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Initial commit (pstack v1.2)

tags/pstack-1.3
Thomas Preud'homme 9 years ago
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pstack

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COPYING View File

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GNU GENERAL PUBLIC LICENSE
Version 2, June 1991

Copyright (C) 1989, 1991 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

Preamble

The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users. This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it. (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.) You can apply it to
your programs, too.

When we speak of free software, we are referring to freedom, not
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TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

0. This License applies to any program or other work which contains
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END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

<one line to give the program's name and a brief idea of what it does.>
Copyright (C) 19yy <name of author>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA


Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:

Gnomovision version 69, Copyright (C) 19yy name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, the commands you use may
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mouse-clicks or menu items--whatever suits your program.

You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. Here is a sample; alter the names:

Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.

<signature of Ty Coon>, 1 April 1989
Ty Coon, President of Vice

This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library. If this is what you want to do, use the GNU Library General
Public License instead of this License.

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Makefile View File

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#
# This file is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#

VERSION = $(shell awk '/Version:/ { print $$2 }' pstack.spec)
CVSTAG = r$(subst .,-,$(VERSION))

CFLAGS = -Wall -DVERSION=\"$(VERSION)\" $(RPM_OPT_FLAGS)

ifeq ($(RPM_OPT_FLAGS),)
CFLAGS += -g
LDFLAGS += -g
endif

pstack : pstack.c
$(CC) $(CFLAGS) -o pstack pstack.c

clean:
rm pstack

install : pstack
mkdir -p $(BINDIR)
install -m 755 pstack $(BINDIR)
mkdir -p $(MANDIR)/man1
install -m 644 man1/pstack.1 $(MANDIR)/man1

cvstag:
cvs tag -F $(CVSTAG) .

archive: cvstag
@rm -rf /tmp/pstack-$(VERSION) /tmp/pstack
@cd /tmp; cvs export -r$(CVSTAG) pstack; mv pstack pstack-$(VERSION)
@cd /tmp; tar czSpf pstack-$(VERSION).tar.gz pstack-$(VERSION)
@rm -rf /tmp/pstack-$(VERSION)
@cp /tmp/pstack-$(VERSION).tar.gz .
@echo " "
@echo "The final archive is ./pstack-$(VERSION).tar.gz."

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pstack - print stack trace of running processes

pstack dumps a stack trace for a process, given the pid of that
process. If the process named is part of a thread group, then all the threads
inthe group are traced. See the man page for more information.

This program was inspired by the 'pstack' program available on Solaris.

SUPPORTED PLATFORMS:
This program runs on 32 bit x86 machines, using ELF binaries
generated from GNU compilers. If threads are being used, it depends
on a debuggable version of the pthreads library to find the threads in
the thread group. If anyone wants to port this to other
architectures, please let me know about questions you may have, or
achievements you have made. I'd like to incorporate such changes into
my version of the code.

FEATURES:
symbolic address dumping
thread group support

BUILD:
make

INSTALL:
make install

UNINSTALL:
make uninstall

NOTE: you must be root to [un]install. pstack will run fine from any
directory, install just puts the binary and man page in 'normal'
places (/usr/local/...)

USAGE:
pstack pid [...]

See the man page for more details.

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- 0
VERSION View File

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1.0 12/Oct/1999 07:20:09 PDT
1.1 25/Feb/2002
1.2 12/Nov/2003

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man1/pstack.1 View File

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.\"
.\" pstack manual page.
.\" Copyright (c) 1999 Ross Thompson
.\" Copyright (c) 2001, 2002 Red Hat, Inc.
.\"
.\" Original author: Ross Thompson <ross@whatsis.com>
.\"
.\" This program is free software; you can redistribute it and/or modify
.\" it under the terms of the GNU General Public License as published by
.\" the Free Software Foundation; either version 2, or (at your option)
.\" any later version.
.\"
.\" This program is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public License
.\" along with this program; see the file COPYING. If not, write to
.\" the Free Software Foundation, 59 Temple Place - Suite 330,
.\" Boston, MA 02111-1307, USA.
.\"
.TH PSTACK 1 "Feb 25 2002" "Red Hat Linux" "Linux Programmer's Manual"

.SH NAME
pstack \- print a stack trace of running processes

.SH SYNOPSIS
.B pstack
pid [...]

