/*      $NetBSD: meta.c,v 1.225 2026/07/15 00:41:35 sjg Exp $ */

/*
 * Implement 'meta' mode.
 * Adapted from John Birrell's patches to FreeBSD make.
 * --sjg
 */
/*
 * Copyright (c) 2009-2016, Juniper Networks, Inc.
 * Portions Copyright (c) 2009, John Birrell.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#if defined(USE_META)

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <sys/stat.h>
#include <libgen.h>
#include <errno.h>
#if !defined(HAVE_CONFIG_H) || defined(HAVE_ERR_H)
#include <err.h>
#endif

#include "make.h"
#include "dir.h"
#include "job.h"
#include "meta.h"

#ifdef USE_FILEMON
#include "filemon/filemon.h"
#endif

static BuildMon Mybm;                   /* for compat */
static StringList metaBailiwick = LST_INIT; /* our scope of control */
static char *metaBailiwickStr;          /* string storage for the list */
static StringList metaIgnorePaths = LST_INIT; /* paths we deliberately ignore */
static char *metaIgnorePathsStr;        /* string storage for the list */

#define MAKE_META_IGNORE_PATHS ".MAKE.META.IGNORE_PATHS"
#define MAKE_META_IGNORE_PATTERNS ".MAKE.META.IGNORE_PATTERNS"
#define MAKE_META_IGNORE_FILTER ".MAKE.META.IGNORE_FILTER"
#define MAKE_META_CMP_FILTER ".MAKE.META.CMP_FILTER"
#define MAKE_META_FILTER ".MAKE.META.FILTER"

bool useMeta = false;
static bool useFilemon = false;
static bool writeMeta = false;
static bool metaMissing = false;        /* oodate if missing */
static bool filemonMissing = false;     /* oodate if missing */
static bool metaEnv = false;            /* don't save env unless asked */
static bool metaVerbose = false;
static bool metaIgnoreCMDs = false;     /* ignore CMDs in .meta files */
static bool metaIgnorePatterns = false; /* do we need to do pattern matches */
static bool metaIgnoreFilter = false;   /* do we have more complex filtering? */
static bool metaCmpFilter = false;      /* do we have CMP_FILTER ? */
static bool metaFilter = false;         /* do we have FILTER */
static bool metaCurdirOk = false;       /* write .meta in .CURDIR Ok? */
static bool metaSilent = false;         /* if we have a .meta be SILENT */


#define MAKE_META_PREFIX        ".MAKE.META.PREFIX"

#ifndef N2U
# define N2U(n, u)   (((n) + ((u) - 1)) / (u))
#endif
#ifndef ROUNDUP
# define ROUNDUP(n, u)   (N2U((n), (u)) * (u))
#endif

#if !defined(HAVE_STRSEP)
# define strsep(s, d) stresep((s), (d), '\0')
#endif

/*
 * Filemon is a kernel module which snoops certain syscalls.
 *
 * C chdir
 * E exec
 * F [v]fork
 * L [sym]link
 * M rename
 * R read
 * W write
 * S stat
 *
 * See meta_oodate below - we mainly care about 'E' and 'R'.
 *
 * We can still use meta mode without filemon, but
 * the benefits are more limited.
 */
#ifdef USE_FILEMON

/*
 * Open the filemon device.
 */
static void
meta_open_filemon(BuildMon *pbm)
{
    int dupfd;

    pbm->mon_fd = -1;
    pbm->filemon = NULL;
    if (!useFilemon || pbm->mfp == NULL)
        return;

    pbm->filemon = filemon_open();
    if (pbm->filemon == NULL) {
        useFilemon = false;
        warn("Could not open filemon %s", filemon_path());
        return;
    }

    /*
     * We use a file outside of '.'
     * to avoid a FreeBSD kernel bug where unlink invalidates
     * cwd causing getcwd to do a lot more work.
     * We only care about the descriptor.
     */
    if (!opts.compatMake)
        pbm->mon_fd = Job_TempFile("filemon.XXXXXX", NULL, 0);
    else
        pbm->mon_fd = mkTempFile("filemon.XXXXXX", NULL, 0);
    if ((dupfd = dup(pbm->mon_fd)) == -1) {
        Punt("Could not dup filemon output: %s", strerror(errno));
    }
    (void)fcntl(dupfd, F_SETFD, FD_CLOEXEC);
    if (filemon_setfd(pbm->filemon, dupfd) == -1) {
        Punt("Could not set filemon file descriptor: %s", strerror(errno));
    }
    /* we don't need these once we exec */
    (void)fcntl(pbm->mon_fd, F_SETFD, FD_CLOEXEC);
}

/*
 * Read the build monitor output file and write records to the target's
 * metadata file.
 */
static int
filemon_read(FILE *mfp, int fd)
{
    char buf[BUFSIZ];
    int error;

    /* Check if we're not writing to a meta data file.*/
    if (mfp == NULL) {
        if (fd >= 0)
            close(fd);                  /* not interested */
        return 0;
    }
    /* rewind */
    if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
        error = errno;
        warn("Could not rewind filemon");
        fprintf(mfp, "\n");
    } else {
        ssize_t n;

        error = 0;
        fprintf(mfp, "\n-- filemon acquired metadata --\n");

        while ((n = read(fd, buf, sizeof buf)) > 0) {
            if ((ssize_t)fwrite(buf, 1, (size_t)n, mfp) < n)
                error = EIO;
        }
    }
    if (fflush(mfp) != 0)
        Punt("Cannot write filemon data to meta file: %s",
            strerror(errno));
    if (close(fd) < 0)
        error = errno;
    return error;
}
#endif

/*
 * when realpath() fails,
 * we use this, to clean up ./ and ../
 */
static void
eat_dots(char *buf)
{
    char *p;

    while ((p = strstr(buf, "/./")) != NULL)
        memmove(p, p + 2, strlen(p + 2) + 1);

    while ((p = strstr(buf, "/../")) != NULL) {
        char *p2 = p + 3;
        if (p > buf) {
            do {
                p--;
            } while (p > buf && *p != '/');
        }
        if (*p == '/')
            memmove(p, p2, strlen(p2) + 1);
        else
            return;             /* can't happen? */
    }
}

static char *
meta_name(char *mname, size_t mnamelen,
          const char *dname,
          const char *tname,
          const char *cwd)
{
    char buf[MAXPATHLEN];
    char *rp, *cp;
    const char *tname_base;
    char *tp;
    char *dtp;
    size_t ldname;

