diff options
Diffstat (limited to 'freebsd/sys/kern/subr_sbuf.c')
| -rw-r--r-- | freebsd/sys/kern/subr_sbuf.c | 159 |
1 files changed, 113 insertions, 46 deletions
diff --git a/freebsd/sys/kern/subr_sbuf.c b/freebsd/sys/kern/subr_sbuf.c index b51ed52c..42e6f8f0 100644 --- a/freebsd/sys/kern/subr_sbuf.c +++ b/freebsd/sys/kern/subr_sbuf.c @@ -58,11 +58,11 @@ __FBSDID("$FreeBSD$"); #ifdef _KERNEL static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers"); -#define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK|M_ZERO) +#define SBMALLOC(size, flags) malloc(size, M_SBUF, (flags) | M_ZERO) #define SBFREE(buf) free(buf, M_SBUF) #else /* _KERNEL */ #define KASSERT(e, m) -#define SBMALLOC(size) calloc(1, size) +#define SBMALLOC(size, flags) calloc(1, size) #define SBFREE(buf) free(buf) #endif /* _KERNEL */ @@ -72,6 +72,7 @@ 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) @@ -79,6 +80,8 @@ static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers"); #define SBUF_NULINCLUDED(s) ((s)->s_flags & SBUF_INCLUDENUL) #define SBUF_ISDRAINTOEOR(s) ((s)->s_flags & SBUF_DRAINTOEOR) #define SBUF_DODRAINTOEOR(s) (SBUF_ISSECTION(s) && SBUF_ISDRAINTOEOR(s)) +#define SBUF_MALLOCFLAG(s) \ + (((s)->s_flags & SBUF_NOWAIT) ? M_NOWAIT : M_WAITOK) /* * Set / clear flags @@ -173,7 +176,7 @@ sbuf_extend(struct sbuf *s, int addlen) if (!SBUF_CANEXTEND(s)) return (-1); newsize = sbuf_extendsize(s->s_size + addlen); - newbuf = SBMALLOC(newsize); + newbuf = SBMALLOC(newsize, SBUF_MALLOCFLAG(s)); if (newbuf == NULL) return (-1); memcpy(newbuf, s->s_buf, s->s_size); @@ -187,39 +190,6 @@ sbuf_extend(struct sbuf *s, int addlen) } /* - * Initialize the internals of an sbuf. - * If buf is non-NULL, it points to a static or already-allocated string - * big enough to hold at least length characters. - */ -static struct sbuf * -sbuf_newbuf(struct sbuf *s, char *buf, int length, int flags) -{ - - memset(s, 0, sizeof(*s)); - s->s_flags = flags; - s->s_size = length; - s->s_buf = buf; - - if ((s->s_flags & SBUF_AUTOEXTEND) == 0) { - KASSERT(s->s_size >= SBUF_MINSIZE, - ("attempt to create an sbuf smaller than %d bytes", - SBUF_MINSIZE)); - } - - if (s->s_buf != NULL) - return (s); - - if ((flags & SBUF_AUTOEXTEND) != 0) - s->s_size = sbuf_extendsize(s->s_size); - - s->s_buf = SBMALLOC(s->s_size); - if (s->s_buf == NULL) - return (NULL); - SBUF_SETFLAG(s, SBUF_DYNAMIC); - return (s); -} - -/* * Initialize an sbuf. * If buf is non-NULL, it points to a static or already-allocated string * big enough to hold at least length characters. @@ -232,19 +202,56 @@ sbuf_new(struct sbuf *s, char *buf, int length, int flags) ("attempt to create an sbuf of negative length (%d)", length)); KASSERT((flags & ~SBUF_USRFLAGMSK) == 0, ("%s called with invalid flags", __func__)); + KASSERT((flags & SBUF_AUTOEXTEND) || length >= SBUF_MINSIZE, + ("sbuf buffer %d smaller than minimum %d bytes", length, + SBUF_MINSIZE)); flags &= SBUF_USRFLAGMSK; - if (s != NULL) - return (sbuf_newbuf(s, buf, length, flags)); - s = SBMALLOC(sizeof(*s)); - if (s == NULL) - return (NULL); - if (sbuf_newbuf(s, buf, length, flags) == NULL) { - SBFREE(s); - return (NULL); + /* + * Allocate 'DYNSTRUCT' sbuf from the heap, if NULL 's' was provided. + */ + if (s == NULL) { + s = SBMALLOC(sizeof(*s), + (flags & SBUF_NOWAIT) ? M_NOWAIT : M_WAITOK); + if (s == NULL) + goto out; + SBUF_SETFLAG(s, SBUF_DYNSTRUCT); + } else { + /* + * DYNSTRUCT SBMALLOC sbufs are allocated with M_ZERO, but + * user-provided sbuf objects must be initialized. + */ + memset(s, 0, sizeof(*s)); + } + + 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 + * buffer was provided. + */ + if (s->s_buf == NULL) { + if (SBUF_CANEXTEND(s)) + s->s_size = sbuf_extendsize(s->s_size); + s->s_buf = SBMALLOC(s->s_size, SBUF_MALLOCFLAG(s)); + if (s->s_buf == NULL) + goto out; + SBUF_SETFLAG(s, SBUF_DYNAMIC); + } + +out: + if (s != NULL && s->s_buf == NULL) { + if (SBUF_ISDYNSTRUCT(s)) + SBFREE(s); + s = NULL; } - SBUF_SETFLAG(s, SBUF_DYNSTRUCT); return (s); } @@ -310,6 +317,8 @@ 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; @@ -344,6 +353,21 @@ sbuf_setpos(struct sbuf *s, ssize_t pos) } /* + * Drain into a counter. Counts amount of data without producing output. + * Useful for cases like sysctl, where user may first request only size. + * This allows to avoid pointless allocation/freeing of large buffers. + */ +int +sbuf_count_drain(void *arg, const char *data __unused, int len) +{ + size_t *sizep; + + sizep = (size_t *)arg; + *sizep += len; + return (len); +} + +/* * Set up a drain function and argument on an sbuf to flush data to * when the sbuf buffer overflows. */ @@ -369,6 +393,7 @@ 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, @@ -385,8 +410,18 @@ 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. @@ -702,6 +737,38 @@ 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 |