From 734c1c10ecff98130c5f45493dc5295f5b2ab7b5 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 13:36:59 +0100 Subject: [PATCH 1/8] Use bitmasking to keep track of flags --- writeimg.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/writeimg.c b/writeimg.c index 7bcd467..932a20d 100644 --- a/writeimg.c +++ b/writeimg.c @@ -32,6 +32,10 @@ #define BLOCKSIZE (1024 * 1024) #endif +#define WI_VERIFY (1 << 0) +#define WI_WRITE (1 << 1) +#define WI_ASK (1 << 2) + #define BYTES_TO_MIB(bts) ((double)bts / (1024 * 1024)) #define BAR_WIDTH 50 @@ -76,7 +80,7 @@ struct write_job { size_t bufsize; size_t block_size; size_t total_bytes; - char verify_only; + char flags; } wjob = {0}; typedef struct write_job write_job_t; @@ -114,7 +118,7 @@ int perform_write(write_job_t *job) { if (read_bytes == 0) { crc = crc32_finalize(crc); - if (!job->verify_only) { + if (job->flags & WI_WRITE) { printf("\nWriting done...\n"); assert(job->total_bytes == b_written); } else @@ -131,7 +135,7 @@ int perform_write(write_job_t *job) { crc = crc32_update(crc, job->buffer, read_bytes); - if (!job->verify_only) { + if (job->flags & WI_WRITE) { ssize_t written_bytes = write(block_fd, job->buffer, read_bytes); if (written_bytes < 0) { fprintf(stderr, "%s: Write error\n", job->dev_name); @@ -206,14 +210,18 @@ int main(int argc, char *argv[]) { signal(SIGHUP, int_handler); signal(SIGTERM, int_handler); - int ask_permission = 1; + wjob.flags = WI_VERIFY | WI_WRITE | WI_ASK; + int c = {0}; while ((c = getopt_long(argc, argv, "vd:hnV", longopts, 0)) != -1) { switch (c) { - case 'v': ++wjob.verify_only; continue; + case 'v': + wjob.flags |= WI_VERIFY; + wjob.flags &= ~WI_WRITE; + continue; case 'd': wjob.dev_name = optarg; continue; case 'h': break; - case 'n': --ask_permission; continue; + case 'n': wjob.flags &= ~WI_ASK; continue; case 'V': exit(EXIT_SUCCESS); } printf("In honor of SwePwnage - the OG disk destroyer\n"); @@ -264,13 +272,13 @@ int main(int argc, char *argv[]) { wjob.total_bytes = file_stat.st_size; assert(file_stat.st_size >= 0); - if (!wjob.verify_only) + if (wjob.flags & WI_WRITE) printf("Writing \"%s\" (%.1f MiB) to \"%s\"\n", basename(wjob.filename), BYTES_TO_MIB(wjob.total_bytes), wjob.dev_name); - if (ask_permission && !wjob.verify_only) { + if ((wjob.flags & WI_ASK) && (wjob.flags & WI_WRITE)) { printf("Is this okay? (y/N): "); fflush(stdout); if ('y' != getchar()) { From 078ba792f065284104b3ab28fc8ab25e8b78f232 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 13:52:57 +0100 Subject: [PATCH 2/8] Get version string from git, instead of hardcoded in makefile --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 416e4c1..c26b039 100644 --- a/Makefile +++ b/Makefile @@ -1,7 +1,7 @@ GITREV ?= $(shell git describe --dirty --always) BLDDATE ?= $(shell date -I) CR_YEAR ?= $(shell date +%Y) -VERSION ?= "v0.2.1" +VERSION ?= "$(shell git describe --tags --always --abbrev=0 2>/dev/null || git rev-parse --short HEAD)" CFLAGS ?= -Wall -Wextra -Wpedantic -O2 -std=gnu99 CFLAGS += -DGITREV='"$(GITREV)"' From d0a3db77e914128a3482470c363bc548afc56d99 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 13:53:26 +0100 Subject: [PATCH 3/8] Remove commented CFLAGS appends for libudev --- Makefile | 4 ---- 1 file changed, 4 deletions(-) diff --git a/Makefile b/Makefile index c26b039..5f38eca 100644 --- a/Makefile +++ b/Makefile @@ -10,10 +10,6 @@ CFLAGS += -DCR_YEAR='"$(CR_YEAR)"' CFLAGS += -DVERSION='$(VERSION)' CFLAGS += $(EXTRA_CFLAGS) -# Soon... -# CFLAGS += $(shell pkg-config --cflags libudev) -# LIBS += $(shell pkg-config --libs libudev) - PREFIX ?= /usr/local DESTDIR ?