cmd/logadm/conf.c

/*
 * 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 (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2013, Joyent, Inc. All rights reserved.
 */

/*
 * logadm/conf.c -- configuration file module
 */

#include <stdio.h>
#include <libintl.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <ctype.h>
#include <strings.h>
#include <unistd.h>
#include <stdlib.h>
#include <limits.h>
#include "err.h"
#include "lut.h"
#include "fn.h"
#include "opts.h"
#include "conf.h"

/* forward declarations of functions private to this module */
static void fillconflist(int lineno, const char *entry,
    struct opts *opts, const char *com, int flags);
static void fillargs(char *arg);
static char *nexttok(char **ptrptr);
static void conf_print(FILE *cstream, FILE *tstream);

static const char *Confname;    /* name of the confile file */
static int Conffd = -1;     /* file descriptor for config file */
static char *Confbuf;       /* copy of the config file (a la mmap()) */
static int Conflen;     /* length of mmap'd config file area */
static const char *Timesname;   /* name of the timestamps file */
static int Timesfd = -1;    /* file descriptor for timestamps file */
static char *Timesbuf;      /* copy of the timestamps file (a la mmap()) */
static int Timeslen;        /* length of mmap'd timestamps area */
static int Singlefile;      /* Conf and Times in the same file */
static int Changed;     /* what changes need to be written back */
static int Canchange;       /* what changes can be written back */
static int Changing;        /* what changes have been requested */
#define CHG_NONE    0
#define CHG_TIMES   1
#define CHG_BOTH    3

/*
 * our structured representation of the configuration file
 * is made up of a list of these
 */
struct confinfo {
    struct confinfo *cf_next;
    int cf_lineno;      /* line number in file */
    const char *cf_entry;   /* name of entry, if line has an entry */
    struct opts *cf_opts;   /* parsed rhs of entry */
    const char *cf_com; /* any comment text found */
    int cf_flags;
};

#define CONFF_DELETED   1   /* entry should be deleted on write back */

static struct confinfo *Confinfo;   /* the entries in the config file */
static struct confinfo *Confinfolast;   /* end of list */
static struct lut *Conflut;     /* lookup table keyed by entry name */
static struct fn_list *Confentries; /* list of valid entry names */

/* allocate & fill in another entry in our list */
static void
fillconflist(int lineno, const char *entry,
    struct opts *opts, const char *com, int flags)
{
    struct confinfo *cp = MALLOC(sizeof (*cp));

    cp->cf_next = NULL;
    cp->cf_lineno = lineno;
    cp->cf_entry = entry;
    cp->cf_opts = opts;
    cp->cf_com = com;
    cp->cf_flags = flags;
    if (entry != NULL) {
        Conflut = lut_add(Conflut, entry, cp);
        fn_list_adds(Confentries, entry);
    }
    if (Confinfo == NULL)
        Confinfo = Confinfolast = cp;
    else {
        Confinfolast->cf_next = cp;
        Confinfolast = cp;
    }
}

static char **Args; /* static buffer for args */
static int ArgsN;   /* size of our static buffer */
static int ArgsI;   /* index into Cmdargs as we walk table */
#define CONF_ARGS_INC   1024

/* callback for lut_walk to build a cmdargs vector */
static void
fillargs(char *arg)
{
    if (ArgsI >= ArgsN) {
        /* need bigger table */
        Args = REALLOC(Args, sizeof (char *) * (ArgsN + CONF_ARGS_INC));
        ArgsN += CONF_ARGS_INC;
    }
    Args[ArgsI++] = arg;
}

/* isolate and return the next token */
static char *
nexttok(char **ptrptr)
{
    char *ptr = *ptrptr;
    char *eptr;
    char *quote = NULL;

    while (*ptr && isspace(*ptr))
        ptr++;

    if (*ptr == '"' || *ptr == '\'')
        quote = ptr++;

    for (eptr = ptr; *eptr; eptr++)
        if (quote && *eptr == *quote) {
            /* found end quote */
            *eptr++ = '\0';
            *ptrptr = eptr;
            return (ptr);
        } else if (!quote && isspace(*eptr)) {
            /* found end of unquoted area */
            *eptr++ = '\0';
            *ptrptr = eptr;
            return (ptr);
        }

    if (quote != NULL)
        err(EF_FILE|EF_JMP, "Unbalanced %c quote", *quote);
        /*NOTREACHED*/

