Assorted read_poll() and zpty cleanup.

5 files changed, 147 insertions, 74 deletions

diff --git a/ChangeLog b/ChangeLog
index 2a78b4056..6d8482b3c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2000-11-05  Bart Schaefer  <schaefer@zsh.org>
+
+	* 13120: Doc/Zsh/mod_zpty.yo, Functions/Misc/nslookup,
+	Src/utils.c, Src/Modules/zpty.c: Merge Sven's uncommitted patch
+	from 13061 with 13116.  WARNING: This reverses the meaning of
+	`zpty -b'; the default is now blocking, -b selects non-blocking.
+	Fix nslookup accordingly.  Clean up read_poll() somewhat.
+	Document that `zpty -w' and `zpty -r' can stream to/from the pty.
+
 2000-11-04  Bart Schaefer  <schaefer@zsh.org>
 
 	* 13118: Completion/Core/compinit: Add `bareglobqual' to the
diff --git a/Doc/Zsh/mod_zpty.yo b/Doc/Zsh/mod_zpty.yo
index 664e2fabd..e90b36d09 100644
--- a/Doc/Zsh/mod_zpty.yo
+++ b/Doc/Zsh/mod_zpty.yo
@@ -5,42 +5,73 @@ The tt(zsh/zpty) module offers one builtin:
 
 startitem()
 findex(zpty)
-xitem(tt(zpty) [ tt(-e) ] [ tt(-b) ] var(name) var(command) [ var(args ...) ])
-xitem(tt(zpty) tt(-d) [ var(names) ... ])
-xitem(tt(zpty) tt(-w) [ tt(-n) ] var(name) var(strings ...))
-xitem(tt(zpty) tt(-r) var(name) [ var(param) [ var(pattern) ] ])
-xitem(tt(zpty) tt(-t) var(name))
-item(tt(zpty) [ tt(-L) ])(
+item(tt(zpty) [ tt(-e) ] [ tt(-b) ] var(name) var(command) [ var(args ...) ])(
 In the first form, the var(command) is started with the var(args) as
 arguments.  The command runs under a newly assigned pseudo-terminal; this
 is useful for running commands non-interactively which expect an
-interactive environment.  The var(name) given is used to refer to this
-command in later calls to tt(pty).  With the tt(-e) option given, the
-pseudo-terminal will be set up so that input characters are echoed and 
-with the tt(-b) option given, input and output from and to the
-pseudo-terminal will be blocking.
-
-The second form with the tt(-d) option is used to delete commands
-previously started by supplying a list of their var(name)s.  If no
+interactive environment.  The var(name) is used to refer to this command
+in later calls to tt(zpty).
+
+With the tt(-e) option, the pseudo-terminal is set up so that input
+characters are echoed.
+
+With the tt(-b) option, input to and output from the pseudo-terminal are
+made non-blocking.
+)
+item(tt(zpty) tt(-d) [ var(names) ... ])(
+The second form, with the tt(-d) option, is used to delete commands
+previously started, by supplying a list of their var(name)s.  If no
 var(names) are given, all commands are deleted.  Deleting a command causes
 the HUP signal to be sent to the corresponding process.
-
-The tt(-w) option can be used to send the command var(name) the given
+)
+item(tt(zpty) tt(-w) [ tt(-n) ] var(name) [ var(strings ...) ])(
+The tt(-w) option can be used to send the to command var(name) the given
 var(strings) as input (separated by spaces).  If the tt(-n) option is
-not given, a newline will be added at the end.
+em(not) given, a newline is added at the end.
 
-The tt(-r) option can be used to read the output of the command
-var(name).  Without a var(param) argument, the string read will be
-printed to standard output.  With a var(param) argument, the string
-read will be put in the parameter named var(param).  If the
-var(pattern) is also given, output will be read until the whole string 
-read matches the var(pattern).
+If no var(strings) are provided, the standard input is copied to the
+pseudo-terminal; this may stop before copying the full input if the
+pseudo-terminal is non-blocking.
 