= From 97239242226b91541ad5fcc95e097b2c7f7caee6 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 13:53:46 +0100 Subject: [PATCH 4/8] Use stylized name in help section --- writeimg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/writeimg.c b/writeimg.c index 932a20d..1c500b4 100644 --- a/writeimg.c +++ b/writeimg.c @@ -199,7 +199,7 @@ static const struct option longopts[] = { }; int main(int argc, char *argv[]) { - printf("%s %s, Rev. %s\n", basename(argv[0]), VERSION, GITREV); + printf("%s %s, Rev. %s\n", "WriteIMG", VERSION, GITREV); /* Line buffering, system allocated */ setvbuf(stdout, NULL, _IOLBF, 0); From 36a98b26308610a84efb2da5cd97994cf16fd948 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 13:59:10 +0100 Subject: [PATCH 5/8] Simple test --- test.sh | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 test.sh diff --git a/test.sh b/test.sh new file mode 100644 index 0000000..6aa0b58 --- /dev/null +++ b/test.sh @@ -0,0 +1,43 @@ +#!/usr/env/bin bash + +set -e + +DISKFILE="/tmp/disk.img" +BINFILE="/tmp/file.bin" +LOOPNUM=$((RANDOM % 156 + 100)) +LOOPDEV="/dev/loop${LOOPNUM}" + +echo "Using device: ${LOOPDEV}" + +cleanup() { + echo "Cleaning up..." + set +e + sudo losetup -d ${LOOPDEV} + sudo rm ${LOOPDEV} + sudo rm ${BINFILE} ${DISKFILE} +} + +trap cleanup EXIT INT TERM + +if losetup ${LOOPDEV} >/dev/null 2>&1; then + echo "${LOOPDEV} already in use" >&2 + cleanup + exit 1 +fi + +if [ ! -f ${DISKFILE} ]; then + dd if=/dev/zero of=${DISKFILE} bs=1M count=256 +fi + +if [ ! -f ${BINFILE} ]; then + dd if=/dev/urandom of=${BINFILE} bs=1M count=64 +fi + +if [ ! -e ${LOOPDEV} ]; then + sudo losetup ${LOOPDEV} ${DISKFILE} +fi + +sudo ./writeimg -nd ${LOOPDEV} ${BINFILE} +sudo ./writeimg -vnd ${LOOPDEV} ${BINFILE} + +echo "Looks good!" From d1d3b3cd453e18a83ac690543c76922cae9660f2 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 14:42:28 +0100 Subject: [PATCH 6/8] Rename dev_name and filename to iname/oname in preparation for enabling file outputs --- writeimg.c | 34 ++++++++++++++++------------------ 1 file changed, 16 insertions(+), 18 deletions(-) diff --git a/writeimg.c b/writeimg.c index 1c500b4..2d27a98 100644 --- a/writeimg.c +++ b/writeimg.c @@ -73,8 +73,8 @@ const char help[] = const char copyright[] = "Copyright (C) %s Imbus, BSD-2-Clause\n"; struct write_job { - char *filename; - char *dev_name; + char *iname; + char *oname; char *buffer; char *buffer2; /* For memcmp integrity checks */ size_t bufsize; @@ -98,8 +98,8 @@ void int_handler(int signum) { } int perform_write(write_job_t *job) { - int block_fd = open(job->dev_name, O_RDWR); - int file_fd = open(job->filename, O_RDONLY); + int block_fd = open(job->oname, O_RDWR); + int file_fd = open(job->iname, O_RDONLY); assert(block_fd >= 0); assert(file_fd >= 0); @@ -128,7 +128,7 @@ int perform_write(write_job_t *job) { } if (read_bytes < 0) { - fprintf(stderr, "%s: Read error\n", job->filename); + fprintf(stderr, "%s: Read error\n", job->iname); perror("Read"); exit(EXIT_FAILURE); } @@ -138,7 +138,7 @@ int perform_write(write_job_t *job) { if (job->flags & WI_WRITE) { ssize_t written_bytes = write(block_fd, job->buffer, read_bytes); if (written_bytes < 0) { - fprintf(stderr, "%s: Write error\n", job->dev_name); + fprintf(stderr, "%s: Write error\n", job->oname); perror("Write"); exit(EXIT_FAILURE); } @@ -219,7 +219,7 @@ int main(int argc, char *argv[]) { wjob.flags |= WI_VERIFY; wjob.flags &= ~WI_WRITE; continue; - case 'd': wjob.dev_name = optarg; continue; + case 'd': wjob.oname = optarg; continue; case 'h': break; case 'n': wjob.flags &= ~WI_ASK; continue; case 'V': exit(EXIT_SUCCESS); @@ -244,27 +244,27 @@ int main(int argc, char *argv[]) { exit(EXIT_FAILURE); } - wjob.filename = argv[0]; + wjob.iname = argv[0]; struct stat file_stat = {0}; - if (0 != stat(wjob.filename, &file_stat)) { + if (0 != stat(wjob.iname, &file_stat)) { printf("File does not exist...