OILS / cpp / osh.cc View on Github | oilshell.org

161 lines, 85 significant
1// osh.cc
2
3#include "cpp/osh.h"
4
5#include <fcntl.h> // AT_* Constants
6#include <sys/stat.h>
7#include <unistd.h>
8
9#include "mycpp/gc_builtins.h"
10// To avoid circular dependency with e_die()
11#include "prebuilt/core/error.mycpp.h"
12
13using error::e_die;
14using id_kind_asdl::Id; // used below
15using syntax_asdl::loc;
16
17namespace arith_parse {
18
19GcGlobal<tdop::ParserSpec> kArithSpec_ = {
20 ObjHeader::Global(TypeTag::OtherClass)};
21tdop::ParserSpec* kArithSpec = &kArithSpec_.obj;
22
23} // namespace arith_parse
24
25namespace bool_stat {
26
27bool isatty(BigStr* fd_str, word_t* blame_word) {
28 int fd;
29 try {
30 fd = to_int(fd_str);
31 } catch (ValueError* e) {
32 e_die(StrFormat("Invalid file descriptor %r", fd_str),
33 Alloc<loc::Word>(blame_word));
34 }
35 // note: we don't check errno
36 int result = ::isatty(fd);
37 return result;
38}
39
40bool DoUnaryOp(Id_t op_id, BigStr* s) {
41 const char* zPath = s->data_;
42
43 if (op_id == Id::BoolUnary_h || op_id == Id::BoolUnary_L) {
44 struct stat st;
45 if (lstat(zPath, &st) < 0) {
46 return false;
47 }
48
49 return S_ISLNK(st.st_mode);
50 } else {
51 struct stat st;
52 if (stat(zPath, &st) < 0) {
53 return false;
54 }
55
56 auto mode = st.st_mode;
57
58 switch (op_id) {
59 case Id::BoolUnary_a: // synonyms for existence
60 case Id::BoolUnary_e:
61 return true;
62
63 case Id::BoolUnary_c:
64 return S_ISCHR(mode);
65
66 case Id::BoolUnary_d:
67 return S_ISDIR(mode);
68
69 case Id::BoolUnary_f:
70 return S_ISREG(mode);
71
72 case Id::BoolUnary_g:
73 return mode & S_ISGID;
74
75 // NOTE(Jesse): This implementation MAY have a bug. On my system (Ubuntu
76 // 20.04) it returns a correct result if the user is root (elevated with
77 // sudo) and no execute bits are set for a file.
78 //
79 // A bug worked around in the python `posix` module here is that the above
80 // (working) scenario is not always the case.
81 //
82 // https://github.com/python/cpython/blob/8d999cbf4adea053be6dbb612b9844635c4dfb8e/Modules/posixmodule.c#L2547
83 //
84 // As well as the dash source code found here (relative to this repo
85 // root):
86 //
87 // _cache/spec-bin/dash-0.5.10.2/src/bltin/test.c
88 // See `test_file_access()`
89 //
90 // We could also use the `stat` struct to manually compute the
91 // permissions, as shown in the above `test.c`, though the code is
92 // somewhat obtuse.
93 //
94 // There is further discussion of this issue in:
95 // https://github.com/oilshell/oil/pull/1168
96 //
97 // And a bug filed for it at:
98 //
99 // https://github.com/oilshell/oil/issues/1170
100
101 case Id::BoolUnary_k:
102 return (mode & S_ISVTX) != 0;
103
104 case Id::BoolUnary_p:
105 return S_ISFIFO(mode);
106
107 case Id::BoolUnary_r:
108 return faccessat(AT_FDCWD, zPath, R_OK, AT_EACCESS) == 0;
109
110 case Id::BoolUnary_s:
111 return st.st_size != 0;
112
113 case Id::BoolUnary_u:
114 return mode & S_ISUID;
115
116 case Id::BoolUnary_w:
117 return faccessat(AT_FDCWD, zPath, W_OK, AT_EACCESS) == 0;
118
119 case Id::BoolUnary_x:
120 return faccessat(AT_FDCWD, zPath, X_OK, AT_EACCESS) == 0;
121
122 case Id::BoolUnary_G:
123 return st.st_gid == getegid();
124
125 case Id::BoolUnary_O:
126 return st.st_uid == geteuid();
127
128 case Id::BoolUnary_S:
129 return S_ISSOCK(mode);
130 }
131 }
132
133 FAIL(kShouldNotGetHere);
134}
135
136bool DoBinaryOp(Id_t op_id, BigStr* s1, BigStr* s2) {
137 int m1 = 0;
138 struct stat st1;
139 if (stat(s1->data_, &st1) == 0) {
140 m1 = st1.st_mtime;
141 }
142
143 int m2 = 0;
144 struct stat st2;
145 if (stat(s2->data_, &st2) == 0) {
146 m2 = st2.st_mtime;
147 }
148
149 switch (op_id) {
150 case Id::BoolBinary_nt:
151 return m1 > m2;
152 case Id::BoolBinary_ot:
153 return m1 < m2;
154 case Id::BoolBinary_ef:
155 return st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino;
156 }
157
158 FAIL(kShouldNotGetHere);
159}
160
161} // namespace bool_stat