    /*
     * Weed out relative paths from the target file name.
     * We have to be careful though since if target is a
     * symlink, the result will be unstable.
     * So we use realpath() just to get the dirname, and leave the
     * basename as given to us.
     */
    if ((tname_base = strrchr(tname, '/')) != NULL) {
        if (cached_realpath(tname, buf) != NULL) {
            if ((rp = strrchr(buf, '/')) != NULL) {
                rp++;
                tname_base++;
                if (strcmp(tname_base, rp) != 0)
                    strlcpy(rp, tname_base, sizeof buf - (size_t)(rp - buf));
            }
            tname = buf;
        } else {
            /*
             * We likely have a directory which is about to be made.
             * We pretend realpath() succeeded, to have a chance
             * of generating the same meta file name that we will
             * next time through.
             */
            if (tname[0] == '/') {
                strlcpy(buf, tname, sizeof buf);
            } else {
                snprintf(buf, sizeof buf, "%s/%s", cwd, tname);
            }
            eat_dots(buf);
            tname = buf;
        }
    }
    /* on some systems dirname may modify its arg */
    tp = bmake_strdup(tname);
    dtp = dirname(tp);
    if (strcmp(dname, dtp) == 0) {
        if (snprintf(mname, mnamelen, "%s.meta", tname) >= (int)mnamelen)
            mname[mnamelen - 1] = '\0';
    } else {
        int x;

        ldname = strlen(dname);
        if (strncmp(dname, dtp, ldname) == 0 && dtp[ldname] == '/')
            x = snprintf(mname, mnamelen, "%s/%s.meta", dname, &tname[ldname+1]);
        else
            x = snprintf(mname, mnamelen, "%s/%s.meta", dname, tname);
        if (x >= (int)mnamelen)
            mname[mnamelen - 1] = '\0';
        /*
         * Replace path separators in the file name after the
         * current object directory path.
         */
        cp = mname + strlen(dname) + 1;

        while (*cp != '\0') {
            if (*cp == '/')
                *cp = '_';
            cp++;
        }
    }
    free(tp);
    return mname;
}

static bool
any_is_submake(GNode *gn)
{
    StringListNode *ln;
    char *cmd;

    for (ln = gn->commands.first; ln != NULL; ln = ln->next) {
        cmd = Var_Subst(ln->datum, gn, VARE_EVAL);
        if (MaybeSubMake(cmd)) {
            free(cmd);
            return true;
        }
        free(cmd);
    }
    return false;
}

static void
printCMD(const char *ucmd, FILE *fp, GNode *gn)
{
    FStr xcmd = FStr_InitRefer(ucmd);

    Var_Expand(&xcmd, gn, VARE_EVAL);
    fprintf(fp, "CMD %s\n", xcmd.str);
    FStr_Done(&xcmd);
}

static void
printCMDs(GNode *gn, FILE *fp)
{
    StringListNode *ln;

    for (ln = gn->commands.first; ln != NULL; ln = ln->next)
        printCMD(ln->datum, fp, gn);
}

/*
 * Certain node types never get a .meta file
 */
#define SKIP_META_TYPE(flag, str) do { \
    if ((gn->type & (flag))) { \
        if (verbose) \
            debug_printf("Skipping meta for %s: .%s\n", gn->name, str); \
        return false; \
    } \
} while (false)


/*
 * Do we need/want a .meta file ?
 */
static bool
meta_needed(GNode *gn, const char *dname,
            char *objdir_realpath, bool verbose)
{
    struct cached_stat cst;

    if (verbose)
        verbose = DEBUG(META);

    /* This may be a phony node which we don't want meta data for... */
    /* Skip .meta for .BEGIN, .END, .ERROR etc as well. */
    /* Or it may be explicitly flagged as .NOMETA */
    SKIP_META_TYPE(OP_NOMETA, "NOMETA");
    /* Unless it is explicitly flagged as .META */
    if (!(gn->type & OP_META)) {
        SKIP_META_TYPE(OP_PHONY, "PHONY");
        SKIP_META_TYPE(OP_SPECIAL, "SPECIAL");
        SKIP_META_TYPE(OP_MAKE, "MAKE");
        SKIP_META_TYPE(OP_SUBMAKE, "SUBMAKE");
    }

    /* Check if there are no commands to execute. */
    if (Lst_IsEmpty(&gn->commands)) {
        if (verbose)
            debug_printf("Skipping meta for %s: no commands\n", gn->name);
        return false;
    }

    /*
     * If called from meta_oodate, gn->flags.doneSubmake will be false.
     * While OP_SUBMAKE only matters in jobs mode,
     * we normally skip .meta files for sub-makes, so we want to check
     * even in compat mode.
     */
    if (gn->flags.doneSubmake == false
        && (gn->type & (OP_MAKE | OP_META)) == 0) {
            gn->flags.doneSubmake = true;
        if (any_is_submake(gn)) {
            gn->type |= OP_SUBMAKE;
            SKIP_META_TYPE(OP_SUBMAKE, "SUBMAKE");
        }
    }

    /* The object directory may not exist. Check it.. */
    if (cached_stat(dname, &cst) != 0) {
        if (verbose)
            debug_printf("Skipping meta for %s: no .OBJDIR\n", gn->name);
        return false;
    }

    /* make sure these are canonical */
    if (cached_realpath(dname, objdir_realpath) != NULL)
        dname = objdir_realpath;

    /* If we aren't in the object directory, don't create a meta file. */
    if (!metaCurdirOk && strcmp(curdir, dname) == 0) {
        if (verbose)
            debug_printf("Skipping meta for %s: .OBJDIR == .CURDIR\n",
                         gn->name);
        return false;
    }
    return true;
}


static FILE *
meta_create(BuildMon *pbm, GNode *gn)
{
    FILE *fp;
    char buf[MAXPATHLEN];
    char objdir_realpath[MAXPATHLEN];
    char **ptr;
    FStr dname;
    const char *tname;
    char *fname;
    const char *cp;

    fp = NULL;

    dname = Var_Value(gn, ".OBJDIR");
    tname = GNode_VarTarget(gn);

    /* if this succeeds objdir_realpath is realpath of dname */
    if (!meta_needed(gn, dname.str, objdir_realpath, true))
        goto out;
    dname.str = objdir_realpath;

    if (metaVerbose) {
        /* Describe the target we are building */
        char *mp = Var_Subst("${" MAKE_META_PREFIX "}", gn, VARE_EVAL);
        /* TODO: handle errors */
        if (mp[0] != '\0')
            fprintf(stdout, "%s\n", mp);
        free(mp);
    }

    fflush(stdout);

    if (!writeMeta)
        /* Don't create meta data. */
        goto out;

    fname = meta_name(pbm->meta_fname, sizeof pbm->meta_fname,
                      dname.str, tname, objdir_realpath);

#ifdef DEBUG_META_MODE
    DEBUG1(META, "meta_create: %s\n", fname);
#endif

    if ((fp = fopen(fname, "w")) == NULL)
        Punt("Could not open meta file '%s': %s", fname, strerror(errno));

    fprintf(fp, "# Meta data file %s\n", fname);

    printCMDs(gn, fp);

    fprintf(fp, "CWD %s\n", getcwd(buf, sizeof buf));
    fprintf(fp, "TARGET %s\n", tname);
    cp = GNode_VarOodate(gn);
    if (cp != NULL && *cp != '\0') {
        fprintf(fp, "OODATE %s\n", cp);
    }
    if (metaEnv) {
        for (ptr = environ; *ptr != NULL; ptr++)
            fprintf(fp, "ENV %s\n", *ptr);
    }

    fprintf(fp, "-- command output --\n");
    if (fflush(fp) != 0)
        Punt("Cannot write expanded command to meta file: %s",
            strerror(errno));