.SH DESCRIPTION

\f3pstack\f1 attaches to the active processes named by the \f3pid\f1s
on the command line, and prints out an execution stack trace,
including a hint at what the function arguments are. If symbols exist
in the binary (usually the case unless you have run strip(1)), then
symbolic addresses are printed as well.

If the process is part of a thread group, then \f3pstack\f1 will print
out a stack trace for each of the threads in the group.

.SH RESTRICTIONS

\f3pstack\f1 currently works only on Linux, only on an x86 machine
running 32 bit ELF binaries (64 bit not supported). Also, for
symbolic information, you need to use a GNU compiler to generate your
program, and you can't strip symbols from the binaries. For thread
information to be dumped, you have to use the debug-aware version of
the LinuxThreads libpthread.so library.
(To check, run nm(1) on your pthreads library, and make sure that the
symbol "__pthread_threads_debug" is defined.)
Threads are not supported with the newer NPTL libpthread.so library.

.SH SEE ALSO
nm(1), ptrace(2)

.SH AUTHORS
Ross Thompson <ross@whatsis.com>

Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>

+ 645
- 0
pstack.c View File

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/*
pstack.c -- asynchronous stack trace of a running process
Copyright (c) 1999 Ross Thompson
Copyright (c) 2001, 2003 Red Hat, Inc.

Original Author: Ross Thompson <ross@whatsis.com>
Critical bug fix: Tim Waugh

*/

/*
This file is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

/* RESTRICTIONS:

pstack currently works only on Linux, only on an x86 machine running
32 bit ELF binaries (64 bit not supported). Also, for symbolic
information, you need to use a GNU compiler to generate your
program, and you can't strip symbols from the binaries. For thread
information to be dumped, you have to use the debug-aware version
of libpthread.so. (To check, run 'nm' on your libpthread.so, and
make sure that the symbol "__pthread_threads_debug" is defined.)
*/

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

#include <fcntl.h>
#include <link.h>
#include <malloc.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

static int thePid; /* pid requested by caller. */
static struct {
int found;
int *pids; /* pid[0] is dad, pid[1] is manager */
int *attached; /* pid[i] is attached? 1 = yes, 0 = no */
int npids;
} threads;

/* ------------------------------ */

static int attach(int pid)
{
int status;

errno = 0;
ptrace(PTRACE_ATTACH, pid, 0, 0);

if (errno)
return errno;

waitpid (pid, &status, WUNTRACED);

/* If we failed due to an ECHILD, then retry with the __WCLONE
flag. Note we loop as the the PID we get back may not be
one we care about. */
if (errno == ECHILD) {
int x;

errno = 0;
while (1) {
x = waitpid (-1, &status, (__WCLONE));

if (x == pid || x < 0 || errno != 0) break;
}
}

return errno;
}

static int detachall(void)
{
int i;

/* First detach from all the threads, except the one we initially
attached to. Note that the PTRACE_DETACH will continue the
thread, so there is no need to issue a separate PTRACE_CONTINUE
call. */
if (threads.found) {
for (i = 0; i < threads.npids; i++) {
if (threads.pids[i] != thePid && threads.attached[i]) {
errno = 0;
ptrace(PTRACE_DETACH, threads.pids[i], 0, 0);
if (errno) perror("detach");
}
}
}

/* Now attach from the thread we initially attached to. Note that
the PTRACE_DETACH will continue the thread, so there is no need
is issue a separate PTRACE_CONTINUE call. */
ptrace(PTRACE_DETACH, thePid, 0, 0);

return errno;
}

static void handle_signal (int signum)
{
signal (signum, SIG_DFL);
psignal (signum, "pstack signal received");
if (thePid) detachall();
exit (1);
}

static void quit(char *msg)
{
fputs(msg, stderr);
fputc('\n', stderr);
if (thePid) detachall();
exit(1);
}

