bin/52190: [Patch] decode more syscalls in truss
Dan Nelson
dnelson at allantgroup.com
Tue Jun 3 16:00:34 PDT 2003
The following reply was made to PR bin/52190; it has been noted by GNATS.
From: Dan Nelson <dnelson at allantgroup.com>
To: FreeBSD-gnats-submit at FreeBSD.org
Cc:
Subject: Re: bin/52190: [Patch] decode more syscalls in truss
Date: Tue, 3 Jun 2003 17:54:06 -0500
Updated patch that decodes struct pollfd and fd_set, fixes a memory
leak in get_struct(), and avoids a unnecessary abort when a NULL
sockaddr is passed to recvfrom().
Index: syscall.h
===================================================================
RCS file: /home/ncvs/src/usr.bin/truss/syscall.h,v
retrieving revision 1.10
diff -p -u -r1.10 syscall.h
--- syscall.h 4 Aug 2002 02:24:21 -0000 1.10
+++ syscall.h 2 Jun 2003 19:15:54 -0000
@@ -9,9 +9,16 @@
* write() arguments as such, even though they may *not* be
* printable data.
* Ptr -- pointer to some specific structure. Just print as hex for now.
- * Quad -- a double-word value. e.g., lseek(int, offset_t, int)
* Stat -- a pointer to a stat buffer. Currently unused.
* Ioctl -- an ioctl command. Woefully limited.
+ * Quad -- a double-word value. e.g., lseek(int, offset_t, int)
+ * Signal -- a signal number. Prints the signal name (SIGxxx)
+ * Sockaddr -- a pointer to a struct sockaddr. Prints symbolic AF, and IP:Port
+ * StringArray -- a pointer to an array of string pointers.
+ * Timespec -- a pointer to a struct timespec. Prints both elements.
+ * Timeval -- a pointer to a struct timeval. Prints both elements.
+ * Pollfd -- a pointer to an array of struct pollfd. Prints .fd and .events.
+ * Fd_set -- a pointer to an array of fd_set. Prints the fds that are set.
*
* In addition, the pointer types (String, Ptr) may have OUT masked in --
* this means that the data is set on *return* from the system call -- or
@@ -22,7 +29,7 @@
*/
enum Argtype { None = 1, Hex, Octal, Int, String, Ptr, Stat, Ioctl, Quad,
- Signal, Sockaddr, StringArray };
+ Signal, Sockaddr, StringArray, Timespec, Timeval, Pollfd, Fd_set };
#define ARG_MASK 0xff
#define OUT 0x100
Index: syscalls.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/truss/syscalls.c,v
retrieving revision 1.28
diff -p -u -r1.28 syscalls.c
--- syscalls.c 15 Apr 2003 06:12:12 -0000 1.28
+++ syscalls.c 3 Jun 2003 22:45:57 -0000
@@ -48,6 +48,7 @@ static const char rcsid[] =
#include <ctype.h>
#include <err.h>
+#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
@@ -131,9 +132,21 @@ struct syscall syscalls[] = {
{ "kldnext", 0, 1, { { Int, 0 }}},
{ "kldstat", 0, 2, { { Int, 0 }, { Ptr, 1 }}},
{ "kldfirstmod", 0, 1, { { Int, 0 }}},
+ { "nanosleep", 0, 1, { { Timespec, 0 }}},
+ { "select", 1, 5, { { Int, 0 }, { Fd_set, 1 }, { Fd_set, 2 }, { Fd_set, 3 }, { Timeval, 4 }}},
+ { "poll", 1, 3, { { Pollfd, 0 }, { Int, 1 }, { Int, 2 }}},
+ { "gettimeofday", 1, 2, { { Timeval | OUT, 0 }, { Ptr, 1 }}},
+ { "clock_gettime", 1, 2, { { Int, 0 }, { Timeval | OUT, 1 }}},
+ { "recvfrom", 1, 6, { { Int, 0 }, { Ptr | OUT, 1 }, { Int, 2 }, { Int, 3 }, { Sockaddr | OUT, 4}, {Ptr | OUT, 5}}},
{ 0, 0, 0, { { 0, 0 }}},
};
+const char* const pollflags[] = {
+ "IN", "PRI", "OUT", "ERR", /* 0x000n */
+ "HUP", "NVAL", "RDNORM", "RDBAND", /* 0x00n0 */
+ "WRBAND", "INIGNEOF", NULL /* 0x0n00 */
+};
+
/*
* If/when the list gets big, it might be desirable to do it
* as a hash table or binary search.
