/* Distributed Checksum Clearinghouse
 *
 * Copyright (c) 2005 by Rhyolite Software
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND RHYOLITE SOFTWARE DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL RHYOLITE SOFTWARE
 * BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 *
 * Rhyolite Software DCC 1.2.74-1.23 $Revision$
 */

#include "dcc_defs.h"
#ifdef DCC_WIN32
#include <direct.h>
#define MKDIR(nm,perm) mkdir(nm)
#else
#include <dirent.h>
#define MKDIR(nm,perm) mkdir(nm,perm)
#endif

static u_int32_t gen;


static char *
mkstr(char str[DCC_MKSTEMP_LEN+1])
{
	static const char digits[] = "0123456789"
				    "abcdefghijklmnopqrstuvwxyz"
				    "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	u_int32_t n;
	int i;

	i = DCC_MKSTEMP_LEN;
	str[i] = '\0';
	n = ++gen;
	do {
		str[--i] = digits[n % (sizeof(digits)-1)];
		n /= (sizeof(digits)-1);
	} while (i > 0);
	return str;
}



#define MKSEQ() (gen += (getpid() << 16) + time(0))



/* Some platforms have broken implementations of mkstemp() that generate
 * only 32 different names.
 * Given the main uses for mkstemp() in the DCC for log files in directories
 * used only by the DCC, it is nice to try to make the names sort of
 * sequential for a given dccm process.  That means nothing more than putting
 * the random bits in the most significant bits of the seed and using
 * a small constant for the addition in the random number
 * generator that is commonly used, and remembering the generator. */
int					/* -1 or FD of temporary file */
dcc_mkstemp(DCC_EMSG emsg,
	    char *nm, int nm_len,	/* put the name here */
	    const char *p1,		/* concatenate these strings */
	    const char *p2,		/*	to generate the name */
	    u_char close_del,		/* 1=delete on close */
	    int gen_delta,		/* adjust generator by this */
	    int mode)			/* add these mode bits */
{
	char str[DCC_MKSTEMP_LEN+1];
	int fd, i;
#ifdef DCC_WIN32
	HANDLE h;
	DWORD flags;
#endif

	if (!gen) {
		MKSEQ();
	} else {
		gen += gen_delta;
	}

	/* this loop should almost always need only a single pass */
	for (;;) {
		i = snprintf(nm, nm_len, "%s%s%s",
			     p1 ? p1 : "", p2 ? p2 : "", mkstr(str));
		if (i >= nm_len) {
			dcc_pemsg(EX_SOFTWARE, emsg,
				  "temporary file name \"%s\" too big", nm);
			return -1;
		}

#ifdef DCC_WIN32
		/* Given the uses of this function, if the temporary
		 * file is open, then it has been abandoned.  All valid
		 * uses have the file renamed.  Windows does not allow
		 * open files to be unlinked.  FILE_FLAGS_DELETE_ON_CLOSE
		 * does not seem to be supported everywhere or it is
		 * unreliable.  So open existing files without sharing
		 * but truncated.
		 * Use CreateFile() because the Borland and Microsoft
		 * open(), _open(), and _sopen() functions differ */
		flags = (close_del
			 ? FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE
			 : FILE_ATTRIBUTE_NORMAL);
		h = CreateFile(nm, GENERIC_READ | GENERIC_WRITE, 0,
			       0, CREATE_NEW, flags, 0);
		if (h == INVALID_HANDLE_VALUE)
			h = CreateFile(nm, GENERIC_READ | GENERIC_WRITE, 0,
				       0, TRUNCATE_EXISTING, flags, 0);
		if (h != INVALID_HANDLE_VALUE) {
			fd = _open_osfhandle((long)h, 0);
			if (fd >= 0)
				return fd;
			dcc_pemsg(EX_SOFTWARE, emsg,
				  "_open_osfhandle(%s): %s",
				  nm, ERROR_STR());
			CloseHandle(h);
			return -1;
		}
#else
		fd = open(nm, O_RDWR | O_CREAT | O_EXCL, (mode & 0777) | 0600);
		if (fd >= 0) {
			if (close_del
			    && 0 > unlink(nm)) {
				dcc_pemsg(EX_SOFTWARE, emsg, "unlink(%s): %s",
					  nm, ERROR_STR());
				close(fd);
				return -1;
			}
			return fd;
		}
#endif

		if (errno != EEXIST) {
			dcc_pemsg(EX_IOERR, emsg, "open(%s): %s",
				  nm, ERROR_STR());
			return -1;
		}