    Global_Append(".MAKE.META.FILES", fname);
    Global_Append(".MAKE.META.CREATED", fname);

    gn->type |= OP_META;                /* in case anyone wants to know */
    if (metaSilent) {
            gn->type |= OP_SILENT;
    }
 out:
    FStr_Done(&dname);

    return fp;
}

static bool
boolValue(const char *s)
{
    switch (*s) {
    case '0':
    case 'N':
    case 'n':
    case 'F':
    case 'f':
        return false;
    }
    return true;
}

/*
 * Initialization we need before reading makefiles.
 */
void
meta_init(void)
{
#ifdef USE_FILEMON
        /* this allows makefiles to test if we have filemon support */
        Global_Set(".MAKE.PATH_FILEMON", filemon_path());
#endif
}


#define get_mode_bf(bf, token) \
    if ((cp = strstr(make_mode, token)) != NULL) \
        bf = boolValue(cp + sizeof (token) - 1)

/*
 * Initialization we need after reading makefiles.
 */
void
meta_mode_init(const char *make_mode)
{
    static bool once = false;
    const char *cp;

    useMeta = true;
    useFilemon = true;
    writeMeta = true;

    if (make_mode != NULL) {
        if (strstr(make_mode, "env") != NULL)
            metaEnv = true;
        if (strstr(make_mode, "verb") != NULL)
            metaVerbose = true;
        if (strstr(make_mode, "read") != NULL)
            writeMeta = false;
        if (strstr(make_mode, "nofilemon") != NULL)
            useFilemon = false;
        if (strstr(make_mode, "ignore-cmd") != NULL)
            metaIgnoreCMDs = true;
        if (useFilemon)
            get_mode_bf(filemonMissing, "missing-filemon=");
        get_mode_bf(metaCurdirOk, "curdirok=");
        get_mode_bf(metaMissing, "missing-meta=");
        get_mode_bf(metaSilent, "silent=");
    }
    if (metaVerbose && !Var_Exists(SCOPE_GLOBAL, MAKE_META_PREFIX)) {
        /*
         * The default value for MAKE_META_PREFIX
         * prints the absolute path of the target.
         * This works be cause :H will generate '.' if there is no /
         * and :tA will resolve that to cwd.
         */
        Global_Set(MAKE_META_PREFIX,
            "Building ${.TARGET:H:tA}/${.TARGET:T}");
    }
    if (once)
        return;
    once = true;
    memset(&Mybm, 0, sizeof Mybm);
    /*
     * We consider ourselves master of all within ${.MAKE.META.BAILIWICK}
     */
    metaBailiwickStr = Var_Subst("${.MAKE.META.BAILIWICK:O:u:tA}",
                                 SCOPE_GLOBAL, VARE_EVAL);
    /* TODO: handle errors */
    AppendWords(&metaBailiwick, metaBailiwickStr);
    /*
     * We ignore any paths that start with ${.MAKE.META.IGNORE_PATHS}
     */
    Global_Append(MAKE_META_IGNORE_PATHS,
               "/dev /etc /proc /tmp /var/run /var/tmp ${TMPDIR}");
    metaIgnorePathsStr = Var_Subst("${" MAKE_META_IGNORE_PATHS ":O:u:tA}",
                                   SCOPE_GLOBAL, VARE_EVAL);
    /* TODO: handle errors */
    AppendWords(&metaIgnorePaths, metaIgnorePathsStr);

    /*
     * We ignore any paths that match ${.MAKE.META.IGNORE_PATTERNS}
     */
    metaIgnorePatterns = Var_Exists(SCOPE_GLOBAL, MAKE_META_IGNORE_PATTERNS);
    metaIgnoreFilter = Var_Exists(SCOPE_GLOBAL, MAKE_META_IGNORE_FILTER);
    metaCmpFilter = Var_Exists(SCOPE_GLOBAL, MAKE_META_CMP_FILTER);
    metaFilter = Var_Exists(SCOPE_GLOBAL, MAKE_META_FILTER);
}

MAKE_INLINE BuildMon *
BM(Job *job)
{

        return job != NULL ? Job_BuildMon(job) : &Mybm;
}

/*
 * In each case below we allow for job==NULL
 */
void
meta_job_start(Job *job, GNode *gn)
{
    BuildMon *pbm;

    pbm = BM(job);
    pbm->mfp = meta_create(pbm, gn);
#ifdef USE_FILEMON_ONCE
    /* compat mode we open the filemon dev once per command */
    if (job == NULL)
        return;
#endif
#ifdef USE_FILEMON
    if (pbm->mfp != NULL && useFilemon) {
        meta_open_filemon(pbm);
    } else {
        pbm->mon_fd = -1;
        pbm->filemon = NULL;
    }
#endif
}

/*
 * The child calls this before doing anything.
 * It does not disturb our state.
 */
void
meta_job_child(Job *job MAKE_ATTR_UNUSED)
{
#ifdef USE_FILEMON
    BuildMon *pbm;

    pbm = BM(job);
    if (pbm->mfp != NULL) {
        close(fileno(pbm->mfp));
        if (useFilemon && pbm->filemon != NULL) {
            pid_t pid;

            pid = getpid();
            if (filemon_setpid_child(pbm->filemon, pid) == -1) {
                Punt("Could not set filemon pid: %s", strerror(errno));
            }
        }
    }
#endif
}

void
meta_job_parent(Job *job MAKE_ATTR_UNUSED, pid_t pid MAKE_ATTR_UNUSED)
{
#if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
    BuildMon *pbm;

    pbm = BM(job);
    if (useFilemon && pbm->filemon != NULL) {
        filemon_setpid_parent(pbm->filemon, pid);
    }
#endif
}

int
meta_job_fd(Job *job MAKE_ATTR_UNUSED)
{
#if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
    BuildMon *pbm;

    pbm = BM(job);
    if (useFilemon && pbm->filemon != NULL) {
        return filemon_readfd(pbm->filemon);
    }
#endif
    return -1;
}

int
meta_job_event(Job *job MAKE_ATTR_UNUSED)
{
#if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
    BuildMon *pbm;

    pbm = BM(job);
    if (useFilemon && pbm->filemon != NULL) {
        return filemon_process(pbm->filemon);
    }
#endif
    return 0;
}

void
meta_job_error(Job *job, GNode *gn, bool ignerr, int status)
{
    char cwd[MAXPATHLEN];
    BuildMon *pbm;

    pbm = BM(job);
    if (job != NULL && gn == NULL)
            gn = Job_Node(job);
    if (pbm->mfp != NULL) {
        fprintf(pbm->mfp, "\n*** Error code %d%s\n",
                status, ignerr ? "(ignored)" : "");
    }
    if (gn != NULL)
        Global_Set(".ERROR_TARGET", GNode_Path(gn));
    if (getcwd(cwd, sizeof cwd) == NULL)
        Punt("getcwd: %s", strerror(errno));