\n"); exit(EXIT_FAILURE); } - if (NULL == wjob.dev_name) { + if (NULL == wjob.oname) { printf("You need to specify a device.\n"); exit(EXIT_FAILURE); } - if (0 != strncmp(wjob.dev_name, "/dev/", 4)) { - printf("\"%s\" does not appear to be a block device...\n", wjob.dev_name); + if (!(wjob.flags & WI_FILE) && 0 != strncmp(wjob.oname, "/dev/", 4)) { + printf("\"%s\" does not appear to be a block device...\n", wjob.oname); exit(EXIT_FAILURE); } /* Seems to be the cleanest way to check for write perm on a blockdev */ - int fd = open(wjob.dev_name, O_WRONLY); + int fd = open(wjob.oname, O_WRONLY); if (fd < 0) { - printf("Cannot write to \"%s\", do you have write permissions?\n", wjob.dev_name); + printf("Cannot write to \"%s\", do you have write permissions?\n", wjob.oname); exit(1); } close(fd); @@ -273,10 +273,8 @@ int main(int argc, char *argv[]) { assert(file_stat.st_size >= 0); if (wjob.flags & WI_WRITE) - printf("Writing \"%s\" (%.1f MiB) to \"%s\"\n", - basename(wjob.filename), - BYTES_TO_MIB(wjob.total_bytes), - wjob.dev_name); + printf( + "Writing \"%s\" (%.1f MiB) to \"%s\"\n", basename(wjob.iname), BYTES_TO_MIB(wjob.total_bytes), wjob.oname); if ((wjob.flags & WI_ASK) && (wjob.flags & WI_WRITE)) { printf("Is this okay? (y/N): "); From 4127ad6333f345c2e304e634bb0c54d50405ece4 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 14:42:56 +0100 Subject: [PATCH 7/8] More tests Include some notes about cleanup and accidentally deleting loop-control --- test.sh | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/test.sh b/test.sh index 6aa0b58..70cfae9 100644 --- a/test.sh +++ b/test.sh @@ -1,6 +1,16 @@ #!/usr/env/bin bash set -e +# set -x # For debugging + +# If you ever mess this up: +# $ sudo mknod /dev/loop-control c 10 237 +# $ sudo chmod 600 /dev/loop-control +# $ sudo chown root:root /dev/loop-control +# +# For cleanup: +# $ sudo find /dev -maxdepth 1 -type b -name 'loop[0-9]*' -exec rm -f {} \; + DISKFILE="/tmp/disk.img" BINFILE="/tmp/file.bin" @@ -11,7 +21,7 @@ echo "Using device: ${LOOPDEV}" cleanup() { echo "Cleaning up..." - set +e + set +e -x sudo losetup -d ${LOOPDEV} sudo rm ${LOOPDEV} sudo rm ${BINFILE} ${DISKFILE} @@ -40,4 +50,16 @@ fi sudo ./writeimg -nd ${LOOPDEV} ${BINFILE} sudo ./writeimg -vnd ${LOOPDEV} ${BINFILE} -echo "Looks good!" +sudo ./writeimg -nd ${LOOPDEV} ./writeimg +sudo ./writeimg -vnd ${LOOPDEV} ./writeimg + +sudo ./writeimg -nd ${LOOPDEV} ./LICENSE +sudo ./writeimg -vnd ${LOOPDEV} ./LICENSE + +# Redirect this to avoid confusion +! sudo ./writeimg -vnd ${LOOPDEV} ./crc32.h 2>/dev/null + +GREEN="\e[32m" +RESET="\e[0m" + +echo -e "\n\n${GREEN}Looks good!${RESET}" From f37e28c4ef2fd1ecd04f8d69e44103754d970607 Mon Sep 17 00:00:00 2001 From: Imbus Date: Mon, 9 Feb 2026 14:44:42 +0100 Subject: [PATCH 8/8] Remove accidental inclusion of unfinished WI_FILE check --- writeimg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/writeimg.c b/writeimg.c index 2d27a98..38cf3d0 100644 --- a/writeimg.c +++ b/writeimg.c @@ -256,7 +256,7 @@ int main(int argc, char *argv[]) { exit(EXIT_FAILURE); } - if (!(wjob.flags & WI_FILE) && 0 != strncmp(wjob.oname, "/dev/", 4)) { + if (0 != strncmp(wjob.oname, "/dev/", 4)) { printf("\"%s\" does not appear to be a block device...\n", wjob.oname); exit(EXIT_FAILURE); }