/* vi: set sw=4 ts=4 :*/ /* functions.c - reusable stuff. * * Functions with the x prefix are wrappers for library functions. They either * succeed or kill the program with an error message, but never return failure. * They usually have the same arguments and return value as the function they * wrap. * * Copyright 2006 Rob Landley <rob@landley.net> */ #include "toys.h" void verror_msg(char *msg, int err, va_list va) { fprintf(stderr, "%s: ", toys.which->name); vfprintf(stderr, msg, va); if (err) fprintf(stderr, ": %s", strerror(err)); putc('\n', stderr); } void error_msg(char *msg, ...) { va_list va; va_start(va, msg); verror_msg(msg, 0, va); va_end(va); } void perror_msg(char *msg, ...) { va_list va; va_start(va, msg); verror_msg(msg, errno, va); va_end(va); } // Die with an error message. void error_exit(char *msg, ...) { va_list va; va_start(va, msg); verror_msg(msg, 0, va); va_end(va); exit(toys.exitval); } // Die with an error message and strerror(errno) void perror_exit(char *msg, ...) { va_list va; va_start(va, msg); verror_msg(msg, errno, va); va_end(va); exit(toys.exitval); } // Like strncpy but always null terminated. void strlcpy(char *dest, char *src, size_t size) { strncpy(dest,src,size); dest[size-1] = 0; } // Die unless we can allocate memory. void *xmalloc(size_t size) { void *ret = malloc(size); if (!ret) error_exit("xmalloc"); return ret; } // Die unless we can allocate prezeroed memory. void *xzalloc(size_t size) { void *ret = xmalloc(size); bzero(ret,size); return ret; } // Die unless we can change the size of an existing allocation, possibly // moving it. (Notice different arguments from libc function.) void xrealloc(void **ptr, size_t size) { *ptr = realloc(*ptr, size); if (!*ptr) error_exit("xrealloc"); } // Die unless we can allocate a copy of this many bytes of string. void *xstrndup(char *s, size_t n) { void *ret = xmalloc(++n); strlcpy(ret, s, n); return ret; } // Die unless we can allocate a copy of this string. void *xstrdup(char *s) { return xstrndup(s,strlen(s)); } // Die unless we can allocate enough space to sprintf() into. char *xmsprintf(char *format, ...) { va_list va; int len; char *ret; // How long is it? va_start(va, format); len = vsnprintf(0, 0, format, va); len++; va_end(va); // Allocate and do the sprintf() ret = xmalloc(len); va_start(va, format); vsnprintf(ret, len, format, va); va_end(va); return ret; } // Die unless we can exec argv[] (or run builtin command). Note that anything // with a path isn't a builtin, so /bin/sh won't match the builtin sh. void xexec(char **argv) { toy_exec(argv); execvp(argv[0], argv); error_exit("No %s", argv[0]); } // Die unless we can open/create a file, returning file descriptor. int xopen(char *path, int flags, int mode) { int fd = open(path, flags, mode); if (fd == -1) error_exit("No file %s\n", path); return fd; } // Die unless we can open/create a file, returning FILE *. FILE *xfopen(char *path, char *mode) { FILE *f = fopen(path, mode); if (!f) error_exit("No file %s\n", path); return f; } // Read from file handle, retrying if interrupted. ssize_t reread(int fd, void *buf, size_t count) { ssize_t len; for (;;) { len = read(fd, buf, count); if (len >= 0 || errno != EINTR) return len; } } // Keep reading until full or EOF ssize_t readall(int fd, void *buf, size_t count) { size_t len = 0; while (len<count) { int i = reread(fd, buf, count); if (!i) return len; if (i<0) return i; count += i; } return count; } // Die if we can't fill a buffer void xread(int fd, char *buf, size_t count) { if (count != readall(fd, buf, count)) perror_exit("xread"); } char *xgetcwd(void) { char *buf = getcwd(NULL, 0); if (!buf) error_exit("xgetcwd"); return buf; } // Cannonicalizes path by removing ".", "..", and "//" elements. This is not // the same as realpath(), where "dir/.." char *xabspath(char *path) { char *from, *to; // If this isn't an absolute path, make it one with cwd. if (path[0]!='/') { char *cwd=xgetcwd(); path = xmsprintf("%s/%s",cwd,path); free(cwd); } else path = xstrdup(path); // Loop through path elements from = to = path; while (*from) { // Continue any current path component. if (*from!='/') { *(to++) = *(from++); continue; } // Skip duplicate slashes. while (*from=='/') from++; // Start of a new filename. Handle . and .. while (*from=='.') { // Skip . if (from[1]=='/') from += 2; else if (!from[1]) from++; // Back up for .. else if (from[1]=='.') { if (from[2]=='/') from +=3; else if(!from[2]) from+=2; else break; while (to>path && *(--to)!='/'); } else break; } // Add directory separator slash. *(to++) = '/'; } *to = 0; return path; } // Find all file in a colon-separated path with access type "type" (generally // X_OK or R_OK). Returns a list of absolute paths to each file found, in // order. struct string_list *find_in_path(char *path, char *filename) { struct string_list *rlist = NULL; char *cwd = xgetcwd(); for (;;) { char *next = path ? index(path, ':') : NULL; int len = next ? next-path : strlen(path); struct string_list *rnext; struct stat st; rnext = xmalloc(sizeof(void *) + strlen(filename) + (len ? len : strlen(cwd)) + 2); if (!len) sprintf(rnext->str, "%s/%s", cwd, filename); else { char *res = rnext->str; strncpy(res, path, len); res += len; *(res++) = '/'; strcpy(res, filename); } // Confirm it's not a directory. if (!stat(rnext->str, &st) && S_ISREG(st.st_mode)) { rnext->next = rlist; rlist = rnext; } else free(rnext); if (!next) break; path += len; path++; } free(cwd); return rlist; } // Convert unsigned int to ascii, writing into supplied buffer. A truncated // result contains the first few digits of the result ala strncpy, and is // always null terminated (unless buflen is 0). void utoa_to_buf(unsigned n, char *buf, unsigned buflen) { int i, out = 0; if (buflen) { for (i=1000000000; i; i/=10) { int res = n/i; if ((res || out || i == 1) && --buflen>0) { out++; n -= res*i; *buf++ = '0' + res; } } *buf = 0; } } // Convert signed integer to ascii, using utoa_to_buf() void itoa_to_buf(int n, char *buf, unsigned buflen) { if (buflen && n<0) { n = -n; *buf++ = '-'; buflen--; } utoa_to_buf((unsigned)n, buf, buflen); } // This static buffer is used by both utoa() and itoa(), calling either one a // second time will overwrite the previous results. // // The longest 32 bit integer is -2 billion plus a null terminator: 12 bytes. // Note that int is always 32 bits on any remotely unix-like system, see // http://www.unix.org/whitepapers/64bit.html for details. static char itoa_buf[12]; // Convert unsigned integer to ascii, returning a static buffer. char *utoa(unsigned n) { utoa_to_buf(n, itoa_buf, sizeof(itoa_buf)); return itoa_buf; } char *itoa(int n) { itoa_to_buf(n, itoa_buf, sizeof(itoa_buf)); return itoa_buf; }