/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/stack.h>
#include <sys/regset.h>
#include <sys/frame.h>
#include <sys/sysmacros.h>
#include <sys/machelf.h>

#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include <string.h>

#include "Pcontrol.h"
#include "Pstack.h"
#include "Pisadep.h"

#define SYSCALL32 0x91d02008    /* 32-bit syscall (ta 8) instruction */

#ifndef WINDOWSIZE32
#define WINDOWSIZE32    (16 * sizeof (int32_t))
#endif

const char *
Ppltdest(struct ps_prochandle *P, uintptr_t pltaddr)
{
        map_info_t *mp = Paddr2mptr(P, pltaddr);

        uintptr_t r_addr;
        file_info_t *fp;
        Elf32_Rela r;
        size_t i;

        if (mp == NULL || (fp = mp->map_file) == NULL ||
            fp->file_plt_base == 0 || pltaddr < fp->file_plt_base ||
            pltaddr >= fp->file_plt_base + fp->file_plt_size) {
                errno = EINVAL;
                return (NULL);
        }

        i = (pltaddr - fp->file_plt_base -
            M_PLT_XNumber * M32_PLT_ENTSIZE) / M32_PLT_ENTSIZE;

        r_addr = fp->file_jmp_rel + i * sizeof (Elf32_Rela);

        if (Pread(P, &r, sizeof (r), r_addr) == sizeof (r) &&
            (i = ELF32_R_SYM(r.r_info)) < fp->file_dynsym.sym_symn) {

                Elf_Data *data = fp->file_dynsym.sym_data_pri;
                Elf32_Sym *symp = &(((Elf32_Sym *)data->d_buf)[i]);

                return (fp->file_dynsym.sym_strs + symp->st_name);
        }

        return (NULL);
}

int
Pissyscall(struct ps_prochandle *P, uintptr_t addr)
{
        instr_t sysinstr;
        instr_t instr;

        sysinstr = SYSCALL32;

        if (Pread(P, &instr, sizeof (instr), addr) != sizeof (instr) ||
            instr != sysinstr)
                return (0);
        else
                return (1);
}

int
Pissyscall_prev(struct ps_prochandle *P, uintptr_t addr, uintptr_t *dst)
{
        uintptr_t prevaddr = addr - sizeof (instr_t);

        if (Pissyscall(P, prevaddr)) {
                if (dst)
                        *dst = prevaddr;
                return (1);
        }

        return (0);
}

/* ARGSUSED */
int
Pissyscall_text(struct ps_prochandle *P, const void *buf, size_t buflen)
{
        instr_t sysinstr;

        sysinstr = SYSCALL32;

        if (buflen >= sizeof (instr_t) &&
            memcmp(buf, &sysinstr, sizeof (instr_t)) == 0)
                return (1);
        else
                return (0);
}

/*
 * For gwindows_t support, we define a structure to pass arguments to
 * a Plwp_iter() callback routine.
 */
typedef struct {
        struct ps_prochandle *gq_proc;  /* libproc handle */
        struct rwindow *gq_rwin;        /* rwindow destination buffer */
        uintptr_t gq_addr;              /* stack address to match */
} gwin_query_t;

static int
find_gwin(gwin_query_t *gqp, const lwpstatus_t *psp)
{
        gwindows_t gwin;
        struct stat64 st;
        char path[64];
        ssize_t n;
        int fd, i;
        int rv = 0; /* Return value for skip to next lwp */

        (void) snprintf(path, sizeof (path), "/proc/%d/lwp/%d/gwindows",
            (int)gqp->gq_proc->pid, (int)psp->pr_lwpid);

        if (stat64(path, &st) == -1 || st.st_size == 0)
                return (0); /* Nothing doing; skip to next lwp */

        if ((fd = open64(path, O_RDONLY)) >= 0) {
                /*
                 * Zero out the gwindows_t because the gwindows file only has
                 * as much data as needed to represent the saved windows.
                 */
                (void) memset(&gwin, 0, sizeof (gwin));
                n = read(fd, &gwin, sizeof (gwin));

                if (n > 0) {
                        /*
                         * If we actually found a non-zero gwindows file and
                         * were able to read it, iterate through the buffers
                         * looking for a stack pointer match; if one is found,
                         * copy out the corresponding register window.
                         */
                        for (i = 0; i < gwin.wbcnt; i++) {
                                if (gwin.spbuf[i] == (greg_t *)gqp->gq_addr) {
                                        (void) memcpy(gqp->gq_rwin,
                                            &gwin.wbuf[i],
                                            sizeof (struct rwindow));

                                        rv = 1; /* We're done */
                                        break;
                                }
                        }
                }
                (void) close(fd);
        }

        return (rv);
}

static int
read_gwin(struct ps_prochandle *P, struct rwindow *rwp, uintptr_t sp)
{
        gwin_query_t gq;

        if (P->state == PS_DEAD) {
                core_info_t *core = P->data;
                lwp_info_t *lwp;
                int i;

                for (lwp = list_head(&core->core_lwp_head); lwp != NULL;
                    lwp = list_next(&core->core_lwp_head, lwp)) {
                        gwindows_t *gwin = lwp->lwp_gwins;

                        if (gwin == NULL)
                                continue; /* No gwindows for this lwp */

