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35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)subr_prf.c 8.3 (Berkeley) 1/21/94
39 * $FreeBSD: src/sys/kern/subr_prf.c,v 1.61.2.5 2002/08/31 18:22:08 dwmalone Exp $
40 * $DragonFly: src/sys/kern/subr_prf.c,v 1.21 2008/07/17 23:56:23 dillon Exp $
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/msgbuf.h>
49 #include <sys/malloc.h>
53 #include <sys/tprintf.h>
54 #include <sys/stdint.h>
55 #include <sys/syslog.h>
58 #include <sys/sysctl.h>
60 #include <sys/ctype.h>
61 #include <sys/eventhandler.h>
62 #include <sys/kthread.h>
64 #include <sys/thread2.h>
65 #include <sys/spinlock2.h>
72 * Note that stdarg.h and the ANSI style va_start macro is used for both
73 * ANSI and traditional C compilers. We use the __ machine version to stay
74 * within the kernel header file set.
76 #include <machine/stdarg.h>
83 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
84 #define MAXNBUF (sizeof(intmax_t) * NBBY + 1)
99 struct tty *constty; /* pointer to console "window" tty */
101 static void msglogchar(int c, int pri);
102 static void msgaddchar(int c, void *dummy);
103 static void kputchar (int ch, void *arg);
104 static char *ksprintn (char *nbuf, uintmax_t num, int base, int *lenp,
106 static void snprintf_func (int ch, void *arg);
108 static int consintr = 1; /* Ok to handle console interrupts? */
109 static int msgbufmapped; /* Set when safe to use msgbuf */
110 static struct spinlock cons_spin = SPINLOCK_INITIALIZER(cons_spin);
111 static thread_t constty_td = NULL;
115 static int log_console_output = 1;
116 TUNABLE_INT("kern.log_console_output", &log_console_output);
117 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
118 &log_console_output, 0, "");
120 static int unprivileged_read_msgbuf = 1;
121 SYSCTL_INT(_security, OID_AUTO, unprivileged_read_msgbuf, CTLFLAG_RW,
122 &unprivileged_read_msgbuf, 0,
123 "Unprivileged processes may read the kernel message buffer");
126 * Warn that a system table is full.
129 tablefull(const char *tab)
132 log(LOG_ERR, "%s: table is full\n", tab);
136 * Uprintf prints to the controlling terminal for the current process.
139 uprintf(const char *fmt, ...)
141 struct proc *p = curproc;
143 struct putchar_arg pca;
146 if (p && p->p_flag & P_CONTROLT &&
147 p->p_session->s_ttyvp) {
149 pca.tty = p->p_session->s_ttyp;
152 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
159 tprintf_open(struct proc *p)
162 if ((p->p_flag & P_CONTROLT) && p->p_session->s_ttyvp) {
163 sess_hold(p->p_session);
164 return ((tpr_t) p->p_session);
166 return ((tpr_t) NULL);
170 tprintf_close(tpr_t sess)
173 sess_rele((struct session *) sess);
177 * tprintf prints on the controlling terminal associated
178 * with the given session.
181 tprintf(tpr_t tpr, const char *fmt, ...)
183 struct session *sess = (struct session *)tpr;
184 struct tty *tp = NULL;
187 struct putchar_arg pca;
190 if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
198 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
205 * Ttyprintf displays a message on a tty; it should be used only by
206 * the tty driver, or anything that knows the underlying tty will not
207 * be revoke(2)'d away. Other callers should use tprintf.
210 ttyprintf(struct tty *tp, const char *fmt, ...)
213 struct putchar_arg pca;
219 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
225 * Log writes to the log buffer, and guarantees not to sleep (so can be
226 * called by interrupt routines). If there is no process reading the
227 * log yet, it writes to the console also.
230 log(int level, const char *fmt, ...)
234 struct putchar_arg pca;
238 pca.flags = log_open ? TOLOG : TOCONS;
241 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
248 #define CONSCHUNK 128
251 log_console(struct uio *uio)
253 int c, i, error, iovlen, nl;
255 struct iovec *miov = NULL;
259 if (!log_console_output)
262 pri = LOG_INFO | LOG_CONSOLE;
264 iovlen = uio->uio_iovcnt * sizeof (struct iovec);
265 MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
266 MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
267 bcopy((caddr_t)muio.uio_iov, (caddr_t)miov, iovlen);
272 while (uio->uio_resid > 0) {
273 c = (int)szmin(uio->uio_resid, CONSCHUNK);
274 error = uiomove(consbuffer, (size_t)c, uio);
277 for (i = 0; i < c; i++) {
278 msglogchar(consbuffer[i], pri);
279 if (consbuffer[i] == '\n')
286 msglogchar('\n', pri);
289 FREE(consbuffer, M_TEMP);
294 * Output to the console.