@@ -159,21 +172,8 @@ get_syscall(const char *name) {
static int
get_struct(int procfd, void *offset, void *buf, int len) {
- char *pos;
- FILE *p;
- int c, fd;
-
- if ((fd = dup(procfd)) == -1)
- err(1, "dup");
- if ((p = fdopen(fd, "r")) == NULL)
- err(1, "fdopen");
- fseeko(p, (uintptr_t)offset, SEEK_SET);
- for (pos = (char *)buf; len--; pos++) {
- if ((c = fgetc(p)) == EOF)
+ if (pread(procfd, buf, len, (uintptr_t)offset) != len)
return -1;
- *pos = c;
- }
- fclose(p);
return 0;
}
@@ -333,6 +333,127 @@ print_arg(int fd, struct syscall_args *s
}
}
break;
+ case Timespec:
+ {
+ struct timespec ts;
+ if (get_struct(fd, (void *)args[sc->offset], &ts, sizeof(struct timespec)) != -1)
+ asprintf(&tmp, "{%d %d}", ts.tv_sec, ts.tv_nsec);
+ else
+ asprintf(&tmp, "0x%lx", args[sc->offset]);
+ }
+ break;
+ case Timeval:
+ {
+ struct timeval tv;
+ if (get_struct(fd, (void *)args[sc->offset], &tv, sizeof(struct timeval)) != -1)
+ asprintf(&tmp, "{%d %d}", tv.tv_sec, tv.tv_usec);
+ else
+ asprintf(&tmp, "0x%lx", args[sc->offset]);
+ }
+ break;
+ case Pollfd:
+ {
+ /* XXX: A Pollfd argument expects the /next/ syscall argument to be
+ the number of fds in the array, which is what poll() does.
+ */
+ struct pollfd *pfd;
+ int numfds = args[sc->offset+1];
+ int bytes = sizeof(struct pollfd) * numfds;
+ pfd = malloc(bytes);
+ if (!pfd)
+ err(1, "Cannot malloc %d bytes for pollfd array", bytes);
+ if (get_struct(fd, (void *)args[sc->offset], pfd, bytes) != -1)
+ {
+ int i;
+ int used = 0;
+ int tmpsize = 1024;
+ char *tmp2;
+
+ /*
+ Pollfd's output can vary wildly in size, so just allocate a 1k
+ buffer and double its size whenever it gets close to filling up.
+ */
+ tmp = malloc(tmpsize);
+ if (!tmp)
+ err(1, "Cannot realloc %d bytes for poll output", tmpsize);
+
+ used += sprintf(tmp + used, "{");
+ for (i = 0; i < numfds; i++)
+ {
+ used += sprintf(tmp + used, "%s%d", i>0 ? " " : "", pfd[i].fd);
+ if (pfd[i].events)
+ {
+ int j;
+ for (j = 0; pollflags[j]; j++)
+ if (pfd[i].events & 1<<j)
+ used += sprintf(tmp + used, "|%s", pollflags[j]);
+ }
+
+ if (used + 100 > tmpsize)
+ {
+ tmpsize = tmpsize * 2;
+ tmp = realloc(tmp, tmpsize);
+ if (!tmp)
+ err(1, "Cannot realloc %d bytes for poll output", tmpsize);
+ }
+ }
+ used += sprintf(tmp + used, "}");
+ }
+ else
+ asprintf(&tmp, "0x%lx", args[sc->offset]);
+ free(pfd);
+ }
+ break;
+ case Fd_set:
+ {
+ /* XXX: A Fd_set argument expects the /first/ syscall argument to be
+ the number of fds in the array, which is what select() does.
+ */
+ fd_set *fds;
+ int numfds = args[0];
+ int bytes = _howmany(numfds, _NFDBITS) * _NFDBITS;
+ fds = malloc(bytes);
+ if (!fds)
+ err(1, "Cannot malloc %d bytes for fd_set array", bytes);
+ if (get_struct(fd, (void *)args[sc->offset], fds, bytes) != -1)
+ {
+ char *tmp2;
+ int tmpsize = 1024;
+ int used = 0;
+ int i;
+
+ /*
+ FD_set's output can vary wildly in size, so just allocate a 1k
+ buffer and double its size whenever it gets close to filling up.
+ */
+
+ tmp = malloc(tmpsize);
+ if (!tmp)
+ err(1, "Cannot realloc %d bytes for fd_set output", tmpsize);
+
+ used += sprintf(tmp + used, "{");
+ for (i = 0; i < numfds; i++)
+ {
+ if (FD_ISSET(i, fds))
+ used += sprintf(tmp + used, "%d ", i);
+
+ if (used + 100 > tmpsize)
+ {
+ tmpsize = tmpsize * 2;
+ tmp = realloc(tmp, tmpsize);
+ if (!tmp)
+ err(1, "Cannot realloc %d bytes for fd_set output", tmpsize);
+ }
+ }
+ if (tmp[used-1] == ' ')
+ used--;
+ used += sprintf(tmp + used, "}");
+ }
+ else
+ asprintf(&tmp, "0x%lx", args[sc->offset]);
+ free(fds);
+ }
+ break;
case Signal:
{
long sig;
@@ -360,6 +481,12 @@ print_arg(int fd, struct syscall_args *s
char *p;
u_char *q;
int i;
+
+ if (args[sc->offset] == NULL)
+ {
+ asprintf(&tmp, "0x0");
+ break;
+ }
/* yuck: get ss_len */
if (get_struct(fd, (void *)args[sc->offset], (void *)&ss,
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