arch.c

早期freebsd实现

    /*
     * We don't have this archive on the list yet, so we want to find out
     * everything that's in it and cache it so we can get at it quickly.
     */
    arch = fopen (archive, "r");
    if (arch == (FILE *) NULL) {
	return ((struct ar_hdr *) NULL);
    }
    
    /*
     * We use the ARMAG string to make sure this is an archive we
     * can handle...
     */
    if ((fread (magic, SARMAG, 1, arch) != 1) ||
    	(strncmp (magic, ARMAG, SARMAG) != 0)) {
	    fclose (arch);
	    return ((struct ar_hdr *) NULL);
    }

    ar = (Arch *)emalloc (sizeof (Arch));
    ar->name = strdup (archive);
    Hash_InitTable (&ar->members, -1);
    memName[AR_MAX_NAME_LEN] = '\0';
    
    while (fread ((char *)&arh, sizeof (struct ar_hdr), 1, arch) == 1) {
	if (strncmp ( arh.ar_fmag, ARFMAG, sizeof (arh.ar_fmag)) != 0) {
				 /*
				  * The header is bogus, so the archive is bad
				  * and there's no way we can recover...
				  */
				 fclose (arch);
				 Hash_DeleteTable (&ar->members);
				 free ((Address)ar);
				 return ((struct ar_hdr *) NULL);
	} else {
	    (void) strncpy (memName, arh.ar_name, sizeof(arh.ar_name));
	    for (cp = &memName[AR_MAX_NAME_LEN]; *cp == ' '; cp--) {
		continue;
	    }
	    cp[1] = '\0';

	    he = Hash_CreateEntry (&ar->members, strdup (memName),
				   (Boolean *)NULL);
	    Hash_SetValue (he, (ClientData)emalloc (sizeof (struct ar_hdr)));
	    memcpy ((Address)Hash_GetValue (he), (Address)&arh, 
		sizeof (struct ar_hdr));
	}
	/*
	 * We need to advance the stream's pointer to the start of the
	 * next header. Files are padded with newlines to an even-byte
	 * boundary, so we need to extract the size of the file from the
	 * 'size' field of the header and round it up during the seek.
	 */
	arh.ar_size[sizeof(arh.ar_size)-1] = '\0';
	(void) sscanf (arh.ar_size, "%10d", &size);
	fseek (arch, (size + 1) & ~1, 1);
    }

    fclose (arch);

    (void) Lst_AtEnd (archives, (ClientData) ar);

    /*
     * Now that the archive has been read and cached, we can look into
     * the hash table to find the desired member's header.
     */
    he = Hash_FindEntry (&ar->members, member);

    if (he != (Hash_Entry *) NULL) {
	return ((struct ar_hdr *) Hash_GetValue (he));
    } else {
	return ((struct ar_hdr *) NULL);
    }
}

/*-
 *-----------------------------------------------------------------------
 * ArchFindMember --
 *	Locate a member of an archive, given the path of the archive and
 *	the path of the desired member. If the archive is to be modified,
 *	the mode should be "r+", if not, it should be "r".
 *
 * Results:
 *	An FILE *, opened for reading and writing, positioned at the
 *	start of the member's struct ar_hdr, or NULL if the member was
 *	nonexistent. The current struct ar_hdr for member.
 *
 * Side Effects:
 *	The passed struct ar_hdr structure is filled in.
 *
 *-----------------------------------------------------------------------
 */
static FILE *
ArchFindMember (archive, member, arhPtr, mode)
    char	  *archive;   /* Path to the archive */
    char	  *member;    /* Name of member. If it is a path, only the
			       * last component is used. */
    struct ar_hdr *arhPtr;    /* Pointer to header structure to be filled in */
    char	  *mode;      /* The mode for opening the stream */
{
    FILE *	  arch;	      /* Stream to archive */
    int		  size;       /* Size of archive member */
    char	  *cp;	      /* Useful character pointer */
    char	  magic[SARMAG];
    int		  len;

    arch = fopen (archive, mode);
    if (arch == (FILE *) NULL) {
	return ((FILE *) NULL);
    }
    
    /*
     * We use the ARMAG string to make sure this is an archive we
     * can handle...
     */
    if ((fread (magic, SARMAG, 1, arch) != 1) ||
    	(strncmp (magic, ARMAG, SARMAG) != 0)) {
	    fclose (arch);
	    return ((FILE *) NULL);
    }

