| 修订版 | b08d5b5caca499902844099ab6ddf016a7ec8e3d (tree) |
|---|---|
| 时间 | 2018-01-21 20:44:19 |
| 作者 | Waldemar Brodkorb <wbx@ucli...> |
| Commiter | Waldemar Brodkorb |
simplify and fix getcwd
The fallback code is not used as all supported kernels have the
syscall. Check if a absolute path is returned from syscall.
libc/sysdeps/linux/common/getcwd.c (diff)| @@ -16,154 +16,10 @@ | ||
| 16 | 16 | #include <sys/syscall.h> |
| 17 | 17 | |
| 18 | 18 | |
| 19 | - | |
| 20 | -#ifdef __NR_getcwd | |
| 21 | - | |
| 22 | 19 | # define __NR___syscall_getcwd __NR_getcwd |
| 23 | 20 | static __always_inline |
| 24 | 21 | _syscall2(int, __syscall_getcwd, char *, buf, unsigned long, size) |
| 25 | 22 | |
| 26 | -#else | |
| 27 | - | |
| 28 | -/* If the syscall is not present, we have to walk up the | |
| 29 | - * directory tree till we hit the root. Now we _could_ | |
| 30 | - * use /proc/self/cwd if /proc is mounted... That approach | |
| 31 | - * is left an an exercise for the reader... */ | |
| 32 | - | |
| 33 | - | |
| 34 | -/* Seems a few broken filesystems (like coda) don't like this */ | |
| 35 | -/* #undef FAST_DIR_SEARCH_POSSIBLE on Linux */ | |
| 36 | - | |
| 37 | - | |
| 38 | -/* Routine to find the step back down */ | |
| 39 | -static char *search_dir(dev_t this_dev, ino_t this_ino, char *path_buf, int path_size) | |
| 40 | -{ | |
| 41 | - DIR *dp; | |
| 42 | - struct dirent *d; | |
| 43 | - char *ptr; | |
| 44 | - int slen; | |
| 45 | - struct stat st; | |
| 46 | - | |
| 47 | -# ifdef FAST_DIR_SEARCH_POSSIBLE | |
| 48 | - /* The test is for ELKS lib 0.0.9, this should be fixed in the real kernel */ | |
| 49 | - int slow_search = (sizeof(ino_t) != sizeof(d->d_ino)); | |
| 50 | -# endif | |
| 51 | - | |
| 52 | - if (stat(path_buf, &st) < 0) { | |
| 53 | - goto oops; | |
| 54 | - } | |
| 55 | -# ifdef FAST_DIR_SEARCH_POSSIBLE | |
| 56 | - if (this_dev != st.st_dev) | |
| 57 | - slow_search = 1; | |
| 58 | -# endif | |
| 59 | - | |
| 60 | - slen = strlen(path_buf); | |
| 61 | - ptr = path_buf + slen - 1; | |
| 62 | - if (*ptr != '/') { | |
| 63 | - if (slen + 2 > path_size) { | |
| 64 | - goto oops; | |
| 65 | - } | |
| 66 | - strcpy(++ptr, "/"); | |
| 67 | - slen++; | |
| 68 | - } | |
| 69 | - slen++; | |
| 70 | - | |
| 71 | - dp = opendir(path_buf); | |
| 72 | - if (!dp) { | |
| 73 | - goto oops; | |
| 74 | - } | |
| 75 | - | |
| 76 | - while ((d = readdir(dp)) != 0) { | |
| 77 | -# ifdef FAST_DIR_SEARCH_POSSIBLE | |
| 78 | - if (slow_search || this_ino == d->d_ino) { | |
| 79 | -# endif | |
| 80 | - if (slen + strlen(d->d_name) > path_size) { | |
| 81 | - closedir(dp); | |
| 82 | - goto oops; | |
| 83 | - } | |
| 84 | - strcpy(ptr + 1, d->d_name); | |
| 85 | - if (stat(path_buf, &st) < 0) | |
| 86 | - continue; | |
| 87 | - if (st.st_ino == this_ino && st.st_dev == this_dev) { | |
| 88 | - closedir(dp); | |