    Global_Set(".ERROR_CWD", cwd);
    if (pbm->meta_fname[0] != '\0') {
        Global_Set(".ERROR_META_FILE", pbm->meta_fname);
    }
    meta_job_finish(job);
}

void
meta_job_output(Job *job, const char *cp, size_t len)
{
    BuildMon *pbm;

    pbm = BM(job);
    if (pbm->mfp != NULL) {
        if (metaVerbose) {
            static char *meta_prefix = NULL;
            static size_t meta_prefix_len;

            if (meta_prefix == NULL) {
                meta_prefix = Var_Subst("${" MAKE_META_PREFIX "}",
                                        SCOPE_GLOBAL, VARE_EVAL);
                /* TODO: handle errors */
                meta_prefix_len = strcspn(meta_prefix, "$");
            }
            if (strncmp(cp, meta_prefix, meta_prefix_len) == 0) {
                cp = strchr(cp + 1, '\n');
                if (cp == NULL)
                    return;
                cp++;
            }
        }
        fprintf(pbm->mfp, "%.*s", (int)len, cp);
    }
}

int
meta_cmd_finish(void *pbmp)
{
    int error = 0;
    BuildMon *pbm = pbmp;
#ifdef USE_FILEMON
    int x;
#endif

    if (pbm == NULL)
        pbm = &Mybm;

#ifdef USE_FILEMON
    if (pbm->filemon != NULL) {
        while (filemon_process(pbm->filemon) > 0)
            continue;
        if (filemon_close(pbm->filemon) == -1) {
            error = errno;
            Punt("filemon failed: %s", strerror(errno));
        }
        x = filemon_read(pbm->mfp, pbm->mon_fd);
        if (error == 0 && x != 0)
            error = x;
        pbm->mon_fd = -1;
        pbm->filemon = NULL;
        return error;
    }
#endif

    fprintf(pbm->mfp, "\n");    /* ensure end with newline */
    return error;
}

int
meta_job_finish(Job *job)
{
    BuildMon *pbm;
    int error = 0;
    int x;

    pbm = BM(job);
    if (pbm->mfp != NULL) {
        error = meta_cmd_finish(pbm);
        x = fclose(pbm->mfp);
        if (error == 0 && x != 0)
            error = errno;
        pbm->mfp = NULL;
        pbm->meta_fname[0] = '\0';
    }
    return error;
}

void
meta_finish(void)
{
    Lst_Done(&metaBailiwick);
    free(metaBailiwickStr);
    Lst_Done(&metaIgnorePaths);
    free(metaIgnorePathsStr);
}

/*
 * Fetch a full line from fp - growing bufp if needed
 * Return length in bufp.
 */
static int
fgetLine(char **bufp, size_t *szp, int o, FILE *fp)
{
    char *buf = *bufp;
    size_t bufsz = *szp;
    struct stat fs;
    int x;

    if (fgets(&buf[o], (int)bufsz - o, fp) != NULL) {
    check_newline:
        x = o + (int)strlen(&buf[o]);
        if (buf[x - 1] == '\n')
            return x;
        /*
         * We need to grow the buffer.
         * The meta file can give us a clue.
         */
        if (fstat(fileno(fp), &fs) == 0) {
            size_t newsz;
            char *p;

            newsz = ROUNDUP(((size_t)fs.st_size / 2), BUFSIZ);
            if (newsz <= bufsz)
                newsz = ROUNDUP((size_t)fs.st_size, BUFSIZ);
            if (newsz <= bufsz)
                return x;               /* truncated */
            DEBUG2(META, "growing buffer %u -> %u\n",
                   (unsigned)bufsz, (unsigned)newsz);
            p = bmake_realloc(buf, newsz);
            *bufp = buf = p;
            *szp = bufsz = newsz;
            /* fetch the rest */
            if (fgets(&buf[x], (int)bufsz - x, fp) == NULL)
                return x;               /* truncated! */
            goto check_newline;
        }
    }
    return 0;
}

static bool
prefix_match(const char *prefix, const char *path)
{
    size_t n = strlen(prefix);

    return strncmp(path, prefix, n) == 0;
}

static bool
has_any_prefix(const char *path, StringList *prefixes)
{
    StringListNode *ln;

    for (ln = prefixes->first; ln != NULL; ln = ln->next)
        if (prefix_match(ln->datum, path))
            return true;
    return false;
}

/* See if the path equals prefix or starts with "prefix/". */
static bool
path_starts_with(const char *path, const char *prefix)
{
    size_t n = strlen(prefix);

    if (strncmp(path, prefix, n) != 0)
        return false;
    return path[n] == '\0' || path[n] == '/';
}

static bool
meta_ignore(GNode *gn, const char *p)
{
    char fname[MAXPATHLEN];
    const char *expr;
    char *fm;

    if (p == NULL)
        return true;

    if (*p == '/') {
        /* first try the raw path "as is" */
        if (has_any_prefix(p, &metaIgnorePaths)) {
#ifdef DEBUG_META_MODE
            DEBUG1(META, "meta_oodate: ignoring path: %s\n", p);
#endif
            return true;
        }
        cached_realpath(p, fname); /* clean it up */
        if (has_any_prefix(fname, &metaIgnorePaths)) {
#ifdef DEBUG_META_MODE
            DEBUG1(META, "meta_oodate: ignoring path: %s\n", p);
#endif
            return true;
        }
    }

    if (metaIgnorePatterns || metaIgnoreFilter)
        /*
         * XXX: This variable is set on a target GNode but is not one of
         * the usual local variables.  It should be deleted afterwards.
         * Ideally it would not be created in the first place, just like
         * in a .for loop.
         */
        Var_Set(gn, ".p.", p);

    if (metaIgnorePatterns) {
        expr = "${.p.:${" MAKE_META_IGNORE_PATTERNS ":S,^,N,:ts:}}";
        fm = Var_Subst(expr, gn, VARE_EVAL);
        /* TODO: handle errors */
        if (*fm == '\0') {
#ifdef DEBUG_META_MODE
            DEBUG1(META, "meta_oodate: ignoring pattern: %s\n", p);
#endif
            free(fm);
            return true;
        }
        free(fm);
    }

    if (metaIgnoreFilter) {
        expr = "${.p.:${" MAKE_META_IGNORE_FILTER ":ts:}}";
        fm = Var_Subst(expr, gn, VARE_EVAL);
        /* TODO: handle errors */
        if (*fm == '\0') {
#ifdef DEBUG_META_MODE
            DEBUG1(META, "meta_oodate: ignoring filtered: %s\n", p);
#endif
            free(fm);
            return true;
        }
        free(fm);
    }
    return false;
}

/*
 * When running with 'meta' functionality, a target can be out-of-date
 * if any of the references in its meta data file is more recent.
 * We have to track the latestdir on a per-process basis.
 */
#define LCWD_VNAME_FMT ".meta.%d.lcwd"
#define LDIR_VNAME_FMT ".meta.%d.ldir"