    /*
     * Because of space constraints and similar things, files are archived
     * using their final path components, not the entire thing, so we need
     * to point 'member' to the final component, if there is one, to make
     * the comparisons easier...
     */
    cp = strrchr (member, '/');
    if (cp != (char *) NULL) {
	member = cp + 1;
    }
    len = strlen (member);
    if (len > sizeof (arhPtr->ar_name)) {
	len = sizeof (arhPtr->ar_name);
    }
    
    while (fread ((char *)arhPtr, sizeof (struct ar_hdr), 1, arch) == 1) {
	if (strncmp(arhPtr->ar_fmag, ARFMAG, sizeof (arhPtr->ar_fmag) ) != 0) {
	     /*
	      * The header is bogus, so the archive is bad
	      * and there's no way we can recover...
	      */
	     fclose (arch);
	     return ((FILE *) NULL);
	} else if (strncmp (member, arhPtr->ar_name, len) == 0) {
	    /*
	     * If the member's name doesn't take up the entire 'name' field,
	     * we have to be careful of matching prefixes. Names are space-
	     * padded to the right, so if the character in 'name' at the end
	     * of the matched string is anything but a space, this isn't the
	     * member we sought.
	     */
	    if (len != sizeof(arhPtr->ar_name) && arhPtr->ar_name[len] != ' '){
		continue;
	    } else {
		/*
		 * To make life easier, we reposition the file at the start
		 * of the header we just read before we return the stream.
		 * In a more general situation, it might be better to leave
		 * the file at the actual member, rather than its header, but
		 * not here...
		 */
		fseek (arch, -sizeof(struct ar_hdr), 1);
		return (arch);
	    }
	} else {
	    /*
	     * This isn't the member we're after, so we need to advance the
	     * stream's pointer to the start of the next header. Files are
	     * padded with newlines to an even-byte boundary, so we need to
	     * extract the size of the file from the 'size' field of the
	     * header and round it up during the seek.
	     */
	    arhPtr->ar_size[sizeof(arhPtr->ar_size)-1] = '\0';
	    (void)sscanf (arhPtr->ar_size, "%10d", &size);
	    fseek (arch, (size + 1) & ~1, 1);
	}
    }

    /*
     * We've looked everywhere, but the member is not to be found. Close the
     * archive and return NULL -- an error.
     */
    fclose (arch);
    return ((FILE *) NULL);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_Touch --
 *	Touch a member of an archive.
 *
 * Results:
 *	The 'time' field of the member's header is updated.
 *
 * Side Effects:
 *	The modification time of the entire archive is also changed.
 *	For a library, this could necessitate the re-ranlib'ing of the
 *	whole thing.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_Touch (gn)
    GNode	  *gn;	  /* Node of member to touch */
{
    FILE *	  arch;	  /* Stream open to archive, positioned properly */
    struct ar_hdr arh;	  /* Current header describing member */

    arch = ArchFindMember(Var_Value (ARCHIVE, gn),
			  Var_Value (TARGET, gn),
			  &arh, "r+");
    sprintf(arh.ar_date, "%-12ld", (long) now);

    if (arch != (FILE *) NULL) {
	(void)fwrite ((char *)&arh, sizeof (struct ar_hdr), 1, arch);
	fclose (arch);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Arch_TouchLib --
 *	Given a node which represents a library, touch the thing, making
 *	sure that the table of contents also is touched.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	Both the modification time of the library and of the RANLIBMAG
 *	member are set to 'now'.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_TouchLib (gn)
    GNode	    *gn;      	/* The node of the library to touch */
{
    FILE *	    arch;	/* Stream open to archive */
    struct ar_hdr   arh;      	/* Header describing table of contents */
    struct timeval  times[2];	/* Times for utimes() call */

    arch = ArchFindMember (gn->path, RANLIBMAG, &arh, "r+");
    sprintf(arh.ar_date, "%-12ld", (long) now);

    if (arch != (FILE *) NULL) {
	(void)fwrite ((char *)&arh, sizeof (struct ar_hdr), 1, arch);
	fclose (arch);

	times[0].tv_sec = times[1].tv_sec = now;
	times[0].tv_usec = times[1].tv_usec = 0;
	utimes(gn->path, times);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Arch_MTime --
 *	Return the modification time of a member of an archive.
 *
 * Results:
 *	The modification time (seconds).
 *
 * Side Effects:
 *	The mtime field of the given node is filled in with the value
 *	returned by the function.
 *
 *-----------------------------------------------------------------------
 */
int
Arch_MTime (gn)
    GNode	  *gn;	      /* Node describing archive member */
{
    struct ar_hdr *arhPtr;    /* Header of desired member */
    int		  modTime;    /* Modification time as an integer */

    arhPtr = ArchStatMember (Var_Value (ARCHIVE, gn),
			     Var_Value (TARGET, gn),
			     TRUE);
    if (arhPtr != (struct ar_hdr *) NULL) {
	(void)sscanf (arhPtr->ar_date, "%12d", &modTime);
    } else {
	modTime = 0;
    }

    gn->mtime = modTime;
    return (modTime);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_MemMTime --
 *	Given a non-existent archive member's node, get its modification
 *	time from its archived form, if it exists.
 *
 * Results:
 *	The modification time.
 *
 * Side Effects:
 *	The mtime field is filled in.
 *
 *-----------------------------------------------------------------------
 */
int
Arch_MemMTime (gn)
    GNode   	  *gn;
{
    LstNode 	  ln;
    GNode   	  *pgn;
    char    	  *nameStart,
		  *nameEnd;