/* ------------------------------ */

static Elf32_Addr DebugInfo;

typedef struct _t_Symbols {
struct _t_Symbols *next;
char *name;
Elf32_Sym *symbols;
int nsyms;
char *strings;
int strslen, noffsets;
Elf32_Addr baseAddr;
Elf32_Dyn *dynamic;
int ndyns;
} *Symbols;

static Symbols allSyms;

static Symbols newSyms(const char *name)
{
Symbols syms = (Symbols) calloc(sizeof(struct _t_Symbols), 1);

if (!syms) quit("Out of memory");
syms->next = allSyms;
allSyms = syms;
syms->name = strdup(name);

return syms;
}

static void deleteSyms(Symbols syms)
{
Symbols s2;

if (syms == allSyms) allSyms = syms->next;
else {
for (s2 = allSyms; s2 && s2->next != syms; s2 = s2->next);
if (s2) s2->next = syms->next;
}
if (syms->symbols) free(syms->symbols);
if (syms->strings) free(syms->strings);
if (syms->dynamic) free(syms->dynamic);
if (syms->name) free(syms->name);
free(syms);
}

static const Elf32_Sym *lookupSymInTable(const char *name, Symbols syms)
{
Elf32_Sym *sym;
int i;

for (i = 0, sym = syms->symbols; i < syms->nsyms; i++, sym++) {
if (!strcmp(name, &syms->strings[sym->st_name]))
return sym;
}

return 0;
}

static void findCodeAddress(Elf32_Addr addr, Elf32_Sym **ans,
Symbols *symtab)
{
Elf32_Sym *sym;
Symbols tab;
int i;

for (tab = allSyms, *ans = 0, *symtab = 0; tab; tab = tab->next) {
if (addr < tab->baseAddr) continue;
for (sym = tab->symbols, i = 0; i < tab->nsyms; i++, sym++) {
if (sym->st_value <= addr && sym->st_shndx != SHN_UNDEF &&
sym->st_shndx < tab->noffsets &&
ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
(!*ans || (*ans)->st_value < sym->st_value))
*ans = sym, *symtab = tab;
}
}
}

/* ------------------------------ */

static void resetData(void)
{
Symbols syms, ns;

if (threads.pids) free(threads.pids);
if (threads.attached) free(threads.attached);
threads.pids = 0;
threads.attached = 0;
threads.found = 0;

for (syms = allSyms; syms; syms = ns) {
ns = syms->next;
deleteSyms(syms);
}
}

/* ------------------------------ */

static const Elf32_Sym *findLocalSym(const char *name, Symbols syms)
{
const Elf32_Sym *sym = lookupSymInTable(name, syms);

return (!sym || sym->st_shndx == SHN_UNDEF ||
sym->st_shndx >= syms->noffsets) ? 0 : sym;
}

static int readSym(Symbols syms, int pid, const char *name, int *val)
{
const Elf32_Sym *sym;

if (!(sym = findLocalSym(name, syms))) return 0;
errno = 0;
*val = ptrace(PTRACE_PEEKDATA, pid, sym->st_value, 0);
if (errno) {
perror("ptrace");
quit("Could not read thread debug info.");
}
return 1;
}

static void checkForThreads(Symbols syms, int pid)
{
const Elf32_Sym *handles;
int i, tpid, hsize, descOff, pidOff, numPids, *pptr;
Elf32_Addr descr;

if (!findLocalSym("__pthread_threads_debug", syms) ||
!(handles = findLocalSym("__pthread_handles", syms)) ||
!readSym(syms, pid, "__pthread_sizeof_handle", &hsize) ||
!readSym(syms, pid, "__pthread_offsetof_descr", &descOff) ||
!readSym(syms, pid, "__pthread_offsetof_pid", &pidOff) ||
!readSym(syms, pid, "__pthread_handles_num", &numPids) ||
numPids == 1 ||
!(threads.pids = (int *) calloc(numPids + 2, sizeof(int))) ||
!(threads.attached = (int *) calloc(numPids + 2, sizeof(int)))) {
if (threads.pids) {
free(threads.pids);
threads.pids = 0;
}
if (threads.attached) {
free(threads.attached);
threads.attached = 0;
}
return;
}
errno = 0;

for (pptr = &threads.pids[0], i = 0; i < numPids && !errno; i++) {
descr = ptrace(PTRACE_PEEKDATA, pid,
handles->st_value + (i * hsize) + descOff, 0);
if (!descr && i == 0)
/* The initial thread's descriptor was not initialized yet. */
*pptr++ = pid;
else if (descr && !errno) {
tpid = ptrace(PTRACE_PEEKDATA, pid, descr + pidOff, 0);
if (!errno)
*pptr++ = tpid;
}
}
threads.npids = pptr - threads.pids;

if (errno) {
perror("ptrace");
quit("Could not read thread debug info.");
}

threads.found = 1;

for (i = 0; i < threads.npids; i++) {
if (threads.pids[i] && threads.pids[i] != pid) {
if (attach(threads.pids[i]) != 0)
printf("Could not attach to thread %d.\n", threads.pids[i]);
else threads.attached[i] = 1;
} else if (threads.pids[i] == pid) {
threads.attached[i] = 1;
}