-The tt(-t) option can be used to test whether the command var(name) is 
-still running.  It returns a zero value if the command is running and
-a non-zero value otherwise.
+Note that the command under the pseudo-terminal sees this input as if it
+were typed, so beware when sending special tty driver characters such as
+word-erase, line-kill, and end-of-file.
+)
+item(tt(zpty) tt(-r) [ tt(-t) ] var(name) [ var(param) [ var(pattern) ] ])(
+The tt(-r) option can be used to read the output of the command var(name).
+With only a var(name) argument, the output read is copied to the standard
+output.  Unless the pseudo-terminal is non-blocking, copying continues
+until the command under the pseudo-terminal exits; when non-blocking, only
+as much output as is immediately available is copied.  The return value is
+zero if any output is copied.
 
-The last form without any arguments is used to list the commands
+When also given a var(param) argument, at most one line is read and stored
+in the parameter named var(param).  Less than a full line may be read if
+the pseudo-terminal is non-blocking.  The return value is zero if at least
+one character is stored in var(param).
+
+If a var(pattern) is given as well, output is read until the whole string
+read matches the var(pattern), even in the non-blocking case.  The return
+value is zero if the string read matches the pattern, or if the command
+has exited but at least one character could still be read.  As of this
+writing, a maximum of one megabyte of output can be consumed this way; if
+a full megabyte is read without matching the pattern, the return value is
+non-zero.
+
+In all cases, the return value is non-zero if nothing could be read, and
+is tt(2) if this is because the command has finished.
+
+If the tt(-r) option is combined with the tt(-t) option, tt(zpty) tests
+whether output is available before trying to read.  If no output is
+available, tt(zpty) immediately returns the value tt(1).
+)
+item(tt(zpty) tt(-t) var(name))(
+The tt(-t) option without the tt(-r) option can be used to test
+whether the command var(name) is still running.  It returns a zero
+value if the command is running and a non-zero value otherwise.
+)
+item(tt(zpty) [ tt(-L) ])(
+The last form, without any arguments, is used to list the commands
 currently defined.  If the tt(-L) option is given, this is done in the
 form of calls to the tt(zpty) builtin.
 )
diff --git a/Functions/Misc/nslookup b/Functions/Misc/nslookup
index 1751ef68a..d4f7e96b9 100644
--- a/Functions/Misc/nslookup
+++ b/Functions/Misc/nslookup
@@ -24,7 +24,7 @@ zstyle -s ':nslookup' pager tmp &&
     [[ -z "$pager" ]] && pager="${opager:-more}"
 (( $#pmpt )) || pmpt=(-p '> ')
 
-zpty -b nslookup nslookup "$@"
+zpty nslookup nslookup "$@"
 
 zpty -r nslookup line '*
 > '
diff --git a/Src/Modules/zpty.c b/Src/Modules/zpty.c
index b854fe8e3..463fbdf75 100644
--- a/Src/Modules/zpty.c
+++ b/Src/Modules/zpty.c
@@ -34,7 +34,6 @@
  * upper bound on the number of bytes we read (even if we are give a
  * pattern). */
 
-#define READ_LEN 1024
 #define READ_MAX (1024 * 1024)
 
 typedef struct ptycmd *Ptycmd;
@@ -46,9 +45,10 @@ struct ptycmd {
     int fd;
     int pid;
     int echo;
-    int block;
+    int nblock;
     int fin;
     int read;
+    char *old;
 };
 
 static Ptycmd ptycmds;
@@ -264,7 +264,7 @@ get_pty(int master, int *retfd)
 #endif /* __SVR4 */
 
 static int
-newptycmd(char *nam, char *pname, char **args, int echo, int block)
+newptycmd(char *nam, char *pname, char **args, int echo, int nblock)
 {
     Ptycmd p;
     int master, slave, pid;
@@ -380,14 +380,15 @@ newptycmd(char *nam, char *pname, char **args, int echo, int block)
     p->fd = master;
     p->pid = pid;
     p->echo = echo;
-    p->block = block;
+    p->nblock = nblock;
     p->fin = 0;
     p->read = -1;
+    p->old = NULL;
 
     p->next = ptycmds;
     ptycmds = p;
 
-    if (!block)
+    if (nblock)
 	ptynonblock(master);
 
     return 0;
@@ -411,12 +412,12 @@ deleteptycmd(Ptycmd cmd)
     zsfree(p->name);
     freearray(p->args);
 
