I'm attaching the strace output for the following code you asked:
int main(void){
sqlite3* db_handle=NULL;
if(sqlite3_open("guido.db",&db_handle))
{ //abro DB
fprintf(stderr,"Error while open
DB:%s\n",sqlite3_errmsg(db_handle));
printf("No pude abrir la DB\n");
exit(1);
}
ping_pong("10.0.0.3",2);
if(sqlite3_close(db_handle))
{
fprintf(stderr,"Error while open
DB:%s\n",sqlite3_errmsg(db_handle));
printf("No pude abrir la DB\n");
exit(1);
}
return 0;
}
I' running Ubuntu 8.04, using gcc like this:
gcc ping.c main.c -o output.o -lsqlite3
How do I compile that with the threadsafe otpion you mentioned?
Thanks a lot for your help.
Martin
On Wed, Mar 24, 2010 at 1:09 PM, paivanof <paiva...@gmail.com> wrote:
> > I don't notice any cases of where a stale file descriptor is being
> > accessed. I'm stumped :-/
>
> Can it be a problem with clone() calls? AFAIK, it's how SQLite checks
> if it can work safely from multiple threads. Martin, can you recompile
> SQLite with SQLITE_THREADSAFE set to 0 and look if your pinging will
> work with that?
>
> BTW, what OS are you using, what compiler and what is your compilation
> command?
>
> Also it would be interesting to see strace results when your
> successful pinging is made before sqlite3_close() and when
> unsuccessful pinging is made after statement execution.
>
>
> Pavel
>
> On Wed, Mar 24, 2010 at 11:45 AM, David Baird <dhba...@gmail.com> wrote:
> > On Wed, Mar 24, 2010 at 9:24 AM, David Baird <dhba...@gmail.com> wrote:
> >> On Wed, Mar 24, 2010 at 9:05 AM, Martin Sigwald <msigw...@gmail.com>
> wrote:
> >>> While I could gather, both the open system called generated by the DB
> and
> >>> the socket() syscall are returning a FD=3.
> >>> That is, they are both trying to use the same filedescriptor. My guess
> is
> >>> packets get sent to that file descriptor, instead of the port. How can
> I
> >>> changed this? I just followed standar procedure to allocate a socket:
> >>> sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP))
> >>>
> >>> Shouldn't the Kernel take care of this and provide an unused FD??
> >>
> >> According to the strace, the kernel is taking care of that properly.
> >> You get a socket, call sendto, select, recvfrom, then close it. And
> >> then you open guido.db. Since you just closed your socket, the fd=3
> >> is reused for guido.db. This is perfectly legitimate. Something else
> >> funny is going on. Here's the relevant portions from the strace:
> >
> > Actually, I just realized that a socket is opened twice in your
> > strace. So, here's the portion that includes both socket opens and
> > the database open:
> >
> > First socket open and close:
> >
> > socket(PF_INET, SOCK_RAW, IPPROTO_ICMP) = 3
> > setsockopt(3, SOL_IP, IP_HDRINCL, [1], 4) = 0
> > sendto(3, "E\0\34\0Eg\0\0\377\1P\223\0\0\0\0\n\0\0\3\10\0;\320#\306"...,
> > 28, 0, {sa_family=AF_INET, sin_port=htons(0),
> > sin_addr=inet_addr("10.0.0.3")}, 16) = 28
> > select(4, [3], NULL, NULL, {2, 500000}) = 1 (in [3], left {2, 496000})
> > recvfrom(3, "e\0\0\0...@\0\0@
> \0015\233\n\0\0\3\n\0\0\4\0\0C\320#\306"...,
> > 28, 0, {sa_family=AF_INET, sin_port=htons(0),
> > sin_addr=inet_addr("10.0.0.3")}, [16]) = 28
> > fstat64(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 2), ...}) = 0
> > mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> > 0) = 0xb7f16000
> > write(1, "El Server 10.0.0.3 esta en el es"..., 43) = 43
> > close(3) = 0
> >
> > Database open and close (with a dup in the middle that also creates
> fd=4)...
