Mercurial > hg > nginx
comparison src/os/unix/ngx_errno.c @ 7784:8cc5b0365ee5
Improved maximum errno detection.
Previously, systems without sys_nerr (or _sys_nerr) were handled with an
assumption that errors start at 0 and continuous. This is, however, not
something POSIX requires, and not true on some platforms.
Notably, on Linux, where sys_nerr is no longer available for newly linked
binaries starting with glibc 2.32, there are gaps in error list, which
used to stop us from properly detecting maximum errno. Further, on
GNU/Hurd errors start at 0x40000001.
With this change, maximum errno detection is moved to the runtime code,
now able to ignore gaps, and also detects the first error if needed.
This fixes observed "Unknown error" messages as seen on Linux with
glibc 2.32 and on GNU/Hurd.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 01 Mar 2021 20:00:43 +0300 |
parents | f1a0de6eb505 |
children | c43a2e8fdf7e |
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7783:171682010da4 | 7784:8cc5b0365ee5 |
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25 */ | 25 */ |
26 | 26 |
27 | 27 |
28 static ngx_str_t *ngx_sys_errlist; | 28 static ngx_str_t *ngx_sys_errlist; |
29 static ngx_str_t ngx_unknown_error = ngx_string("Unknown error"); | 29 static ngx_str_t ngx_unknown_error = ngx_string("Unknown error"); |
30 static ngx_err_t ngx_first_error; | |
31 static ngx_err_t ngx_last_error; | |
30 | 32 |
31 | 33 |
32 u_char * | 34 u_char * |
33 ngx_strerror(ngx_err_t err, u_char *errstr, size_t size) | 35 ngx_strerror(ngx_err_t err, u_char *errstr, size_t size) |
34 { | 36 { |
35 ngx_str_t *msg; | 37 ngx_str_t *msg; |
36 | 38 |
37 msg = ((ngx_uint_t) err < NGX_SYS_NERR) ? &ngx_sys_errlist[err]: | 39 if (err >= ngx_first_error && err < ngx_last_error) { |
38 &ngx_unknown_error; | 40 msg = &ngx_sys_errlist[err - ngx_first_error]; |
41 | |
42 } else { | |
43 msg = &ngx_unknown_error; | |
44 } | |
45 | |
39 size = ngx_min(size, msg->len); | 46 size = ngx_min(size, msg->len); |
40 | 47 |
41 return ngx_cpymem(errstr, msg->data, size); | 48 return ngx_cpymem(errstr, msg->data, size); |
42 } | 49 } |
43 | 50 |
48 char *msg; | 55 char *msg; |
49 u_char *p; | 56 u_char *p; |
50 size_t len; | 57 size_t len; |
51 ngx_err_t err; | 58 ngx_err_t err; |
52 | 59 |
60 #if (NGX_SYS_NERR) | |
61 ngx_first_error = 0; | |
62 ngx_last_error = NGX_SYS_NERR; | |
63 | |
64 #elif (EPERM > 1000 && EPERM < 0x7fffffff - 1000) | |
65 | |
66 /* | |
67 * If number of errors is not known, and EPERM error code has large | |
68 * but reasonable value, guess possible error codes based on the error | |
69 * messages returned by strerror(), starting from EPERM. Notably, | |
70 * this covers GNU/Hurd, where errors start at 0x40000001. | |
71 */ | |
72 | |
73 for (err = EPERM; err > EPERM - 1000; err--) { | |
74 ngx_set_errno(0); | |
75 msg = strerror(err); | |
76 | |
77 if (errno == EINVAL | |
78 || msg == NULL | |
79 || strncmp(msg, "Unknown error", 13) == 0) | |
80 { | |
81 continue; | |
82 } | |
83 | |
84 ngx_first_error = err; | |
85 } | |
86 | |
87 for (err = EPERM; err < EPERM + 1000; err++) { | |
88 ngx_set_errno(0); | |
89 msg = strerror(err); | |
90 | |
91 if (errno == EINVAL | |
92 || msg == NULL | |
93 || strncmp(msg, "Unknown error", 13) == 0) | |
94 { | |
95 continue; | |
96 } | |
97 | |
98 ngx_last_error = err + 1; | |
99 } | |
100 | |
101 #else | |
102 | |
103 /* | |
104 * If number of errors is not known, guess it based on the error | |
105 * messages returned by strerror(). | |
106 */ | |
107 | |
108 ngx_first_error = 0; | |
109 | |
110 for (err = 0; err < 1000; err++) { | |
111 ngx_set_errno(0); | |
112 msg = strerror(err); | |
113 | |
114 if (errno == EINVAL | |
115 || msg == NULL | |
116 || strncmp(msg, "Unknown error", 13) == 0) | |
117 { | |
118 continue; | |
119 } | |
120 | |
121 ngx_last_error = err + 1; | |
122 } | |
123 | |
124 #endif | |
125 | |
53 /* | 126 /* |
54 * ngx_strerror() is not ready to work at this stage, therefore, | 127 * ngx_strerror() is not ready to work at this stage, therefore, |
55 * malloc() is used and possible errors are logged using strerror(). | 128 * malloc() is used and possible errors are logged using strerror(). |
56 */ | 129 */ |
57 | 130 |
58 len = NGX_SYS_NERR * sizeof(ngx_str_t); | 131 len = (ngx_last_error - ngx_first_error) * sizeof(ngx_str_t); |
59 | 132 |
60 ngx_sys_errlist = malloc(len); | 133 ngx_sys_errlist = malloc(len); |
61 if (ngx_sys_errlist == NULL) { | 134 if (ngx_sys_errlist == NULL) { |
62 goto failed; | 135 goto failed; |
63 } | 136 } |
64 | 137 |
65 for (err = 0; err < NGX_SYS_NERR; err++) { | 138 for (err = ngx_first_error; err < ngx_last_error; err++) { |
66 msg = strerror(err); | 139 msg = strerror(err); |
140 | |
141 if (msg == NULL) { | |
142 ngx_sys_errlist[err - ngx_first_error] = ngx_unknown_error; | |
143 continue; | |
144 } | |
145 | |
67 len = ngx_strlen(msg); | 146 len = ngx_strlen(msg); |
68 | 147 |
69 p = malloc(len); | 148 p = malloc(len); |
70 if (p == NULL) { | 149 if (p == NULL) { |
71 goto failed; | 150 goto failed; |
72 } | 151 } |
73 | 152 |
74 ngx_memcpy(p, msg, len); | 153 ngx_memcpy(p, msg, len); |
75 ngx_sys_errlist[err].len = len; | 154 ngx_sys_errlist[err - ngx_first_error].len = len; |
76 ngx_sys_errlist[err].data = p; | 155 ngx_sys_errlist[err - ngx_first_error].data = p; |
77 } | 156 } |
78 | 157 |
79 return NGX_OK; | 158 return NGX_OK; |
80 | 159 |
81 failed: | 160 failed: |