297 kprintf(const char *fmt, ...)
301 struct putchar_arg pca;
304 savintr = consintr; /* disable interrupts */
308 pca.flags = TOCONS | TOLOG;
310 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
314 consintr = savintr; /* reenable interrupts */
319 kvprintf(const char *fmt, __va_list ap)
322 struct putchar_arg pca;
325 savintr = consintr; /* disable interrupts */
328 pca.flags = TOCONS | TOLOG;
330 retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
333 consintr = savintr; /* reenable interrupts */
338 * Limited rate kprintf. The passed rate structure must be initialized
339 * with the desired reporting frequency. A frequency of 0 will result in
342 * count may be initialized to a negative number to allow an initial
346 krateprintf(struct krate *rate, const char *fmt, ...)
350 if (rate->ticks != (int)time_second) {
351 rate->ticks = (int)time_second;
355 if (rate->count < rate->freq) {
364 * Print a character to the dmesg log, the console, and/or the user's
367 * NOTE: TOTTY does not require nonblocking operation, but TOCONS
368 * and TOLOG do. When we have a constty we still output to
369 * the real console but we have a monitoring thread which
370 * we wakeup which tracks the log.
373 kputchar(int c, void *arg)
375 struct putchar_arg *ap = (struct putchar_arg*) arg;
376 int flags = ap->flags;
377 struct tty *tp = ap->tty;
381 if ((flags & TOCONS) && tp == NULL && constty)
382 flags |= TOLOG | TOWAKEUP;
384 msglogchar(c, ap->pri);
385 if ((flags & TOCONS) && c)
387 if (flags & TOWAKEUP)
392 * Scaled down version of sprintf(3).
395 ksprintf(char *buf, const char *cfmt, ...)
400 __va_start(ap, cfmt);
401 retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
408 * Scaled down version of vsprintf(3).
411 kvsprintf(char *buf, const char *cfmt, __va_list ap)
415 retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
421 * Scaled down version of snprintf(3).
424 ksnprintf(char *str, size_t size, const char *format, ...)
429 __va_start(ap, format);
430 retval = kvsnprintf(str, size, format, ap);
436 * Scaled down version of vsnprintf(3).
439 kvsnprintf(char *str, size_t size, const char *format, __va_list ap)
441 struct snprintf_arg info;
446 retval = kvcprintf(format, snprintf_func, &info, 10, ap);
447 if (info.remain >= 1)
453 ksnrprintf(char *str, size_t size, int radix, const char *format, ...)
458 __va_start(ap, format);
459 retval = kvsnrprintf(str, size, radix, format, ap);
465 kvsnrprintf(char *str, size_t size, int radix, const char *format, __va_list ap)
467 struct snprintf_arg info;
472 retval = kvcprintf(format, snprintf_func, &info, radix, ap);
473 if (info.remain >= 1)
479 kvasnrprintf(char **strp, size_t size, int radix,
480 const char *format, __va_list ap)
482 struct snprintf_arg info;
485 *strp = kmalloc(size, M_TEMP, M_WAITOK);
488 retval = kvcprintf(format, snprintf_func, &info, radix, ap);
489 if (info.remain >= 1)
495 kvasfree(char **strp)
498 kfree(*strp, M_TEMP);
504 snprintf_func(int ch, void *arg)
506 struct snprintf_arg *const info = arg;
508 if (info->remain >= 2) {
515 * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
516 * order; return an optional length and a pointer to the last character
517 * written in the buffer (i.e., the first character of the string).
518 * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
521 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
528 c = hex2ascii(num % base);
529 *++p = upper ? toupper(c) : c;
530 } while (num /= base);
537 * Scaled down version of printf(3).
539 * Two additional formats:
541 * The format %b is supported to decode error registers.
544 * kprintf("reg=%b\n", regval, "<base><arg>*");
546 * where <base> is the output base expressed as a control character, e.g.
547 * \10 gives octal; \20 gives hex. Each arg is a sequence of characters,
548 * the first of which gives the bit number to be inspected (origin 1), and
549 * the next characters (up to a control character, i.e. a character <= 32),
550 * give the name of the register. Thus:
552 * kvcprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
554 * would produce output:
556 * reg=3<BITTWO,BITONE>
558 * XXX: %D -- Hexdump, takes pointer and separator string:
559 * ("%6D", ptr, ":") -> XX:XX:XX:XX:XX:XX
560 * ("%*D", len, ptr, " " -> XX XX XX XX ...