> >
> > getcwd("/home/martin", 5000) = 13
> > open("/home/martin/guido.db", O_RDWR|O_CREAT|O_LARGEFILE, 0644) = 3
> > fcntl64(3, F_GETFD) = 0
> > fcntl64(3, F_SETFD, FD_CLOEXEC) = 0
> > fstat64(3, {st_mode=S_IFREG|0777, st_size=2048, ...}) = 0
> > dup(3) = 4
> > mmap2(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
> > -1, 0) = 0xb7537000
> > mprotect(0xb7537000, 4096, PROT_NONE) = 0
> > clone(child_stack=0xb7d374c4,
> >
> flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID,
> > parent_tidptr=0xb7d37bd8, {entry_number:6, base_addr:0xb7d37b90,
> > limit:1048575, seg_32bit:1, contents:0, read_exec_only:0,
> > limit_in_pages:1, seg_not_present:0, useable:1},
> > child_tidptr=0xb7d37bd8) = 6240
> > mmap2(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
> > -1, 0) = 0xb6d36000
> > mprotect(0xb6d36000, 4096, PROT_NONE) = 0
> > clone(child_stack=0xb75364c4,
> >
> flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID,
> > parent_tidptr=0xb7536bd8, {entry_number:6, base_addr:0xb7536b90,
> > limit:1048575, seg_32bit:1, contents:0, read_exec_only:0,
> > limit_in_pages:1, seg_not_present:0, useable:1},
> > child_tidptr=0xb7536bd8) = 6241
> > close(4) = 0
> > _llseek(3, 0, [0], SEEK_SET) = 0
> > read(3, "SQLite format 3\0\4\0\1\1\0@ \0\0\0\4\0\0\0\0"..., 100) = 100
> > close(3) = 0
> > getuid32() = 0
> >
> > And second socket open and close....
> >
> > socket(PF_INET, SOCK_RAW, IPPROTO_ICMP) = 3
> > setsockopt(3, SOL_IP, IP_HDRINCL, [1], 4) = 0
> > sendto(3, "E\0\34\0Hs\4\10\377\1I\177\0\0\0\0\n\0\0\3\10\0\276\256"...,
> > 28, 0, {sa_family=AF_INET, sin_port=htons(0),
> > sin_addr=inet_addr("10.0.0.3")}, 16) = 28
> > select(4, [3], NULL, NULL, {2, 500000}) = 0 (Timeout)
> > write(1, "TIMEOUT\n", 8) = 8
> > close(3) = 0
> >
> >
> > In both cases that you call sendto, it appears to have succeeded (i.e.
> > because they returned a positive value, i.e. 28). In the second case,
> > select timed out (as you said it does).