+    zclose(cmd->fd);
+
     /* We kill the process group the command put itself in. */
 
     kill(-(p->pid), SIGHUP);
 
-    zclose(cmd->fd);
-
     zfree(p, sizeof(*p));
 }
 
@@ -438,7 +439,7 @@ checkptycmd(Ptycmd cmd)
 {
     if (cmd->read != -1)
 	return;
-    if (!read_poll(cmd->fd, &cmd->read, !cmd->block) &&
+    if (!read_poll(cmd->fd, &cmd->read, 0) &&
 	kill(cmd->pid, 0) < 0) {
 	cmd->fin = 1;
 	zclose(cmd->fd);
@@ -448,8 +449,8 @@ checkptycmd(Ptycmd cmd)
 static int
 ptyread(char *nam, Ptycmd cmd, char **args)
 {
-    int blen = 256, used = 0, seen = 0, ret = 1;
-    char *buf = (char *) zhalloc((blen = 256) + 1);
+    int blen, used, seen = 0, ret = 0;
+    char *buf;
     Patprog prog = NULL;
 
     if (*args && args[1]) {
@@ -469,10 +470,20 @@ ptyread(char *nam, Ptycmd cmd, char **args)
     } else
 	fflush(stdout);
 
+    if (cmd->old) {
+	used = strlen(cmd->old);
+	buf = (char *) zhalloc((blen = 256 + used) + 1);
+	strcpy(buf, cmd->old);
+	zsfree(cmd->old);
+	cmd->old = NULL;
+    } else {
+	used = 0;
+	buf = (char *) zhalloc((blen = 256) + 1);
+    }
     if (cmd->read != -1) {
-	buf[0] = (char) cmd->read;
-	buf[1] = '\0';
-	used = 1;
+	buf[used] = (char) cmd->read;
+	buf[used + 1] = '\0';
+	seen = used = 1;
 	cmd->read = -1;
     }
     do {
@@ -495,36 +506,60 @@ ptyread(char *nam, Ptycmd cmd, char **args)
 	}
 	buf[used] = '\0';
 
-	if (!prog && ret <= 0)
+	if (!prog && (ret <= 0 || (*args && buf[used - 1] == '\n')))
 	    break;
-    } while (!errflag && !breaks && !retflag && !contflag &&
-	     (prog ? (used < READ_MAX && (!ret || !pattry(prog, buf))) :
-	      (used < READ_LEN)));
+    } while (!(errflag || breaks || retflag || contflag) &&
+	     used < READ_MAX && !(prog && ret && pattry(prog, buf)));
+
+    if (prog && ret < 0 &&
+#ifdef EWOULDBLOCK
+	errno == EWOULDBLOCK
+#else
+#ifdef EAGAIN
+	errno == EAGAIN
+#endif
+#endif
+	) {
+	cmd->old = ztrdup(buf);
+	used = 0;
 
+	return 1;
+    }
     if (*args)
 	setsparam(*args, ztrdup(metafy(buf, used, META_HREALLOC)));
-    else
+    else if (used)
 	write(1, buf, used);
 
-    return !seen;
+    return (seen ? 0 : cmd->fin + 1);
 }
 
 static int
 ptywritestr(Ptycmd cmd, char *s, int len)
 {
-    int written;
+    int written, all = 0;
 
-    for (; len; len -= written, s += written) {
-	if ((written = write(cmd->fd, s, len)) < 0)
-	    return 1;
+    for (; !errflag && !breaks && !retflag && !contflag && len;
+	 len -= written, s += written) {
+	if ((written = write(cmd->fd, s, len)) < 0 && cmd->nblock &&
+#ifdef EWOULDBLOCK
+	    errno == EWOULDBLOCK
+#else
+#ifdef EAGAIN
+	    errno == EAGAIN
+#endif
+#endif
+	    )
+	    return !all;
 	if (written < 0) {
 	    checkptycmd(cmd);
 	    if (cmd->fin)
 		break;
 	    written = 0;
 	}
+	if (written > 0)
+	    all += written;
     }
-    return 0;
+    return (all ? 0 : cmd->fin + 1);
 }
 