563 #define PCHAR(c) {int cc=(c); if(func) (*func)(cc,arg); else *d++=cc; retval++;}
566 kvcprintf(char const *fmt, void (*func)(int, void*), void *arg,
567 int radix, __va_list ap)
571 const char *p, *percent, *q;
575 int base, tmp, width, ladjust, sharpflag, neg, sign, dot;
576 int cflag, hflag, jflag, lflag, qflag, tflag, zflag;
579 int retval = 0, stop = 0;
583 * Make a supreme effort to avoid reentrant panics or deadlocks.
585 if (func == kputchar) {
586 if (mycpu->gd_flags & GDF_KPRINTF)
588 atomic_set_long(&mycpu->gd_flags, GDF_KPRINTF);
598 fmt = "(fmt null)\n";
600 if (radix < 2 || radix > 36)
603 usespin = (panic_cpu_gd != mycpu &&
605 (((struct putchar_arg *)arg)->flags & TOTTY) == 0);
608 spin_lock(&cons_spin);
614 while ((ch = (u_char)*fmt++) != '%' || stop) {
620 dot = dwidth = ladjust = neg = sharpflag = sign = upper = 0;
621 cflag = hflag = jflag = lflag = qflag = tflag = zflag = 0;
624 switch (ch = (u_char)*fmt++) {
642 width = __va_arg(ap, int);
648 dwidth = __va_arg(ap, int);
656 case '1': case '2': case '3': case '4':
657 case '5': case '6': case '7': case '8': case '9':
658 for (n = 0;; ++fmt) {
659 n = n * 10 + ch - '0';
661 if (ch < '0' || ch > '9')
670 num = (u_int)__va_arg(ap, int);
671 p = __va_arg(ap, char *);
672 for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
680 if (num & (1 << (n - 1))) {
681 PCHAR(tmp ? ',' : '<');
682 for (; (n = *p) > ' '; ++p)
686 for (; *p > ' '; ++p)
693 PCHAR(__va_arg(ap, int));
696 up = __va_arg(ap, u_char *);
697 p = __va_arg(ap, char *);
701 PCHAR(hex2ascii(*up >> 4));
702 PCHAR(hex2ascii(*up & 0x0f));
733 *(__va_arg(ap, char *)) = retval;
735 *(__va_arg(ap, short *)) = retval;
737 *(__va_arg(ap, intmax_t *)) = retval;
739 *(__va_arg(ap, long *)) = retval;
741 *(__va_arg(ap, quad_t *)) = retval;
743 *(__va_arg(ap, int *)) = retval;
750 sharpflag = (width == 0);
752 num = (uintptr_t)__va_arg(ap, void *);
763 p = __va_arg(ap, char *);
769 for (n = 0; n < dwidth && p[n]; n++)
774 if (!ladjust && width > 0)
779 if (ladjust && width > 0)
801 num = (u_char)__va_arg(ap, int);
803 num = (u_short)__va_arg(ap, int);
805 num = __va_arg(ap, uintmax_t);
807 num = __va_arg(ap, u_long);
809 num = __va_arg(ap, u_quad_t);
811 num = __va_arg(ap, ptrdiff_t);
813 num = __va_arg(ap, size_t);
815 num = __va_arg(ap, u_int);
819 num = (char)__va_arg(ap, int);
821 num = (short)__va_arg(ap, int);
823 num = __va_arg(ap, intmax_t);
825 num = __va_arg(ap, long);
827 num = __va_arg(ap, quad_t);
829 num = __va_arg(ap, ptrdiff_t);
831 num = __va_arg(ap, ssize_t);
833 num = __va_arg(ap, int);
835 if (sign && (intmax_t)num < 0) {
837 num = -(intmax_t)num;
839 p = ksprintn(nbuf, num, base, &tmp, upper);
840 if (sharpflag && num != 0) {
849 if (!ladjust && padc != '0' && width &&
850 (width -= tmp) > 0) {
856 if (sharpflag && num != 0) {
859 } else if (base == 16) {
864 if (!ladjust && width && (width -= tmp) > 0)
871 if (ladjust && width && (width -= tmp) > 0)
877 while (percent < fmt)
880 * Since we ignore an formatting argument it is no
881 * longer safe to obey the remaining formatting
882 * arguments as the arguments will no longer match
891 * Cleanup reentrancy issues.
893 if (func == kputchar)
894 atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
896 spin_unlock(&cons_spin);
905 * Called from the panic code to try to get the console working
906 * again in case we paniced inside a kprintf().
911 spin_init(&cons_spin);
912 atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
916 * Console support thread for constty intercepts. This is needed because
917 * console tty intercepts can block. Instead of having kputchar() attempt
918 * to directly write to the console intercept we just force it to log
919 * and wakeup this baby to track and dump the log to constty.
929 EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc,
930 constty_td, SHUTDOWN_PRI_FIRST);
931 constty_td->td_flags |= TDF_SYSTHREAD;
934 kproc_suspend_loop();
938 if (mbp == NULL || msgbufmapped == 0 ||
939 windex == mbp->msg_bufx) {
940 tsleep(constty_td, 0, "waiting", hz*60);
944 windex = mbp->msg_bufx;
948 * Get message buf FIFO indices. rindex is tracking.