    *ptrptr = eptr;

    if (ptr == eptr)
        return (NULL);
    else
        return (ptr);
}

/*
 * scan the memory image of a file
 *  returns: 0: error, 1: ok, 3: -P option found
 */
static int
conf_scan(const char *fname, char *buf, int buflen, int timescan)
{
    int ret = 1;
    int lineno = 0;
    char *line;
    char *eline;
    char *ebuf;
    char *entry, *comment;

    ebuf = &buf[buflen];

    if (buf[buflen - 1] != '\n')
        err(EF_WARN|EF_FILE, "file %s doesn't end with newline, "
            "last line ignored.", fname);

    for (line = buf; line < ebuf; line = eline) {
        char *ap;
        struct opts *opts = NULL;
        struct confinfo *cp;

        lineno++;
        err_fileline(fname, lineno);
        eline = line;
        comment = NULL;
        for (; eline < ebuf; eline++) {
            /* check for continued lines */
            if (comment == NULL && *eline == '\\' &&
                eline + 1 < ebuf && *(eline + 1) == '\n') {
                *eline = ' ';
                *(eline + 1) = ' ';
                lineno++;
                err_fileline(fname, lineno);
                continue;
            }

            /* check for comments */
            if (comment == NULL && *eline == '#') {
                *eline = '\0';
                comment = (eline + 1);
                continue;
            }

            /* check for end of line */
            if (*eline == '\n')
                break;
        }
        if (comment >= ebuf)
            comment = NULL;
        if (eline >= ebuf) {
            /* discard trailing unterminated line */
            continue;
        }
        *eline++ = '\0';

        /*
         * now we have the entry, if any, at "line"
         * and the comment, if any, at "comment"
         */

        /* entry is first token */
        entry = nexttok(&line);
        if (entry == NULL) {
            /* it's just a comment line */
            if (!timescan)
                fillconflist(lineno, entry, NULL, comment, 0);
            continue;
        }
        if (strcmp(entry, "logadm-version") == 0) {
            /*
             * we somehow opened some future format
             * conffile that we likely don't understand.
             * if the given version is "1" then go on,
             * otherwise someone is mixing versions
             * and we can't help them other than to
             * print an error and exit.
             */
            if ((entry = nexttok(&line)) != NULL &&
                strcmp(entry, "1") != 0)
                err(0, "%s version not supported "
                    "by this version of logadm.",
                    fname);
            continue;
        }

        /* form an argv array */
        ArgsI = 0;
        while (ap = nexttok(&line))
            fillargs(ap);

        /*
         * If there is no next token on the line, make sure that
         * we get a non-NULL Args array.
         */
        if (Args == NULL)
            fillargs(NULL);

        Args[ArgsI] = NULL;

        LOCAL_ERR_BEGIN {
            if (SETJMP) {
                err(EF_FILE, "cannot process invalid entry %s",
                    entry);
                ret = 0;
                LOCAL_ERR_BREAK;
            }

            if (timescan) {
                /* append to config options */
                cp = lut_lookup(Conflut, entry);
                if (cp != NULL) {
                    opts = cp->cf_opts;
                }
            }
            opts = opts_parse(opts, Args, OPTF_CONF);
            if (!timescan || cp == NULL) {
                /*
                 * If we're not doing timescan, we track this
                 * entry.  If we are doing timescan and have
                 * what looks like an orphaned entry (cp ==
                 * NULL) then we also have to track. See the
                 * comment in rotatelog. We need to allow for
                 * the case where the logname is not the same as
                 * the log file name.
                 */
                fillconflist(lineno, entry, opts, comment, 0);
            }
        LOCAL_ERR_END }

        if (ret == 1 && opts && opts_optarg(opts, "P") != NULL)
            ret = 3;
    }

    err_fileline(NULL, 0);
    return (ret);
}

/*
 * conf_open -- open the configuration file, lock it if we have write perms
 */
int
conf_open(const char *cfname, const char *tfname, struct opts *cliopts)
{
    struct stat stbuf1, stbuf2, stbuf3;
    struct flock    flock;
    int ret;

    Confname = cfname;
    Timesname = tfname;
    Confentries = fn_list_new(NULL);
    Changed = CHG_NONE;

