diff options
Diffstat (limited to 'runfd.c')
| -rw-r--r-- | runfd.c | 26 |
1 files changed, 21 insertions, 5 deletions
@@ -11,6 +11,7 @@ */ #define DEFAULT_FD 3 +#define BIN_HDR_LEN 2 char *args[] = { "batchrun", NULL }; @@ -32,10 +33,17 @@ set_async(int fd, int on) err(1, "fcntl()"); } +void +set_cloexec(int fd, int on) +{ + if (fcntl(fd, F_SETFD, on ? FD_CLOEXEC : 0) == -1) + err(1, "fcntl()"); +} + int main(int argc, char **argv) { - char buf[2], *end = NULL; + char buf[BIN_HDR_LEN], *end = NULL; ssize_t ret; int tries = 0, fd = DEFAULT_FD; @@ -46,6 +54,7 @@ main(int argc, char **argv) errx(1, "Filedescriptor supplied (\"%s\") is not a number", argv[1]); } + set_cloexec(fd, 1); set_async(fd, 1); retry: @@ -53,9 +62,9 @@ retry: errx(1, "Failed to read file header"); ret = pread(fd, buf, sizeof(buf), 0); - if (ret == 2) { - if (strncmp(buf, "#!", 2) != 0) { - fcntl(fd, F_SETFD, FD_CLOEXEC); + if (ret == sizeof(buf)) { + if (strncmp(buf, "#!", sizeof(buf)) == 0) { + set_cloexec(fd, 0); } } else if (ret == -1) { if (errno == EINTR) @@ -63,7 +72,14 @@ retry: else if (errno != EAGAIN) err(1, "pread()"); } else if (ret != 0) { - goto retry; + /** + * We take a lazy approach here and only want to know if the + * file has more contents (and don't care about errors). + */ + ret = pread(fd, buf + ret, sizeof(buf) - ret, ret); + if (ret != 0) { + goto retry; + } } set_async(fd, 0); |