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#include <sys/sendfile.h>
#include <sys/stat.h>
#include <err.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#define warn(...) \
do { \
warn(__VA_ARGS__); \
rv = EXIT_FAILURE; \
} while (0)
static int rv = EXIT_SUCCESS;
static bool out_is_reg;
static char buf[BUFSIZ];
static void cat(const char *);
static void cat_sendfile(const char *, int, size_t);
static void cat_readwrite(const char *, int);
int
main(int argc, char **argv)
{
struct stat sb;
if (fstat(STDOUT_FILENO, &sb) == -1)
warn("fstat: /dev/stdout");
else
out_is_reg = S_ISREG(sb.st_mode);
if (argc == 1)
cat("-");
for (int i = 1; i < argc; i++)
cat(argv[i]);
return rv;
}
void
cat(const char *file)
{
int fd;
struct stat sb;
if (strcmp(file, "-") == 0)
fd = STDIN_FILENO;
else if ((fd = open(file, O_RDONLY)) == -1) {
warn("open: %s", file);
return;
}
if (fstat(fd, &sb) == -1) {
warn("fstat: %s", file);
goto out;
}
if (S_ISREG(sb.st_mode) && out_is_reg)
cat_sendfile(file, fd, sb.st_size);
else
cat_readwrite(file, fd);
out:
close(fd);
}
void
cat_sendfile(const char *file, int fd, size_t n)
{
off_t off = 0;
ssize_t nw;
do {
nw = sendfile(STDOUT_FILENO, fd, &off, n);
off += nw;
} while (nw != -1 && (size_t)off < n);
if (nw == -1)
warn("sendfile: %s", file);
}
void
cat_readwrite(const char *file, int fd)
{
ssize_t nr, nw;
while ((nr = read(fd, buf, BUFSIZ)) > 0) {
for (ssize_t off = 0; nr > 0; nr -= nw, off += nw) {
if ((nw = write(STDOUT_FILENO, buf + off, nr)) == -1) {
warn("write: %s", file);
return;
}
}
}
if (nr == -1)
warn("read: %s", file);
}
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