diff options
Diffstat (limited to 'xa.c')
| -rw-r--r-- | xa.c | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/xa.c b/xa.c new file mode 100644 index 0000000..666ec3e --- /dev/null +++ b/xa.c @@ -0,0 +1,262 @@ +/* + * xa - simple xargs and apply replacement + * + * To the extent possible under law, + * Christian Neukirchen <chneukirchen@gmail.com> + * has waived all copyright and related or neighboring rights to this work. + * http://creativecommons.org/publicdomain/zero/1.0/ + */ + +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/wait.h> + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <fcntl.h> + +static char delim = '\n'; +static char default_replace[] = "{}"; +static char *replace = default_replace; +static char default_argsep[] = "--"; +static char *argsep = default_argsep; +static char **args; +static char *sflag; + +static int maxatonce = 1; +static int maxjobs = 1; +static int runjobs = 0; +static int aflag, nflag, vflag; + +static char * +xstrdup(const char *s) +{ + char *d = strdup(s); + if (!d) + exit(1); + return d; +} + +static char *getarg_line = 0; +static size_t getarg_len = 0; + +static char * +getarg() +{ + if (aflag) { + if (args && *args) + return xstrdup(*args++); + else + return 0; + } + + int read = getdelim(&getarg_line, &getarg_len, delim, stdin); + if (read == -1) { + if (feof(stdin)) + return 0; + else + exit(1); + } + if (getarg_line[read-1] == delim) // strip delimiter + getarg_line[read-1] = 0; + + return xstrdup(getarg_line); +} + +static int +mywait() +{ + int status; + pid_t pid; + + pid = wait(&status); + if (pid < 0) { + if (errno == ECHILD) + return 0; + // no other error possible? + } + + if (WIFEXITED(status)) { + if (WEXITSTATUS(status) >= 1 && WEXITSTATUS(status) <= 125) { + exit(123); + } else if (WEXITSTATUS(status) == 255) { + fprintf(stderr, "xa: %d exited with status 255\n", pid); + exit(124); + } else if (WEXITSTATUS(status) > 125) { + exit(WEXITSTATUS(status)); + } + } else if (WIFSIGNALED(status)) { + fprintf(stderr, "xa: %d terminated by signal %d\n", + pid, WTERMSIG(status)); + exit(125); + } + + runjobs--; + return 1; +} + +static void +shquote(const char *s) +{ + if (!strpbrk(s, "\001\002\003\004\005\006\007\010" + "\011\012\013\014\015\016\017\020" + "\021\022\023\024\025\026\027\030" + "\031\032\033\034\035\036\037\040" + "`^#*[]=|\\?${}()'\"<>&;\127")) { + printf("%s", s); + return; + } + + putchar('\''); + for (; *s; s++) + if (*s == '\'') + printf("'\\''"); + else + putchar(*s); + putchar('\''); +} + +static int +trace(char *cmd[]) +{ + int i; + + for (i = 0; cmd[i]; i++) { + if (i > 0) + printf(" "); + shquote(cmd[i]); + } + printf("\n"); + + return 0; +} + +static int +run(char *cmd[]) +{ + pid_t pid; + int i; + + if (runjobs >= maxjobs) + mywait(); + runjobs++; + + if (vflag || nflag) + trace(cmd); + if (nflag) { + runjobs--; + return 0; + } + + pid = fork(); + if (pid == 0) { // in child + // redirect stdin to /dev/null + int fd = open("/dev/null", O_RDONLY); + if (fd >= 0) { + if (dup2(fd, 0) != 0) + exit(1); + close(fd); + execvp(cmd[0], cmd); + } + fprintf(stderr, "xa: %s: %s\n", cmd[0], strerror(errno)); + exit(errno == ENOENT ? 127 : 126); + } + + if (pid < 0) + exit(126); + + for (i = 0; cmd[i]; i++) + free(cmd[i]); + + return 0; +} + +int +main(int argc, char *argv[]) +{ + char c; + int i, cmdend; + char *arg, **cmd; + + while ((c = getopt(argc, argv, "+0A:I:N:anj:s:v")) != -1) + switch(c) { + case '0': delim = '\0'; break; + case 'A': argsep = optarg; aflag++; break; + case 'I': replace = optarg; break; + case 'N': maxatonce = atoi(optarg); break; + case 'a': aflag++; break; + case 'n': nflag++; break; + case 'j': maxjobs = atoi(optarg); break; + case 's': sflag = optarg; break; + case 'v': vflag++; break; + default: + fprintf(stderr, + "Usage: %s [-0nv] [-I arg] [-N maxargs] [-j maxjobs] COMMAND...\n" + " | -s SHELLSCRIPT\n" + " | -a COMMAND... -- ARGS...\n" + " | -A ARGSEP COMMAND... ARGSEP ARGS...\n", + argv[0]); + exit(1); + } + + cmdend = argc; + if (aflag) // find argsep in argv + for (i = optind; i < argc; i++) + if (strcmp(argv[i], argsep) == 0) { + args = argv + i+1; + cmdend = i; + break; + } + + cmd = calloc(argc-optind+maxatonce+1+(sflag ? 4 : 0), sizeof (char *)); + if (!cmd) + exit(1); + + while ((arg = getarg())) { + int l = 0; + + if (sflag) { + cmd[l++] = xstrdup("/bin/sh"); + cmd[l++] = xstrdup("-c"); + cmd[l++] = xstrdup(sflag); + cmd[l++] = xstrdup("-"); + } + + if (maxatonce == 1) { + // substitute {} + int substituted = 0; + for (i = optind; i < cmdend; i++) { + if (strcmp(argv[i], replace) == 0) { + cmd[l++] = arg; + substituted = 1; + } else { + cmd[l++] = xstrdup(argv[i]); + } + } + if (!substituted) + cmd[l++] = arg; + } else { + // just append to cmd + for (i = optind; i < cmdend; i++) + cmd[l++] = xstrdup(argv[i]); + cmd[l++] = arg; + for (i = 0; i < maxatonce - 1; i++) { + cmd[l] = getarg(); + if (!cmd[l++]) + break; + } + } + cmd[l] = 0; + run(cmd); + } + + while (mywait()) + ; + + free(cmd); + free(getarg_line); + return 0; +} |