"
	    "\t-o  set output file\n"
	    "\t-p  grab specified process-ID and cache its symbol tables\n"
	    "\t-P  enable or list probes matching the specified provider name\n"
	    "\t-q  set quiet mode (only output explicitly traced data)\n"
	    "\t-s  enable or list probes according to the specified D script\n"
	    "\t-S  print D compiler intermediate code\n"
	    "\t-U  undefine symbol when invoking preprocessor\n"
	    "\t-v  set verbose mode (report program stability attributes)\n"
	    "\t-V  report DTrace API version\n"
	    "\t-w  permit destructive actions\n"
	    "\t-x  enable or modify compiler and tracing options\n"
	    "\t-X  specify ISO C conformance settings for preprocessor\n"
	    "\t-Z  permit probe descriptions that match zero probes\n");

	return (E_USAGE);
}

static void
verror(const char *fmt, va_list ap)
{
	int error = errno;

	(void) fprintf(stderr, "%s: ", g_pname);
	(void) vfprintf(stderr, fmt, ap);

	if (fmt[strlen(fmt) - 1] != '\n')
		(void) fprintf(stderr, ": %s\n", strerror(error));
}

/*PRINTFLIKE1*/
static void
fatal(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	verror(fmt, ap);
	va_end(ap);

	exit(E_ERROR);
}

/*PRINTFLIKE1*/
static void
dfatal(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);

	(void) fprintf(stderr, "%s: ", g_pname);
	if (fmt != NULL)
		(void) vfprintf(stderr, fmt, ap);

	va_end(ap);

	if (fmt != NULL && fmt[strlen(fmt) - 1] != '\n') {
		(void) fprintf(stderr, ": %s\n",
		    dtrace_errmsg(g_dtp, dtrace_errno(g_dtp)));
	} else if (fmt == NULL) {
		(void) fprintf(stderr, "%s\n",
		    dtrace_errmsg(g_dtp, dtrace_errno(g_dtp)));
	}

	exit(E_ERROR);
}

/*PRINTFLIKE1*/
static void
error(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	verror(fmt, ap);
	va_end(ap);
}

/*PRINTFLIKE1*/
static void
notice(const char *fmt, ...)
{
	va_list ap;

	if (g_quiet)
		return; /* -q or quiet pragma suppresses notice()s */

	va_start(ap, fmt);
	verror(fmt, ap);
	va_end(ap);
}

/*PRINTFLIKE1*/
static void
oprintf(const char *fmt, ...)
{
	va_list ap;
	int n;

	va_start(ap, fmt);
	n = vfprintf(g_ofp, fmt, ap);
	va_end(ap);

	if (n < 0) {
		if (errno != EINTR) {
			fatal("failed to write to %s",
			    g_ofile ? g_ofile : "<stdout>");
		}
		clearerr(g_ofp);
	}
}

static char **
make_argv(char *s)
{
	const char *ws = "\f\n\r\t\v ";
	char **argv = malloc(sizeof (char *) * (strlen(s) / 2 + 1));
	int argc = 0;
	char *p = s;

	if (argv == NULL)
		return (NULL);

	for (p = strtok(s, ws); p != NULL; p = strtok(NULL, ws))
		argv[argc++] = p;

	if (argc == 0)
		argv[argc++] = s;

	argv[argc] = NULL;
	return (argv);
}

static void
list_probes(void)
{
	dtrace_probedesc_t probe;

	bzero(&probe, sizeof (probe));

	while (ioctl(g_fd, DTRACEIOC_PROBES, &probe) != -1) {
		oprintf("%5d %10s %17s %33s %s\n", probe.dtpd_id,
		    probe.dtpd_provider, probe.dtpd_mod,
		    probe.dtpd_func, probe.dtpd_name);
		probe.dtpd_id++;
	}
}

static void
dof_prune(const char *fname)
{
	struct stat sbuf;
	size_t sz, i, j, mark, len;
	char *buf;
	int msg = 0, fd;

	if ((fd = open(fname, O_RDONLY)) == -1) {
		/*
		 * This is okay only if the file doesn't exist at all.
		 */
		if (errno != ENOENT)
			fatal("failed to open %s", fname);
		return;
	}

	if (fstat(fd, &sbuf) == -1)
		fatal("failed to fstat %s", fname);

	if ((buf = malloc((sz = sbuf.st_size) + 1)) == NULL)
		fatal("failed to allocate memory for %s", fname);

	if (read(fd, buf, sz) != sz)
		fatal("failed to read %s", fname);

	buf[sz] = '\0';
	(void) close(fd);

	if ((fd = open(fname, O_WRONLY | O_TRUNC)) == -1)
		fatal("failed to open %s for writing", fname);

	len = strlen("dof-data-");

	for (mark = 0, i = 0; i < sz; i++) {
		if (strncmp(&buf[i], "dof-data-", len) != 0)
			continue;

