Oil and gambling issues shared star-performer billing today as the stock market struggled to its fourth straight gain.

The Dow Jones average of 30 industrials managed a .60 rise to 867.46, extending its advance since last Thursday's close to 12.21 points.

Gainers held a 5-4 edge on losers in the daily tally at the New York Stock Exchange.

Volume on the Big Board totaled 31.75 million shares, down from 35.54 million Tuesday.

Winners in the gambling sector included Playboy Enterprises, up 3 3/8 at 23 as of the 4 p.m. close in New York; Ramada Inns, up 1 1/4 at 12 7/8; Bally Manufacturing, ahead 3 1/2 at 77 1/4, and Del E. Webb, up 1 1/8 at 20 3/8.

Golden Nugget, up 1 1/8 at 21 7/8, and Resorts International Class A stock, up 2 1/8 at 47 7/8, were the volume leaders at the American Stock Exchange. And in the over-the-counter market, Elsinore rose 1 5/8 to 16 1/8 bid.

The oil stocks continued to benefit from strong first-quarter earnings reports by many companies in the industry. Amerada Hess gained 2 1/4 to 35; Texaco 1/2 to 27 1/4; Gulf Oil 1/2 to 27 5/8, and Exxon 3/8 to 53 1/2.

Among other big-name companies posting quarterly earnings gains, Eastman Kodak added 1/4 to 64 1/4 and Procter & Gamble 3/8 to 80 1/8.

Analysts said favorable first-quarter earnings reports have helped the market as a whole in recent sessions.

Nationwide turnover in NYSE-listed issues, including trades in those stocks on regional exchanges and in the over-the-counter market, came to 35.61 million shares. The exchange's composite index picked up .18 to 57.80.

Standard & Poor's index of 400 industrials was up .44 at 114.57, and S&P's 500-stock composite index rose .30 to 102.50.

Riley Co., which said it called off merger talks with another concern that it didn't identify, fell 5 3/8 to 39 5/8 for the biggest percentage loss on the Big Board.

The Amex market value index gained 1.07 to 183.51, and the NASDAQ composite index of OTC issues was up .49 at 134.78.