mirror of
https://github.com/freebsd/freebsd-src
synced 2024-09-06 17:18:32 +00:00
Improve handling SIGURG and OOB commands on the control channel.
The major change is to process STAT sent as an OOB command w/o breaking the current data transfer. As a side effect, this gives better error checking in the code performing data transfers. A lesser, but in no way cosmetic, change is using the flag `recvurg' in the only signal-safe way that has been blessed by SUSv3. The other flag, `transflag,' becomes private to the SIGURG machinery, serves debugging purposes only, and may be dropped in the future. The `byte_count' global variable is now accounting bytes actually transferred over the network. This can give status messages looking strange, like "X of Y bytes transferred," where X > Y, but that has more sense than trying to compensate for combinations of data formats on the server and client when transferring ASCII type data. BTW, getting the size of a file in advance is unreliable for a number of reasons in the first place. See question 18.8 of the Infrequently Asked Questions in comp.lang.c for details. PR: bin/52072 Tested by: Nick Leuta (earlier versions), a stress-testing tool (final) MFC after: 1 month
This commit is contained in:
Yaroslav Tykhiy
parent
303793b564
commit
4cd51076c5
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=140472
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@ -147,8 +147,6 @@ int noguestretr = 0; /* RETR command is disabled for anon users. */
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int noguestmkd = 0; /* MKD command is disabled for anon users. */
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int noguestmod = 1; /* anon users may not modify existing files. */
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static volatile sig_atomic_t recvurg;
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sig_atomic_t transflag;
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off_t file_size;
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off_t byte_count;
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#if !defined(CMASK) || CMASK == 0
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@ -221,13 +219,34 @@ char proctitle[LINE_MAX]; /* initial part of title */
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#define LOGCMD2(cmd, file1, file2) logcmd((cmd), (file1), (file2), -1)
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#define LOGBYTES(cmd, file, cnt) logcmd((cmd), (file), NULL, (cnt))
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static volatile sig_atomic_t recvurg;
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static int transflag; /* NB: for debugging only */
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#define STARTXFER flagxfer(1)
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#define ENDXFER flagxfer(0)
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#define START_UNSAFE maskurg(1)
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#define END_UNSAFE maskurg(0)
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/* It's OK to put an `else' clause after this macro. */
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#define CHECKOOB(action) \
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if (recvurg) { \
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recvurg = 0; \
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if (myoob()) { \
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ENDXFER; \
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action; \
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} \
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}
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#ifdef VIRTUAL_HOSTING
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static void inithosts(void);
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static void selecthost(union sockunion *);
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#endif
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static void ack(char *);
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static void sigurg(int);
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static void myoob(void);
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static void maskurg(int);
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static void flagxfer(int);
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static int myoob(void);
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static int checkuser(char *, char *, int, char **);
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static FILE *dataconn(char *, off_t, char *);
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static void dolog(struct sockaddr *);
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@ -1981,6 +2000,30 @@ dataconn(char *name, off_t size, char *mode)
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return (file);
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}
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/*
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* A helper macro to avoid code duplication
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* in send_data() and receive_data().
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*
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* XXX We have to block SIGURG during putc() because BSD stdio
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* is unable to restart interrupted write operations and hence
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* the entire buffer contents will be lost as soon as a write()
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* call indicates EINTR to stdio.
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*/
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#define FTPD_PUTC(ch, file, label) \
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do { \
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int ret; \
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\
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do { \
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START_UNSAFE; \
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ret = putc((ch), (file)); \
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END_UNSAFE; \
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CHECKOOB(return (-1)) \
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else if (ferror(file)) \
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goto label; \
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clearerr(file); \
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} while (ret == EOF); \
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} while (0)
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/*
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* Tranfer the contents of "instr" to "outstr" peer using the appropriate
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* encapsulation of the data subject to Mode, Structure, and Type.
