diff options
Diffstat (limited to 'common/iobuf.c')
| -rw-r--r-- | common/iobuf.c | 295 |
1 files changed, 150 insertions, 145 deletions
diff --git a/common/iobuf.c b/common/iobuf.c index 770b67c29..8a128b3f6 100644 --- a/common/iobuf.c +++ b/common/iobuf.c @@ -1720,49 +1720,49 @@ iobuf_push_filter2 (iobuf_t a, } /* We want to create a new filter and put it in front of A. A - simple implementation would do: - - b = iobuf_alloc (...); - b->chain = a; - return a; - - This is a bit problematic: A is the head of the pipeline and - there are potentially many pointers to it. Requiring the caller - to update all of these pointers is a burden. - - An alternative implementation would add a level of indirection. - For instance, we could use a pipeline object, which contains a - pointer to the first filter in the pipeline. This is not what we - do either. - - Instead, we allocate a new buffer (B) and copy the first filter's - state into that and use the initial buffer (A) for the new - filter. One limitation of this approach is that it is not - practical to maintain a pointer to a specific filter's state. - - Before: - - A - | - v 0x100 0x200 - +----------+ +----------+ - | filter x |--------->| filter y |---->.... - +----------+ +----------+ - - After: B - | - v 0x300 - +----------+ - A | filter x | - | +----------+ - v 0x100 ^ v 0x200 - +----------+ +----------+ - | filter w | | filter y |---->.... - +----------+ +----------+ - - Note: filter x's address changed from 0x100 to 0x300, but A still - points to the head of the pipeline. - */ + * simple implementation would do: + * + * b = iobuf_alloc (...); + * b->chain = a; + * return a; + * + * This is a bit problematic: A is the head of the pipeline and + * there are potentially many pointers to it. Requiring the caller + * to update all of these pointers is a burden. + * + * An alternative implementation would add a level of indirection. + * For instance, we could use a pipeline object, which contains a + * pointer to the first filter in the pipeline. This is not what we + * do either. + * + * Instead, we allocate a new buffer (B) and copy the first filter's + * state into that and use the initial buffer (A) for the new + * filter. One limitation of this approach is that it is not + * practical to maintain a pointer to a specific filter's state. + * + * Before: + * + * A + * | + * v 0x100 0x200 + * +----------+ +----------+ + * | filter x |--------->| filter y |---->.... + * +----------+ +----------+ + * + * After: B + * | + * v 0x300 + * +----------+ + * A | filter x | + * | +----------+ + * v 0x100 ^ v 0x200 + * +----------+ +----------+ + * | filter w | | filter y |---->.... + * +----------+ +----------+ + * + * Note: filter x's address changed from 0x100 to 0x300, but A still + * points to the head of the pipeline. + */ b = xmalloc (sizeof *b); memcpy (b, a, sizeof *b); @@ -1776,51 +1776,51 @@ iobuf_push_filter2 (iobuf_t a, a->filter_ov_owner = 0; a->filter_eof = 0; if (a->use == IOBUF_OUTPUT_TEMP) - /* A TEMP filter buffers any data sent to it; it does not forward - any data down the pipeline. If we add a new filter to the - pipeline, it shouldn't also buffer data. It should send it - downstream to be buffered. Thus, the correct type for a filter - added in front of an IOBUF_OUTPUT_TEMP filter is IOBUF_OUPUT, not - IOBUF_OUTPUT_TEMP. */ { + /* A TEMP filter buffers any data sent to it; it does not + * forward any data down the pipeline. If we add a new filter + * to the pipeline, it shouldn't also buffer data. It should + * send it downstream to be buffered. Thus, the correct type + * for a filter added in front of an IOBUF_OUTPUT_TEMP filter is + * IOBUF_OUPUT, not IOBUF_OUTPUT_TEMP. */ a->use = IOBUF_OUTPUT; /* When pipeline is written to, the temp buffer's