| 89 | - return path_buf; | |
| 90 | - } | |
| 91 | -# ifdef FAST_DIR_SEARCH_POSSIBLE | |
| 92 | - } | |
| 93 | -# endif | |
| 94 | - } | |
| 95 | - | |
| 96 | - closedir(dp); | |
| 97 | - return 0; | |
| 98 | - | |
| 99 | -oops: | |
| 100 | - __set_errno(ERANGE); | |
| 101 | - return 0; | |
| 102 | -} | |
| 103 | - | |
| 104 | -/* Routine to go up tree */ | |
| 105 | -static char *recurser(char *path_buf, int path_size, dev_t root_dev, ino_t root_ino) | |
| 106 | -{ | |
| 107 | - struct stat st; | |
| 108 | - dev_t this_dev; | |
| 109 | - ino_t this_ino; | |
| 110 | - | |
| 111 | - if (stat(path_buf, &st) < 0) { | |
| 112 | - if (errno != EFAULT) | |
| 113 | - goto oops; | |
| 114 | - return 0; | |
| 115 | - } | |
| 116 | - this_dev = st.st_dev; | |
| 117 | - this_ino = st.st_ino; | |
| 118 | - if (this_dev == root_dev && this_ino == root_ino) { | |
| 119 | - if (path_size < 2) { | |
| 120 | - goto oops; | |
| 121 | - } | |
| 122 | - strcpy(path_buf, "/"); | |
| 123 | - return path_buf; | |
| 124 | - } | |
| 125 | - if (strlen(path_buf) + 4 > path_size) { | |
| 126 | - goto oops; | |
| 127 | - } | |
| 128 | - strcat(path_buf, "/.."); | |
| 129 | - if (recurser(path_buf, path_size, root_dev, root_ino) == 0) | |
| 130 | - return 0; | |
| 131 | - | |
| 132 | - return search_dir(this_dev, this_ino, path_buf, path_size); | |
| 133 | -oops: | |
| 134 | - __set_errno(ERANGE); | |
| 135 | - return 0; | |
| 136 | -} | |
| 137 | - | |
| 138 | -static __always_inline | |
| 139 | -int __syscall_getcwd(char * buf, unsigned long size) | |
| 140 | -{ | |
| 141 | - int len; | |
| 142 | - char *cwd; | |
| 143 | - struct stat st; | |
| 144 | - int olderrno; | |
| 145 | - | |
| 146 | - olderrno = errno; | |
| 147 | - len = -1; | |
| 148 | - | |
| 149 | - /* get stat for root to have a valid parameters for the terminating condition */ | |
| 150 | - if (stat("/", &st) < 0) { | |
| 151 | - /* root dir not found! */ | |
| 152 | - return -1; | |
| 153 | - } | |
| 154 | - /* start with actual dir */ | |
| 155 | - if (buf) strncpy(buf, ".", size); | |
| 156 | - | |
| 157 | - cwd = recurser(buf, size, st.st_dev, st.st_ino); | |
| 158 | - if (cwd) { | |
| 159 | - len = strlen(buf) + 1; | |
| 160 | - __set_errno(olderrno); | |
| 161 | - } | |
| 162 | - return len; | |
| 163 | -} | |
| 164 | - | |
| 165 | -#endif /* __NR_getcwd */ | |
| 166 | - | |
| 167 | 23 | char *getcwd(char *buf, size_t size) |
| 168 | 24 | { |
| 169 | 25 | int ret; |
| @@ -184,7 +40,7 @@ char *getcwd(char *buf, size_t size) | ||
| 184 | 40 | return NULL; |
| 185 | 41 | } |
| 186 | 42 | ret = __syscall_getcwd(path, alloc_size); |
| 187 | - if (ret >= 0) | |
| 43 | + if (ret > 0 && path[0] == '/') | |
| 188 | 44 | { |
| 189 | 45 | if (buf == NULL && size == 0) |
| 190 | 46 | buf = realloc(path, ret); |
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