    if (Lst_Open (gn->parents) != SUCCESS) {
	gn->mtime = 0;
	return (0);
    }
    while ((ln = Lst_Next (gn->parents)) != NILLNODE) {
	pgn = (GNode *) Lst_Datum (ln);

	if (pgn->type & OP_ARCHV) {
	    /*
	     * If the parent is an archive specification and is being made
	     * and its member's name matches the name of the node we were
	     * given, record the modification time of the parent in the
	     * child. We keep searching its parents in case some other
	     * parent requires this child to exist...
	     */
	    nameStart = strchr (pgn->name, '(') + 1;
	    nameEnd = strchr (nameStart, ')');

	    if (pgn->make &&
		strncmp(nameStart, gn->name, nameEnd - nameStart) == 0) {
				     gn->mtime = Arch_MTime(pgn);
	    }
	} else if (pgn->make) {
	    /*
	     * Something which isn't a library depends on the existence of
	     * this target, so it needs to exist.
	     */
	    gn->mtime = 0;
	    break;
	}
    }

    Lst_Close (gn->parents);

    return (gn->mtime);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_FindLib --
 *	Search for a library along the given search path. 
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The node's 'path' field is set to the found path (including the
 *	actual file name, not -l...). If the system can handle the -L
 *	flag when linking (or we cannot find the library), we assume that
 *	the user has placed the .LIBRARIES variable in the final linking
 *	command (or the linker will know where to find it) and set the
 *	TARGET variable for this node to be the node's name. Otherwise,
 *	we set the TARGET variable to be the full path of the library,
 *	as returned by Dir_FindFile.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_FindLib (gn, path)
    GNode	    *gn;	      /* Node of library to find */
    Lst	    	    path;	      /* Search path */
{
    char	    *libName;   /* file name for archive */

    libName = (char *)emalloc (strlen (gn->name) + 6 - 2);
    sprintf(libName, "lib%s.a", &gn->name[2]);

    gn->path = Dir_FindFile (libName, path);

    free (libName);

#ifdef LIBRARIES
    Var_Set (TARGET, gn->name, gn);
#else
    Var_Set (TARGET, gn->path == (char *) NULL ? gn->name : gn->path, gn);
#endif LIBRARIES
}

/*-
 *-----------------------------------------------------------------------
 * Arch_LibOODate --
 *	Decide if a node with the OP_LIB attribute is out-of-date. Called
 *	from Make_OODate to make its life easier.
 *
 *	There are several ways for a library to be out-of-date that are
 *	not available to ordinary files. In addition, there are ways
 *	that are open to regular files that are not available to
 *	libraries. A library that is only used as a source is never
 *	considered out-of-date by itself. This does not preclude the
 *	library's modification time from making its parent be out-of-date.
 *	A library will be considered out-of-date for any of these reasons,
 *	given that it is a target on a dependency line somewhere:
 *	    Its modification time is less than that of one of its
 *	    	  sources (gn->mtime < gn->cmtime).
 *	    Its modification time is greater than the time at which the
 *	    	  make began (i.e. it's been modified in the course
 *	    	  of the make, probably by archiving).
 *	    Its modification time doesn't agree with the modification
 *	    	  time of its RANLIBMAG member (i.e. its table of contents
 *	    	  is out-of-date).
 *
 *
 * Results:
 *	TRUE if the library is out-of-date. FALSE otherwise.
 *
 * Side Effects:
 *	The library will be hashed if it hasn't been already.
 *
 *-----------------------------------------------------------------------
 */
Boolean
Arch_LibOODate (gn)
    GNode   	  *gn;  	/* The library's graph node */
{
    Boolean 	  oodate;
    
    if (OP_NOP(gn->type) && Lst_IsEmpty(gn->children)) {
	oodate = FALSE;
    } else if ((gn->mtime > now) || (gn->mtime < gn->cmtime)) {
	oodate = TRUE;
    } else {
	struct ar_hdr  	*arhPtr;    /* Header for __.SYMDEF */
	int 	  	modTimeTOC; /* The table-of-contents's mod time */

	arhPtr = ArchStatMember (gn->path, RANLIBMAG, FALSE);

	if (arhPtr != (struct ar_hdr *)NULL) {
	    (void)sscanf (arhPtr->ar_date, "%12d", &modTimeTOC);

	    if (DEBUG(ARCH) || DEBUG(MAKE)) {
		printf("%s modified %s...", RANLIBMAG, Targ_FmtTime(modTimeTOC));
	    }
	    oodate = (gn->mtime > modTimeTOC);
	} else {
	    /*
	     * A library w/o a table of contents is out-of-date
	     */
	    if (DEBUG(ARCH) || DEBUG(MAKE)) {
		printf("No t.o.c....");
	    }
	    oodate = TRUE;
	}
    }
    return (oodate);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_Init --
 *	Initialize things for this module.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The 'archives' list is initialized.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_Init ()
{
    archives = Lst_Init (FALSE);
}