		/* there is already a file of that name,
		 * so look for another sequence of names */
		MKSEQ();
	}
}


static enum {
	LOG_FLAT,			/* use logdir/ */
	LOG_DAY,			/* use logdir/ddd/ */
	LOG_HOUR,			/* use logdir/ddd/hh/ */
	LOG_MIN				/* use logdir/ddd/hh/mm/ */
} log_mode;

DCC_PATH dcc_logdir;
static DCC_PATH log_daydir_pat;
static DCC_PATH log_hourdir_pat;
static DCC_PATH log_mindir_pat;
static int dcc_logdir_len;		/* strlen(dcc_logdir)+subdirectory */
char dcc_have_logdir;			/* create log files here */



int					/* 1=ok, 0=non-existent, -1=bad */
dcc_logdir_ck(DCC_EMSG emsg,
	      const char *dir,		/* check this name */
	      int *modep)		/* put file mode bits here */
{
	struct stat sb;

	if (0 > stat(dir, &sb)) {
		if (errno == ENOTDIR || errno == ENOENT) {
			dcc_pemsg(EX_IOERR, emsg, "stat(log directory %s): %s",
				  DCC_NM2PATH(dir), ERROR_STR());
			return 0;
		} else {
			dcc_pemsg(EX_IOERR, emsg, "stat(log directory %s): %s",
				  DCC_NM2PATH(dir), ERROR_STR());
			return -1;
		}
	}

	if (!S_ISDIR(sb.st_mode)) {
		dcc_pemsg(EX_IOERR, emsg, "log directory %s is %s",
			  DCC_NM2PATH(dir), ERROR_STR1(ENOTDIR));
		return -1;
	}

#ifndef DCC_WIN32
	if (0 > access(dir, R_OK|W_OK|X_OK)) {
		dcc_pemsg(EX_IOERR, emsg, "access(log directory %s): %s",
			  DCC_NM2PATH(dir), ERROR_STR());
		return -1;
	}
#endif

	if (modep)
		*modep = sb.st_mode & 0666;
	return 1;
}



/* check and initialize main DCC client log directory */
u_char
dcc_log_init(DCC_EMSG emsg, const char *arg)
{
	/* if the directory name starts with "D?", "H?", or "M?",
	 * automatically add subdirectories */
	if (!CSTRCMP(arg, "D?")) {
		log_mode = LOG_DAY;
		dcc_logdir_len = 4;
		arg += 2;

	} else if (!CSTRCMP(arg, "H?")) {
		log_mode = LOG_HOUR;
		dcc_logdir_len = 4+3;
		arg += 2;

	} else if (!CSTRCMP(arg, "M?")) {
		log_mode = LOG_MIN;
		dcc_logdir_len = 4+3+3;
		arg += 2;

	} else {
		log_mode = LOG_FLAT;
		dcc_logdir_len = 0;
	}

	dcc_logdir_len += strlen(arg);
	snprintf(dcc_logdir, sizeof(dcc_logdir), "%s", arg);
	snprintf(log_daydir_pat, sizeof(log_daydir_pat), "%s/%%j", arg);
	snprintf(log_hourdir_pat, sizeof(log_hourdir_pat), "%s/%%j/%%H", arg);
	snprintf(log_mindir_pat, sizeof(log_mindir_pat), "%s/%%j/%%H/%%M", arg);

	if (dcc_logdir_ck(emsg, dcc_logdir, 0) <= 0) {
		dcc_logdir_len = 0;
		dcc_have_logdir = 0;
		return 0;
	}

