config/pathsub.c

   1 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5 /*
   6 ** Pathname subroutines.
   7 **
   8 ** Brendan Eich, 8/29/95
   9 */
  10 #include <assert.h>
  11 #include <sys/types.h>
  12 #include <dirent.h>
  13 #include <errno.h>
  14 #include <stdarg.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <unistd.h>
  19 #include <sys/stat.h>
  20 #include "pathsub.h"
  21
  22 #ifdef USE_REENTRANT_LIBC
  23 #include <libc_r.h>
  24 #endif
  25
  26 #ifdef SUNOS4
  27 #include "sunos4.h"
  28 #endif
  29
  30 #ifndef D_INO
  31 #define D_INO   d_ino
  32 #endif
  33
  34 char *program;
  35
  36 void
  37 fail(char *format, ...)
  38 {
  39     int error;
  40     va_list ap;
  41
  42 #ifdef USE_REENTRANT_LIBC
  43     R_STRERROR_INIT_R();
  44 #endif
  45
  46     error = errno;
  47     fprintf(stderr, "%s: ", program);
  48     va_start(ap, format);
  49     vfprintf(stderr, format, ap);
  50     va_end(ap);
  51     if (error) {
  52
  53 #ifdef USE_REENTRANT_LIBC
  54     R_STRERROR_R(errno);
  55         fprintf(stderr, ": %s", r_strerror_r);
  56 #else
  57         fprintf(stderr, ": %s", strerror(errno));
  58 #endif
  59     }
  60
  61     putc('\n', stderr);
  62     exit(1);
  63 }
  64
  65 char *
  66 getcomponent(char *path, char *name)
  67 {
  68     if (*path == '\0')
  69         return 0;
  70     if (*path == '/') {
  71         *name++ = '/';
  72     } else {
  73         do {
  74             *name++ = *path++;
  75         } while (*path != '/' && *path != '\0');
  76     }
  77     *name = '\0';
  78     while (*path == '/')
  79         path++;
  80     return path;
  81 }
  82
  83 #ifdef LAME_READDIR
  84 #include <sys/param.h>
  85 /*
  86 ** The static buffer in Unixware's readdir is too small.
  87 */
  88 struct dirent *readdir(DIR *d)
  89 {
  90         static struct dirent *buf = NULL;
  91
  92         if(buf == NULL)
  93                 buf = (struct dirent *) malloc(sizeof(struct dirent) + MAXPATHLEN);
  94         return(readdir_r(d, buf));
  95 }
  96 #endif
  97
  98 char *
  99 ino2name(ino_t ino)
 100 {
 101     DIR *dp;
 102     struct dirent *ep;
 103     char *name;
 104
 105     dp = opendir("..");
 106     if (!dp)
 107         fail("cannot read parent directory");
 108     for (;;) {
 109         if (!(ep = readdir(dp)))
 110             fail("cannot find current directory");
 111         if (ep->D_INO == ino)
 112             break;
 113     }
 114     name = xstrdup(ep->d_name);
 115     closedir(dp);
 116     return name;
 117 }
 118
 119 void *
 120 xmalloc(size_t size)
 121 {
 122     void *p = malloc(size);
 123     if (!p)
 124         fail("cannot allocate %u bytes", size);
 125     return p;
 126 }
 127
 128 char *
 129 xstrdup(char *s)
 130 {
 131     return strcpy(xmalloc(strlen(s) + 1), s);
 132 }
 133
 134 char *
 135 xbasename(char *path)
 136 {
 137     char *cp;
 138
 139     while ((cp = strrchr(path, '/')) && cp[1] == '\0')
 140         *cp = '\0';
 141     if (!cp) return path;
 142     return cp + 1;
 143 }
 144
 145 void
 146 xchdir(char *dir)
 147 {
 148     if (chdir(dir) < 0)
 149         fail("cannot change directory to %s", dir);
 150 }
 151
 152 int
 153 relatepaths(char *from, char *to, char *outpath)
 154 {
 155     char *cp, *cp2;
 156     int len;
 157     char buf[NAME_MAX];
 158
 159     assert(*from == '/' && *to == '/');
 160     for (cp = to, cp2 = from; *cp == *cp2; cp++, cp2++)
 161         if (*cp == '\0')
 162             break;
 163     while (cp[-1] != '/')
 164         cp--, cp2--;
 165     if (cp - 1 == to) {
 166         /* closest common ancestor is /, so use full pathname */
 167         len = strlen(strcpy(outpath, to));
 168         if (outpath[len] != '/') {
 169             outpath[len++] = '/';
 170             outpath[len] = '\0';
 171         }
 172     } else {
 173         len = 0;
 174         while ((cp2 = getcomponent(cp2, buf)) != 0) {
 175             strcpy(outpath + len, "../");
 176             len += 3;
 177         }
 178         while ((cp = getcomponent(cp, buf)) != 0) {
 179             sprintf(outpath + len, "%s/", buf);
 180             len += strlen(outpath + len);
 181         }
 182     }
 183     return len;
 184 }
 185
 186 void
 187 reversepath(char *inpath, char *name, int len, char *outpath)
 188 {
 189     char *cp, *cp2;
 190     char buf[NAME_MAX];
 191     struct stat sb;
 192
 193     cp = strcpy(outpath + PATH_MAX - (len + 1), name);
 194     cp2 = inpath;
 195     while ((cp2 = getcomponent(cp2, buf)) != 0) {
 196         if (strcmp(buf, ".") == 0)
 197             continue;
 198         if (strcmp(buf, "..") == 0) {
 199             if (stat(".", &sb) < 0)
 200                 fail("cannot stat current directory");
 201             name = ino2name(sb.st_ino);
 202             len = strlen(name);
 203             cp -= len + 1;
 204             strcpy(cp, name);
 205             cp[len] = '/';
 206             free(name);
 207             xchdir("..");
 208         } else {
 209             cp -= 3;
 210             strncpy(cp, "../", 3);
 211             xchdir(buf);
 212         }
 213     }
 214     strcpy(outpath, cp);
 215 }