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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.
53 is not intended to be a security auditing tool.
54 Many system calls are not tracked and binaries of foreign ABI will not be fully
56 It is intended for auditing of processes for the purpose of determining its
57 dependencies in an efficient and easily parsable format.
60 which uses this module with
62 to handle incremental builds more smartly.
64 System calls are denoted using the following single letters:
66 .Bl -tag -width indent -compact
69 The next log entry may be lacking an absolute path or be inaccurate.
104 records can represent a single
113 Note that only successful system calls are captured.
115 User mode programs communicate with the
117 driver through a number of ioctls which are described below.
118 Each takes a single argument.
119 .Bl -tag -width ".Dv FILEMON_SET_PID"
120 .It Dv FILEMON_SET_FD
121 Write the internal tracing buffer to the supplied open file descriptor.
122 .It Dv FILEMON_SET_PID
123 Child process ID to trace.
124 This should normally be done under the control of a parent in the child after
126 but before anything else.
127 See the example below.
133 function returns the value 0 if successful;
134 otherwise the value \-1 is returned and the global variable
136 is set to indicate the error.
148 handle is already associated with a file descriptor.
159 No process having the specified process ID exists.
161 The process ID specified is already being traced and was not the current
167 system call on the filemon file descriptor may fail with the errors from
169 if any error is encountered while writing the log.
173 An invalid address was used for a traced system call argument, resulting in
174 no log entry for the system call.
175 .It Bq Er ENAMETOOLONG
176 An argument for a traced system call was too long, resulting in
177 no log entry for the system call.
180 .Bl -tag -width ".Pa /dev/filemon"
185 #include <sys/types.h>
186 #include <sys/stat.h>
187 #include <sys/wait.h>
188 #include <sys/ioctl.h>
189 #include <dev/filemon/filemon.h>
200 if ((fm_fd = open("/dev/filemon", O_RDWR | O_CLOEXEC)) == -1)
201 err(1, "open(\e"/dev/filemon\e", O_RDWR)");
202 if ((fm_log = open("filemon.out",
203 O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, DEFFILEMODE)) == -1)
204 err(1, "open(filemon.out)");
206 if (ioctl(fm_fd, FILEMON_SET_FD, &fm_log) == -1)
207 err(1, "Cannot set filemon log file descriptor");
209 if ((child = fork()) == 0) {
211 if (ioctl(fm_fd, FILEMON_SET_PID, &child) == -1)
212 err(1, "Cannot set filemon PID");
213 /* Do something here. */
227 buffer contents to it.
240 Unloading the module may panic the system, thus requires using