	dcc_have_logdir = 1;
	return 1;
}



/* create and open a DCC client log file */
int
dcc_log_open(DCC_EMSG emsg,
	     char *nm, int nm_len)	/* put the name here */
{
	time_t now;
	struct tm tm;
	DCC_PATH dir;
	const char *p1;

	if (nm_len < dcc_logdir_len + DCC_MKSTEMP_LEN + 1) {
		dcc_pemsg(EX_SOFTWARE, emsg,
			  "directory path buffer too small");
		return -1;
	}


	if (log_mode == LOG_FLAT) {
		p1 = dcc_logdir;
	} else {
		now = time(0);
		strftime(dir, sizeof(dir), log_daydir_pat,
			 dcc_localtime(now, &tm));
		MKDIR(dir, 0755);

		if (log_mode == LOG_HOUR
		    || log_mode == LOG_MIN) {
			strftime(dir, sizeof(dir), log_hourdir_pat, &tm);
			MKDIR(dir, 0755);
			if (log_mode == LOG_MIN) {
				strftime(dir, sizeof(dir), log_mindir_pat, &tm);
				MKDIR(dir, 0755);
			}
		}
		p1 = dir;
	}

	return dcc_mkstemp(emsg, nm, nm_len, p1, DCC_TMP_LOG_PAT, 0, 0, 0);
}



/* rename a DCC client log file to a unique name */
u_char
dcc_log_keep(DCC_EMSG emsg, char *cur_nm, int cur_nm_len)
{
	DCC_PATH new_nm;
	char str[DCC_MKSTEMP_LEN+1];

	if (cur_nm_len <= (dcc_logdir_len
			   + ISZ(DCC_FIN_LOG_PAT) + DCC_MKSTEMP_LEN)
	    || cur_nm_len <= (dcc_logdir_len
			      + ISZ(DCC_TMP_LOG_PAT) + DCC_MKSTEMP_LEN)) {
		dcc_pemsg(EX_SOFTWARE, emsg,
			  "dcc_log_keep(): target path buffer too small");
		return 0;
	}
	memcpy(new_nm, cur_nm, dcc_logdir_len);
	memcpy(new_nm+dcc_logdir_len, DCC_FIN_LOG_PAT,
	       sizeof(DCC_FIN_LOG_PAT)-1);
	strcpy(new_nm+dcc_logdir_len+sizeof(DCC_FIN_LOG_PAT)-1,
	       cur_nm+dcc_logdir_len+sizeof(DCC_TMP_LOG_PAT)-1);

	for (;;) {
#ifdef DCC_WIN32
		/* Windows does not have hard links */
		if (!rename(cur_nm, new_nm)) {
			strncpy(cur_nm, new_nm, cur_nm_len);
			return 1;
		}
		if (errno != EACCES) {
			dcc_pemsg(EX_IOERR, emsg, "rename(%s,%s): %s",
				  DCC_NM2PATH(cur_nm), new_nm, ERROR_STR());
			return 0;
		}
#else
		/* rename() on some UNIX systems deletes existing new_nm */
		if (link(cur_nm, new_nm) >= 0) {
			if (unlink(cur_nm) < 0) {
				strncpy(cur_nm, new_nm, cur_nm_len);
				dcc_pemsg(EX_IOERR, emsg, "unlink(%s): %s",
					  DCC_NM2PATH(cur_nm), ERROR_STR());
				return 0;
			}
			strncpy(cur_nm, new_nm, cur_nm_len);
			return 1;
		}
		if (errno != EEXIST) {
			dcc_pemsg(EX_IOERR, emsg, "link(%s,%s): %s",
				  DCC_NM2PATH(cur_nm), new_nm, ERROR_STR());
			return 0;
		}
#endif

		/* if our name was taken,
		 * look for another sequence of names */
		MKSEQ();
		strcpy(new_nm+dcc_logdir_len+sizeof(DCC_FIN_LOG_PAT)-1,
		       mkstr(str));
	}
}