1#include "cache.h" 2 3/* 4 * Do not use this for inspecting *tracked* content. When path is a 5 * symlink to a directory, we do not want to say it is a directory when 6 * dealing with tracked content in the working tree. 7 */ 8int is_directory(const char *path) 9{ 10 struct stat st; 11 return (!stat(path, &st) && S_ISDIR(st.st_mode)); 12} 13 14/* We allow "recursive" symbolic links. Only within reason, though. */ 15#define MAXDEPTH 5 16 17/* 18 * Return the real path (i.e., absolute path, with symlinks resolved 19 * and extra slashes removed) equivalent to the specified path. (If 20 * you want an absolute path but don't mind links, use 21 * absolute_path().) The return value is a pointer to a static 22 * buffer. 23 * 24 * The input and all intermediate paths must be shorter than MAX_PATH. 25 * The directory part of path (i.e., everything up to the last 26 * dir_sep) must denote a valid, existing directory, but the last 27 * component need not exist. If die_on_error is set, then die with an 28 * informative error message if there is a problem. Otherwise, return 29 * NULL on errors (without generating any output). 30 * 31 * If path is our buffer, then return path, as it's already what the 32 * user wants. 33 */ 34static const char *real_path_internal(const char *path, int die_on_error) 35{ 36 static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1]; 37 char *retval = NULL; 38 char cwd[1024] = ""; 39 int buf_index = 1; 40 41 int depth = MAXDEPTH; 42 char *last_elem = NULL; 43 struct stat st; 44 45 /* We've already done it */ 46 if (path == buf || path == next_buf) 47 return path; 48 49 if (!*path) { 50 if (die_on_error) 51 die("The empty string is not a valid path"); 52 else 53 goto error_out; 54 } 55 56 if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) { 57 if (die_on_error) 58 die("Too long path: %.*s", 60, path); 59 else 60 goto error_out; 61 } 62 63 while (depth--) { 64 if (!is_directory(buf)) { 65 char *last_slash = find_last_dir_sep(buf); 66 if (last_slash) { 67 last_elem = xstrdup(last_slash + 1); 68 last_slash[1] = '\0'; 69 } else { 70 last_elem = xstrdup(buf); 71 *buf = '\0'; 72 } 73 } 74 75 if (*buf) { 76 if (!*cwd && !getcwd(cwd, sizeof(cwd))) { 77 if (die_on_error) 78 die_errno("Could not get current working directory"); 79 else 80 goto error_out; 81 } 82 83 if (chdir(buf)) { 84 if (die_on_error) 85 die_errno("Could not switch to '%s'", buf); 86 else 87 goto error_out; 88 } 89 } 90 if (!getcwd(buf, PATH_MAX)) { 91 if (die_on_error) 92 die_errno("Could not get current working directory"); 93 else 94 goto error_out; 95 } 96 97 if (last_elem) { 98 size_t len = strlen(buf); 99 if (len + strlen(last_elem) + 2 > PATH_MAX) { 100 if (die_on_error) 101 die("Too long path name: '%s/%s'", 102 buf, last_elem); 103 else 104 goto error_out; 105 } 106 if (len && !is_dir_sep(buf[len-1])) 107 buf[len++] = '/'; 108 strcpy(buf + len, last_elem); 109 free(last_elem); 110 last_elem = NULL; 111 } 112 113 if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) { 114 ssize_t len = readlink(buf, next_buf, PATH_MAX); 115 if (len < 0) { 116 if (die_on_error) 117 die_errno("Invalid symlink '%s'", buf); 118 else 119 goto error_out; 120 } 121 if (PATH_MAX <= len) { 122 if (die_on_error) 123 die("symbolic link too long: %s", buf); 124 else 125 goto error_out; 126 } 127 next_buf[len] = '\0'; 128 buf = next_buf; 129 buf_index = 1 - buf_index; 130 next_buf = bufs[buf_index]; 131 } else 132 break; 133 } 134 135 retval = buf; 136error_out: 137 free(last_elem); 138 if (*cwd && chdir(cwd)) 139 die_errno ("Could not change back to '%s'", cwd); 140 141 return retval; 142} 143 144const char *real_path(const char *path) 145{ 146 return real_path_internal(path, 1); 147} 148 149static const char *get_pwd_cwd(void) 150{ 151 static char cwd[PATH_MAX + 1]; 152 char *pwd; 153 struct stat cwd_stat, pwd_stat; 154 if (getcwd(cwd, PATH_MAX) == NULL) 155 return NULL; 156 pwd = getenv("PWD"); 157 if (pwd && strcmp(pwd, cwd)) { 158 stat(cwd, &cwd_stat); 159 if ((cwd_stat.st_dev || cwd_stat.st_ino) && 160 !stat(pwd, &pwd_stat) && 161 pwd_stat.st_dev == cwd_stat.st_dev && 162 pwd_stat.st_ino == cwd_stat.st_ino) { 163 strlcpy(cwd, pwd, PATH_MAX); 164 } 165 } 166 return cwd; 167} 168 169/* 170 * Use this to get an absolute path from a relative one. If you want 171 * to resolve links, you should use real_path. 172 * 173 * If the path is already absolute, then return path. As the user is 174 * never meant to free the return value, we're safe. 175 */ 176const char *absolute_path(const char *path) 177{ 178 static char buf[PATH_MAX + 1]; 179 180 if (!*path) { 181 die("The empty string is not a valid path"); 182 } else if (is_absolute_path(path)) { 183 if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) 184 die("Too long path: %.*s", 60, path); 185 } else { 186 size_t len; 187 const char *fmt; 188 const char *cwd = get_pwd_cwd(); 189 if (!cwd) 190 die_errno("Cannot determine the current working directory"); 191 len = strlen(cwd); 192 fmt = (len > 0 && is_dir_sep(cwd[len-1])) ? "%s%s" : "%s/%s"; 193 if (snprintf(buf, PATH_MAX, fmt, cwd, path) >= PATH_MAX) 194 die("Too long path: %.*s", 60, path); 195 } 196 return buf; 197} 198 199/* 200 * Unlike prefix_path, this should be used if the named file does 201 * not have to interact with index entry; i.e. name of a random file 202 * on the filesystem. 203 */ 204const char *prefix_filename(const char *pfx, int pfx_len, const char *arg) 205{ 206 static char path[PATH_MAX]; 207#ifndef WIN32 208 if (!pfx_len || is_absolute_path(arg)) 209 return arg; 210 memcpy(path, pfx, pfx_len); 211 strcpy(path + pfx_len, arg); 212#else 213 char *p; 214 /* don't add prefix to absolute paths, but still replace '\' by '/' */ 215 if (is_absolute_path(arg)) 216 pfx_len = 0; 217 else if (pfx_len) 218 memcpy(path, pfx, pfx_len); 219 strcpy(path + pfx_len, arg); 220 for (p = path + pfx_len; *p; p++) 221 if (*p == '\\') 222 *p = '/'; 223#endif 224 return path; 225}