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39 .Nd the filemon device
41 .In dev/filemon/filemon.h
45 device allows a process to collect file operations data of its children.
52 System calls are denoted using the following single letters:
54 .Bl -tag -width indent -compact
87 records can represent a single
96 Note that only successful system calls are captured.
98 User mode programs communicate with the
100 driver through a number of ioctls which are described below.
101 Each takes a single argument.
102 .Bl -tag -width ".Dv FILEMON_SET_PID"
103 .It Dv FILEMON_SET_FD
104 Write the internal tracing buffer to the supplied open file descriptor.
105 .It Dv FILEMON_SET_PID
106 Child process ID to trace.
112 function returns the value 0 if successful;
113 otherwise the value \-1 is returned and the global variable
115 is set to indicate the error.
117 .Bl -tag -width ".Pa /dev/filemon"
122 #include <sys/types.h>
123 #include <sys/stat.h>
124 #include <sys/wait.h>
125 #include <sys/ioctl.h>
126 #include <dev/filemon/filemon.h>
137 if ((fm_fd = open("/dev/filemon", O_RDWR | O_CLOEXEC)) == -1)
138 err(1, "open(\e"/dev/filemon\e", O_RDWR)");
139 if ((fm_log = open("filemon.out",
140 O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, DEFFILEMODE)) == -1)
141 err(1, "open(filemon.out)");
143 if (ioctl(fm_fd, FILEMON_SET_FD, &fm_log) == -1)
144 err(1, "Cannot set filemon log file descriptor");
146 if ((child = fork()) == 0) {
148 if (ioctl(fm_fd, FILEMON_SET_PID, &child) == -1)
149 err(1, "Cannot set filemon PID");
150 /* Do something here. */
164 buffer contents to it.