}
}

/* ------------------------------ */

static void verify_ident(Elf32_Ehdr *hdr)
{
if (memcmp(&hdr->e_ident[EI_MAG0], ELFMAG, SELFMAG))
quit("Bad magic number.");
if (hdr->e_ident[EI_CLASS] != ELFCLASS32)
quit("only 32 bit objects supported.");
if (hdr->e_ident[EI_DATA] != ELFDATA2LSB)
quit("big endian object files not supported.");
if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_version != EV_CURRENT)
quit("Unsupported ELF format version.");
if (hdr->e_machine != EM_386)
quit("Not an IA32 executable.");
}

static int find_stables(Elf32_Ehdr *hdr, int fd, Symbols syms)
{
int i, idx, spot;
Elf32_Shdr shdr;

spot = hdr->e_shoff;
if (lseek(fd, spot, SEEK_SET) != spot) quit("seek failed.");

memset(&shdr, 0, sizeof(shdr));

syms->noffsets = hdr->e_shnum;

for (idx = 0; idx < hdr->e_shnum; idx++) {
if (read(fd, &shdr, hdr->e_shentsize) != hdr->e_shentsize)
quit("premature eof.");
spot += hdr->e_shentsize;
switch (shdr.sh_type) {
case SHT_SYMTAB:
syms->nsyms = shdr.sh_size / sizeof(Elf32_Sym);

if (!(syms->symbols = (Elf32_Sym *) malloc(shdr.sh_size)))
quit("Could not allocate symbol table.");

if (lseek(fd, shdr.sh_offset, SEEK_SET) != shdr.sh_offset ||
read(fd, syms->symbols, shdr.sh_size) != shdr.sh_size)
quit("Could not read symbol table.");

i = hdr->e_shoff + shdr.sh_link * hdr->e_shentsize;
if (lseek(fd, i, SEEK_SET) != i)
quit("Could not seek and find.");
if (read(fd, &shdr, hdr->e_shentsize) != hdr->e_shentsize)
quit("Could not read string table section header.");
if (!(syms->strings = malloc(shdr.sh_size)))
quit("Could not allocate string table.");
if (lseek(fd, shdr.sh_offset, SEEK_SET) != shdr.sh_offset ||
read(fd, syms->strings, shdr.sh_size) != shdr.sh_size)
quit("Could not read string table.");
lseek(fd, spot, SEEK_SET);
break;
case SHT_DYNAMIC:
syms->ndyns = shdr.sh_size / sizeof(Elf32_Dyn);
if (!(syms->dynamic = (Elf32_Dyn *) malloc(shdr.sh_size)))
quit("Out of memory.");
if (lseek(fd, shdr.sh_offset, SEEK_SET) != shdr.sh_offset ||
read(fd, syms->dynamic, shdr.sh_size) != shdr.sh_size)
quit("Could not read dynamic table.");
lseek(fd, spot, SEEK_SET);
break;
}
}

return (syms->nsyms > 0);
}

static Symbols loadSyms(const char *fname)
{
Elf32_Ehdr hdr;
int fd;
Symbols syms;

syms = newSyms(fname);
if ((fd = open(fname, O_RDONLY)) < 0)
quit("Could not open object file.");
read(fd, &hdr, sizeof(hdr));
verify_ident(&hdr);
if (!find_stables(&hdr, fd, syms)) {
deleteSyms(syms);
syms = 0;
}
close(fd);

return syms;
}

static void readDynoData(Symbols syms, int pid)
{
int val, done;
Elf32_Addr addr;
const Elf32_Sym *dyn = lookupSymInTable("_DYNAMIC", syms);