size is - increased accordingly. We don't need to allocate a 10 MB - buffer for a non-terminal filter. Just use the default - size. */ + * increased accordingly. We don't need to allocate a 10 MB + * buffer for a non-terminal filter. Just use the default + * size. */ a->d.size = iobuf_buffer_size; } else if (a->use == IOBUF_INPUT_TEMP) - /* Same idea as above. */ { + /* Same idea as above. */ a->use = IOBUF_INPUT; a->d.size = iobuf_buffer_size; } /* The new filter (A) gets a new buffer. - - If the pipeline is an output or temp pipeline, then giving the - buffer to the new filter means that data that was written before - the filter was pushed gets sent to the filter. That's clearly - wrong. - - If the pipeline is an input pipeline, then giving the buffer to - the new filter (A) means that data that has read from (B), but - not yet read from the pipeline won't be processed by the new - filter (A)! That's certainly not what we want. */ + * + * If the pipeline is an output or temp pipeline, then giving the + * buffer to the new filter means that data that was written before + * the filter was pushed gets sent to the filter. That's clearly + * wrong. + * + * If the pipeline is an input pipeline, then giving the buffer to + * the new filter (A) means that data that has read from (B), but + * not yet read from the pipeline won't be processed by the new + * filter (A)! That's certainly not what we want. */ a->d.buf = xmalloc (a->d.size); a->d.len = 0; a->d.start = 0; - /* disable nlimit for the new stream */ + /* Disable nlimit for the new stream. */ a->ntotal = b->ntotal + b->nbytes; a->nlimit = a->nbytes = 0; a->nofast = 0; - /* make a link from the new stream to the original stream */ + /* Make a link from the new stream to the original stream. */ a->chain = b; - /* setup the function on the new stream */ + /* Setup the function on the new stream. */ a->filter = f; a->filter_ov = ov; a->filter_ov_owner = rel_ov; @@ -1835,13 +1835,14 @@ iobuf_push_filter2 (iobuf_t a, print_chain (a); } - /* now we can initialize the new function if we have one */ + /* Now we can initialize the new function if we have one. */ if (a->filter && (rc = a->filter (a->filter_ov, IOBUFCTRL_INIT, a->chain, NULL, &dummy_len))) log_error ("IOBUFCTRL_INIT failed: %s\n", gpg_strerror (rc)); return rc; } + /**************** * Remove an i/o filter. */ @@ -1865,7 +1866,7 @@ iobuf_pop_filter (iobuf_t a, int (*f) (void *opaque, int control, return 0; } if (!a->filter) - { /* this is simple */ + { /* (this is simple) */ b = a->chain; log_assert (b); xfree (a->d.buf); @@ -1880,14 +1881,14 @@ iobuf_pop_filter (iobuf_t a, int (*f) (void *opaque, int control, if (!b) log_bug ("iobuf_pop_filter(): filter function not found\n"); - /* flush this stream if it is an output stream */ + /* Flush this stream if it is an output stream ... */ if (a->use == IOBUF_OUTPUT && (rc = filter_flush (b))) { log_error ("filter_flush failed in iobuf_pop_filter: %s\n", gpg_strerror (rc)); return rc; } - /* and tell the filter to free it self */ + /* and tell the filter to free it self */ if (b->filter && (rc = b->filter (b->filter_ov, IOBUFCTRL_FREE, b->chain, NULL, &dummy_len))) { @@ -1905,10 +1906,9 @@ iobuf_pop_filter (iobuf_t a, int (*f) (void *opaque, int control, if (a == b && !b->chain) log_bug ("can't remove the last filter from the chain\n"); else if (a == b) - { /* remove the first iobuf from the chain */ - /* everything from b is copied to a. This is save because - * a flush has been done on the to be removed entry - */ + { /* Remove the first iobuf from the chain. + * Everything from B is copied to A. This is save because + * a flush has been done on the to be removed entry. */ b = a->chain; xfree (a->d.buf); xfree (a->real_fname); @@ -1918,11 +1918,11 @@ iobuf_pop_filter (iobuf_t a, int (*f) (void *opaque, int control, log_debug ("iobuf-%d.