xref: /illumos-gate/usr/src/man/man2/upanic.2 (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
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12.\" Copyright 2020 Oxide Computer Company
13.\"
14.Dd October 31, 2020
15.Dt UPANIC 2
16.Os
17.Sh NAME
18.Nm upanic
19.Nd user process panic
20.Sh SYNOPSIS
21.In upanic.h
22.Ft void noreturn
23.Fo upanic
24.Fa "const char *msg"
25.Fa "size_t len"
26.Fc
27.Sh DESCRIPTION
28The
29.Fn upanic
30system call terminates the calling process and generates a core file in
31the process, subject to the current core file settings as described in
32.Xr core 5
33and controlled by
34.Xr coreadm 8 .
35.Pp
36Unlike
37.Xr abort 3C ,
38signals are not generated, which avoids two related challenges:
39.Bl -enum
40.It
41A signal handler attempting to catch a
42.Dv SIGABRT .
43.It
44Needing to make multiple system calls and potentially unmasking the
45signal.
46.El
47.Pp
48The
49.Fn upanic
50system call allows an optional message to be transmitted that will be
51put in a
52.Dv NT_UPANIC
53elf note in the resulting core file.
54If a message is not desired, then one should pass
55.Dv NULL
56for
57.Fa msg .
58In general, it is expected that
59.Fa msg
60is a character string with a human-readable message; however, it may
61include binary data.
62The system will copy
63.Fa len
64bytes regardless of whether the string has a NUL character to terminate
65it or not.
66If
67.Fa msg
68points to an invalid value or
69.Fa len
70is a size that is larger than the system's internal maximum size, then
71the process will still terminate; however, this will be noted in the
72.Dv NT_UPANIC
73elf note.
74.Pp
75The
76.Fn upanic
77system call is illumos-specific and not portable to other systems.
78For portable applications, instead use
79.Xr abort 3C .
80.Sh RETURN VALUES
81The
82.Fn upanic
83system call does not return.
84It always terminates the process.
85.Sh INTERFACE STABILITY
86.Sy Committed
87.Sh MT-LEVEL
88.Sy Async-Signal-Safe
89.Sh SEE ALSO
90.Xr elfdump 1 ,
91.Xr mdb 1 ,
92.Xr upanic.h 3HEAD ,
93.Xr core 5 ,
94.Xr coreadm 8
95