for (errno = done = 0, addr = dyn->st_value; !done && !errno; addr += 8) {
val = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
if (errno) break;
switch (val) {
case DT_NULL: done = 1; break;
case DT_DEBUG:
// point to the r_debug struct -- see link.h
DebugInfo = (Elf32_Addr) ptrace(PTRACE_PEEKDATA, pid, addr + 4, 0);
// point to the head of the link_map chain.
DebugInfo = (Elf32_Addr) ptrace(PTRACE_PEEKDATA, pid, DebugInfo + 4, 0);
break;
}
}
if (errno) {
perror("pstack");
quit("failed to read target.");
}
}

static void resolveSymbols(Symbols syms, int offset)
{
Elf32_Sym *sym;
int i;

syms->baseAddr = offset;

for (i = 0, sym = syms->symbols; i < syms->nsyms; i++, sym++) {
if (sym->st_shndx && sym->st_shndx < syms->noffsets) {
sym->st_value += offset;
}
}
}

static void loadString(int pid, int addr, char *dp, int bytes)
{
long *lp = (long *) dp, nr;

memset(dp, 0, bytes);
errno = 0;

addr = ptrace(PTRACE_PEEKDATA, pid, addr, 0);

for (nr = 0, errno = 0; !errno && bytes > 4 && strlen(dp) == nr;
addr += 4, bytes -= 4, nr += 4) {
*lp++ = ptrace(PTRACE_PEEKDATA, pid, addr, 0);
}

if (errno) {
perror("ptrace");
quit("loadString failed.");
}
}

#define OFFSET(f, s) ((int) ((char *) &(s).f - (char *) &(s)))
static void readLinkMap(int pid, Elf32_Addr base,
struct link_map *lm, char *name, int namelen)
{
errno = 0;

/* base address */
lm->l_addr = (Elf32_Addr) ptrace(PTRACE_PEEKDATA, pid,
base + OFFSET(l_addr, *lm), 0);
/* next element of link map chain */
if (!errno)
lm->l_next = (struct link_map *) ptrace(PTRACE_PEEKDATA, pid,
base + OFFSET(l_next, *lm), 0);
if (errno) {
perror("ptrace");
quit("can't read target.");
}

loadString(pid, base + OFFSET(l_name, *lm), name, namelen);
}

static void loadSymbols(int pid)
{
char buf[256];
Symbols syms;
struct link_map lm;

sprintf(buf, "/proc/%d/exe", pid);
if (!(syms = loadSyms(buf))) {
fputs("(No symbols found)\n", stdout);
return;
}

readDynoData(syms, pid);
readLinkMap(pid, DebugInfo, &lm, buf, sizeof(buf));

for ( ; lm.l_next; ) {
readLinkMap(pid, (Elf32_Addr) lm.l_next, &lm, buf, sizeof(buf));
if (!(syms = loadSyms(buf))) {
printf("(No symbols found in %s)\n", buf);
continue;
}
resolveSymbols(syms, lm.l_addr);
if (!threads.found) checkForThreads(syms, pid);
}
}

/* ------------------------------ */

static void print_pc(Elf32_Addr addr)
{
Elf32_Sym *sym;
Symbols syms;

findCodeAddress(addr, &sym, &syms);

if (!sym)
printf("0x%08lx: ????", (unsigned long) addr);
else if (sym->st_value < addr)
printf("0x%08lx: %s + 0x%x", (unsigned long) addr,
&syms->strings[sym->st_name], addr - sym->st_value);
else
printf("0x%08lx: %s", (unsigned long) addr, &syms->strings[sym->st_name]);
}

/* ------------------------------ */

#define MAXARGS 6

static int crawl(int pid)
{
unsigned long pc, fp, nextfp, nargs, i, arg;

errno = 0;
fp = -1;

pc = ptrace(PTRACE_PEEKUSER, pid, EIP * 4, 0);
if (!errno)
fp = ptrace(PTRACE_PEEKUSER, pid, EBP * 4, 0);

if (!errno) {
print_pc(pc);
for ( ; !errno && fp; ) {
nextfp = ptrace(PTRACE_PEEKDATA, pid, fp, 0);
if (errno) break;

nargs = (nextfp - fp - 8) / 4;
if (nargs > MAXARGS) nargs = MAXARGS;
if (nargs > 0) {
fputs(" (", stdout);
for (i = 1; i <= nargs; i++) {
arg = ptrace(PTRACE_PEEKDATA, pid, fp + 4 * (i + 1), 0);
if (errno) break;
printf("%lx", arg);
if (i < nargs) fputs(", ", stdout);
}
fputc(')', stdout);
nargs = nextfp - fp - 8 - (4 * nargs);
if (!errno && nargs > 0) printf(" + %lx\n", nargs);
else fputc('\n', stdout);
} else fputc('\n', stdout);

