/* 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 */ #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); } // Stub until the online help system goes in. void usage_exit(void) { exit(1); } // 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; } void xprintf(char *format, ...) { va_list va; va_start(va, format); vprintf(format, va); if (ferror(stdout)) perror_exit("write"); } void xputc(char c) { if (EOF == fputc(c, stdout)) perror_exit("write"); } void xflush(void) { if (fflush(stdout)) perror_exit("write");; } // 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]); } void xaccess(char *path, int flags) { if (access(path, flags)) perror_exit("Can't access '%s'\n", path); } // Die unless we can open/create a file, returning file descriptor. int xcreate(char *path, int flags, int mode) { int fd = open(path, flags, mode); if (fd == -1) perror_exit("No file %s\n", path); return fd; } // Die unless we can open a file, returning file descriptor. int xopen(char *path, int flags) { return xcreate(path, flags, 0); } // Die unless we can open/create a file, returning FILE *. FILE *xfopen(char *path, char *mode) { FILE *f = fopen(path, mode); if (!f) perror_exit("No file %s\n", path); return f; } // Keep reading until full or EOF ssize_t readall(int fd, void *buf, size_t len) { size_t count = 0; while (countpath && *(--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; } // Return how long the file at fd is, if there's any way to determine it. off_t fdlength(int fd) { off_t bottom = 0, top = 0, pos; int size; // If the ioctl works for this, return it. if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512L; // If not, do a binary search for the last location we can read. (Some // block devices don't do BLKGETSIZE right.) This should probably have // a CONFIG option... do { char temp; pos = bottom + (top - bottom) / 2; // If we can read from the current location, it's bigger. if (lseek(fd, pos, 0)>=0 && read(fd, &temp, 1)==1) { if (bottom == top) bottom = top = (top+1) * 2; else bottom = pos; // If we can't, it's smaller. } else { if (bottom == top) { if (!top) return 0; bottom = top/2; } else top = pos; } } while (bottom + 1 != top); return pos + 1; } /* This might be of use or might not. Unknown yet... // Read contents of file as a single freshly allocated nul-terminated string. char *readfile(char *name) { off_t len; int fd; char *buf; fd = open(pidfile, O_RDONLY); if (fd == -1) return 0; len = fdlength(fd); buf = xmalloc(len+1); buf[xread(fd, buf, len)] = 0; return buf; } char *xreadfile(char *name) { char *buf = readfile(name); if (!buf) perror_exit("xreadfile %s", name); return buf; } */ // Open a /var/run/NAME.pid file, dying if we can't write it or if it currently // exists and is this executable. void xpidfile(char *name) { char pidfile[256], spid[32]; int i, fd; pid_t pid; sprintf(pidfile, "/var/run/%s.pid", name); // Try three times to open the sucker. for (i=0; i<3; i++) { fd = open(pidfile, O_CREAT|O_EXCL, 0644); if (fd != -1) break; // If it already existed, read it. Loop for race condition. fd = open(pidfile, O_RDONLY); if (fd == -1) continue; // Is the old program still there? spid[xread(fd, spid, sizeof(spid)-1)] = 0; close(fd); pid = atoi(spid); if (fd < 1 || kill(pid, 0) == ESRCH) unlink(pidfile); // An else with more sanity checking might be nice here. } if (i == 3) error_exit("xpidfile %s", name); xwrite(fd, spid, sprintf(spid, "%ld\n", (long)getpid())); close(fd); } // Create a dirtree node from a path. struct dirtree *read_dirtree_node(char *path) { struct dirtree *dt; char *name; // Find last chunk of name. for (;;) { name = strrchr(path, '/'); if (!name) name = path; else { if (*(name+1)) name++; else { *name=0; continue; } } break; } dt = xzalloc(sizeof(struct dirtree)+strlen(name)+1); xstat(path, &(dt->st)); strcpy(dt->name, name); return dt; } // Given a directory (in a writeable PATH_MAX buffer), recursively read in a // directory tree. struct dirtree *read_dirtree(char *path, struct dirtree *parent) { struct dirtree *dt = NULL, **ddt = &dt; DIR *dir; int len = strlen(path); if (!(dir = opendir(path))) perror_msg("No %s", path); for (;;) { struct dirent *entry = readdir(dir); if (!entry) break; // Skip "." and ".." if (entry->d_name[0]=='.') { if (!entry->d_name[1]) continue; if (entry->d_name[1]=='.' && !entry->d_name[2]) continue; } snprintf(path+len, sizeof(toybuf)-len, "/%s", entry->d_name); *ddt = read_dirtree_node(path); (*ddt)->parent = parent; if (entry->d_type == DT_DIR) (*ddt)->child = read_dirtree(path, *ddt); ddt = &((*ddt)->next); path[len]=0; } return dt; }