/*
 * It is possible that a .meta file is corrupted,
 * if we detect this we want to reproduce it.
 * Setting oodate true will have that effect.
 */
#define CHECK_VALID_META(p) if (!(p != NULL && *p != '\0')) { \
    warnx("%s:%u: malformed", fname, lineno); \
    oodate = true; \
    continue; \
    }

#define DEQUOTE(p) if (*p == '\'') {    \
    char *ep; \
    p++; \
    if ((ep = strchr(p, '\'')) != NULL) \
        *ep = '\0'; \
    }

static void
append_if_new(StringList *list, const char *str)
{
    StringListNode *ln;

    for (ln = list->first; ln != NULL; ln = ln->next)
        if (strcmp(ln->datum, str) == 0)
            return;
    Lst_Append(list, bmake_strdup(str));
}

/* remove any missingFiles entries that match p */
static void
remove_missing(StringList *missingFiles, const char *p)
{
    StringListNode *ln = missingFiles->first;

    while (ln != NULL) {
        StringListNode *next = ln->next;
        if (path_starts_with(ln->datum, p)) {
            free(ln->datum);
            Lst_Remove(missingFiles, ln);
        }
        ln = next;
    }
}

static void
remove_relative_missing(StringList *missingFiles, const char *p, char *sdirs[])
{
    char buf[MAXPATHLEN];
    char **sdp;

    for (sdp = sdirs; *sdp != NULL; sdp++) {
        snprintf(buf, sizeof(buf), "%s/%s", *sdp, p);
        remove_missing(missingFiles, buf);
    }
}

/* try to find a relative path */
static char *
meta_resolve_path(char *buf, size_t bufsz, const char *p,
  char *cwd, struct cached_stat *cstp, char *sdirs[])
{
    char **sdp;

    if (strcmp(p, ".") == 0)
        return cwd;

    for (sdp = sdirs; *sdp != NULL; sdp++) {
        snprintf(buf, bufsz, "%s/%s", *sdp, p);
        if (cached_stat(buf, cstp) == 0)
            return buf;
    }
    return NULL;
}

/*
 * Update sdirs to contain a NULL terminated list of
 * unique dirs to try and resolve relative paths against.
 */
static void
set_sdirs(char *sdirs[], size_t sdsz,
  char *latestdir, char *lcwd, char *cwd)
{
    size_t i = 0;

    sdirs[i++] = latestdir;
    if (i < sdsz && strcmp(latestdir, lcwd) != 0)
        sdirs[i++] = lcwd;
    if (i < sdsz && strcmp(lcwd, cwd) != 0)
        sdirs[i++] = cwd;
    if (i < sdsz)
        sdirs[i] = NULL;
    else
        sdirs[i - 1] = NULL;            /* should never happen */
}

/* A "reserved" variable to store the string to be filtered */
#define META_FILTER_VAR ".MAKE.META._filtered_"

static char *
meta_filter(GNode *gn, char *s, const char *filter)
{
    char buf[sizeof(META_FILTER_VAR) + sizeof(MAKE_META_CMP_FILTER) + 24];

    Var_Set(gn, META_FILTER_VAR, s);
    /* ":N" is a harmless do nothing */
    snprintf(buf, sizeof(buf), "${%s:${%s:UN:ts:}}",
      META_FILTER_VAR, filter);
    s = Var_Subst(buf, gn, VARE_EVAL);
    return s;
}

static int
meta_cmd_cmp(GNode *gn, char *a, char *b, bool filter)
{
    int rc;

    rc = strcmp(a, b);
    if (rc == 0 || !filter)
        return rc;
    a = meta_filter(gn, a, MAKE_META_CMP_FILTER);
    b = meta_filter(gn, b, MAKE_META_CMP_FILTER);
    rc = strcmp(a, b);
    free(a);
    free(b);
    return rc;
}

typedef enum MetaSection {
    META_HEADER,
    META_CMD,
    META_CWD,
    META_TARGET,
    META_OODATE,
    META_ENV,
    META_OUTPUT,
    META_FILEMON
} MetaSection;

bool
meta_oodate(GNode *gn, bool oodate)
{
    static char *tmpdir = NULL;
    static char cwd[MAXPATHLEN];
    char lcwd_vname[64];
    char ldir_vname[64];
    char lcwd[MAXPATHLEN];
    char latestdir[MAXPATHLEN];
    char fname[MAXPATHLEN];
    char fname1[MAXPATHLEN];
    char fname2[MAXPATHLEN];
    FStr dname;
    const char *tname;
    char *p;
    char *link_src;
    char *move_target;
    static size_t cwdlen = 0;
    static size_t tmplen = 0;
    FILE *fp;
    bool needOODATE = false;
    StringList missingFiles;
    bool cmp_filter;

    if (oodate)
        return oodate;          /* we're done */

    dname = Var_Value(gn, ".OBJDIR");
    tname = GNode_VarTarget(gn);

    /* if this succeeds fname2 is realpath of dname */
    if (!meta_needed(gn, dname.str, fname2, false))
        goto oodate_out;
    dname.str = fname2;

    Lst_Init(&missingFiles);

    /*
     * We need to check if the target is out-of-date. This includes
     * checking if the expanded command has changed. This in turn
     * requires that all variables are set in the same way that they
     * would be if the target needs to be re-built.
     */
    GNode_SetLocalVars(gn);

    meta_name(fname, sizeof fname, dname.str, tname, dname.str);

#ifdef DEBUG_META_MODE
    DEBUG1(META, "meta_oodate: %s\n", fname);
#endif

    if ((fp = fopen(fname, "r")) != NULL) {
        static char *buf = NULL;
        static size_t bufsz;
        char *rp;
        char *freeit = NULL;
        char *sdirs[4];
        unsigned lineno = 0;
        int lastpid = 0;
        int pid;
        int x;
        bool found;
        StringListNode *cmdNode;
        struct cached_stat cst;
        MetaSection section = META_HEADER;

        if (buf == NULL) {
            bufsz = 8 * BUFSIZ;
            buf = bmake_malloc(bufsz);
        }

        if (cwdlen == 0) {
            if (getcwd(cwd, sizeof cwd) == NULL)
                err(1, "Could not get current working directory");
            cwdlen = strlen(cwd);
        }
        strlcpy(lcwd, cwd, sizeof lcwd);
        strlcpy(latestdir, cwd, sizeof latestdir);

        /* adjust this when lcwd or latestdir change */
        sdirs[0] = cwd;
        sdirs[1] = NULL;

        if (tmpdir == NULL) {
            tmpdir = getTmpdir();
            tmplen = strlen(tmpdir);
        }