%d: popped filter\n", a->no, a->subno); } else if (!b->chain) - { /* remove the last iobuf from the chain */ + { /* Remove the last iobuf from the chain. */ log_bug ("Ohh jeee, trying to remove a head filter\n"); } else - { /* remove an intermediate iobuf from the chain */ + { /* Remove an intermediate iobuf from the chain. */ log_bug ("Ohh jeee, trying to remove an intermediate filter\n"); } @@ -1958,17 +1958,19 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) (int) (a->d.size - (a->d.len - a->d.start))); if (a->use == IOBUF_INPUT_TEMP) - /* By definition, there isn't more data to read into the - buffer. */ - return -1; + { + /* By definition, there isn't more data to read into the + buffer. */ + return -1; + } log_assert (a->use == IOBUF_INPUT); a->e_d.used = 0; /* If there is still some buffered data, then move it to the start - of the buffer and try to fill the end of the buffer. (This is - useful if we are called from iobuf_peek().) */ + * of the buffer and try to fill the end of the buffer. (This is + * useful if we are called from iobuf_peek().) */ log_assert (a->d.start <= a->d.len); a->d.len -= a->d.start; if (a->d.len) @@ -1976,11 +1978,11 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) a->d.start = 0; if (a->d.len < target && a->filter_eof) - /* The last time we tried to read from this filter, we got an EOF. - We couldn't return the EOF, because there was buffered data. - Since there is no longer any buffered data, return the - error. */ { + /* The last time we tried to read from this filter, we got an + * EOF. We couldn't return the EOF, because there was buffered + * data. Since there is no longer any buffered data, return the + * error. */ if (DBG_IOBUF) log_debug ("iobuf-%d.%d: underflow: eof (pending eof)\n", a->no, a->subno); @@ -1988,8 +1990,8 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) return -1; if (a->chain) - /* A filter follows this one. Free this filter. */ { + /* A filter follows this one. Free this filter. */ iobuf_t b = a->chain; if (DBG_IOBUF) log_debug ("iobuf-%d.%d: filter popped (pending EOF returned)\n", @@ -2006,11 +2008,11 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) } if (a->d.len == 0 && a->error) - /* The last time we tried to read from this filter, we got an - error. We couldn't return the error, because there was - buffered data. Since there is no longer any buffered data, - return the error. */ { + /* The last time we tried to read from this filter, we got an + * error. We couldn't return the error, because there was + * buffered data. Since there is no longer any buffered data, + * return the error. */ if (DBG_IOBUF) log_debug ("iobuf-%d.%d: pending error (%s) returned\n", a->no, a->subno, gpg_strerror (a->error)); @@ -2018,10 +2020,10 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) } if (a->filter && ! a->filter_eof && ! a->error) - /* We have a filter function and the last time we tried to read we - didn't get an EOF or an error. Try to fill the buffer. */ { - /* Be careful to account for any buffered data. */ + /* We have a filter function and the last time we tried to read + * we didn't get an EOF or an error. Try to fill the buffer. + * Be careful to account for any buffered data. */ len = a->d.size - a->d.len; if (a->e_d.preferred && a->d.len < IOBUF_ZEROCOPY_THRESHOLD_SIZE @@ -2034,51 +2036,54 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) } if (len == 0) - /* There is no space for more data. Don't bother calling - A->FILTER. */ - rc = 0; + { + /* There is no space for more data. Don't bother calling + * A->FILTER. */ + rc = 0; + } else - { - /* If no buffered data and drain buffer has been setup, and drain - * buffer is largish, read data directly to drain buffer. */ - if (a->d.len == 0 - && a->e_d.buf - && a->e_d.len >= IOBUF_ZEROCOPY_THRESHOLD_SIZE) - { - len = a->e_d.len; + { + /* If no buffered data and drain buffer has been setup, and + * drain buffer is largish, read data directly to drain buffer. */ + if (a->d.len == 0 + && a->e_d.buf + && a->e_d.len >= IOBUF_ZEROCOPY_THRESHOLD_SIZE) + { + len = a->e_d.len; - if (DBG_IOBUF) - log_debug ("iobuf-%d.