950 if ((tp = constty) == NULL) {
951 rindex = mbp->msg_bufx;
956 * Don't blow up if the message buffer is broken
958 if (windex < 0 || windex >= mbp->msg_size)
960 if (rindex < 0 || rindex >= mbp->msg_size)
964 * And dump it. If constty gets stuck will give up.
966 while (rindex != windex) {
967 if (tputchar((uint8_t)mbp->msg_ptr[rindex], tp) < 0) {
969 rindex = mbp->msg_bufx;
972 if (++rindex >= mbp->msg_size)
974 if (tp->t_outq.c_cc >= tp->t_ohiwat) {
975 tsleep(constty_daemon, 0, "blocked", hz / 10);
976 if (tp->t_outq.c_cc >= tp->t_ohiwat) {
985 static struct kproc_desc constty_kp = {
990 SYSINIT(bufdaemon, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY,
991 kproc_start, &constty_kp)
994 * Put character in log buffer with a particular priority.
999 msglogchar(int c, int pri)
1001 static int lastpri = -1;
1002 static int dangling;
1008 if (c == '\0' || c == '\r')
1010 if (pri != -1 && pri != lastpri) {
1012 msgaddchar('\n', NULL);
1015 msgaddchar('<', NULL);
1016 for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
1017 msgaddchar(*p--, NULL);
1018 msgaddchar('>', NULL);
1021 msgaddchar(c, NULL);
1031 * Put char in log buffer. Make sure nothing blows up beyond repair if
1032 * we have an MP race.
1037 msgaddchar(int c, void *dummy)
1046 windex = mbp->msg_bufx;
1047 mbp->msg_ptr[windex] = c;
1048 if (++windex >= mbp->msg_size)
1050 rindex = mbp->msg_bufr;
1051 if (windex == rindex) {
1053 if (rindex >= mbp->msg_size)
1054 rindex -= mbp->msg_size;
1055 mbp->msg_bufr = rindex;
1057 mbp->msg_bufx = windex;
1061 msgbufcopy(struct msgbuf *oldp)
1065 pos = oldp->msg_bufr;
1066 while (pos != oldp->msg_bufx) {
1067 msglogchar(oldp->msg_ptr[pos], -1);
1068 if (++pos >= oldp->msg_size)
1074 msgbufinit(void *ptr, size_t size)
1077 static struct msgbuf *oldp = NULL;
1079 size -= sizeof(*msgbufp);
1081 msgbufp = (struct msgbuf *) (cp + size);
1082 if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size ||
1083 msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) {
1085 bzero(msgbufp, sizeof(*msgbufp));
1086 msgbufp->msg_magic = MSG_MAGIC;
1087 msgbufp->msg_size = (char *)msgbufp - cp;
1089 msgbufp->msg_ptr = cp;
1090 if (msgbufmapped && oldp != msgbufp)
1096 /* Sysctls for accessing/clearing the msgbuf */
1099 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
1105 * Only wheel or root can access the message log.
1107 if (unprivileged_read_msgbuf == 0) {
1108 KKASSERT(req->td->td_proc);
1109 cred = req->td->td_proc->p_ucred;
1111 if ((cred->cr_prison || groupmember(0, cred) == 0) &&
1112 priv_check(req->td, PRIV_ROOT) != 0
1119 * Unwind the buffer, so that it's linear (possibly starting with
1120 * some initial nulls).
1122 error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr + msgbufp->msg_bufx,
1123 msgbufp->msg_size - msgbufp->msg_bufx, req);
1126 if (msgbufp->msg_bufx > 0) {
1127 error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr,
1128 msgbufp->msg_bufx, req);
1133 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
1134 0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
1136 static int msgbuf_clear;
1139 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
1142 error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
1143 if (!error && req->newptr) {
1144 /* Clear the buffer and reset write pointer */
1145 bzero(msgbufp->msg_ptr, msgbufp->msg_size);
1146 msgbufp->msg_bufr = msgbufp->msg_bufx = 0;
1152 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
1153 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0,
1154 sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
1158 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
1162 if (!msgbufmapped) {
1163 db_printf("msgbuf not mapped yet\n");
1166 db_printf("msgbufp = %p\n", msgbufp);
1167 db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
1168 msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr,
1169 msgbufp->msg_bufx, msgbufp->msg_ptr);
1170 for (i = 0; i < msgbufp->msg_size; i++) {
1171 j = (i + msgbufp->msg_bufr) % msgbufp->msg_size;
1172 db_printf("%c", msgbufp->msg_ptr[j]);