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06121a0a83
unix_stream_connect and unix_stream_listen return -1 on error, with errno set by the failing underlying call to allow the caller to write a useful diagnosis. Unfortunately the error path involves a few system calls itself, such as close(), that can themselves touch errno. This is not as worrisome as it might sound. If close() fails, this just means substituting one meaningful error message for another, which is perfectly fine. However, when the call _succeeds_, it is allowed to (and sometimes might) clobber errno along the way with some undefined value, so it is good higiene to save errno and restore it immediately before returning to the caller. Do so. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
122 lines
2.4 KiB
C
122 lines
2.4 KiB
C
#include "cache.h"
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#include "unix-socket.h"
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static int unix_stream_socket(void)
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{
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int fd = socket(AF_UNIX, SOCK_STREAM, 0);
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if (fd < 0)
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die_errno("unable to create socket");
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return fd;
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}
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static int chdir_len(const char *orig, int len)
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{
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char *path = xmemdupz(orig, len);
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int r = chdir(path);
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free(path);
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return r;
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}
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struct unix_sockaddr_context {
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char orig_dir[PATH_MAX];
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};
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static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
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{
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if (!ctx->orig_dir[0])
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return;
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/*
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* If we fail, we can't just return an error, since we have
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* moved the cwd of the whole process, which could confuse calling
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* code. We are better off to just die.
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*/
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if (chdir(ctx->orig_dir) < 0)
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die("unable to restore original working directory");
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}
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static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
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struct unix_sockaddr_context *ctx)
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{
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int size = strlen(path) + 1;
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ctx->orig_dir[0] = '\0';
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if (size > sizeof(sa->sun_path)) {
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const char *slash = find_last_dir_sep(path);
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const char *dir;
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if (!slash) {
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errno = ENAMETOOLONG;
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return -1;
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}
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dir = path;
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path = slash + 1;
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size = strlen(path) + 1;
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if (size > sizeof(sa->sun_path)) {
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errno = ENAMETOOLONG;
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return -1;
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}
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if (!getcwd(ctx->orig_dir, sizeof(ctx->orig_dir))) {
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errno = ENAMETOOLONG;
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return -1;
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}
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if (chdir_len(dir, slash - dir) < 0)
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return -1;
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}
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memset(sa, 0, sizeof(*sa));
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sa->sun_family = AF_UNIX;
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memcpy(sa->sun_path, path, size);
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return 0;
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}
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int unix_stream_connect(const char *path)
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{
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int fd, saved_errno;
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struct sockaddr_un sa;
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struct unix_sockaddr_context ctx;
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if (unix_sockaddr_init(&sa, path, &ctx) < 0)
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return -1;
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fd = unix_stream_socket();
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if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
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goto fail;
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unix_sockaddr_cleanup(&ctx);
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return fd;
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fail:
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saved_errno = errno;
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unix_sockaddr_cleanup(&ctx);
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close(fd);
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errno = saved_errno;
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return -1;
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}
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int unix_stream_listen(const char *path)
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{
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int fd, saved_errno;
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struct sockaddr_un sa;
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struct unix_sockaddr_context ctx;
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if (unix_sockaddr_init(&sa, path, &ctx) < 0)
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return -1;
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fd = unix_stream_socket();
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unlink(path);
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if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
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goto fail;
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if (listen(fd, 5) < 0)
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goto fail;
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unix_sockaddr_cleanup(&ctx);
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return fd;
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fail:
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saved_errno = errno;
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unix_sockaddr_cleanup(&ctx);
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close(fd);
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errno = saved_errno;
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return -1;
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}
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