%d: underflow: A->FILTER (%lu bytes, to external drain)\n", - a->no, a->subno, (ulong)len); + if (DBG_IOBUF) + log_debug ("iobuf-%d.%d: underflow:" + " A->FILTER (%lu bytes, to external drain)\n", + a->no, a->subno, (ulong)len); - rc = a->filter (a->filter_ov, IOBUFCTRL_UNDERFLOW, a->chain, - a->e_d.buf, &len); - a->e_d.used = len; - len = 0; - } - else - { - if (DBG_IOBUF) - log_debug ("iobuf-%d.%d: underflow: A->FILTER (%lu bytes)\n", - a->no, a->subno, (ulong)len); + rc = a->filter (a->filter_ov, IOBUFCTRL_UNDERFLOW, a->chain, + a->e_d.buf, &len); + a->e_d.used = len; + len = 0; + } + else + { + if (DBG_IOBUF) + log_debug ("iobuf-%d.%d: underflow: A->FILTER (%lu bytes)\n", + a->no, a->subno, (ulong)len); - rc = a->filter (a->filter_ov, IOBUFCTRL_UNDERFLOW, a->chain, - &a->d.buf[a->d.len], &len); - } - } + rc = a->filter (a->filter_ov, IOBUFCTRL_UNDERFLOW, a->chain, + &a->d.buf[a->d.len], &len); + } + } a->d.len += len; if (DBG_IOBUF) - log_debug ("iobuf-%d.%d: A->FILTER() returned rc=%d (%s), read %lu bytes%s\n", + log_debug ("iobuf-%d.%d: A->FILTER() returned rc=%d (%s)," + " read %lu bytes%s\n", a->no, a->subno, rc, rc == 0 ? "ok" : rc == -1 ? "EOF" : gpg_strerror (rc), (ulong)(a->e_d.used ? a->e_d.used : len), a->e_d.used ? " (to external buffer)" : ""); -/* if( a->no == 1 ) */ -/* log_hexdump (" data:", a->d.buf, len); */ + /* if ( a->no == 1 ) */ + /* log_hexdump (" data:", a->d.buf, len); */ - if (rc == -1) - /* EOF. */ + if (rc == -1) /* EOF. */ { size_t dummy_len = 0; @@ -2096,39 +2101,40 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) if (clear_pending_eof && a->d.len == 0 && a->e_d.used == 0 && a->chain) - /* We don't need to keep this filter around at all: - - - we got an EOF - - we have no buffered data - - a filter follows this one. - - Unlink this filter. */ { + /* We don't need to keep this filter around at all: + * + * - we got an EOF + * - we have no buffered data + * - a filter follows this one. + * + * Unlink this filter. */ iobuf_t b = a->chain; if (DBG_IOBUF) - log_debug ("iobuf-%d.%d: pop in underflow (nothing buffered, got EOF)\n", - a->no, a->subno); + log_debug ("iobuf-%d.%d: pop in underflow" + " (nothing buffered, got EOF)\n", a->no, a->subno); xfree (a->d.buf); xfree (a->real_fname); memcpy (a, b, sizeof *a); xfree (b); print_chain (a); - return -1; } else if (a->d.len == 0 && a->e_d.used == 0) - /* We can't unlink this filter (it is the only one in the - pipeline), but we can immediately return EOF. */ - return -1; + { + /* We can't unlink this filter (it is the only one in + * the pipeline), but we can immediately return EOF. */ + return -1; + } + } - else if (rc) - /* Record the error. */ + else if (rc) /* Record the error. */ { a->error = rc; + /* If there is no buffered data, immediately return EOF. */ if (a->d.len == 0 && a->e_d.used == 0) - /* There is no buffered data. Immediately return EOF. */ return -1; } } @@ -2139,8 +2145,7 @@ underflow_target (iobuf_t a, int clear_pending_eof, size_t target) if (a->d.start < a->d.len) return a->d.buf[a->d.start++]; - /* EOF. */ - return -1; + return -1; /* EOF. */ } @@ -2156,7 +2161,7 @@ filter_flush (iobuf_t a) a->e_d.used = 0; if (a->use == IOBUF_OUTPUT_TEMP) - { /* increase the temp buffer */ + { /* Increase the temp buffer. */ size_t newsize = a->d.size + iobuf_buffer_size; if (DBG_IOBUF) |