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[/] [or1k/] [trunk/] [uclinux/] [uC-libc/] [misc/] [getcwd.c] - Rev 199
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#include <errno.h> #include <sys/stat.h> #include <dirent.h> #include <string.h> /* * These functions find the absolute path to the current working directory. * * They don't use malloc or large amounts of stack space. */ static char * recurser(); /* Routine to go up tree */ static char * search_dir(); /* Routine to find the step back down */ static char * path_buf; static int path_size; static dev_t root_dev; static ino_t root_ino; static struct stat st; char * getcwd(buf, size) char * buf; int size; { path_buf = buf; path_size = size; if( size < 3 ) { errno = ERANGE; return 0; } strcpy(path_buf, "."); if( stat("/", &st) < 0 ) return 0; root_dev = st.st_dev; root_ino = st.st_ino; return recurser(); } static char * recurser() { dev_t this_dev; ino_t this_ino; if( stat(path_buf, &st) < 0 ) return 0; this_dev = st.st_dev; this_ino = st.st_ino; if( this_dev == root_dev && this_ino == root_ino ) { strcpy(path_buf, "/"); return path_buf; } if( strlen(path_buf) + 4 > path_size ) { errno = ERANGE; return 0; } strcat(path_buf, "/.."); if( recurser() == 0 ) return 0; return search_dir(this_dev, this_ino); } static char * search_dir(this_dev, this_ino) dev_t this_dev; ino_t this_ino; { DIR * dp; struct dirent * d; char * ptr; int slen; /* The test is for ELKS lib 0.0.9, this should be fixed in the real kernel*/ int slow_search = (sizeof(ino_t) != sizeof(d->d_ino)); if( stat(path_buf, &st) < 0 ) return 0; if( this_dev != st.st_dev ) slow_search = 1; slen = strlen(path_buf); ptr = path_buf + slen -1; if( *ptr != '/' ) { if( slen + 2 > path_size ) { errno = ERANGE; return 0; } strcpy(++ptr, "/"); slen++; } slen++; dp = opendir(path_buf); if( dp == 0 ) return 0; while( (d=readdir(dp)) != 0 ) { if( slow_search || this_ino == d->d_ino ) { if( slen + strlen(d->d_name) > path_size ) { errno = ERANGE; return 0; } strcpy(ptr+1, d->d_name); if( stat(path_buf, &st) < 0 ) continue; if( st.st_ino == this_ino && st.st_dev == this_dev ) { closedir(dp); return path_buf; } } } closedir(dp); errno = ENOENT; return 0; }
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