61 lines
1.8 KiB
Plaintext
61 lines
1.8 KiB
Plaintext
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/*++
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/* NAME
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/* dup2_pass_on_exec 1
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/* SUMMARY
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/* dup2 close-on-exec behaviour test program
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/* SYNOPSIS
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/* dup2_pass_on_exec
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/* DESCRIPTION
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/* dup2_pass_on_exec sets the close-on-exec flag on its
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/* standard input and then dup2() to duplicate it.
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/* Posix-1003.1 specifies in section 6.2.1.2 that dup2(o,n) should behave
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/* as: close(n); n = fcntl(o, F_DUPFD, n); as long as o is a valid
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/* file-descriptor, n!=o, and 0<=n<=[OPEN_MAX].
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/* Section 6.5.2.2 states that the close-on-exec flag of the result of a
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/* successful fcntl(o, F_DUPFD, n) is cleared.
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/*
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/* At least Ultrix4.3a does not clear the close-on-exec flag of n on
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/* dup2(o, n).
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/* DIAGNOSTICS
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/* Problems are reported to the standard error stream.
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/* LICENSE
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/* .ad
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/* .fi
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/* The Secure Mailer license must be distributed with this software.
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/* AUTHOR(S)
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/* Christian von Roques <roques@pond.sub.org>
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/* Forststrasse 71
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/* 76131 Karlsruhe, GERMANY
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/*--*/
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#include <stdio.h>
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#include <fcntl.h>
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#define DO(s) if (s < 0) { perror(#s); exit(1); }
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int main(int unused_argc, char **unused_argv)
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{
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int res;
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printf("Setting the close-on-exec flag of file-descriptor 0.\n");
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DO(fcntl(0, F_SETFD, 1));
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printf("Duplicating file-descriptor 0 to 3.\n");
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DO(dup2(0, 3));
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printf("Testing if the close-on-exec flag of file-descriptor 3 is set.\n");
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DO((res = fcntl(3, F_GETFD, 0)));
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if (res & 1)
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printf("Yes, a newly dup2()ed file-descriptor has the close-on-exec "
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"flag cloned.\n"
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"THIS VIOLATES Posix1003.1 section 6.2.1.2 or 6.5.2.2!\n"
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"You should #define DUP2_DUPS_CLOSE_ON_EXEC in sys_defs.h "
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"for your OS.\n");
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else
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printf("No, a newly dup2()ed file-descriptor has the close-on-exec "
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"flag cleared.\n"
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"This complies with Posix1003.1 section 6.2.1.2 and 6.5.2.2!\n");
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return 0;
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}
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