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windows closefrom

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This commit is contained in:
Jean-Francois Dockes 2022-01-19 12:30:40 +01:00
parent 497b61e017
commit fbcf0f42e9
2 changed files with 58 additions and 56 deletions
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44
src/testmains/trclosefrom.cpp Normal file
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@ -0,0 +1,44 @@
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include "closefrom.h"
int main(int argc, char **argv)
{
int i;
int fd0 = open("/etc/group", 0);
if (fd0 < 0) {
perror("open /etc/group");
exit(1);
}
if (dup2(fd0, 11) < 0) {
perror("dup2->11");
exit(1);
}
if (dup2(fd0, 19) < 0) {
perror("dup2->19");
exit(1);
}
if (dup2(fd0, 99)< 0) {
perror("dup2->99 (ok)");
}
if (dup2(fd0, 999) < 0) {
perror("dup3->999 (ok)");
}
libclf_closefrom(11);
for (i = 0; i < 10000; i++) {
if (fcntl(i, F_GETFL) != -1) {
fprintf(stderr, "Descriptor %d is still open", i);
if (i < 11)
fprintf(stderr, " (OK)\n");
else
fprintf(stderr, " (BAD)\n");
}
}
exit(0);
}

66
src/utils/closefrom.cpp
View File

@ -57,9 +57,11 @@
* - Has nothing. The method we initially used (listing /dev/fd) could * - Has nothing. The method we initially used (listing /dev/fd) could
* deadlock in multithread fork/exec context. We now use a close() * deadlock in multithread fork/exec context. We now use a close()
* loop but there is no completely reliable way to determine the high limit. * loop but there is no completely reliable way to determine the high limit.
* glibc maintainers think that closefrom() is a bad idea * The glibc maintainer (drepper) thinks that closefrom() is a bad idea
* *especially* because it is implemented on *BSD and Solaris. Go * *especially* because it is implemented on *BSD and Solaris. Go figure...
* figure...: https://sourceware.org/bugzilla/show_bug.cgi?id=10353 * https://sourceware.org/bugzilla/show_bug.cgi?id=10353
* Bug updated 2021/07/08, apparently fixed in glibc 2.35 (not yet available 2022-01, fed35 and
* tumble are at 2.34).
* *
* Interface: * Interface:
* *
@ -68,8 +70,6 @@
* values will be closed. fd needs not be a valid descriptor. * values will be closed. fd needs not be a valid descriptor.
* @return 0 for success, -1 for error. * @return 0 for success, -1 for error.
*/ */
#ifndef TEST_CLOSEFROM
#include "closefrom.h" #include "closefrom.h"
#include <stdio.h> #include <stdio.h>
@ -165,6 +165,7 @@ int libclf_closefrom(int fd0)
} }
/*************************************************************************/ /*************************************************************************/
#else #else
/* System has no native support for this functionality. /* System has no native support for this functionality.
@ -218,56 +219,13 @@ int libclf_closefrom(int fd0)
// both POSIX.1-2001? // both POSIX.1-2001?
int libclf_maxfd(int) int libclf_maxfd(int)
{ {
#ifdef _WIN32
// https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/setmaxstdio?view=msvc-170
return 8192;
#else
struct rlimit lim; struct rlimit lim;
getrlimit(RLIMIT_NOFILE, &lim); getrlimit(RLIMIT_NOFILE, &lim);
return int(lim.rlim_cur); return int(lim.rlim_cur);
}
#else /* TEST_CLOSEFROM */
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include "closefrom.h"
int main(int argc, char **argv)
{
int i;
int fd0 = open("/etc/group", 0);
if (fd0 < 0) {
perror("open /etc/group");
exit(1);
}
if (dup2(fd0, 11) < 0) {
perror("dup2->11");
exit(1);
}
if (dup2(fd0, 19) < 0) {
perror("dup2->19");
exit(1);
}
if (dup2(fd0, 99)< 0) {
perror("dup2->99 (ok)");
}
if (dup2(fd0, 999) < 0) {
perror("dup3->999 (ok)");
}
libclf_closefrom(11);
for (i = 0; i < 10000; i++) {
if (fcntl(i, F_GETFL) != -1) {
fprintf(stderr, "Descriptor %d is still open", i);
if (i < 11)
fprintf(stderr, " (OK)\n");
else
fprintf(stderr, " (BAD)\n");
}
}
exit(0);
}
#endif #endif
}