        /* we want to track all the .meta we read */
        Global_Append(".MAKE.META.FILES", fname);

        cmp_filter = metaFilter || metaCmpFilter || Var_Exists(gn, MAKE_META_CMP_FILTER);

        cmdNode = gn->commands.first;
        while (!oodate && (x = fgetLine(&buf, &bufsz, 0, fp)) > 0) {
            if (freeit != NULL) {
                free(freeit);
                freeit = NULL;
            }
            lineno++;
            if (buf[x - 1] == '\n')
                buf[x - 1] = '\0';
            else {
                warnx("%s:%u: line truncated at %u", fname, lineno, x);
                oodate = true;
                break;
            }
            link_src = NULL;
            move_target = NULL;
            /*
             * Track which section of the meta file we are in.
             * For CMD, CWD, and FILEMON we may have to do filtering
             * the rest are of no interest here.
             */
            switch (section) {
            case META_HEADER:
                section = META_CMD;
                continue;
            case META_CMD:
                if (strncmp(buf, "CWD", 3) == 0)
                    section = META_CWD;
                break;
            case META_CWD:
                if (strncmp(buf, "TARG", 4) == 0)
                    section = META_TARGET;
                break;
            case META_TARGET:
            case META_OODATE:
            case META_ENV:
                if (strncmp(buf, "-- command", 10) == 0)
                    section = META_OUTPUT;
                continue;
            case META_OUTPUT:
                if (strncmp(buf, "-- filemon", 10) == 0)
                    section = META_FILEMON;
                if (strncmp(buf, "# buildmon", 10) == 0)
                    section = META_FILEMON;
                continue;
            case META_FILEMON:
                break;
            }

            /* Delimit the record type. */
            p = buf;
#ifdef DEBUG_META_MODE
            DEBUG3(META, "%s:%u: %s\n", fname, lineno, buf);
#endif
            if (metaFilter) {
                switch (buf[0]) {
                case '#':               /* these do not need filtering */
                case 'F':
                case 'V':
                case 'X':
                    break;
                default:
                    switch (section) {
                    default:
                        break;
                    case META_CMD:
                    case META_CWD:
                    case META_FILEMON:
                        freeit = p = meta_filter(gn, p, MAKE_META_FILTER);
#ifdef DEBUG_META_MODE
                        DEBUG3(META, "%s:%u: filtered: %s\n", fname, lineno, p);
#endif
                        break;
                    }
                    break;
                }
            }

            strsep(&p, " ");
            switch (section) {
            default:
                break;
            case META_FILEMON:
                /*
                 * We are in the 'filemon' output section.
                 * Each record from filemon follows the general form:
                 *
                 * <key> <pid> <data>
                 *
                 * Where:
                 * <key> is a single letter, denoting the syscall.
                 * <pid> is the process that made the syscall.
                 * <data> is the arguments (of interest).
                 */
                switch(buf[0]) {
                case '#':               /* comment */
                case 'V':               /* version */
                    break;
                default:
                    /*
                     * We need to track pathnames per-process.
                     *
                     * Each process run by make starts off in the 'CWD'
                     * recorded in the .meta file, if it chdirs ('C')
                     * elsewhere we need to track that - but only for
                     * that process.  If it forks ('F'), we initialize
                     * the child to have the same cwd as its parent.
                     *
                     * We also need to track the 'latestdir' of
                     * interest.  This is usually the same as cwd, but
                     * not if a process is reading directories.
                     *
                     * Each time we spot a different process ('pid')
                     * we save the current value of 'latestdir' in a
                     * variable qualified by 'lastpid', and
                     * re-initialize 'latestdir' to any pre-saved
                     * value for the current 'pid' and 'CWD' if none.
                     */
                    CHECK_VALID_META(p);
                    pid = atoi(p);
                    if (pid > 0 && pid != lastpid) {
                        FStr ldir;

                        if (lastpid > 0) {
                            /* We need to remember these. */
                            Global_Set(lcwd_vname, lcwd);
                            Global_Set(ldir_vname, latestdir);
                        }
                        snprintf(lcwd_vname, sizeof lcwd_vname, LCWD_VNAME_FMT, pid);
                        snprintf(ldir_vname, sizeof ldir_vname, LDIR_VNAME_FMT, pid);
                        lastpid = pid;
                        ldir = Var_Value(SCOPE_GLOBAL, ldir_vname);
                        if (ldir.str != NULL) {
                            strlcpy(latestdir, ldir.str, sizeof latestdir);
                            FStr_Done(&ldir);
                        }
                        ldir = Var_Value(SCOPE_GLOBAL, lcwd_vname);
                        if (ldir.str != NULL) {
                            strlcpy(lcwd, ldir.str, sizeof lcwd);
                            FStr_Done(&ldir);
                        }
                        set_sdirs(sdirs, 4, latestdir, lcwd, cwd);
                    }
                    /* Skip past the pid. */
                    if (strsep(&p, " ") == NULL)
                        continue;
#ifdef DEBUG_META_MODE
                    if (DEBUG(META))
                        debug_printf("%s:%u: %d: %c: cwd=%s lcwd=%s ldir=%s\n",
                                     fname, lineno,
                                     pid, buf[0], cwd, lcwd, latestdir);
#endif
                    break;
                }

                CHECK_VALID_META(p);

                /* Process according to record type. */
                switch (buf[0]) {
                case 'X':               /* eXit */
                    Var_Delete(SCOPE_GLOBAL, lcwd_vname);
                    Var_Delete(SCOPE_GLOBAL, ldir_vname);
                    lastpid = 0;        /* no need to save ldir_vname */
                    break;

                case 'F':               /* [v]Fork */
                    {
                        char cldir[64];
                        int child;

                        child = atoi(p);
                        if (child > 0) {
                            snprintf(cldir, sizeof cldir, LCWD_VNAME_FMT, child);
                            Global_Set(cldir, lcwd);
                            snprintf(cldir, sizeof cldir, LDIR_VNAME_FMT, child);
                            Global_Set(cldir, latestdir);
#ifdef DEBUG_META_MODE
                            if (DEBUG(META))
                                debug_printf(
                                        "%s:%u: %d: cwd=%s lcwd=%s ldir=%s\n",
                                        fname, lineno,
                                        child, cwd, lcwd, latestdir);
#endif
                        }
                    }
                    break;

                case 'C':               /* Chdir */
                    /* Update lcwd and latest directory. */
                    strlcpy(latestdir, p, sizeof latestdir);
                    strlcpy(lcwd, p, sizeof lcwd);
                    Global_Set(lcwd_vname, lcwd);
                    Global_Set(ldir_vname, lcwd);
#ifdef DEBUG_META_MODE
                    DEBUG4(META, "%s:%u: cwd=%s ldir=%s\n",
                           fname, lineno, cwd, lcwd);
#endif
                    set_sdirs(sdirs, 4, latestdir, lcwd, cwd);
                    break;