    Changing = CHG_TIMES;
    if (opts_count(cliopts, "Vn") != 0)
        Changing = CHG_NONE;
    else if (opts_count(cliopts, "rw") != 0)
        Changing = CHG_BOTH;

    Singlefile = strcmp(Confname, Timesname) == 0;
    if (Singlefile && Changing == CHG_TIMES)
        Changing = CHG_BOTH;

    /* special case this so we don't even try locking the file */
    if (strcmp(Confname, "/dev/null") == 0)
        return (0);

    while (Conffd == -1) {
        Canchange = CHG_BOTH;
        if ((Conffd = open(Confname, O_RDWR)) < 0) {
            if (Changing == CHG_BOTH)
                err(EF_SYS, "open %s", Confname);
            Canchange = CHG_TIMES;
            if ((Conffd = open(Confname, O_RDONLY)) < 0)
                err(EF_SYS, "open %s", Confname);
        }

        flock.l_type = (Canchange == CHG_BOTH) ? F_WRLCK : F_RDLCK;
        flock.l_whence = SEEK_SET;
        flock.l_start = 0;
        flock.l_len = 1;
        if (fcntl(Conffd, F_SETLKW, &flock) < 0)
            err(EF_SYS, "flock on %s", Confname);

        /* wait until after file is locked to get filesize */
        if (fstat(Conffd, &stbuf1) < 0)
            err(EF_SYS, "fstat on %s", Confname);

        /* verify that we've got a lock on the active file */
        if (stat(Confname, &stbuf2) < 0 ||
            !(stbuf2.st_dev == stbuf1.st_dev &&
            stbuf2.st_ino == stbuf1.st_ino)) {
            /* wrong config file, try again */
            (void) close(Conffd);
            Conffd = -1;
        }
    }

    while (!Singlefile && Timesfd == -1) {
        if ((Timesfd = open(Timesname, O_CREAT|O_RDWR, 0644)) < 0) {
            if (Changing != CHG_NONE)
                err(EF_SYS, "open %s", Timesname);
            Canchange = CHG_NONE;
            if ((Timesfd = open(Timesname, O_RDONLY)) < 0)
                err(EF_SYS, "open %s", Timesname);
        }

        flock.l_type = (Canchange != CHG_NONE) ? F_WRLCK : F_RDLCK;
        flock.l_whence = SEEK_SET;
        flock.l_start = 0;
        flock.l_len = 1;
        if (fcntl(Timesfd, F_SETLKW, &flock) < 0)
            err(EF_SYS, "flock on %s", Timesname);

        /* wait until after file is locked to get filesize */
        if (fstat(Timesfd, &stbuf2) < 0)
            err(EF_SYS, "fstat on %s", Timesname);

        /* verify that we've got a lock on the active file */
        if (stat(Timesname, &stbuf3) < 0 ||
            !(stbuf2.st_dev == stbuf3.st_dev &&
            stbuf2.st_ino == stbuf3.st_ino)) {
            /* wrong timestamp file, try again */
            (void) close(Timesfd);
            Timesfd = -1;
            continue;
        }

        /* check that Timesname isn't an alias for Confname */
        if (stbuf2.st_dev == stbuf1.st_dev &&
            stbuf2.st_ino == stbuf1.st_ino)
            err(0, "Timestamp file %s can't refer to "
                "Configuration file %s", Timesname, Confname);
    }

    Conflen = stbuf1.st_size;
    Timeslen = stbuf2.st_size;

    if (Conflen == 0)
        return (1); /* empty file, don't bother parsing it */

    if ((Confbuf = (char *)mmap(0, Conflen,
        PROT_READ | PROT_WRITE, MAP_PRIVATE, Conffd, 0)) == (char *)-1)
        err(EF_SYS, "mmap on %s", Confname);

    ret = conf_scan(Confname, Confbuf, Conflen, 0);
    if (ret == 3 && !Singlefile && Canchange == CHG_BOTH) {
        /*
         * arrange to transfer any timestamps
         * from conf_file to timestamps_file
         */
        Changing = Changed = CHG_BOTH;
    }

    if (Timesfd != -1 && Timeslen != 0) {
        if ((Timesbuf = (char *)mmap(0, Timeslen,
            PROT_READ | PROT_WRITE, MAP_PRIVATE,
            Timesfd, 0)) == (char *)-1)
            err(EF_SYS, "mmap on %s", Timesname);
        ret &= conf_scan(Timesname, Timesbuf, Timeslen, 1);
    }