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@ -1992,33 +2035,50 @@ send_data(FILE *instr, FILE *outstr, size_t blksize, off_t filesize, int isreg)
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{
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int c, cp, filefd, netfd;
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char *buf;
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off_t cnt;
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transflag++;
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STARTXFER;
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switch (type) {
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case TYPE_A:
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cp = '\0';
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while ((c = getc(instr)) != EOF) {
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if (recvurg)
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goto got_oob;
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byte_count++;
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if (c == '\n' && cp != '\r') {
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if (ferror(outstr))
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goto data_err;
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(void) putc('\r', outstr);
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cp = EOF;
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for (;;) {
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c = getc(instr);
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CHECKOOB(return (-1))
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else if (c == EOF && ferror(instr))
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goto file_err;
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if (c == EOF) {
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if (ferror(instr)) { /* resume after OOB */
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clearerr(instr);
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continue;
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}
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if (feof(instr)) /* EOF */
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break;
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syslog(LOG_ERR, "Internal: impossible condition"
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" on file after getc()");
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goto file_err;
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}
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(void) putc(c, outstr);
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if (c == '\n' && cp != '\r') {
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FTPD_PUTC('\r', outstr, data_err);
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byte_count++;
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}
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FTPD_PUTC(c, outstr, data_err);
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byte_count++;
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cp = c;
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}
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if (recvurg)
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goto got_oob;
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fflush(outstr);
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transflag = 0;
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if (ferror(instr))
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goto file_err;
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if (ferror(outstr))
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#ifdef notyet /* BSD stdio isn't ready for that */
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while (fflush(outstr) == EOF) {
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CHECKOOB(return (-1))
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else
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goto data_err;
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clearerr(outstr);
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}
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ENDXFER;
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#else
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ENDXFER;
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if (fflush(outstr) == EOF)
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goto data_err;
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#endif
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reply(226, "Transfer complete.");
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return (0);
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@ -2033,7 +2093,7 @@ send_data(FILE *instr, FILE *outstr, size_t blksize, off_t filesize, int isreg)
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if (isreg) {
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char *msg = "Transfer complete.";
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off_t offset;
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off_t cnt, offset;
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int err;
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cnt = offset = 0;
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@ -2046,18 +2106,17 @@ send_data(FILE *instr, FILE *outstr, size_t blksize, off_t filesize, int isreg)
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* It can be used in myoob() later.
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*/
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byte_count += cnt;
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if (recvurg)
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goto got_oob;
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offset += cnt;
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filesize -= cnt;
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if (err == -1) {
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if (cnt == 0 && offset == 0)
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CHECKOOB(return (-1))
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else if (err == -1) {
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if (errno != EINTR &&
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cnt == 0 && offset == 0)
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goto oldway;
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goto data_err;
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}
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if (err == -1) /* resume after OOB */
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continue;
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/*
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* We hit the EOF prematurely.
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* Perhaps the file was externally truncated.
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@ -2068,52 +2127,65 @@ send_data(FILE *instr, FILE *outstr, size_t blksize, off_t filesize, int isreg)
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break;
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}
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}
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transflag = 0;
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ENDXFER;
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reply(226, msg);
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return (0);
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}
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oldway:
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if ((buf = malloc(blksize)) == NULL) {
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transflag = 0;
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ENDXFER;
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reply(451, "Ran out of memory.");
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return (-1);
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}
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while ((cnt = read(filefd, buf, blksize)) > 0 &&
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write(netfd, buf, cnt) == cnt)
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byte_count += cnt;
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transflag = 0;
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free(buf);
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if (cnt != 0) {
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if (cnt < 0)
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for (;;) {
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int cnt, len;
