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Fix client's command abort feature

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The server aborts the current command when it receives a special line
of input for a prompt.  To make the client send it, you type the INTR
character (normally ^C).  This sends the client the SIGINT signal.
Unfortunately, it never quite worked.

Because we use a special line of input to signal interrupt, the client
can do that only after a complete line of input.

What if SIGINT arrives in the middle of a line?  We split the line in
two then and there, by inserting a newline.  Nasty, but it's simple,
and happens rarely.

However, we inserted the newline always, even after a complete line.
In that case, we inserted an empty line of input before the interrupt.
If you hit INTR at a server prompt, the server received an empty line
of input for that prompt, and the interrupt only for the *next*
prompt.  Which may well be too late to abort the command you wanted to
abort.

Fix by inserting the newline only when needed.
This commit is contained in:
Markus Armbruster 2010-04-02 18:22:52 +02:00
parent 6c639f1481
commit 3cceb59bb1
1 changed files with 10 additions and 5 deletions
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15
src/client/play.c
View file

@ -302,7 +302,7 @@ w32_ring_from_file_or_bounce_buf(struct ring *r, int fd)
#endif
#define EOF_COOKIE "ctld\n"
#define INTR_COOKIE "\naborted\n"
#define INTR_COOKIE "aborted\n"
int input_fd;
int send_eof; /* need to send EOF_COOKIE */
@ -465,6 +465,7 @@ play(int sock)
struct sigaction sa;
struct ring inbuf; /* input buffer, draining to SOCK */
int eof_fd0; /* read fd 0 hit EOF? */
int input_eol; /* input ends with '\n'? */
fd_set rdfd, wrfd;
int n;
@ -476,7 +477,7 @@ play(int sock)
sigaction(SIGPIPE, &sa, NULL);
ring_init(&inbuf);
eof_fd0 = send_eof = send_intr = 0;
eof_fd0 = input_eol = send_eof = send_intr = 0;
input_fd = 0;
sysdep_stdin_init();
@ -505,10 +506,13 @@ play(int sock)
}
}
if (send_eof
if ((send_eof || send_intr) && !input_eol
&& ring_putc(&inbuf, '\n') != EOF)
input_eol = 1;
if (send_eof && input_eol
&& ring_putm(&inbuf, EOF_COOKIE, sizeof(EOF_COOKIE) - 1) >= 0)
send_eof--;
if (send_intr
if (send_intr && input_eol
&& ring_putm(&inbuf, INTR_COOKIE, sizeof(INTR_COOKIE) - 1) >= 0) {
send_intr = 0;
if (input_fd) {
@ -542,7 +546,8 @@ play(int sock)
sa.sa_handler = SIG_DFL;
sigaction(SIGINT, &sa, NULL);
}
}
} else
input_eol = ring_peek(&inbuf, -1) == '\n';
}
/* send it to the server */