    /*
     * possible future enhancement:  go through and mark any entries:
     *      logfile -P <date>
     * as DELETED if the logfile doesn't exist
     */

    return (ret);
}

/*
 * conf_close -- close the configuration file
 */
void
conf_close(struct opts *opts)
{
    char cuname[PATH_MAX], tuname[PATH_MAX];
    int cfd, tfd;
    FILE *cfp = NULL, *tfp = NULL;
    boolean_t safe_update = B_TRUE;

    if (Changed == CHG_NONE || opts_count(opts, "n") != 0) {
        if (opts_count(opts, "v"))
            (void) out("# %s and %s unchanged\n",
                Confname, Timesname);
        goto cleanup;
    }

    if (Debug > 1) {
        (void) fprintf(stderr, "conf_close, saving logadm context:\n");
        conf_print(stderr, NULL);
    }

    cuname[0] = tuname[0] = '\0';
    LOCAL_ERR_BEGIN {
        if (SETJMP) {
            safe_update = B_FALSE;
            LOCAL_ERR_BREAK;
        }
        if (Changed == CHG_BOTH) {
            if (Canchange != CHG_BOTH)
                err(EF_JMP, "internal error: attempting "
                    "to update %s without locking", Confname);
            (void) snprintf(cuname, sizeof (cuname), "%sXXXXXX",
                Confname);
            if ((cfd = mkstemp(cuname)) == -1)
                err(EF_SYS|EF_JMP, "open %s replacement",
                    Confname);
            if (opts_count(opts, "v"))
                (void) out("# writing changes to %s\n", cuname);
            if (fchmod(cfd, 0644) == -1)
                err(EF_SYS|EF_JMP, "chmod %s", cuname);
            if ((cfp = fdopen(cfd, "w")) == NULL)
                err(EF_SYS|EF_JMP, "fdopen on %s", cuname);
        } else {
            /* just toss away the configuration data */
            cfp = fopen("/dev/null", "w");
        }
        if (!Singlefile) {
            if (Canchange == CHG_NONE)
                err(EF_JMP, "internal error: attempting "
                    "to update %s without locking", Timesname);
            (void) snprintf(tuname, sizeof (tuname), "%sXXXXXX",
                Timesname);
            if ((tfd = mkstemp(tuname)) == -1)
                err(EF_SYS|EF_JMP, "open %s replacement",
                    Timesname);
            if (opts_count(opts, "v"))
                (void) out("# writing changes to %s\n", tuname);
            if (fchmod(tfd, 0644) == -1)
                err(EF_SYS|EF_JMP, "chmod %s", tuname);
            if ((tfp = fdopen(tfd, "w")) == NULL)
                err(EF_SYS|EF_JMP, "fdopen on %s", tuname);
        }

        conf_print(cfp, tfp);
        if (fclose(cfp) < 0)
            err(EF_SYS|EF_JMP, "fclose on %s", Confname);
        if (tfp != NULL && fclose(tfp) < 0)
            err(EF_SYS|EF_JMP, "fclose on %s", Timesname);
    LOCAL_ERR_END }

    if (!safe_update) {
        if (cuname[0] != 0)
            (void) unlink(cuname);
        if (tuname[0] != 0)
            (void) unlink(tuname);
        err(EF_JMP, "unsafe to update configuration file "
            "or timestamps");
        return;
    }

    /* rename updated files into place */
    if (cuname[0] != '\0')
        if (rename(cuname, Confname) < 0)
            err(EF_SYS, "rename %s to %s", cuname, Confname);
    if (tuname[0] != '\0')
        if (rename(tuname, Timesname) < 0)
            err(EF_SYS, "rename %s to %s", tuname, Timesname);
    Changed = CHG_NONE;

cleanup:
    if (Conffd != -1) {
        (void) close(Conffd);
        Conffd = -1;
    }
    if (Timesfd != -1) {
        (void) close(Timesfd);
        Timesfd = -1;
    }
    if (Conflut) {
        lut_free(Conflut, free);
        Conflut = NULL;
    }
    if (Confentries) {
        fn_list_free(Confentries);
        Confentries = NULL;
    }
}