		/*
		 * This is only a match if it's in the 0th column.
		 */
		if (i != 0 && buf[i - 1] != '\n')
			continue;

		if (msg++ == 0) {
			error("cleaned up old anonymous "
			    "enabling in %s\n", fname);
		}

		/*
		 * We have a match.  First write out our data up until now.
		 */
		if (i != mark) {
			if (write(fd, &buf[mark], i - mark) != i - mark)
				fatal("failed to write to %s", fname);
		}

		/*
		 * Now scan forward until we scan past a newline.
		 */
		for (j = i; j < sz && buf[j] != '\n'; j++)
			continue;

		/*
		 * Reset our mark.
		 */
		if ((mark = j + 1) >= sz)
			break;

		i = j;
	}

	if (mark < sz) {
		if (write(fd, &buf[mark], sz - mark) != sz - mark)
			fatal("failed to write to %s", fname);
	}

	(void) close(fd);
	free(buf);
}

static void
etcsystem_prune(void)
{
	struct stat sbuf;
	size_t sz;
	char *buf, *start, *end;
	int fd;
	char *fname = g_etcfile, *tmpname;

	if ((fd = open(fname, O_RDONLY)) == -1)
		fatal("failed to open %s", fname);

	if (fstat(fd, &sbuf) == -1)
		fatal("failed to fstat %s", fname);

	if ((buf = malloc((sz = sbuf.st_size) + 1)) == NULL)
		fatal("failed to allocate memory for %s", fname);

	if (read(fd, buf, sz) != sz)
		fatal("failed to read %s", fname);

	buf[sz] = '\0';
	(void) close(fd);

	if ((start = strstr(buf, g_etcbegin)) == NULL)
		goto out;

	if (strlen(buf) != sz) {
		fatal("embedded nul byte in %s; manual repair of %s "
		    "required\n", fname, fname);
	}

	if (strstr(start + 1, g_etcbegin) != NULL) {
		fatal("multiple start sentinels in %s; manual repair of %s "
		    "required\n", fname, fname);
	}

	if ((end = strstr(buf, g_etcend)) == NULL) {
		fatal("missing end sentinel in %s; manual repair of %s "
		    "required\n", fname, fname);
	}

	if (start > end) {
		fatal("end sentinel preceeds start sentinel in %s; manual "
		    "repair of %s required\n", fname, fname);
	}

	end += strlen(g_etcend) + 1;
	bcopy(end, start, strlen(end) + 1);

	tmpname = alloca(sz = strlen(fname) + 80);
	(void) snprintf(tmpname, sz, "%s.dtrace.%d", fname, getpid());

	if ((fd = open(tmpname,
	    O_WRONLY | O_CREAT | O_EXCL, sbuf.st_mode)) == -1)
		fatal("failed to create %s", tmpname);

	if (write(fd, buf, strlen(buf)) < strlen(buf)) {
		(void) unlink(tmpname);
		fatal("failed to write to %s", tmpname);
	}

	(void) close(fd);

	if (chown(tmpname, sbuf.st_uid, sbuf.st_gid) != 0) {
		(void) unlink(tmpname);
		fatal("failed to chown(2) %s to uid %d, gid %d", tmpname,
		    (int)sbuf.st_uid, (int)sbuf.st_gid);
	}

	if (rename(tmpname, fname) == -1)
		fatal("rename of %s to %s failed", tmpname, fname);

	error("cleaned up forceload directives in %s\n", fname);
out:
	free(buf);
}

static void
etcsystem_add(void)
{
	const char *mods[20];
	int nmods, line;

	if ((g_ofp = fopen(g_ofile = g_etcfile, "a")) == NULL)
		fatal("failed to open output file '%s'", g_ofile);

	oprintf("%s\n", g_etcbegin);

	for (line = 0; g_etc[line] != NULL; line++)
		oprintf("%s\n", g_etc[line]);

	nmods = dtrace_provider_modules(g_dtp, mods,
	    sizeof (mods) / sizeof (char *) - 1);

	if (nmods >= sizeof (mods) / sizeof (char *))
		fatal("unexpectedly large number of modules!");

	mods[nmods++] = "dtrace";

	for (line = 0; line < nmods; line++)
		oprintf("forceload: drv/%s\n", mods[line]);

	oprintf("%s\n", g_etcend);

	if (fclose(g_ofp) == EOF)
		fatal("failed to close output file '%s'", g_ofile);

	error("added forceload directives to %s\n", g_ofile);
}

/*
 * Execute the specified program by enabling the corresponding instrumentation.
 * If -e has been specified, we get the program info but do not enable it.  If
 * -v has been specified, we print a stability report for the program.
 */
static void