diff options
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/subr_sbuf.c | 52 |
1 files changed, 51 insertions, 1 deletions
diff --git a/sys/kern/subr_sbuf.c b/sys/kern/subr_sbuf.c index ebde3bee6405..17fde523fc67 100644 --- a/sys/kern/subr_sbuf.c +++ b/sys/kern/subr_sbuf.c @@ -70,6 +70,7 @@ static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers"); #define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC) #define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT) #define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED) +#define SBUF_ISDRAINATEOL(s) ((s)->s_flags & SBUF_DRAINATEOL) #define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1) #define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1)) #define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND) @@ -225,6 +226,10 @@ sbuf_new(struct sbuf *s, char *buf, int length, int flags) s->s_flags |= flags; s->s_size = length; s->s_buf = buf; + /* + * Never-written sbufs do not need \n termination. + */ + SBUF_SETFLAG(s, SBUF_DRAINATEOL); /* * Allocate DYNAMIC, i.e., heap data buffer backing the sbuf, if no @@ -310,6 +315,8 @@ sbuf_clear(struct sbuf *s) assert_sbuf_integrity(s); /* don't care if it's finished or not */ + KASSERT(s->s_drain_func == NULL, + ("%s makes no sense on sbuf %p with drain", __func__, s)); SBUF_CLEARFLAG(s, SBUF_FINISHED); s->s_error = 0; @@ -384,6 +391,7 @@ sbuf_drain(struct sbuf *s) KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s)); KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s)); + if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0) return (s->s_error = EDEADLK); len = s->s_drain_func(s->s_drain_arg, s->s_buf, @@ -400,8 +408,18 @@ sbuf_drain(struct sbuf *s) * Fast path for the expected case where all the data was * drained. */ - if (s->s_len == 0) + if (s->s_len == 0) { + /* + * When the s_buf is entirely drained, we need to remember if + * the last character was a '\n' or not for + * sbuf_nl_terminate(). + */ + if (s->s_buf[len - 1] == '\n') + SBUF_SETFLAG(s, SBUF_DRAINATEOL); + else + SBUF_CLEARFLAG(s, SBUF_DRAINATEOL); return (0); + } /* * Move the remaining characters to the beginning of the * string. @@ -717,6 +735,38 @@ sbuf_putc(struct sbuf *s, int c) } /* + * Append a trailing newline to a non-empty sbuf, if one is not already + * present. Handles sbufs with drain functions correctly. + */ +int +sbuf_nl_terminate(struct sbuf *s) +{ + + assert_sbuf_integrity(s); + assert_sbuf_state(s, 0); + + /* + * If the s_buf isn't empty, the last byte is simply s_buf[s_len - 1]. + * + * If the s_buf is empty because a drain function drained it, we + * remember if the last byte was a \n with the SBUF_DRAINATEOL flag in + * sbuf_drain(). + * + * In either case, we only append a \n if the previous character was + * something else. + */ + if (s->s_len == 0) { + if (!SBUF_ISDRAINATEOL(s)) + sbuf_put_byte(s, '\n'); + } else if (s->s_buf[s->s_len - 1] != '\n') + sbuf_put_byte(s, '\n'); + + if (s->s_error != 0) + return (-1); + return (0); +} + +/* * Trim whitespace characters from end of an sbuf. */ int |