                case 'M':               /* renaMe */
                    /*
                     * For 'M'oves we want to check
                     * the src as for 'R'ead
                     * and the target as for 'W'rite.
                     */
                    {
                        char *cp = p;   /* save this for a second */
                        /* now get target */
                        if (strsep(&p, " ") == NULL)
                            continue;
                        CHECK_VALID_META(p);
                        move_target = p;
                        p = cp;
                    }
                    /* 'L' and 'M' put single quotes around the args */
                    DEQUOTE(p);
                    DEQUOTE(move_target);
                    /* FALLTHROUGH */
                case 'D':               /* unlink */
                    if (*p != '/') {
#ifdef DEBUG_META_MODE
                        DEBUG3(META, "%s:%u: looking for: %s ...\n",
                          fname, lineno, p);
#endif
                        rp = meta_resolve_path(fname1, sizeof(fname1), p,
                          lcwd, &cst, sdirs);
                        if (rp != NULL) {
#ifdef DEBUG_META_MODE
                            DEBUG3(META, "%s:%u: found: %s\n",
                              fname, lineno, rp);
#endif
                            p = rp;
                        }
                    }
                    if (*p == '/') {
                        remove_missing(&missingFiles, p);
                    } else {
                        remove_relative_missing(&missingFiles, p, sdirs);
                    }
                    if (buf[0] == 'M') {
                        /* the target of the mv is a file 'W'ritten */
#ifdef DEBUG_META_MODE
                        DEBUG2(META, "meta_oodate: M %s -> %s\n",
                               p, move_target);
#endif
                        p = move_target;
                        goto check_write;
                    }
                    break;
                case 'L':               /* Link */
                    /*
                     * For 'L'inks check
                     * the src as for 'R'ead
                     * and the target as for 'W'rite.
                     */
                    link_src = p;
                    /* now get target */
                    if (strsep(&p, " ") == NULL)
                        continue;
                    CHECK_VALID_META(p);
                    /* 'L' and 'M' put single quotes around the args */
                    DEQUOTE(p);
                    DEQUOTE(link_src);
#ifdef DEBUG_META_MODE
                    DEBUG2(META, "meta_oodate: L %s -> %s\n", link_src, p);
#endif
                    /* FALLTHROUGH */
                case 'W':               /* Write */
                check_write:
                    /*
                     * If a file we generated within our bailiwick
                     * but outside of .OBJDIR is missing,
                     * we need to do it again.
                     */
                    if (*p != '/') {
#ifdef DEBUG_META_MODE
                        DEBUG3(META, "%s:%u: looking for: %s ...\n",
                          fname, lineno, p);
#endif
                        rp = meta_resolve_path(fname1, sizeof(fname1), p,
                          lcwd, &cst, sdirs);
                        if (rp != NULL) {
#ifdef DEBUG_META_MODE
                            DEBUG3(META, "%s:%u: found: %s\n",
                              fname, lineno, rp);
#endif
                            p = rp;
                        }
                    }
                    if (*p != '/') {
                        /*
                         * it is missing or we should have found it
                         */
                        snprintf(fname1, sizeof(fname1), "%s/%s",
                          lcwd, p);
#ifdef DEBUG_META_MODE
                        DEBUG3(META, "%s:%u: maybe missing: %s\n",
                          fname, lineno, fname1);
#endif
                        append_if_new(&missingFiles, fname1);
                        break;
                    }
                    if (Lst_IsEmpty(&metaBailiwick))
                        break;

                    /* ignore cwd - normal dependencies handle those */
                    if (strncmp(p, cwd, cwdlen) == 0)
                        break;

                    if (!has_any_prefix(p, &metaBailiwick))
                        break;

                    /* tmpdir might be within */
                    if (tmplen > 0 && strncmp(p, tmpdir, tmplen) == 0)
                        break;

                    /* ignore anything containing the string "tmp" */
                    /* XXX: The arguments to strstr must be swapped. */
                    if (strstr("tmp", p) != NULL)
                        break;

                    if ((link_src != NULL && cached_lstat(p, &cst) < 0) ||
                        (link_src == NULL && cached_stat(p, &cst) < 0)) {
                        if (!meta_ignore(gn, p))
                            append_if_new(&missingFiles, p);
                    }
                    break;
                check_link_src:
                    p = link_src;
                    link_src = NULL;
#ifdef DEBUG_META_MODE
                    DEBUG1(META, "meta_oodate: L src %s\n", p);
#endif
                    /* FALLTHROUGH */
                case 'R':               /* Read */
                case 'E':               /* Exec */
                    /*
                     * Check for runtime files that can't
                     * be part of the dependencies because
                     * they are _expected_ to change.
                     */
                    if (meta_ignore(gn, p))
                        break;

                    /*
                     * The rest of the record is the file name.
                     */
                    if (*p == '/') {
                        if (cached_stat(p, &cst) == 0) {
                            found = true;
#ifdef DEBUG_META_MODE
                            DEBUG3(META, "%s:%u: found: %s\n",
                              fname, lineno, p);
#endif
                        }
                    } else {
#ifdef DEBUG_META_MODE
                        DEBUG3(META, "%s:%u: looking for: %s ...\n",
                          fname, lineno, p);
#endif
                        rp = meta_resolve_path(fname1, sizeof(fname1), p,
                          lcwd, &cst, sdirs);
                        if (rp != NULL) {
#ifdef DEBUG_META_MODE
                            DEBUG3(META, "%s:%u: found: %s\n",
                              fname, lineno, rp);
#endif
                            p = rp;
                            found = true;
                        }
                    }
                    if (found) {
                        if (!S_ISDIR(cst.cst_mode) &&
                          cst.cst_mtime > gn->mtime) {
                            DEBUG3(META, "%s:%u: file '%s' is newer than the target...\n",
                              fname, lineno, p);
                            oodate = true;
                        } else if (S_ISDIR(cst.cst_mode)) {
                            /* Update the latest directory. */
                            cached_realpath(p, latestdir);
                            set_sdirs(sdirs, 4, latestdir, lcwd, cwd);
                        }
                    } else if (errno == ENOENT) {
                        if (*p != '/' || strncmp(p, cwd, cwdlen) != 0) {
                            /*
                             * A referenced file outside of CWD is missing.
                             * We cannot catch every eventuality here...
                             */
#ifdef DEBUG_META_MODE
                            DEBUG3(META, "%s:%u: maybe missing: %s\n",
                              fname, lineno, p);
#endif
                            append_if_new(&missingFiles, p);
                        }
                    }
                    if (buf[0] == 'E') {
                        /* previous latestdir is no longer relevant */
                        strlcpy(latestdir, lcwd, sizeof latestdir);
                        set_sdirs(sdirs, 4, latestdir, lcwd, cwd);
                    }
                    break;
                default:
                    break;
                }
                if (!oodate && buf[0] == 'L' && link_src != NULL)
                    goto check_link_src;
                break;
            case META_CMD:
                /*
                 * Compare the current command with the one in the
                 * meta data file.
                 */
                if (cmdNode == NULL) {
                    DEBUG2(META, "%s:%u: there were more build commands in the meta data file than there are now...\n",
                           fname, lineno);
                    oodate = true;
                } else {
                    const char *cp;
                    char *cmd = cmdNode->datum;
                    bool hasOODATE = false;

                    if (strstr(cmd, "$?") != NULL)
                        hasOODATE = true;
                    else if ((cp = strstr(cmd, ".OODATE")) != NULL) {
                        /* check for $[{(].OODATE[:)}] */
                        if (cp > cmd + 2 && cp[-2] == '$')
                            hasOODATE = true;
                    }
                    if (hasOODATE) {
                        needOODATE = true;
                        DEBUG2(META, "%s:%u: cannot compare command using .OODATE\n",
                               fname, lineno);
                    }
                    cmd = Var_Subst(cmd, gn, VARE_EVAL_DEFINED);
                    /* TODO: handle errors */

                    if ((cp = strchr(cmd, '\n')) != NULL) {
                        int n;