                        /*
                         * If this lwp has gwindows associated with it, iterate
                         * through the buffers looking for a stack pointer
                         * match; if one is found, copy out the register window.
                         */
                        for (i = 0; i < gwin->wbcnt; i++) {
                                if (gwin->spbuf[i] == (greg_t *)sp) {
                                        (void) memcpy(rwp, &gwin->wbuf[i],
                                            sizeof (struct rwindow));
                                        return (0); /* We're done */
                                }
                        }
                }

                return (-1); /* No gwindows match found */

        }

        gq.gq_proc = P;
        gq.gq_rwin = rwp;
        gq.gq_addr = sp;

        return (Plwp_iter(P, (proc_lwp_f *)find_gwin, &gq) ? 0 : -1);
}

static void
ucontext_n_to_prgregs(const ucontext_t *src, prgregset_t dst)
{
        const greg_t *gregs = &src->uc_mcontext.gregs[0];

        dst[R_PSR] = gregs[REG_PSR];
        dst[R_PC] = gregs[REG_PC];
        dst[R_nPC] = gregs[REG_nPC];
        dst[R_Y] = gregs[REG_Y];

        dst[R_G1] = gregs[REG_G1];
        dst[R_G2] = gregs[REG_G2];
        dst[R_G3] = gregs[REG_G3];
        dst[R_G4] = gregs[REG_G4];
        dst[R_G5] = gregs[REG_G5];
        dst[R_G6] = gregs[REG_G6];
        dst[R_G7] = gregs[REG_G7];

        dst[R_O0] = gregs[REG_O0];
        dst[R_O1] = gregs[REG_O1];
        dst[R_O2] = gregs[REG_O2];
        dst[R_O3] = gregs[REG_O3];
        dst[R_O4] = gregs[REG_O4];
        dst[R_O5] = gregs[REG_O5];
        dst[R_O6] = gregs[REG_O6];
        dst[R_O7] = gregs[REG_O7];
}

int
Pstack_iter(struct ps_prochandle *P, const prgregset_t regs,
    proc_stack_f *func, void *arg)
{
        prgreg_t *prevfp = NULL;
        uint_t pfpsize = 0;
        int nfp = 0;
        prgregset_t gregs;
        long args[6];
        prgreg_t fp;
        int i;
        int rv;
        uintptr_t sp;
        ssize_t n;
        uclist_t ucl;
        ucontext_t uc;

        init_uclist(&ucl, P);
        (void) memcpy(gregs, regs, sizeof (gregs));

        for (;;) {
                fp = gregs[R_FP];
                if (stack_loop(fp, &prevfp, &nfp, &pfpsize))
                        break;

                for (i = 0; i < 6; i++)
                        args[i] = gregs[R_I0 + i];
                if ((rv = func(arg, gregs, 6, args)) != 0)
                        break;

                gregs[R_PC] = gregs[R_I7];
                gregs[R_nPC] = gregs[R_PC] + 4;
                (void) memcpy(&gregs[R_O0], &gregs[R_I0], 8*sizeof (prgreg_t));
                if ((sp = gregs[R_FP]) == 0)
                        break;

                sp += STACK_BIAS;

                if (find_uclink(&ucl, sp + SA(sizeof (struct frame))) &&
                    Pread(P, &uc, sizeof (uc), sp +
                    SA(sizeof (struct frame))) == sizeof (uc)) {
                        ucontext_n_to_prgregs(&uc, gregs);
                        sp = gregs[R_SP] + STACK_BIAS;
                }

                n = Pread(P, &gregs[R_L0], sizeof (struct rwindow), sp);

                if (n == sizeof (struct rwindow))
                        continue;

                /*
                 * If we get here, then our Pread of the register window
                 * failed.  If this is because the address was not mapped,
                 * then we attempt to read this window via any gwindows
                 * information we have.  If that too fails, abort our loop.
                 */
                if (n > 0)
                        break;  /* Failed for reason other than not mapped */

                if (read_gwin(P, (struct rwindow *)&gregs[R_L0], sp) == -1)
                        break;  /* No gwindows match either */
        }

        if (prevfp)
                free(prevfp);

        free_uclist(&ucl);
        return (rv);
}

uintptr_t
Psyscall_setup(struct ps_prochandle *P, int nargs, int sysindex, uintptr_t sp)
{
        sp -= (nargs > 6)?
            WINDOWSIZE32 + sizeof (int32_t) * (1 + nargs) :
            WINDOWSIZE32 + sizeof (int32_t) * (1 + 6);
        sp = PSTACK_ALIGN32(sp);

        P->status.pr_lwp.pr_reg[R_G1] = sysindex;
        P->status.pr_lwp.pr_reg[R_SP] = sp;
        P->status.pr_lwp.pr_reg[R_PC] = P->sysaddr;
        P->status.pr_lwp.pr_reg[R_nPC] = P->sysaddr + sizeof (instr_t);

        return (sp + WINDOWSIZE32 + sizeof (int32_t));
}

int
Psyscall_copyinargs(struct ps_prochandle *P, int nargs, argdes_t *argp,
    uintptr_t ap)
{
        uint32_t arglist[MAXARGS+2];
        int i;
        argdes_t *adp;

        for (i = 0, adp = argp; i < nargs; i++, adp++) {
                arglist[i] = adp->arg_value;

                if (i < 6)
                        (void) Pputareg(P, R_O0+i, adp->arg_value);
        }

        if (nargs > 6 &&
            Pwrite(P, &arglist[0], sizeof (int32_t) * nargs,
            (uintptr_t)ap) != sizeof (int32_t) * nargs)
                return (-1);

        return (0);
}

/* ARGSUSED */
int
Psyscall_copyoutargs(struct ps_prochandle *P, int nargs, argdes_t *argp,
    uintptr_t ap)
{
        /* Do nothing */
        return (0);
}