1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
.TH qlibs: pathexec 3
.SH NAME
pathexec \- run a program within a given environment
.SH SYNTAX
.B #include \(dqpathexec.h\(dq
\fBpathexec_run\fP(const char *\fIp\fR,char **\fIa\fR,char **\fIe\fR);
.br
\fBpathexec\fP(char *const *\fIa\fR);
.br
\fBpathexec_env\fP(const char *\fIs\fR,char *\fIt\fR);
.SH DESCRIPTION
.B pathexec_run
searches for a program named
.IR p .
It replaces the current process with a copy of that program.
The main function in that program will be given arguments
.I a
and environment
.IR e .
.B pathexec_run
looks for
.I p
as specified by the
.I $PATH
environment variable.
.I $PATH
is a colon-separated list of directories
.IR d ;
.B pathexec_run
tries
.B execve
on files named
.IR d/p ,
in the order that the directories appear inside
.IR $PATH .
An empty directory name is treated as a single dot.
If
.I $PATH
is not set,
.B pathexec_run
uses the path
.IR /bin:/usr/bin ;
i.e., it tries
.B execve
on
.IR /bin/p ,
then
.IR /usr/bin/p .
If
.I p
contains a slash,
.B pathexec_run
ignores
.I $PATH
and simply runs
.B execve
on a file named
.IR p .
.B pathexec
calls
.B pathexec_run
with program name
.IR a[0] ,
arguments
.IR a ,
and the same environment as the current process,
modified as described below.
.B pathexec
has the same return behavior as
.BR pathexec_run .
.B pathexec_env
modifies the environment used by
.BR pathexec .
It removes a variable named
.IR s,
if one exists. It then adds a variable named
.I s
with value
.IR t,
if the pointer
.I t
is nonzero. The name
.I s
must not contain
.IR = .
.SH "RETURN CODES"
Normally
.B pathexec_run
does not return, because the process has been replaced.
However, if all the
.B execve
attempts fail,
.B pathexec_run
returns, setting
.I errno
to the most interesting error returned by
.BR execve .
Furthermore,
.B pathexec_run
returns immediately if an
.B execve
attempt fails with an error other than
.IR error_noent ,
.IR error_acces ,
.IR error_perm ,
or
.IR error_isdir .
This list is subject to change.
Normally
.B pathexec_env
returns
.IR 1 .
If it is unable to allocate memory, it returns
.IR 0 ,
leaving the
.B pathexec
environment alone.
.SH "SEE ALSO"
error(3)
|