                        /*
                         * This command contains newlines, we need to
                         * fetch more from the .meta file before we
                         * attempt a comparison.
                         */
                        /* first put the newline back at buf[x - 1] */
                        buf[x - 1] = '\n';
                        do {
                            /* now fetch the next line */
                            if ((n = fgetLine(&buf, &bufsz, x, fp)) <= 0)
                                break;
                            x = n;
                            lineno++;
                            if (buf[x - 1] != '\n') {
                                warnx("%s:%u: line truncated at %u", fname, lineno, x);
                                break;
                            }
                            cp = strchr(cp + 1, '\n');
                        } while (cp != NULL);
                        if (buf[x - 1] == '\n')
                            buf[x - 1] = '\0';
                    }
                    if (p != NULL &&
                        !hasOODATE &&
                        !(gn->type & OP_NOMETA_CMP) &&
                        meta_cmd_cmp(gn, p, cmd, cmp_filter) != 0) {
                        DEBUG4(META, "%s:%u: a build command has changed\n%s\nvs\n%s\n",
                               fname, lineno, p, cmd);
                        if (!metaIgnoreCMDs)
                            oodate = true;
                    }
                    free(cmd);
                    cmdNode = cmdNode->next;
                }
                break;
            case META_CWD:
                /*
                 * Check if there are extra commands now
                 * that weren't in the meta data file.
                 */
                if (!oodate && cmdNode != NULL) {
                    DEBUG2(META, "%s:%u: there are extra build commands now that weren't in the meta data file\n",
                           fname, lineno);
                    oodate = true;
                }
                CHECK_VALID_META(p);
                if (strcmp(p, cwd) != 0) {
                    DEBUG4(META, "%s:%u: the current working directory has changed from '%s' to '%s'\n",
                           fname, lineno, p, curdir);
                    oodate = true;
                }
                break;
            }
        }
        free(freeit);

        if (metaFilter || metaCmpFilter)
            Var_Delete(gn, META_FILTER_VAR);

        fclose(fp);
        if (!Lst_IsEmpty(&missingFiles)) {
            DEBUG2(META, "%s: missing files: %s...\n",
                   fname, (char *)missingFiles.first->datum);
            oodate = true;
        }
#ifdef USE_FILEMON
        if (!oodate && section != META_FILEMON && filemonMissing) {
            DEBUG1(META, "%s: missing filemon data\n", fname);
            oodate = true;
        }
#endif
    } else {
        if (writeMeta && (metaMissing || (gn->type & OP_META))) {
            const char *cp = NULL;

            /* if target is in .CURDIR we do not need a meta file */
            if (gn->path != NULL && (cp = strrchr(gn->path, '/')) != NULL &&
                cp > gn->path) {
                if (strncmp(curdir, gn->path, (size_t)(cp - gn->path)) != 0) {
                    cp = NULL;          /* not in .CURDIR */
                }
            }
            if (cp == NULL) {
                DEBUG1(META, "%s: required but missing\n", fname);
                oodate = true;
                needOODATE = true;      /* assume the worst */
            }
        }
    }

    Lst_DoneFree(&missingFiles);

    if (oodate && needOODATE) {
        /*
         * Target uses .OODATE which is empty; or we wouldn't be here.
         * We have decided it is oodate, so .OODATE needs to be set.
         * All we can sanely do is set it to .ALLSRC.
         */
        Var_Delete(gn, OODATE);
        Var_Set(gn, OODATE, GNode_VarAllsrc(gn));
    }

 oodate_out:
    FStr_Done(&dname);
    return oodate;
}

/* support for compat mode */

static int childPipe[2];

void
meta_compat_start(void)
{
#ifdef USE_FILEMON_ONCE
    /*
     * We need to re-open filemon for each cmd.
     */
    BuildMon *pbm = &Mybm;

    if (pbm->mfp != NULL && useFilemon) {
        meta_open_filemon(pbm);
    } else {
        pbm->mon_fd = -1;
        pbm->filemon = NULL;
    }
#endif
    if (pipe(childPipe) < 0)
        Punt("pipe: %s", strerror(errno));
    /* Set close-on-exec flag for both */
    (void)fcntl(childPipe[0], F_SETFD, FD_CLOEXEC);
    (void)fcntl(childPipe[1], F_SETFD, FD_CLOEXEC);
}

void
meta_compat_child(void)
{
    meta_job_child(NULL);
    if (dup2(childPipe[1], STDOUT_FILENO) < 0
            || dup2(STDOUT_FILENO, STDERR_FILENO) < 0)
        execDie("dup2", "pipe");
}

void
meta_compat_parent(pid_t child)
{
    int outfd, metafd, maxfd, nfds;
    char buf[BUFSIZ+1];
    fd_set readfds;

    meta_job_parent(NULL, child);
    close(childPipe[1]);                        /* child side */
    outfd = childPipe[0];
#ifdef USE_FILEMON
    metafd = Mybm.filemon != NULL ? filemon_readfd(Mybm.filemon) : -1;
#else
    metafd = -1;
#endif
    maxfd = -1;
    if (outfd > maxfd)
            maxfd = outfd;
    if (metafd > maxfd)
            maxfd = metafd;

    while (outfd != -1 || metafd != -1) {
        FD_ZERO(&readfds);
        if (outfd != -1) {
            FD_SET(outfd, &readfds);
        }
        if (metafd != -1) {
            FD_SET(metafd, &readfds);
        }
        nfds = select(maxfd + 1, &readfds, NULL, NULL, NULL);
        if (nfds == -1) {
            if (errno == EINTR)
                continue;
            err(1, "select");
        }

        if (outfd != -1 && FD_ISSET(outfd, &readfds) != 0) do {
            /* XXX this is not line-buffered */
            ssize_t nread = read(outfd, buf, sizeof buf - 1);
            if (nread == -1)
                err(1, "read");
            if (nread == 0) {
                close(outfd);
                outfd = -1;
                break;
            }
            fwrite(buf, 1, (size_t)nread, stdout);
            fflush(stdout);
            buf[nread] = '\0';
            meta_job_output(NULL, buf, (size_t)nread);
        } while (false);
        if (metafd != -1 && FD_ISSET(metafd, &readfds) != 0) {
            if (meta_job_event(NULL) <= 0)
                metafd = -1;
        }
    }
}

#endif /* USE_META */