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char *bp;
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cnt = read(filefd, buf, blksize);
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CHECKOOB(free(buf); return (-1))
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else if (cnt < 0) {
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free(buf);
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goto file_err;
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goto data_err;
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}
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if (cnt < 0) /* resume after OOB */
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continue;
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if (cnt == 0) /* EOF */
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break;
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for (len = cnt, bp = buf; len > 0;) {
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cnt = write(netfd, bp, len);
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CHECKOOB(free(buf); return (-1))
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else if (cnt < 0) {
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free(buf);
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goto data_err;
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}
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if (cnt <= 0)
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continue;
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len -= cnt;
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bp += cnt;
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byte_count += cnt;
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}
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}
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ENDXFER;
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free(buf);
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reply(226, "Transfer complete.");
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return (0);
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default:
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transflag = 0;
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ENDXFER;
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reply(550, "Unimplemented TYPE %d in send_data.", type);
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return (-1);
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}
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data_err:
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transflag = 0;
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ENDXFER;
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perror_reply(426, "Data connection");
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return (-1);
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file_err:
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transflag = 0;
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ENDXFER;
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perror_reply(551, "Error on input file");
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return (-1);
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got_oob:
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myoob();
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recvurg = 0;
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transflag = 0;
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return (-1);
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}
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/*
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@ -2125,63 +2197,98 @@ send_data(FILE *instr, FILE *outstr, size_t blksize, off_t filesize, int isreg)
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static int
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receive_data(FILE *instr, FILE *outstr)
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{
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int c;
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int cnt, bare_lfs;
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char buf[BUFSIZ];
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int c, cp;
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int bare_lfs = 0;
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transflag++;
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bare_lfs = 0;
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STARTXFER;
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switch (type) {
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case TYPE_I:
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case TYPE_L:
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while ((cnt = read(fileno(instr), buf, sizeof(buf))) > 0) {
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if (recvurg)
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goto got_oob;
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if (write(fileno(outstr), buf, cnt) != cnt)
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goto file_err;
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byte_count += cnt;
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for (;;) {
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int cnt, len;
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char *bp;
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char buf[BUFSIZ];
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cnt = read(fileno(instr), buf, sizeof(buf));
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CHECKOOB(return (-1))
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else if (cnt < 0)
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goto data_err;
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if (cnt < 0) /* resume after OOB */
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continue;
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if (cnt == 0) /* EOF */
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break;
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for (len = cnt, bp = buf; len > 0;) {
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cnt = write(fileno(outstr), bp, len);
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CHECKOOB(return (-1))
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else if (cnt < 0)
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goto file_err;
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if (cnt <= 0)
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continue;
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len -= cnt;
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bp += cnt;
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byte_count += cnt;
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}
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}
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if (recvurg)
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goto got_oob;
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if (cnt < 0)
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goto data_err;
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transflag = 0;
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ENDXFER;
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return (0);
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case TYPE_E:
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ENDXFER;
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reply(553, "TYPE E not implemented.");
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transflag = 0;
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return (-1);
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case TYPE_A:
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while ((c = getc(instr)) != EOF) {
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if (recvurg)
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goto got_oob;
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byte_count++;
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if (c == '\n')
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bare_lfs++;
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while (c == '\r') {
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if (ferror(outstr))
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goto data_err;
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if ((c = getc(instr)) != '\n') {
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(void) putc ('\r', outstr);
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if (c == '\0' || c == EOF)
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goto contin2;
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}
