diff --git a/src/dj.c b/src/dj.c index 3b5bc5f..9edee0f 100644 --- a/src/dj.c +++ b/src/dj.c @@ -1,5 +1,6 @@ /* * Copyright (c) 2024 DTB + * Copyright (c) 2024 Emma Tebibyte * SPDX-License-Identifier: AGPL-3.0-or-later * * This program is free software: you can redistribute it and/or modify it under @@ -27,8 +28,8 @@ #endif #include /* close(2), getopt(3), lseek(2), read(2), write(2), * optarg, optind, STDIN_FILENO, STDOUT_FILENO */ -#include /* S_IRGRP, S_IROTH, S_IRUSR, S_IWGRP, S_IWOTH, - S_IWUSR */ +#include /* S_IRGRP, S_IROTH, S_IRUSR, S_IWGRP, S_IWOTH, S_IWUSR */ + extern int errno; char *program_name = "dj"; @@ -36,7 +37,7 @@ char *program_name = "dj"; /* dj uses two structures that respectively correspond to the reading and * writing ends of its jockeyed "pipe". User-configurable members are noted * with their relevant options. */ -struct Io{ +struct Io { char *buf; /* buffer */ char *fn; /* file name (-io) */ size_t bs; /* buffer size (-bB) */ @@ -67,14 +68,13 @@ static int write_flags = O_WRONLY | O_CREAT; /* Macro to check if fd is stdin or stdout */ #define fdisstd(fd) ((fd) == STDIN_FILENO || (fd) == STDOUT_FILENO) -static struct Io * -Io_read(struct Io *io){ +static struct Io * Io_read(struct Io *io) { int t; assert(io->bs > 0); assert(io->bufuse < io->bs); - if((t = read(io->fd, &(io->buf)[io->bufuse], io->bs - io->bufuse)) < 0){ + if ((t = read(io->fd, &(io->buf)[io->bufuse], io->bs - io->bufuse)) < 0) { io->error = errno; t = 0; } @@ -89,17 +89,16 @@ Io_read(struct Io *io){ return io; } -static struct Io * -Io_write(struct Io *io){ +static struct Io * Io_write(struct Io *io) { int t; assert(io->bufuse > 0); assert(io->bufuse <= io->bs); - if((t = write(io->fd, io->buf, io->bufuse)) < 0){ + if ((t = write(io->fd, io->buf, io->bufuse)) < 0) { io->error = errno; t = 0; - }else if(t > 0) + } else if (t > 0) memmove(io->buf, &(io->buf)[t], (io->bufuse -= t)); io->bytes += t; @@ -109,20 +108,24 @@ Io_write(struct Io *io){ return io; } -static int -oserr(char *e, int n){ +static int oserr(char *e, int n) { fprintf(stderr, "%s: %s: %s\n", program_name, e, strerror(n)); return EX_OSERR; } /* Prints statistics regarding the use of dj, particularly partially and * completely read and written records. */ -static void -fprintio(FILE *stream, char *fmt, struct Io io[2]){ - - fprintf(stream, fmt, - io[0].rec, io[0].prec, io[1].rec, io[1].prec, - io[0].bytes, io[1].bytes); +static void fprintio(FILE *stream, char *fmt, struct Io io[2]) { + fprintf( + stream, + fmt, + io[0].rec, + io[0].prec, + io[1].rec, + io[1].prec, + io[0].bytes, + io[1].bytes + ); return; } @@ -130,8 +133,7 @@ fprintio(FILE *stream, char *fmt, struct Io io[2]){ /* Parses the string s to an integer, returning either the integer or in the * case of an error a negative integer. This is used for argument parsing * (e.g. -B [int]) in dj and no negative integer would be valid anyway. */ -static long -parse(char *s){ +static long parse(char *s){ long r; errno = 0; @@ -141,18 +143,17 @@ parse(char *s){ : -1; } -static int -usage(char *s){ - - fprintf(stderr, "Usage: %s [-Hn] [-a byte] [-c count]\n" +static int usage(char *s){ + fprintf( + stderr, "Usage: %s [-Hn] [-a byte] [-c count]\n" "\t[-i file] [-b block_size] [-s offset]\n" - "\t[-o file] [-B block_size] [-S offset]\n", - program_name); + "\t[-o file] [-B block_size] [-S offset]\n", program_name + ); return EX_USAGE; } -int main(int argc, char *argv[]){ +int main(int argc, char *argv[]) { int align; /* low 8b used, negative if no alignment is being done */ int count; /* 0 if dj(1) runs until no more reads are possible */ char *fmt; /* == fmt_asv (default) or fmt_human (-H) */ @@ -165,7 +166,7 @@ int main(int argc, char *argv[]){ count = 0; fmt = fmt_asv; noerror = 0; - for(i = 0; i < (sizeof io) / (sizeof *io); ++i){ + for (i = 0; i < (sizeof io) / (sizeof *io); ++i) { io[i].bs = 1024 /* 1 KiB */; /* GNU dd(1) default; POSIX says 512B */ io[i].bufuse = 0; io[i].bytes = 0; @@ -178,119 +179,144 @@ int main(int argc, char *argv[]){ io[i].seek = 0; } - if(argc > 0){ - int c; + if (!argc < 0) { usage(program_name); } - program_name = argv[0]; - while((c = getopt(argc, argv, ":a:b:B:c:i:hHns:S:o:")) != -1) - switch(c){ - case 'i': case 'o': i = (c == 'o'); - if(optarg[0] == '-' && optarg[1] == '\0'){ /* optarg == "-" */ + int c; + + program_name = argv[0]; + while ((c = getopt(argc, argv, "a:b:B:c:i:hHns:S:o:")) != -1) { + switch (c) { + case 'i': case 'o': /* input, output */ + i = (c == 'o'); + + /* optarg == "-" (stdin/stdout) */ + if (optarg[0] == '-' && optarg[1] == '\0') { io[i].fd = i == 0 ? STDIN_FILENO : STDOUT_FILENO; io[i].fn = i == 0 ? stdin_name : stdout_name; break; - }else{ + } else { int fd; - if((fd = open(optarg, io[i].fl, creat_mode)) != -1 - && (fdisstd(io[i].fd) || close(io[i].fd) == 0)){ + if (( + fd = open(optarg, io[i].fl, creat_mode)) != -1 + && (fdisstd(io[i].fd) || close(io[i].fd) == 0 + )) { io[i].fd = fd; io[i].fn = optarg; break; } } - return oserr(optarg, errno); - case 'n': noerror = 1; break; - case 'H': fmt = fmt_human; break; - case 'a': - if(optarg[0] == '\0' || optarg[1] == '\0'){ + + return oserr(optarg, errno); /* break; */ + case 'n': noerror = 1; break; /* retry failed reads once */ + case 'H': fmt = fmt_human; break; /* human-readable output */ + case 'a': /* input buffer padding */ + if (optarg[0] == '\0' || optarg[1] == '\0') { align = optarg[0]; break; } /* FALLTHROUGH */ - case 'c': case 'b': case 's': case 'B': case 'S': /* numbers */ - if(c == 'c' && (count = parse(optarg)) >= 0) - break; + case 'c': /* number of reads */ + case 'b': case 'B': /* input/output block size */ + case 's': case 'S': /* (s)kip/(S)eek in input/output */ + if (c == 'c' && (count = parse(optarg)) >= 0) { break; } + i = (c >= 'A' && c <= 'Z'); - c |= 0x20 /* 0b 0010 0000 */; /* (ASCII) make lowercase */ - if((c == 'b' && (io[i].bs = parse(optarg)) > 0) - || (c == 's' && (io[i].seek = parse(optarg)) >= 0)) - break; + c |= 0b00100000; /* (ASCII) make lowercase */ + + if(( + c == 'b' && (io[i].bs = parse(optarg)) > 0) + || (c == 's' && (io[i].seek = parse(optarg)) >= 0 + )) { break; } + /* FALLTHROUGH */ default: return usage(program_name); - } + } } assert(io->fd != STDIN_FILENO || io->fl == read_flags); assert(io->fd != STDOUT_FILENO || io->fl == write_flags); - if(argc > optind) - return usage(program_name); + if (argc > optind) { return usage(program_name); } - for(i = 0; i < (sizeof io) / (sizeof *io); ++i){ + for (i = 0; i < (sizeof io) / (sizeof *io); ++i) { /* buffer allocation */ - if((io[i].buf = malloc(io[i].bs * (sizeof *(io[i].buf)))) == NULL){ + if ((io[i].buf = malloc(io[i].bs * (sizeof *(io[i].buf)))) == NULL) { fprintf(stderr, "%s: Failed to allocate %zd bytes\n", program_name, io[i].bs); return EX_OSERR; } + /* easy seeking */ - if(!fdisstd(io[i].fd) && lseek(io[i].fd, io[i].seek, SEEK_SET) != -1) + if (!fdisstd(io[i].fd) && lseek(io[i].fd, io[i].seek, SEEK_SET) != -1) { io[i].seek = 0; + } } /* hard seeking */ - if(io[1].seek > 0){ + if (io[1].seek > 0) { size_t t; - do{ - memset(io[1].buf, '\0', - (t = io[1].bufuse = MIN(io[1].bs, io[1].seek))); - if(Io_write(&io[1])->bufuse == t && !noerror && io[1].error == 0) + + do { + memset( + io[1].buf, '\0', + (t = io[1].bufuse = MIN(io[1].bs, io[1].seek)) + ); + + if (Io_write(&io[1])->bufuse == t && !noerror && io[1].error == 0) { Io_write(&io[1]); /* second chance */ - if(io[1].error != 0) - return oserr(io[1].fn, io[1].error); - }while((io[1].seek -= (t - io[1].bufuse)) > 0 && io[1].bufuse != t); + } + if (io[1].error != 0) { return oserr(io[1].fn, io[1].error); } + } while ((io[1].seek -= (t - io[1].bufuse)) > 0 && io[1].bufuse != t); + io[1].bufuse = 0; } - if(io[1].seek > 0){ + if (io[1].seek > 0) { fprintio(stderr, fmt, io); return oserr(io[1].fn, errno); } - do{ + do { /* while(count == 0 || --count > 0); */ assert(io[0].bufuse == 0); { /* read */ long skipping; - size_t t; /* hack to intentionally get a partial read from Io_read */ - if((skipping = MIN(io[0].seek, io[0].bs)) > 0) + if ((skipping = MIN(io[0].seek, io[0].bs)) > 0) { io[0].bufuse = io[0].bs - (size_t)skipping; + } - t = io[0].bufuse; - if(Io_read(&io[0])->bufuse == t && !noerror && io[0].error == 0) + size_t t = io[0].bufuse; + if (Io_read(&io[0])->bufuse == t && !noerror && io[0].error == 0) { Io_read(&io[0]); /* second chance */ - assert(io[0].bufuse >= t); - if(io[0].bufuse == t) /* that's all she wrote */ - break; + } - if(/* t < io[0].bufuse && */ io[0].bufuse < io[0].bs){ + assert(io[0].bufuse >= t); + + if (io[0].bufuse == t) /* that's all she wrote */ { break; } + + if (/* t < io[0].bufuse && */ io[0].bufuse < io[0].bs) { fprintf(stderr, "%s: Partial read:\n\t", program_name); fprintio(stderr, fmt, io); - if(!noerror) - count = 1; - if(align >= 0){ + + if (!noerror) { count = 1; } + + if (align >= 0) { /* fill the rest of the ibuf with padding */ - memset(&(io[0].buf)[io[0].bufuse], align, - io[0].bs - io[0].bufuse); + memset( + &(io[0].buf)[io[0].bufuse], + align, + io[0].bs - io[0].bufuse + ); + io->bufuse = io->bs; } } - if(skipping > 0){ + if (skipping > 0) { io[0].seek -= skipping; io[0].bufuse = 0; count += (count != 0); @@ -299,55 +325,66 @@ int main(int argc, char *argv[]){ } /* write */ - do{ + do { /* while(io[0].bufuse > 0); */ int t; - if(io[0].bs <= io[1].bs){ + if (io[0].bs <= io[1].bs) { int n; /* saturate obuf */ - memcpy(io[1].buf, io[0].buf, - (io[1].bufuse = (n = MIN(io[0].bufuse, io[1].bs)))); + memcpy( + io[1].buf, io[0].buf, + (io[1].bufuse = (n = MIN(io[0].bufuse, io[1].bs))) + ); /* permute the copied units out of ibuf */ memmove(io[0].buf, &(io[0].buf)[n], (io[0].bufuse -= n)); - }else /* if(io[0].bs < io[1].bs) */ { + } else /* if(io[0].bs < io[1].bs) */ { int n; /* drain what we can from ibuf */ - memcpy(&(io[1].buf)[io[1].bufuse], io[0].buf, - (n = MIN(io[0].bufuse, io[1].bs - io[1].bufuse))); + memcpy( + &(io[1].buf)[io[1].bufuse], io[0].buf, + (n = MIN(io[0].bufuse, io[1].bs - io[1].bufuse)) + ); + io[1].bufuse += n; + /* permute out the copied units */ memmove(io[0].buf, &(io[0].buf)[n], io[0].bs - n); + io[0].bufuse -= n; - if(io[0].bs + io[1].bufuse <= io[1].bs && count != 1) + if(io[0].bs + io[1].bufuse <= io[1].bs && count != 1) { continue; /* obuf not saturated - we could write more */ + } } t = io[1].bufuse; - if(Io_write(&io[1])->bufuse == t && !noerror && io[1].error == 0) + if (Io_write(&io[1])->bufuse == t && !noerror && io[1].error == 0) { Io_write(&io[1]); /* second chance */ + } + assert(io[1].bufuse <= t); - if(io[1].bufuse == t){ /* no more love */ + + if (io[1].bufuse == t) { /* no more love */ count = 1; break; } - if(0 < io[1].bufuse /* && io[1].bufuse < t */){ + if (0 < io[1].bufuse /* && io[1].bufuse < t */) { fprintf(stderr, "%s: Partial write:\n\t", program_name); fprintio(stderr, fmt, io); - if(!noerror) - count = 1; + + if(!noerror) { count = 1; } } - }while(io[0].bufuse > 0); - }while(count == 0 || --count > 0); + } while(io[0].bufuse > 0); + } while(count == 0 || --count > 0); fprintio(stderr, fmt, io); - for(i = 0; i < (sizeof io) / (sizeof *io); ++i) - if(io[i].error) - return oserr(io[i].fn, io[i].error); + for (i = 0; i < (sizeof io) / (sizeof *io); ++i) { + if (io[i].error) { return oserr(io[i].fn, io[i].error); } + } return EX_OK; }