 static int
@@ -559,8 +594,9 @@ static int
 bin_zpty(char *nam, char **args, char *ops, int func)
 {
     if ((ops['r'] && ops['w']) ||
-	((ops['r'] || ops['w']) && (ops['d'] || ops['e'] || ops['t'] ||
+	((ops['r'] || ops['w']) && (ops['d'] || ops['e'] ||
 				    ops['b'] || ops['L'])) ||
+	(ops['w'] && ops['t']) ||
 	(ops['n'] && (ops['b'] || ops['e'] || ops['r'] || ops['t'] ||
 		      ops['d'] || ops['L'])) ||
 	(ops['d'] && (ops['b'] || ops['e'] || ops['L'] || ops['t'])) ||
@@ -579,7 +615,10 @@ bin_zpty(char *nam, char **args, char *ops, int func)
 	    return 1;
 	}
 	if (p->fin)
+	    return 2;
+	if (ops['t'] && p->read == -1 && !read_poll(p->fd, &p->read, 0))
 	    return 1;
+
 	return (ops['r'] ?
 		ptyread(nam, p, args + 1) :
 		ptywrite(p, args + 1, ops['n']));
@@ -629,7 +668,7 @@ bin_zpty(char *nam, char **args, char *ops, int func)
 	    checkptycmd(p);
 	    if (ops['L'])
 		printf("%s %s%s%s ", nam, (p->echo ? "-e " : ""),
-		       (p->block ? "-b " : ""), p->name);
+		       (p->nblock ? "-b " : ""), p->name);
 	    else if (p->fin)
 		printf("(finished) %s: ", p->name);
 	    else
diff --git a/Src/utils.c b/Src/utils.c
index 05865cf67..1190347f7 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -1315,7 +1315,7 @@ setblock_stdin(void)
 mod_export int
 read_poll(int fd, int *readchar, int polltty)
 {
-    int ret = 0;
+    int ret = -1;
     long mode = -1;
     char c;
 #ifdef HAVE_SELECT
@@ -1353,38 +1353,32 @@ read_poll(int fd, int *readchar, int polltty)
      */
     if (polltty) {
 	gettyinfo(&ti);
-	ti.tio.c_cc[VMIN] = 0;
-	settyinfo(&ti);
+	if ((polltty = ti.tio.c_cc[VMIN])) {
+	    ti.tio.c_cc[VMIN] = 0;
+	    settyinfo(&ti);
+	}
     }
 #else
     polltty = 0;
 #endif
 #ifdef HAVE_SELECT
-    if (!ret) {
-	expire_tv.tv_sec = expire_tv.tv_usec = 0;
-	FD_ZERO(&foofd);
-	FD_SET(fd, &foofd);
-	if (select(fd+1, (SELECT_ARG_2_T) &foofd, NULL, NULL, &expire_tv)
-	    > 1)
-	    ret = 1;
-    }
+    expire_tv.tv_sec = expire_tv.tv_usec = 0;
+    FD_ZERO(&foofd);
+    FD_SET(fd, &foofd);
+    ret = select(fd+1, (SELECT_ARG_2_T) &foofd, NULL, NULL, &expire_tv);
 #else
 #ifdef FIONREAD
-    if (!ret) {
-	ioctl(fd, FIONREAD, (char *)&val);
-	if (val)
-	    ret = 1;
-    }
+    if (ioctl(fd, FIONREAD, (char *) &val) == 0)
+	ret = (val > 0);
 #endif
 #endif
 
-    if (!ret) {
+    if (ret <= 0) {
 	/*
 	 * Final attempt: set non-blocking read and try to read a character.
 	 * Praise Bill, this works under Cygwin (nothing else seems to).
 	 */
-	if ((polltty || setblock_fd(0, fd, &mode))
-	    && read(fd, &c, 1) > 0) {
+	if ((polltty || setblock_fd(0, fd, &mode)) && read(fd, &c, 1) > 0) {
 	    *readchar = STOUC(c);
 	    ret = 1;
 	}
@@ -1397,7 +1391,7 @@ read_poll(int fd, int *readchar, int polltty)
 	settyinfo(&ti);
     }
 #endif
-    return ret;
+    return (ret > 0);
 }
 
 /**/