> >
> > I don't notice any cases of where a stale file descriptor is being
> > accessed. I'm stumped :-/
> >
> > -David
> > _______________________________________________
> > sqlite-users mailing list
> > sqlite-users@sqlite.org
> > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
> >
> _______________________________________________
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
execve("./miercoles.o", ["./miercoles.o"], [/* 22 vars */]) = 0
brk(0) = 0x804b000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb7fa9000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=49519, ...}) = 0
mmap2(NULL, 49519, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f9c000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/usr/lib/libsqlite3.so.0", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20\316"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0644, st_size=410036, ...}) = 0
mmap2(NULL, 413188, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) =
0xb7f37000
mmap2(0xb7f9a000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x62) = 0xb7f9a000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/tls/i686/cmov/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\260e\1"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1364388, ...}) = 0
mmap2(NULL, 1369712, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) =
0xb7de8000
mmap2(0xb7f31000, 12288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x149) = 0xb7f31000
mmap2(0xb7f34000, 9840, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7f34000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/tls/i686/cmov/libdl.so.2", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0p\n\0\000"..., 512) =
512
fstat64(3, {st_mode=S_IFREG|0644, st_size=9684, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb7de7000
mmap2(NULL, 12412, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) =
0xb7de3000
mmap2(0xb7de5000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1) = 0xb7de5000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/tls/i686/cmov/libpthread.so.0", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\20H\0\000"..., 512) =
512
fstat64(3, {st_mode=S_IFREG|0755, st_size=112354, ...}) = 0
mmap2(NULL, 94688, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) =
0xb7dcb000
mmap2(0xb7ddf000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x13) = 0xb7ddf000
mmap2(0xb7de1000, 4576, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7de1000
close(3) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb7dca000
set_thread_area({entry_number:-1 -> 6, base_addr:0xb7dca6b0, limit:1048575,
seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0,
useable:1}) = 0
mprotect(0xb7f31000, 4096, PROT_READ) = 0
munmap(0xb7f9c000, 49519) = 0
set_tid_address(0xb7dca6f8) = 6113
set_robust_list(0xb7dca700, 0xc) = 0
futex(0xbfaf8b50, 0x81 /* FUTEX_??? */, 1) = 0
rt_sigaction(SIGRTMIN, {0xb7dcf2c0, [], SA_SIGINFO}, NULL, 8) = 0
rt_sigaction(SIGRT_1, {0xb7dcf340, [], SA_RESTART|SA_SIGINFO}, NULL, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM_INFINITY}) = 0
uname({sys="Linux", node="martin-laptop", ...}) = 0
brk(0) = 0x804b000
brk(0x806c000) = 0x806c000
getcwd("/home/martin", 5000) = 13
open("/home/martin/guido.db", O_RDWR|O_CREAT|O_LARGEFILE, 0644) = 3
fcntl64(3, F_GETFD) = 0
fcntl64(3, F_SETFD, FD_CLOEXEC) = 0
fstat64(3, {st_mode=S_IFREG|0777, st_size=2048, ...}) = 0
dup(3) = 4
mmap2(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb75c9000
mprotect(0xb75c9000, 4096, PROT_NONE) = 0
clone(child_stack=0xb7dc94c4,
flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID,
parent_tidptr=0xb7dc9bd8, {entry_number:6, base_addr:0xb7dc9b90,
limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,
seg_not_present:0, useable:1}, child_tidptr=0xb7dc9bd8) = 6114
mmap2(NULL, 8392704, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb6dc8000
mprotect(0xb6dc8000, 4096, PROT_NONE) = 0
clone(child_stack=0xb75c84c4,
flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID,
parent_tidptr=0xb75c8bd8, {entry_number:6, base_addr:0xb75c8b90,
limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1,
seg_not_present:0, useable:1}, child_tidptr=0xb75c8bd8) = 6115
close(4) = 0
_llseek(3, 0, [0], SEEK_SET) = 0
read(3, "SQLite format 3\0\4\0\1\1\0@ \0\0\0\4\0\0\0\0"..., 100) = 100
getuid32() = 0
socket(PF_INET, SOCK_RAW, IPPROTO_ICMP) = 4
setsockopt(4, SOL_IP, IP_HDRINCL, [1], 4) = 0
sendto(4, "E\0\34\0Eg\0\0\377\1P\223\0\0\0\0\n\0\0\3\10\0;\320#\306"..., 28, 0,
{sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("10.0.0.3")}, 16) = 28
select(5, [4], NULL, NULL, {2, 500000}) = 1 (in [4], left {2, 496000})
recvfrom(4, "E\0\0\34\"o\...@\1d\214\n\0\0\3\n\0\0\4\0\0c\320#\306\230"..., 28,
0, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("10.0.0.3")},
[16]) = 28
fstat64(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 3), ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xb7fa8000
write(1, "El Server 10.0.0.3 esta en el es"..., 43) = 43
close(4) = 0
close(3) = 0
exit_group(0) = ?
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