open
Implemented in Antinomie 0.7.0 · Syscall list
Synopsis
Section titled “Synopsis”long open(const char *filename, int flags, umode_t mode);| Number (x86-64) | 2 |
| ABI | common |
| Kernel entry point | sys_open |
This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.
Description
Section titled “Description”Opens or creates a file by path and returns a file descriptor. Newer programs use openat instead.
Arguments
Section titled “Arguments”| Name | Type | Meaning |
|---|---|---|
filename (arg0) |
const char * |
Path of the file to open. |
flags (arg1) |
int |
Access mode and creation or status flags (O_RDONLY, O_CREAT, …). |
mode (arg2) |
umode_t |
Permission bits for a newly created file; used only with O_CREAT or O_TMPFILE. |
Return value
Section titled “Return value”On success: A new file descriptor (a non-negative number).
In an Antinomie trace the Return column and the ret filter field show the raw kernel return value. On failure that is the negative errno, for example -2 for ENOENT, not the -1 plus errno that the libc wrapper gives. syscall.errno holds the positive errno and syscall.success is false.
Common errors
Section titled “Common errors”| Raw return | Name | Meaning |
|---|---|---|
-13 |
EACCES |
Permission denied. |
-17 |
EEXIST |
The object already exists. |
-21 |
EISDIR |
The path names a directory where a file is needed. |
-24 |
EMFILE |
The process has too many open file descriptors. |
-2 |
ENOENT |
A path component or the named object does not exist. |
Man page
Section titled “Man page”Captured by Antinomie
Section titled “Captured by Antinomie”Coverage mark: Implemented. Every pointer argument has a capture rule in the pinned kernel patch and none of them records a “no decoder”, “address only” or “not observed” gap on any code path. Individual values can still be incomplete on a particular call; see the capture statuses.
Every call is recorded as an Entry record (the six argument words and the pointees copied at entry) and an Exit record (the return value and the pointees copied at exit).
Arguments
Section titled “Arguments”| Argument | When | How | Recorded field key | Condition |
|---|---|---|---|---|
filename (arg0) |
Entry | the pointer itself, as a raw word | args.0, args.raw[0] |
|
| ↳ pointee | Entry | NUL-terminated string, up to 4,096 bytes (PATH_MAX) | arg0.path |
always |
flags (arg1) |
Entry | raw scalar word; Syscall Trace also decodes it into flag names (open group), listing unknown bits separately |
args.1, args.flags |
|
mode (arg2) |
Entry | raw scalar word | args.2, args.mode |
Derived and lifecycle records
Section titled “Derived and lifecycle records”- A
lifecycle.file_idrecord (kind Open) gives the device, inode and generation of the opened file, so Triage can follow one file across its names. Written by a base built for Antinomie 0.7.0 or later.
Filter fields
Section titled “Filter fields”- Result:
ret,syscall.errno,syscall.success,syscall.duration_ns. - Argument words:
args.filename(arg0),args.flags(arg1),args.mode(arg2);args.0toargs.5by position. - Captured strings: the
args.<name>field of a path argument, andargs.path, give the captured text instead of the pointer.
See Syscall Trace filter for the full syntax.
For what the capture statuses mean, see Capture statuses. For what is never recorded, see Known gaps.