15.7.9 -d2.9
Show file descriptors with dumpfd( ) Debug command-line switch
The -d2.9 debugging switchtells sendmail to display the properties of each open file
descriptor. That output is produced by the dumpfd( ) routine, and eachline of output is for
a single file descriptor:
number: fl=flags mode=mode type stats
Here, the number is the count of the open file descriptor. Note that descriptors 0, 1, and 2
are usually tied to the standard input, output, and error output, respectively.
The flags is a hexadecimal representation of the state flags associated with a file descriptor.
F_GETFL is used with ioctl(2) to fetcheach , and all are described in
on most
systems.
The mode is printed in octal and is the st_mode associated withan fstat(2) of the file
descriptor.
The type examines the file type portion of the st_mode and prints SOCK for a socket, CHR:
for a character special device, BLK: for a block special device, FIFO: for a named pipe, DIR:
for a directory, LNK: for a symbolic link, and nothing otherwise (e.g., nothing if it is a file).
The stats are printed for all but the socket. They look like this:
dev=major/minor ino=inum nlink=nlink u/gid=user-id/group-id size=bytes
Here the dev= shows the major and minor device numbers for the device that the file
descriptor is associated with. The inum is the inode number on the disk (if there is one) and
nlink is the number of hard links to the file on disk.
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