diff options
Diffstat (limited to 'wrapper.c')
| -rw-r--r-- | wrapper.c | 177 |
1 files changed, 162 insertions, 15 deletions
@@ -172,8 +172,57 @@ void *xcalloc(size_t nmemb, size_t size) * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in * the absence of bugs, large chunks can result in bad latencies when * you decide to kill the process. + * + * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX + * that is smaller than that, clip it to SSIZE_MAX, as a call to + * read(2) or write(2) larger than that is allowed to fail. As the last + * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value" + * to override this, if the definition of SSIZE_MAX given by the platform + * is broken. */ -#define MAX_IO_SIZE (8*1024*1024) +#ifndef MAX_IO_SIZE +# define MAX_IO_SIZE_DEFAULT (8*1024*1024) +# if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT) +# define MAX_IO_SIZE SSIZE_MAX +# else +# define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT +# endif +#endif + +/** + * xopen() is the same as open(), but it die()s if the open() fails. + */ +int xopen(const char *path, int oflag, ...) +{ + mode_t mode = 0; + va_list ap; + + /* + * va_arg() will have undefined behavior if the specified type is not + * compatible with the argument type. Since integers are promoted to + * ints, we fetch the next argument as an int, and then cast it to a + * mode_t to avoid undefined behavior. + */ + va_start(ap, oflag); + if (oflag & O_CREAT) + mode = va_arg(ap, int); + va_end(ap); + + for (;;) { + int fd = open(path, oflag, mode); + if (fd >= 0) + return fd; + if (errno == EINTR) + continue; + + if ((oflag & O_RDWR) == O_RDWR) + die_errno(_("could not open '%s' for reading and writing"), path); + else if ((oflag & O_WRONLY) == O_WRONLY) + die_errno(_("could not open '%s' for writing"), path); + else + die_errno(_("could not open '%s' for reading"), path); + } +} /* * xread() is the same a read(), but it automatically restarts read() @@ -187,8 +236,24 @@ ssize_t xread(int fd, void *buf, size_t len) len = MAX_IO_SIZE; while (1) { nr = read(fd, buf, len); - if ((nr < 0) && (errno == EAGAIN || errno == EINTR)) - continue; + if (nr < 0) { + if (errno == EINTR) + continue; + if (errno == EAGAIN || errno == EWOULDBLOCK) { + struct pollfd pfd; + pfd.events = POLLIN; + pfd.fd = fd; + /* + * it is OK if this poll() failed; we + * want to leave this infinite loop + * only when read() returns with + * success, or an expected failure, + * which would be checked by the next + * call to read(2). + */ + poll(&pfd, 1, -1); + } + } return nr; } } @@ -297,6 +362,27 @@ int xdup(int fd) return ret; } +/** + * xfopen() is the same as fopen(), but it die()s if the fopen() fails. + */ +FILE *xfopen(const char *path, const char *mode) +{ + for (;;) { + FILE *fp = fopen(path, mode); + if (fp) + return fp; + if (errno == EINTR) + continue; + + if (*mode && mode[1] == '+') + die_errno(_("could not open '%s' for reading and writing"), path); + else if (*mode == 'w' || *mode == 'a') + die_errno(_("could not open '%s' for writing"), path); + else + die_errno(_("could not open '%s' for reading"), path); + } +} + FILE *xfdopen(int fd, const char *mode) { FILE *stream = fdopen(fd, mode); @@ -531,18 +617,6 @@ int access_or_die(const char *path, int mode, unsigned flag) return ret; } -struct passwd *xgetpwuid_self(void) -{ - struct passwd *pw; - - errno = 0; - pw = getpwuid(getuid()); - if (!pw) - die(_("unable to look up current user in the passwd file: %s"), - errno ? strerror(errno) : _("no such user")); - return pw; -} - char *xgetcwd(void) { struct strbuf sb = STRBUF_INIT; @@ -550,3 +624,76 @@ char *xgetcwd(void) die_errno(_("unable to get current working directory")); return strbuf_detach(&sb, NULL); } + +int xsnprintf(char *dst, size_t max, const char *fmt, ...) +{ + va_list ap; + int len; + + va_start(ap, fmt); + len = vsnprintf(dst, max, fmt, ap); + va_end(ap); + + if (len < 0) + die("BUG: your snprintf is broken"); + if (len >= max) + die("BUG: attempt to snprintf into too-small buffer"); + return len; +} + +static int write_file_v(const char *path, int fatal, + const char *fmt, va_list params) +{ + struct strbuf sb = STRBUF_INIT; + int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666); + if (fd < 0) { + if (fatal) + die_errno(_("could not open %s for writing"), path); + return -1; + } + strbuf_vaddf(&sb, fmt, params); + strbuf_complete_line(&sb); + if (write_in_full(fd, sb.buf, sb.len) != sb.len) { + int err = errno; + close(fd); + strbuf_release(&sb); + errno = err; + if (fatal) + die_errno(_("could not write to %s"), path); + return -1; + } + strbuf_release(&sb); + if (close(fd)) { + if (fatal) + die_errno(_("could not close %s"), path); + return -1; + } + return 0; +} + +int write_file(const char *path, const char *fmt, ...) +{ + int status; + va_list params; + + va_start(params, fmt); + status = write_file_v(path, 1, fmt, params); + va_end(params); + return status; +} + +int write_file_gently(const char *path, const char *fmt, ...) +{ + int status; + va_list params; + + va_start(params, fmt); + status = write_file_v(path, 0, fmt, params); + va_end(params); + return status; +} + +void sleep_millisec(int millisec) +{ + poll(NULL, 0, millisec); +} |