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cp = EOF;
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for (;;) {
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c = getc(instr);
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CHECKOOB(return (-1))
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else if (c == EOF && ferror(instr))
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goto data_err;
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if (c == EOF && ferror(instr)) { /* resume after OOB */
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clearerr(instr);
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continue;
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}
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(void) putc(c, outstr);
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contin2: ;
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|
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if (cp == '\r') {
|
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if (c != '\n')
|
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FTPD_PUTC('\r', outstr, file_err);
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} else
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if (c == '\n')
|
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bare_lfs++;
|
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if (c == '\r') {
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byte_count++;
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cp = c;
|
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continue;
|
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}
|
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|
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/* Check for EOF here in order not to lose last \r. */
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if (c == EOF) {
|
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if (feof(instr)) /* EOF */
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break;
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syslog(LOG_ERR, "Internal: impossible condition"
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" on data stream after getc()");
|
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goto data_err;
|
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}
|
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|
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byte_count++;
|
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FTPD_PUTC(c, outstr, file_err);
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cp = c;
|
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}
|
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if (recvurg)
|
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goto got_oob;
|
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fflush(outstr);
|
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if (ferror(instr))
|
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goto data_err;
|
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if (ferror(outstr))
|
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#ifdef notyet /* BSD stdio isn't ready for that */
|
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while (fflush(outstr) == EOF) {
|
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CHECKOOB(return (-1))
|
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else
|
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goto file_err;
|
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clearerr(outstr);
|
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}
|
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ENDXFER;
|
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#else
|
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ENDXFER;
|
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if (fflush(outstr) == EOF)
|
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goto file_err;
|
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transflag = 0;
|
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#endif
|
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if (bare_lfs) {
|
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lreply(226,
|
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"WARNING! %d bare linefeeds received in ASCII mode.",
|
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|
|
@ -2190,26 +2297,20 @@ receive_data(FILE *instr, FILE *outstr)
|
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}
|
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return (0);
|
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default:
|
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ENDXFER;
|
||||
reply(550, "Unimplemented TYPE %d in receive_data.", type);
|
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transflag = 0;
|
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return (-1);
|
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}
|
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|
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data_err:
|
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transflag = 0;
|
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ENDXFER;
|
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perror_reply(426, "Data connection");
|
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return (-1);
|
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|
||||
file_err:
|
||||
transflag = 0;
|
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ENDXFER;
|
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perror_reply(452, "Error writing to file");
|
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return (-1);
|
||||
|
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got_oob:
|
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myoob();
|
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recvurg = 0;
|
||||
transflag = 0;
|
||||
return (-1);
|
||||
}
|
||||
|
||||
void
|
||||
|
|
@ -2625,11 +2726,6 @@ dolog(struct sockaddr *who)
|
|||
void
|
||||
dologout(int status)
|
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{
|
||||
/*
|
||||
* Prevent reception of SIGURG from resulting in a resumption
|
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* back to the main program loop.
|
||||
*/
|
||||
transflag = 0;
|
||||
|
||||
if (logged_in && dowtmp) {
|
||||
(void) seteuid(0);
|
||||
|
|
@ -2647,13 +2743,46 @@ sigurg(int signo)
|
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}
|
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|
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static void
|
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maskurg(int flag)
|
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{
|
||||
int oerrno;
|
||||
sigset_t sset;
|
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|
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if (!transflag) {
|
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syslog(LOG_ERR, "Internal: maskurg() while no transfer");
|
||||
return;
|
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}
|
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oerrno = errno;
|
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sigemptyset(&sset);
|
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sigaddset(&sset, SIGURG);
|
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sigprocmask(flag ? SIG_BLOCK : SIG_UNBLOCK, &sset, NULL);
|
||||
errno = oerrno;
|
||||
}
|
||||
|
||||
static void
|
||||
flagxfer(int flag)
|
||||
{
|
||||
|
||||
maskurg(!flag);
|
||||
if (flag) {
|
||||
recvurg = 0;
|
||||
transflag = 1;
|
||||
} else
|
||||
transflag = 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Returns 0 if OK to resume or -1 if abort requested.
|
||||
*/
|
||||
static int
|
||||
myoob(void)
|
||||
{
|
||||
char *cp;
|
||||
|
||||
/* only process if transfer occurring */
|
||||
if (!transflag)
|
||||
return;
|
||||
if (!transflag) {
|
||||
syslog(LOG_ERR, "Internal: myoob() while no transfer");
|
||||
return (0);
|
||||
}
|
||||
cp = tmpline;
|
||||
if (getline(cp, 7, stdin) == NULL) {
|
||||
reply(221, "You could at least say goodbye.");
|
||||
|
|
@ -2664,6 +2793,7 @@ myoob(void)
|
|||
tmpline[0] = '\0';
|
||||
reply(426, "Transfer aborted. Data connection closed.");
|
||||
reply(226, "Abort successful.");
|
||||
return (-1);
|
||||
}
|
||||
if (strcmp(cp, "STAT\r\n") == 0) {
|
||||
tmpline[0] = '\0';
|
||||
|
|
@ -2674,6 +2804,7 @@ myoob(void)
|
|||
reply(213, "Status: %jd bytes transferred.",
|
||||
(intmax_t)byte_count);
|
||||
}
|
||||
return (0);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -3016,17 +3147,10 @@ send_file_list(char *whichf)
|
|||
* used NLST, do what the user meant.
