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fix iob_write to handle failure properly

document that the iob_write callback should limit itself
master
Felix von Leitner 15 anni fa
parent
commit
074eab6681
4 ha cambiato i file con 38 aggiunte e 9 eliminazioni
  1. +2
    -0
      CHANGES
  2. +8
    -0
      io/iob_write.3
  3. +6
    -8
      io/iob_write.c
  4. +22
    -1
      t.c

+ 2
- 0
CHANGES Vedi File

@@ -4,6 +4,8 @@
#include <unistd.h> in io/io_sendfile.c (broken OpenBSD, thx Rob)
add scan_urlencoded2 (like scan_urlencoded but will not convert '+' to
' '; needed for web servers, so they can serve libstdc++.tar.gz)
fix iob_write to handle failure properly
document that the iob_write callback should limit itself

0.21:
errno cleanup and man page updates (Rolf Eike Beer)


+ 8
- 0
io/iob_write.3 Vedi File

@@ -25,5 +25,13 @@ writable, and then calling iob_write until it returns 0, -1 or -3.

If it returns 0, terminate the loop (everything was written OK). If it
returns -1, call io_wait again. If it returned -3, signal an error.

.SH NOTE
iob_write will continue to call your callback until it returns an error.
So if you are in a state machine, for example a web server using this
for SSL support, make sure to write at most n bytes at a time (e.g. 64k)
and the next time you are called return -1. Otherwise iob_write might
not return until the whole file is served.

.SH "SEE ALSO"
iob_send(3)

+ 6
- 8
io/iob_write.c Vedi File

@@ -18,16 +18,14 @@ int64 iob_write(int64 s,io_batch* b,io_write_callback cb) {
sent=io_mmapwritefile(s,e[i].fd,e[i].offset,e[i].n,cb);
else
sent=cb(s,e[i].buf+e[i].offset,e[i].n);
if (sent > e[i].n) sent=e[i].n; /* can't happen */
if (sent>0 && sent>e[i].n) sent=e[i].n; /* can't happen */
thatsit=(sent != e[i].n);
if (sent==-1 && errno!=EAGAIN)
sent=-3;
if (sent>0) {
e[i].offset+=sent;
e[i].n-=sent;
total+=sent;
} else
if (sent<=0)
return total?total:sent;
e[i].offset+=sent;
e[i].n-=sent;
total+=sent;
b->bytesleft-=sent;
if (thatsit) break;
}
if (total == b->bytesleft)


+ 22
- 1
t.c Vedi File

@@ -19,22 +19,43 @@
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <errmsg.h>
#include "errmsg.h"
#include "iob.h"

#define rdtscl(low) \
__asm__ __volatile__ ("rdtsc" : "=a" (low) : : "edx")

int64 writecb(int64 fd,const void* buf,uint64 n) {
#if 0
int r;
int todo=n>=65536?65536:n;
r=write(fd,buf,todo);
if (r==-1 && r!=EAGAIN) r=-3;
return r;
#endif
return -1;
}

int main(int argc,char* argv[]) {
static io_batch b;
int64 fd=open("t.c",0);
iob_addbuf(&b,"fnord",5);
iob_addfile_close(&b,fd,0,7365);
iob_write(1,&b,writecb);
#if 0
char dest[1024];
unsigned long len;
scan_urlencoded2("libstdc++.tar.gz",dest,&len);
buffer_putmflush(buffer_1,dest,"\n");
#endif
#if 0
static stralloc sa;
stralloc_copym(&sa,"foo ","bar ","baz.\n");
write(1,sa.s,sa.len);
#endif
#if 0
buffer_putmflush(buffer_1,"foo ","bar ","baz.\n");
#endif
#if 0
char* c="fnord";
int fd=open_read(c);


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