/*
 * conf_lookup -- lookup an entry in the config file
 */
void *
conf_lookup(const char *lhs)
{
    struct confinfo *cp = lut_lookup(Conflut, lhs);

    if (cp != NULL)
        err_fileline(Confname, cp->cf_lineno);
    return (cp);
}

/*
 * conf_opts -- return the parsed opts for an entry
 */
struct opts *
conf_opts(const char *lhs)
{
    struct confinfo *cp = lut_lookup(Conflut, lhs);

    if (cp != NULL)
        return (cp->cf_opts);
    return (opts_parse(NULL, NULL, OPTF_CONF));
}

/*
 * conf_replace -- replace an entry in the config file
 */
void
conf_replace(const char *lhs, struct opts *newopts)
{
    struct confinfo *cp = lut_lookup(Conflut, lhs);

    if (Conffd == -1)
        return;

    if (cp != NULL) {
        cp->cf_opts = newopts;
        /* cp->cf_args = NULL; */
        if (newopts == NULL)
            cp->cf_flags |= CONFF_DELETED;
    } else
        fillconflist(0, lhs, newopts, NULL, 0);

    Changed = CHG_BOTH;
}

/*
 * conf_set -- set options for an entry in the config file
 */
void
conf_set(const char *entry, char *o, const char *optarg)
{
    struct confinfo *cp = lut_lookup(Conflut, entry);

    if (Conffd == -1)
        return;

    if (cp != NULL) {
        cp->cf_flags &= ~CONFF_DELETED;
    } else {
        fillconflist(0, STRDUP(entry),
            opts_parse(NULL, NULL, OPTF_CONF), NULL, 0);
        if ((cp = lut_lookup(Conflut, entry)) == NULL)
            err(0, "conf_set internal error");
    }
    (void) opts_set(cp->cf_opts, o, optarg);
    if (strcmp(o, "P") == 0)
        Changed |= CHG_TIMES;
    else
        Changed = CHG_BOTH;
}

/*
 * conf_entries -- list all the entry names
 */
struct fn_list *
conf_entries(void)
{
    return (Confentries);
}

/* print the config file */
static void
conf_print(FILE *cstream, FILE *tstream)
{
    struct confinfo *cp;
    char *exclude_opts = "PFfhnrvVw";
    const char *timestamp;

    if (tstream == NULL) {
        exclude_opts++;     /* -P option goes to config file */
    } else {
        (void) fprintf(tstream, gettext(
            "# This file holds internal data for logadm(1M).\n"
            "# Do not edit.\n"));
    }
    for (cp = Confinfo; cp; cp = cp->cf_next) {
        if (cp->cf_flags & CONFF_DELETED)
            continue;
        if (cp->cf_entry) {
            opts_printword(cp->cf_entry, cstream);
            if (cp->cf_opts)
                opts_print(cp->cf_opts, cstream, exclude_opts);
            /* output timestamps to tstream */
            if (tstream != NULL && (timestamp =
                opts_optarg(cp->cf_opts, "P")) != NULL) {
                opts_printword(cp->cf_entry, tstream);
                (void) fprintf(tstream, " -P ");
                opts_printword(timestamp, tstream);
                (void) fprintf(tstream, "\n");
            }
        }
        if (cp->cf_com) {
            if (cp->cf_entry)
                (void) fprintf(cstream, " ");
            (void) fprintf(cstream, "#%s", cp->cf_com);
        }
        (void) fprintf(cstream, "\n");
    }
}

#ifdef  TESTMODULE

/*
 * test main for conf module, usage: a.out conffile
 */
int
main(int argc, char *argv[])
{
    struct opts *opts;

    err_init(argv[0]);
    setbuf(stdout, NULL);
    opts_init(Opttable, Opttable_cnt);

    opts = opts_parse(NULL, NULL, 0);

    if (argc != 2)
        err(EF_RAW, "usage: %s conffile\n", argv[0]);

    conf_open(argv[1], argv[1], opts);

    printf("conffile <%s>:\n", argv[1]);
    conf_print(stdout, NULL);

    conf_close(opts);

    err_done(0);
    /* NOTREACHED */
    return (0);
}

#endif  /* TESTMODULE */