if (errno || !nextfp) break;
pc = ptrace(PTRACE_PEEKDATA, pid, fp + 4, 0);
fp = nextfp;
if (errno) break;
print_pc(pc);
}
}

if (errno) perror("crawl");
return errno;
}

/* ------------------------------ */

static char cmd[128];

static char *cmdLine(int pid)
{
int fd, len, i;

fd = -1;
sprintf(cmd, "/proc/%d/cmdline", pid);
if ((fd = open(cmd, O_RDONLY)) >= 0 &&
(len = read(fd, cmd, sizeof(cmd))) > 0) {
for (i = 0; i < len; i++) if (!cmd[i]) cmd[i] = ' ';
for ( ; len > 0 && cmd[len - 1] <= ' '; len--);
cmd[len] = 0;
if (len >= sizeof(cmd) - 4)
strcpy(&cmd[sizeof(cmd) - 4], "...");
}
if (fd < 0 || len <= 0) strcpy(cmd, "(command line?)");
if (fd >= 0) close(fd);

return cmd;
}

int main(int argc, char **argv)
{
int i;

/* Arrange to detach if we get an unexpected signal. This prevents
threads from being left in a suspended state if (for example) we
try to get a stack trace from a threaded process which has
been stripped. */
for (i = 0; i < NSIG; i++)
if (i != SIGCHLD)
signal (i, handle_signal);

for (argc--, argv++; argc > 0; argc--, argv++) {
thePid = atoi(*argv);
if (!thePid || thePid == getpid()) {
fprintf(stderr, "Invalid PID %d\n", thePid);
continue;
}

if (attach(thePid) != 0) {
thePid = 0;
fprintf(stderr, "Could not attach to target.\n");
} else {
printf("\n%d: %s\n", thePid, cmdLine(thePid));
loadSymbols(thePid);
if (threads.found) {
for (i = 0; i < threads.npids; i++) {
if (threads.attached[i]) {
printf("----- Thread %d -----\n", threads.pids[i]);
if (crawl(threads.pids[i]) != 0)
fprintf(stderr, "Error tracing through thread %d\n",
threads.pids[i]);
}
}
} else if (crawl(thePid) != 0)
fprintf(stderr, "Error tracing through process %d\n", thePid);
}

detachall();
resetData();
}

exit(0);
}

+ 57
- 0
pstack.spec View File

@@ -0,0 +1,57 @@
Summary: Display stack trace of a running process
Name: pstack
Version: 1.2
Release: 3
Copyright: GPL
Group: Development/Debuggers
Source: %{name}-%{version}.tar.gz
BuildRoot: %{_tmppath}/%{name}-root
ExclusiveArch: %{ix86}

%description
pstack dumps a stack trace for a process, given the pid of that
process. If the process named is part of a thread group, then all the threads
in the group are traced.

%prep
%setup -q

%build
make

%install
rm -rf $RPM_BUILD_ROOT
make install BINDIR=%{buildroot}%{_bindir} MANDIR=%{buildroot}%{_mandir}

%clean
rm -rf $RPM_BUILD_ROOT

%files
%defattr(-,root,root)
%doc COPYING README VERSION
%{_bindir}/pstack
%{_mandir}/man1/*

%changelog
* Wed Nov 12 2003 Roland McGrath <roland@redhat.com> 1.2-3
- updated linuxthreads support for newer linuxthreads internals (#107305)
- avoid buffer overflow in symbol printing (#109642)

* Thu Sep 18 2003 Jakub Jelinek <jakub@redhat.com> 1.1-7
- don't crash if one of shared libraries has stripped .symtab/.strtab
(#98162)

* Mon Feb 24 2003 Elliot Lee <sopwith@redhat.com>
- rebuilt

* Sat Feb 22 2003 Jakub Jelinek <jakub@redhat.com>
- rebuilt

* Fri Jun 21 2002 Tim Powers <timp@redhat.com>
- automated rebuild

* Tue May 28 2002 Jakub Jelinek <jakub@redhat.com>
- build on x86 only

* Mon Feb 25 2002 Preston Brown <pbrown@redhat.com>
- initial packaging

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