|
||||
*/
|
||||
if (dirname[0] == '-' && *dirlist == NULL &&
|
||||
transflag == 0) {
|
||||
dout == NULL)
|
||||
retrieve(_PATH_LS " %s", dirname);
|
||||
goto out;
|
||||
}
|
||||
perror_reply(550, whichf);
|
||||
if (dout != NULL) {
|
||||
(void) fclose(dout);
|
||||
transflag = 0;
|
||||
data = -1;
|
||||
pdata = -1;
|
||||
}
|
||||
else
|
||||
perror_reply(550, whichf);
|
||||
goto out;
|
||||
}
|
||||
|
||||
|
|
@ -3035,11 +3159,17 @@ send_file_list(char *whichf)
|
|||
dout = dataconn("file list", -1, "w");
|
||||
if (dout == NULL)
|
||||
goto out;
|
||||
transflag++;
|
||||
STARTXFER;
|
||||
}
|
||||
START_UNSAFE;
|
||||
fprintf(dout, "%s%s\n", dirname,
|
||||
type == TYPE_A ? "\r" : "");
|
||||
byte_count += strlen(dirname) + 1;
|
||||
END_UNSAFE;
|
||||
if (ferror(dout))
|
||||
goto data_err;
|
||||
byte_count += strlen(dirname) +
|
||||
(type == TYPE_A ? 2 : 1);
|
||||
CHECKOOB(goto abrt);
|
||||
continue;
|
||||
} else if (!S_ISDIR(st.st_mode))
|
||||
continue;
|
||||
|
|
@ -3050,12 +3180,7 @@ send_file_list(char *whichf)
|
|||
while ((dir = readdir(dirp)) != NULL) {
|
||||
char nbuf[MAXPATHLEN];
|
||||
|
||||
if (recvurg) {
|
||||
myoob();
|
||||
recvurg = 0;
|
||||
transflag = 0;
|
||||
goto out;
|
||||
}
|
||||
CHECKOOB(goto abrt);
|
||||
|
||||
if (dir->d_name[0] == '.' && dir->d_namlen == 1)
|
||||
continue;
|
||||
|
|
@ -3076,33 +3201,43 @@ send_file_list(char *whichf)
|
|||
dout = dataconn("file list", -1, "w");
|
||||
if (dout == NULL)
|
||||
goto out;
|
||||
transflag++;
|
||||
STARTXFER;
|
||||
}
|
||||
START_UNSAFE;
|
||||
if (nbuf[0] == '.' && nbuf[1] == '/')
|
||||
fprintf(dout, "%s%s\n", &nbuf[2],
|
||||
type == TYPE_A ? "\r" : "");
|
||||
else
|
||||
fprintf(dout, "%s%s\n", nbuf,
|
||||
type == TYPE_A ? "\r" : "");
|
||||
byte_count += strlen(nbuf) + 1;
|
||||
END_UNSAFE;
|
||||
if (ferror(dout))
|
||||
goto data_err;
|
||||
byte_count += strlen(nbuf) +
|
||||
(type == TYPE_A ? 2 : 1);
|
||||
CHECKOOB(goto abrt);
|
||||
}
|
||||
}
|
||||
(void) closedir(dirp);
|
||||
dirp = NULL;
|
||||
}
|
||||
|
||||
if (dout == NULL)
|
||||
reply(550, "No files found.");
|
||||
else if (ferror(dout) != 0)
|
||||
perror_reply(550, "Data connection");
|
||||
else if (ferror(dout))
|
||||
data_err: perror_reply(550, "Data connection");
|
||||
else
|
||||
reply(226, "Transfer complete.");
|
||||
|
||||
transflag = 0;
|
||||
if (dout != NULL)
|
||||
(void) fclose(dout);
|
||||
data = -1;
|
||||
pdata = -1;
|
||||
out:
|
||||
if (dout) {
|
||||
ENDXFER;
|
||||
abrt:
|
||||
(void) fclose(dout);
|
||||
data = -1;
|
||||
pdata = -1;
|
||||
}
|
||||
if (dirp)
|
||||
(void) closedir(dirp);
|
||||
if (freeglob) {
|
||||
freeglob = 0;
|
||||
globfree(&gl);
|
||||
|
|
|
|||
Loading…
Reference in a new issue